Language：Japanese   Publisher：The Tohoku Society of Forest Science  

DOI： 10.18982/tjfs.24.1_21

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SISEF-SOC ITALIANA SELVICOLTURA ECOL FORESTALE  

We examined the recovery and dynamics of living tree above-ground biomass (AGB) after selective logging in an Amazonian terra firme forest managed by a private company. The forest consisted of 24 blocks (including one set aside for conservation) selectively logged in different years on a managed schedule. Trees >= 10 cm in diameter at breast height (dbh) were surveyed in 2006 in 192 0.25-ha plots, in 2010 in 119 plots, and in 2012-2013 in 54 plots. A logistic growth model factoring in logging dynamics and mean AGB of a block in these years was established. Referencing the mean AGB of the unlogged forest, the model indicated that the logged forest would take on average 14 years to regain its preharvest AGB after selective logging at 1.9 trees ha(-1) (dbh > 50 cm). In 2010 and 2012-2013, the AGB increased significantly for small and large trees (10-20 cm and > 60 cm dbh, respectively) in the logged forest. In contrast, it decreased significantly for medium-sized trees (30-50 cm dbh) in the unlogged forest. Comparisons with the previous studies mainly conducted in the other regions of Amazon suggested that the estimated AGB recovery period with moderate logging intensity was almost appropriate and likely acceptable to forest managers.

DOI： 10.3832/ifor2534-011

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS  

Leaf respiration (R) is a major component of carbon balance in forest ecosystems. Clarifying the variability of leaf R within a canopy is essential for predicting the impact of global warming on forest productivity and the potential future function of the forest ecosystem as a carbon sink. We examined vertical and seasonal variations in short-term temperature responses of leaf R as well as environmental factors (light and mean air temperature) and physiological factors [leaf nitrogen (N), leaf mass per area (LMA), and shoot growth] in the canopy of a 10-year-old stand of hinoki cypress [Chamaecyparis obtusa (Sieb. et Zucc.) Endl.] in Kyushu, Japan. Leaf respiration rate adjusted to 20 degrees C (R-20) exhibited evident vertical gradients in each season and was correlated with light, LMA and leaf N. In contrast, the temperature sensitivity of leaf R (Q(10)) did not vary vertically throughout the seasons. Seasonally, Q(10) was higher in winter than in summer and was strongly negatively correlated to mean air temperature. A negative correlation of R-20 with mean air temperature was also observed for each of the three canopy layers. These results clearly indicate that leaf R was able to adjust to seasonal changes in ambient temperature under field conditions and down-regulate during warmer periods. We also found that the degree of thermal acclimation did not vary with canopy position. Overall, our results suggest that vertical and seasonal variations in temperature responses of leaf R within a hinoki cypress canopy could be predicted by relatively simple parameters (light and temperature). There was an exception of extremely high R-20 values in April that may have been due to the onset of shoot growth in spring. Understanding thermal acclimation and variations in leaf R within forest canopies will improve global terrestrial carbon cycle models.

DOI： 10.1093/treephys/tpx012

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

To elucidate the temporal changes in the radiocesium distribution in forests contaminated by the Fukushima Daiichi Nuclear Power Plant accident, we monitored the Cs-137 concentration and inventory within forests from 2011 to 2015 across nine plots containing variable tree species and different contamination levels. The Cs-137 concentrations in needles and branches decreased exponentially at all coniferous plots, with effective ecological half-lives of 0.45-1.55 yr for needles and 0.83-1.69 yr for branches. By contrast, the Cs-137 concentration in deciduous konara oak leaves did not change over the five years. The concentration of Cs-137 in oak wood increased by 37-75%, whereas that in Japanese red pine decreased by 63% over the five years. In Japanese cedar and hinoki cypress, the Cs-137 concentration in wood showed an increasing trend in half of the plots. The changes in Cs-137 in the organic and mineral soil layers were not strongly related to the tree species or contamination level. Our multi-site, multi-species monitoring results revealed that the pattern of temporal changes in radiocesium in the 9 forest plots was similar overall; however, changes in Cs-137 in needles/leaves and wood differed among tree species.

DOI： 10.1038/s41598-017-08261-x

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Language：Japanese   Publishing type：Research paper (scientific journal)  

We measured leaf and branch radiocesium (137Cs) concentration in planted and naturally regenerated tree species after the accident of Fukushima Daiichi Nuclear Power Plant of TEPCO. We collected current year shoots of planted seedlings of Cryptomeria japonica (Cj) and Quercus serrata (Qs), naturally regenerated seedlings of Pinus densiflora (Pd), and sprouted coppice of Qs at June and July in 2016, respectively in Fukushima, Japan. Concentrations of 137Cs were measured for grinded samples by using germanium semiconductor detector. The highest 137Cs concentration in June observed in current leaves of Cj, whereas Qs leaves showed the lowest values. Leaf 137Cs concentration in the studied species reduced with leaf aging. Negative relation between leaf 137Cs and indicators of leaf maturation such as leaf mass per area and chlorophyll content (SPAD value) in Qs also support this pattern. In contrast, relationship between leaf potassium ion and 137Cs concentrations in Qs leaves was not significant. Those results suggested that leaf 137Cs concentrations decrease with increasing leaf maturation in those tree species.

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

<p>Containerized tree seedlings are expected to exhibit high survivorship and good growth after outplanting; however, a unified consensus on the performance of containerized seedlings in Japan remains undetermined. To understand the universal properties of the performances of containerized seedlings after outplanting, the survival ratio and height and diameter growth rate of two stock types (containerized seedlings and bare-root seedlings) were estimated from 39 experiment sites covering five prefectures and five species and compared between stock types. The result of parameter estimation using hierarchal Bayesian models revealed that the median survival ratio of containerized seedlings across all species was 0.96, which was not different from that of bare-root seedlings (0.97). The estimated height and diameter growth rates were also similar between stock types. The sturdiness quotient (SQ, the ratio of height and diameter) was higher in containerized seedlings than in bare-root seedlings of all species immediately after outplanting. However, the difference in SQ between stock types diminished 1 year after outplanting. These results suggest that containerized tree seedlings generally show performances equivalent to those of bare-root seedlings after outplanting. Therefore, other properties of containerized seedlings, such as ease of cultivation and low-labor planting present more attractive advantages than those of good performance after outplanting.</p>

DOI： 10.4005/jjfs.98.214

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, information about stand-level spatial patterns of radiocesium initially deposited in the surrounding forests was essential for predicting the future dynamics of radiocesium and suggesting a management plan for contaminated forests. In the first summer (approximately 6 months after the accident), we separately estimated the amounts of radio cesium (Cs-134 and Cs-137; Bq m(-2)) in the major components (trees, organic layers, and soils) in forests of three sites with different contamination levels. For a Japanese cedar (Cryptomeria japonica) forest studied at each of the three sites, the radiocesium concentration greatly differed among the components, with the needle and organic layer having the highest concentrations. For these cedar forests, the proportion of the Cs-137 stock in the aboveground tree biomass varied from 22% to 44% of the total Cs-137 stock; it was 44% in highly contaminated sites (7.0 x 10(5) Bq m(-2)) but reduced to 22% in less contaminated sites (1.1 x 104 Bq m(-2)). In the intermediate contaminated site (5.0-5.8 x 10(4) Bq m(-2)), 34% of radiocesium was observed in the aboveground tree biomass of the Japanese cedar stand. However, this proportion was considerably smaller (18-19%) in the nearby mixed forests of the Japanese red pine (Pinus densiflora) and deciduous broad-leaved trees. Non-negligible amounts of Cs-134 and Cs-137 were detected in both the sapwood and heartwood of all the studied tree species. This finding suggested that the uptake or translocation of radiocesium had already started within 6 months after the accident. The belowground compartments were mostly present in the organic layer and the uppermost (0-5 cm deep) mineral soil layer at all the study sites. We discussed the initial transfer process of radiocesium deposited in the forest and inferred that the type of initial deposition (i.e., dry versus wet radiocesium deposition), the amount of rainfall after the accident, and the leaf biomass by the tree species may influence differences in the spatial pattern of radiocesium by study plots. The results of the present study and further studies of the spatial pattern of radiocesium are important for modeling future radiocesium distribution in contaminated forest ecosystems. (C) 2015 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jenvrad.2015.09.016

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

As a part of improving forest management practices, we tested the idea that partial defoliation of container-grown and bare-root Hinoki cypress (Chamaecyparis obtusa) seedlings prior to outplanting can reduce transplant shock and enhance seedling survival during their first growing season after transplanting. For container-grown seedlings, the remaining leaves of defoliated seedlings showed photosynthetic capacity (Amax) about 1.5 times higher than the non-defoliated control in the first 3 weeks. For defoliated bare-root seedlings, Amax ranged 3.3-4.8 times higher than non-defoliated control in the first 4 weeks after transplanting. Thereafter, Amax of defoliated seedlings of both types began to decrease slowly. Amax of newly emerged leaves after transplanting was significantly higher than that of existing leaves for container-grown seedlings but not bare-root seedlings. For container-grown seedlings, both defoliated and non-defoliated plants showed high survival rate (&gt;90%) and there were no significant differences among levels of defoliation. For bare-root seedlings, non-defoliated control showed highest mortality (30%) by the end of the growing season but seedlings that were 25%, 50%, 75% defoliated all suffered little mortality. In terms of initial growth, there was no significant difference between defoliated and non-defoliated control in container seedlings suggesting that defoliation treatment had no effect on reducing their growth. In comparison, bare-root seedlings showed marginally but significantly greater height growth in defoliated plants, suggesting that non-defoliated seedlings suffered greater transplant shock and reducing the amount of leaves may contribute to minimize water stress and mortality. Therefore, we found that for bare-root seedlings, partial defoliation can effectively reduce transplant shock resulting in high survivorship and growth performance; the lack of defoliation response in container-grown seedlings would suggest that defoliation is unnecessary for improving their transplant success. (C) 2016 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.foreco.2016.03.054

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

In Amazonian non-flooded forests with a moderate dry season, many trees do not form anatomically definite annual rings. Alternative indicators of annual rings, such as the oxygen (delta O-18(wc)) and carbon stable isotope ratios of wood cellulose (delta C-13(wc)), have been proposed; however, their applicability in Amazonian forests remains unclear. We examined seasonal variations in the delta O-18(wc) and delta C-13(wc) of three common species (Eschweilera coriacea, Iryanthera coriacea, and Protium hebetatum) in Manaus, Brazil (Central Amazon). E. coriacea was also sampled in two other regions to determine the synchronicity of the isotopic signals among different regions. The annual cyclicity of delta O-18(wc) variation was cross-checked by C-14 dating. The delta O-18(wc) showed distinct seasonal variations that matched the amplitude observed in the delta O-18 of precipitation, whereas seasonal delta C-13(wc) variations were less distinct in most cases. The delta O-18(wc) variation patterns were similar within and between some individual trees in Manaus. However, the delta O-18(wc) patterns of E. coriacea differed by region. The ages of some samples estimated from the delta O-18(wc) cycles were offset from the ages estimated by C-14 dating. In the case of E. coriacea, this phenomenon suggested that missing or wedging rings may occur frequently even in well-grown individuals. Successful cross-dating may be facilitated by establishing delta O-18(wc) master chronologies at both seasonal and inter-annual scales for tree species with distinct annual rings in each region.

DOI： 10.1007/s00442-015-3509-x

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DOI： 10.6090/jarq.50.379

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Language：Japanese   Publisher：一般社団法人 日本土壌肥料学会  

DOI： 10.20710/dohikouen.62.0_157_2

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

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DOI： 10.11519/jfsc.127.0_801

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

[in Japanese]

DOI： 10.11519/jfsc.127.0_543

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

[in Japanese]

DOI： 10.11519/jfsc.127.0_813

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

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DOI： 10.11519/jfsc.127.0_308

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER  

In the present study, we aimed to map canopy heights in the Brazilian Amazon mainly on the basis of spacebome LiDAR and cloud-free MODIS imagery with a new method (the Self-Organizing Relationships method) for spatial modeling of the LiDAR footprint. To evaluate the general versatility, we compared the created canopy height map with two different canopy height estimates on the basis of our original field study plots (799 plots located in eight study sites) and a previously developed canopy height map. The compared canopy height estimates were obtained by: (1) a stem diameter at breast height (D)- tree height (H) relationship specific to each site on the basis of our original field study, (2) a previously developed D-H model involving environmental and structural factors as explanatory variables (Feldpausch et al., 2011), and (3) a previously developed canopy height map derived from the spacebome LiDAR data with different spatial modeling method and explanatory variables (Simard et al., 2011). As a result, our canopy height map successfully detected a spatial distribution pattern in canopy height estimates based on our original field study data (r=0.845, p = 8.31 x 10(-3)) though our canopy height map showed a poor correlation (r= 0.563, p =0.146) with the canopy height estimate based on a previously developed model by Feldpausch et al. (2011). We also confirmed that the created canopy height map showed a similar pattern with the previously developed canopy height map by Simard et al. (2011). It was concluded that the use of the spaceborne LiDAR data provides a sufficient accuracy in estimating the canopy height at regional scale. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jag.2015.04.003

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Key message Besides stem temperature, seasonality and vertical gradient in stem diameter growth strongly affect both seasonal and vertical variations in stem CO2 efflux.
Abstract Stem CO2 efflux (E-s) is known to vary seasonally and vertically along tree stems. We measured E-s at various heights in a 50-year-old hinoki cypress [Chamaecyparis obtusa (Sieb. et Zucc) Endl.] stand over 2 consecutive years in Central Japan. Effects of stem temperature (T-s), daily stem diameter increment (D-i), and difference in vapor pressure deficit between nighttime and daytime (VPDdiff) on seasonal variation in daily E-s were examined by a generalized linear model (GLM). Daily E-s exhibited a substantial seasonal variation, which was mostly affected by T-s and D-i. Any effect of VPDdiff, which was assumed to be an index of daily sap flow rate, was not detected. The GLM prediction of daily E-s from the combination of T-s and D-i showed good agreement with the observed seasonal trend in daily E-s. These results suggest that, in addition to stem temperature as the important environmental factor, stem radial growth is a significant phenological factor influencing seasonal variation in E-s. Additionally, the intercept of GLM, which indicates the basal daily efflux that is independent of T-s and D-i, was closely related to the annual diameter increment. Furthermore, a strong relationship was found between annual E-s and annual diameter increment. These findings suggest that variation in stem diameter growth along stems is considerably responsible for the observed vertical variation in E-s. Therefore, stem radial growth can affect both seasonal and spatial variations in stem CO2 efflux.

DOI： 10.1007/s00468-014-1127-6

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER JAPAN KK  

Bischofia javanica is a non-native tree species in Japan's Ogasawara Islands, where it threatens native tree species due to its rapid propagation and growth. An effective method is needed to limit the expansion of B. javanica populations and to conserve the natural forest ecosystem of the islands. For this purpose, we examined the effectiveness of a new application technique for the herbicide glyphosate on B. javanica. In this method, glyphosate solution is directly injected into holes drilled in the stem, and each hole is then plugged with a cork stopper to prevent loss of the solution, namely the drill-and-plug method. We also developed an allometric regression model linking stem diameter with total aboveground biomass (AGB) to estimate the necessary herbicide dosage. Our results suggest that between 0.1 and 0.5 g kg(-1) (active ingredient per unit AGB) is required to control most B. javanica trees. Verification of the drill-and-plug method using the minimum dosage (0.1 g kg(-1)) showed that most of the herbicide-treated trees were killed. These results suggest that the drill-and-plug method can help control the B. javanica invasion of the Ogasawara Islands.

DOI： 10.1007/s10310-014-0457-y

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：THE JAPANESE FORESTRY SOCIETY  

We examined the dynamics of radiocesium in the forest ecosystems which were contaminated by the Fukushima Daiichi Nuclear Power Plant Accident. Field measurement and sampling were conducted in eight stands; plantations of Japanese cedar (Cryptomeria japonica, n=4), Hinoki cypress (Chamaecyparis obtusa, n=2), Japanese red pine (Pinus densiflora, n=1), and deciduous broad-leaved forest dominated by oak (Quercus serrata, n=1). In each stand, &lt;sup&gt;137&lt;/sup&gt;Cs deposition in trees was estimated separately for each aboveground component (leaves, branches, and stem) using the data of specific &lt;sup&gt;137&lt;/sup&gt;Cs activities and biomass of these components obtained during 2011-2013. We found that tree- &lt;sup&gt;137&lt;/sup&gt;Cs decreased substantially during the period for all forest types. In 2013 however, the &lt;sup&gt;137&lt;/sup&gt;Cs ratio of trees to stand total (i.e., trees plus litter and soil) differed by forest type: Japanese cedar (6-24%) and Hinoki cypress (10-12%) were higher than pine (2%) and deciduous broad-leaved (3%) forests. The results suggested that the early 2-year transfer process of radiocesium from the tree crown to the ground differed depending on the amount of initial &lt;sup&gt;137&lt;/sup&gt;Cs deposition and differences in leaf longevity and biomass of dominant species.

DOI： 10.4005/jjfs.97.33

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Allometric models to estimate biomass components such as stem mass M , foliage mass Ml, root mass M and aboveground mass M , were developed for the palm species Euterpe precatoria Mart., which is the most abundant tree species in the Amazon. We harvested twenty palms including above- and below-ground parts in an old growth Amazonian forest in Brazil. The diameter at breast height D ranged from 3.9-12.7 cm, and the stem height H ranged from 2.3-16.4 m. The D, diameter at ground basis D , crown diameter CD, H, stem specific gravity ρ, and number of fronds Nf were considered as independent variables and incorporated into a power function model. The best predictors were D Hρ for M and M , D HN for Ml, and D for M . Slender index (H/D) ranged from 0.56-1.46 m cm , and the D-H relationship suggested that the stem shape becomes more slender with increasing D. On the other hand, ρ increased with D implying a stiffening of stem tissue. The average root/shoot ratio was estimated as 0.29 which was higher than that reported for the non-palm tree species in the Amazon. Comparisons of several models to estimate M of different palm species, suggested that the variations of the D-H relationship and ρ should be considered to develop allometric models for estimating biomass in palm species. In particular the ρ largely varied depending on individual size, which should be important to consider, when developing the allometric models for palms. s r a 0 s a f r a 2 2 . -1

DOI： 10.3390/f6020450

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier B.V.  

In the present study, we aimed to map canopy heights in the Brazilian Amazon mainly on the basis of spaceborne LiDAR and cloud-free MODIS imagery with a new method (the Self-Organizing Relationships method) for spatial modeling of the LiDAR footprint. To evaluate the general versatility, we compared the created canopy height map with two different canopy height estimates on the basis of our original field study plots (799 plots located in eight study sites) and a previously developed canopy height map. The compared canopy height estimates were obtained by: (1) a stem diameter at breast height (D) - tree height (H) relationship specific to each site on the basis of our original field study, (2) a previously developed D-H model involving environmental and structural factors as explanatory variables (Feldpausch et al., 2011 ), and (3) a previously developed canopy height map derived from the spaceborne LiDAR data with different spatial modeling method and explanatory variables (Simard et al., 2011 ). As a result, our canopy height map successfully detected a spatial distribution pattern in canopy height estimates based on our original field study data (r = 0.845, p = 8.31 × 10 ) though our canopy height map showed a poor correlation (r= 0.563, p = 0.146) with the canopy height estimate based on a previously developed model by Feldpausch et al. (2011). We also confirmed that the created canopy height map showed a similar pattern with the previously developed canopy height map by Simard et al. (2011). It was concluded that the use of the spaceborne LiDAR data provides a sufficient accuracy in estimating the canopy height at regional scale. -3

DOI： 10.1016/j.jag.2015.04.003

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

[in Japanese]

DOI： 10.11519/jfsc.126.0_845

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Language：Japanese   Publisher：森林総合研究所  

森林総合研究所では、福島第一原発事故により汚染された森林における放射性セシウムの分布や長期的な動態を把握するために、事故直後から福島県内の複数地点のスギ林や広葉樹林など異なる森林に試験地を設けて研究を行ってきた。ここでは、調査林分の概況と、研究手法のうち、樹木地上部、小径木及び下層植生を対象にした放射性セシウム濃度と林分全体の蓄積量の測定及び推定法を紹介する。とくに、幹の各部位（樹皮、辺材、心材）に区別した試料の採取や調整の仕方と、これら幹各部位と枝葉の現存量推定法については、調査林分での推定結果の一部を踏まえながら、方法上の問題点や今後の課題などを検討する。

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

The winter climate is changing in many parts of the world, and it is predicted that winter climate change will modify the structure and function of plant-soil systems. An understanding of these changes and their consequences in terrestrial ecosystems requires knowledge of the linkage between above- and below-ground components as well as the species interactions found in plant-soil systems, which have important implications for biogeochemical cycles. However, winter climate-change studies have focused on only a part of the ecosystem or ecological process. We summarize here recent findings related to the effects of winter climate and its changes on soil nitrogen (N) dynamics, greenhouse gas (N2O) emissions from the soil, N use by individual plants, vegetation development, and interactions between vegetation and pollinators to generate an integrative understanding of the response of the plant-soil system to winter climate change. This review indicates that the net effects on plants, soil microbes, pollinators, and the associated biogeochemical cycles are balanced among several processes and are highly variable depending on the context, such as the target species/functional group, original winter condition of the habitat, and type of climate change. The consequences of winter climate change for species interactions among plants, associated animals, and biogeochemical cycles are largely unknown. For further research, a large-scale comparative study to measure ecosystem-level functions is important, especially in less-cold ecosystems.

DOI： 10.1007/s11284-013-1115-0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Forest soils are generally sinks of CH4 and sources of N2O. To characterize the dynamics of these major greenhouse gases in central Siberia during the growing season, we measured fluxes from forest soil and assessed the relationships between CH4 and N2O fluxes and forest floor vegetation types, soil temperature, and moisture conditions. At the soil surface, both CH4 uptake and emission (-6.6 to 3.1 mu g CH4-C m(-2) h(-1)) were observed, and CH4 fluxes did not differ among vegetation types. CH4 flux was positively correlated with soil moisture, but not with soil temperature. The small CH4 uptake compared with previous reports was due to CH4 production in response to high precipitation. N2O was also emitted and taken up by soil (-0.2 to 0.4 mu g N2O-N m(-2) h(-1)), and N2O fluxes did not differ among vegetation types. N2O flux was negatively correlated with soil moisture and not correlated with soil temperature. Our findings suggest that high soil moisture and low availability of mineral nitrogen resulted in N2O uptake due to denitrification. Furthermore, both CH4 and N2O were emitted from a river at the site; these were produced in the basin of the riverbank rather than deep in the soil. (C) 2014 Elsevier B.V. and NIPR. All rights reserved.

DOI： 10.1016/j.polar.2014.01.004

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan International Research Center for Agricultural Sciences  

Fine roots are an important component of the carbon flow of forests. Soil properties in tropical forest (terra firme forest) of the Central Amazon differ substantially along topography, and the biomass and vertical distribution of fine roots may also differ accordingly. Information on the vertical distribution of fine roots is essential to obtain unbiased estimates of fine root biomass. Accordingly, we examined fine root biomass and its vertical pattern along the gradient of topography in a typical terra firme forest in this region. The regressions on the cumulative fine root biomass along soil depth (at 5 cm intervals from 0-40 cm in depth) revealed significantly different vertical distribution of fine root biomass among three topographic habitats (lower-slope valley called baixio, mid-slope, and upper-slope plateau). A shallower rooting pattern was observed in the plateau than the other habitats, while fine root biomass was larger in the baixio than the plateau-a difference likely attributable to the soil physical properties than the aboveground stand structures among the sites. More than 74 and 93% of the fine root biomass was estimated to be distributed within the upper 20-and 40-cm soil layers, respectively. Our results suggested that a shallow sampling depth, which is common in fine root research in the Amazon, would be reasonable, though we should examine the consistency of our results in different regions.

DOI： 10.6090/jarq.48.231

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan International Research Center for Agricultural Sciences  

Allometric models to estimate the aboveground mass AGM, belowground mass BGM and total mass TM of juvenile trees (stem diameter at breast height DBH ≤ 5 cm, tree height H ≥ 30 cm) in open-canopy terra-firme forests after wind disturbance were developed in the Amazon. For comparison, the allometric models were also developed for a closed-canopy terra-firme forest. After six models had been compared in each forest type, the model with diameter at ground basis DGB and H was selected as the best for estimating AGM and TM, and the model with diameter at ground basis DGB as a single variable was selected as the best for estimating BGM considering the adjusted coefficient of determination and standard deviation of the mean. Models based on the diameter at breast height DBH showed poor correlation with each biomass component compared with those based on DGB for the open-canopy forest. The juvenile trees in the open-canopy forest showed higher AGM and H at a given DGB than in the closed-canopy forest, while the DGB-BGM relationships did not differ significantly between the open-and closed-canopy forests. It was concluded that the allometric models used to estimate AGM and TM were unique to each forest type. This would be because light-demanding species show higher allocation to AGM than BGM to be advantageous for competition for light by achieving rapid growth in height.

DOI： 10.6090/jarq.48.213

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

[in Japanese]

DOI： 10.11519/jfsc.125.0_766

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN SOC TROPICAL ECOLOGY  

Limited information on fine roots is hindering understanding of the geographical-scale variations in belowground carbon stock across the Amazon Basin. Fine root biomass (< 2 mm in diameter) was studied in the upper Negro River basin of Brazil, where no previous study on fine roots had been reported. Two plots (20x125 m), each of which included 3 subplots (20x20 m), were set in a tropical moist forest at Sao Gabriel da Cachoeira, north-western Brazil. The diameter of the trees (dbh > 10 cm) within each subplot was measured, and fine roots were sampled by coring soils from depths of 0-5, 5-10 and 10-20 cm at 12 points in each subplot. The fine root, coarse root, and aboveground biomass in the study forest were estimated as 7.03 +/- 0.65 (95 % CI), 32.6 +/- 15.0 and 253.6 +/- 152.7 Mg ha-1, respectively. Most of the spatial variance in fine root biomass was accounted among and within the subplot spatial scale of less than 20x20 m. The fine root biomass of the study site exceeded the values reported for some tropical forests in the central and eastern Amazon, which suggested regional differences in the fine root biomass in Amazonian forests.

DOI： 10.3759/tropics.22.179

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We developed a stem diameter D-height H allometric model that included variability in the D-H relationship along a topographic gradient. The study site was located along a belt transect (2500 × 20 m) established in a primary tropical forest near Manaus, Brazil. The transect included typical topography of the region, characterized by plateaus and valleys called "baixios". The D-H allometric model (n = 1307) indicated that potential tree height increased significantly, from 28 m at the lowest baixio plot to 35 m at the highest plateau plot. Consequently, by combining the D-H allometric model and an allometric equation with the variable D2H, biomass was estimated for trees (D &gt
10 cm) in each sub-plot (20 × 20 m). Ignoring variability in the D-H relationship introduced wide-ranging error to biomass estimation
error values ranged from -5% at a baixio plot to +6% at a plateau plot. Average biomass was 317 ± 28 (SE) Mg ha-1, and tree density and biomass fell significantly with decreasing relative elevation.

DOI： 10.6090/jarq.47.109

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

DOI： 10.11519/jfsc.124.0.208.0

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

DOI： 10.11519/jfsc.124.0.383.0

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

DOI： 10.11519/jfsc.124.0.707.0

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DOI： 10.11519/jfsc.124.0.530.0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Precise estimation of biomass at a regional scale is required for evaluating forest carbon stocks throughout the Amazon. We examined six types of allometric models to identify the best estimator of biomass in primary forests (terra firme) in the northwestern sector of the Brazilian Amazon. We also tested six regression models for estimating tree height. We developed each allometric model using measurements of 101 trees excavated in a primary forest distributed along the upper Rio Negro. A simple power function with stem diameter at breast height D as a single variable was selected as the best model for estimating each biomass component, i.e. above-ground total mass AGW, below-ground total mass BGW, and whole individual mass. Among models developed to estimate tree height H from D, we selected a regression model with a coefficient corresponding to an asymptotic height as the best fit. The D-AGW relationship at our study site differed significantly from models developed previously for other regions of the Amazon. We explain this regional variation in part by regional differences in D-H relationships of sample trees. The D-BGW relationship at our site also differed significantly from that in the central Amazon. However, AGW-BGW relationships were consistent between the upper Rio Negro forest and other forests in the central Amazon, in that the BGW-AGW ratio was constant as 0.136 regardless of tree size. On the basis of D-based allometry and census data from 23 plots established in the upper Rio Negro region, we estimated a stand-level total biomass (dry mass) of 252.6 Mg ha(-1). This estimate is at least 73% lower than the potential stand biomass for the region previously suggested by several meta-analyses. (C) 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.foreco.2012.04.028

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

Individual growth change of Pinus densiflora during 8 years after thinning prescription in a 94-year-old plantation was investigated comparing it with an unthinned plantation of the same age and a 140-year-old natural stand, to test whether growth of trees could be improved by thinning, what individual traits would affect growth improvement, and whether it would be possible or not to produce large sized timber in the plantations as found in the natural stand at 140 years. Trees in the plantations were characterized by smaller size (DBH=41 cm, H=25-30 m) than old-growth natural stand (DBH=68 cm, H=30-35 m). H/DBH ratio and proportion of crown length suggested that trees in the plantations were more vulnerable to external disturbance such as heavy snow and had less leaf mass than those in the natural stand. After thinning, about 40% of the trees showed an improved annual DBH increment (by ca. 0.1 cm yr -1), whereas 80% of the trees in the unthinned plantation showed deceleration of DBH growth. Change in degree of competition with neighbors or individual variation in leaf mass did not explain inter-individual variation in growth improvement. Improved growth did not appear to be enough to reach equivalent size to trees in the natural stand at the age of 140 years.

DOI： 10.4005/jjfs.93.48

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DOI： 10.11519/jfsc.123.0.Pa154.0

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DOI： 10.11519/jfsc.123.0.Pa064.0

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DOI： 10.11519/jfsc.123.0.J06.0

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DOI： 10.11519/jfsc.123.0.I17.0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CAMBRIDGE UNIV PRESS  

Precise estimation of root biomass is important for understanding carbon stocks and dynamics in tropical rain forests. However, limited information is available on individual root masses, especially large trees. We excavated 121 root systems of various species (78) and sizes (up to 116 cm in dbh). and estimated both above- and below-ground biomass in a lowland primary dipterocarp forest in the Pasoh Forest Reserve, Peninsular Malaysia. A tree census was conducted in four research plots (each 0.2 ha) and stand-level biomass was estimated. We examined relationships between tree size parameters and masses of coarse roots (roots &gt;= 5 mm in diameter) and derived a dbh-based allometric equation. The amounts of coarse roots that were lost during excavation were corrected. Coarse-root biomass before and after correction for lost roots was estimated to be 63.8 and 82.7 Mg ha(-1), indicating that significant amounts of roots (23%) were lost during the sampling. We also estimated the biomass of small root (&lt;5 mm) by applying pipe-model theory. The estimate, 13.3 Mg ha(-1), was similar to another estimate of small roots, 16.4 Mg ha(-1), which was obtained directly by the soil-pit sampling method. Total below-ground (BGB) and above-ground biomass (AGB) was estimated to be 95.9 and 536 Mg ha(-1), respectively. The biomass-partitioning ratio (BGB/AGB) was about 0.18. In conclusion, the dbh-based allometric equation for coarse roots developed in this study, which kept good linearity even including the data of larger trees, might be useful for evaluating below-ground carbon stocks in other stands of similar forest (old-growth dipterocarp) in South-East Asia.

DOI： 10.1017/S0266467410000040

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

We examined vertical and seasonal variations in stem respiration rates in a 50-year-old plantation of Japanese cypress, Chamaecyparis obtusa (Sieb. et Zucc.) Endl., in central Japan, and discuss a practical and precise method to scale a point-measured stem CO2 efflux rate up to whole-stem respiration. For five selected trees, stem CO2 efflux rates were measured at breast height (1.3 m) and at five or six points above breast height (at approximately 2 m intervals) every 1 or 2 months over two consecutive years. Daily total stem respiration rate (surface area basis) was greater inside the crown than below the crown, especially during the growing season. By incorporating the vertical profile of the respiration rate, annual whole-stem respiration was estimated for each sample tree (R (y)). We then compared this estimate (R (y)) with another estimate of annual whole-stem respiration (R&apos;(y)) obtained using a conventional method; it is assumed that the area-based respiration rate at breast height is constant throughout the stem. The ratio of these two estimates (R&apos;(y)/R (y)) was usually less than 1, indicating that the assumptions used to calculate R&apos;(y) underestimate annual whole-stem respiration. We found that R&apos;(y)/R (y) was negatively correlated with the ratio of crown length to tree height (crown ratio). These results suggest that annual whole-stem respiration in this C. obtusa plantation is substantially affected by the relative proportion of within-crown stem with higher respiratory activity. Methodologically, our results imply that incorporating the crown ratio into the conventional method would improve the accuracy of annual whole-stem respiration estimates.

DOI： 10.1007/s10310-009-0163-3

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATL ACAD SCIENCES  

The scaling of respiratory metabolism with body mass is one of the most pervasive phenomena in biology. Using a single allometric equation to characterize empirical scaling relationships and to evaluate alternative hypotheses about mechanisms has been controversial. We developed a method to directly measure respiration of 271 whole plants, spanning nine orders of magnitude in body mass, from small seedlings to large trees, and from tropical to boreal ecosystems. Our measurements include the roots, which have often been ignored. Rather than a single power-law relationship, our data are fit by a biphasic, mixed-power function. The allometric exponent varies continuously from 1 in the smallest plants to 3/4 in larger saplings and trees. Therefore, our findings support the recent findings of Reich et al. [Reich PB, Tjoelker MG, Machado JL, Oleksyn J (2006) Universal scaling of respiratory metabolism, size, and nitrogen in plants. Nature 439: 457-461] and West, Brown, and Enquist [West GB, Brown JH, Enquist BJ (1997) A general model for the origin of allometric scaling laws in biology. Science 276: 122 - 126.]. The transition from linear to 3/4-power scaling may indicate fundamental physical and physiological constraints on the allocation of plant biomass between photosynthetic and nonphotosynthetic organs over the course of ontogenetic plant growth.

DOI： 10.1073/pnas.0902554107

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DOI： 10.1007/978-1-4020-9693-8_16

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DOI： 10.1007/978-1-4020-9693-8_6

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER WIEN  

Gmelin larch ( Larix gmelinii) forests are representative vegetation in the continuous permafrost region of Central Siberia. Information on the carbon budget is still limited for this Siberian larch taiga in comparison to boreal forests in other regions, while the larch forests are expected to play a key role in the global carbon balance due to their wide distribution over North-East Eurasia. The authors reported results of eddy covariance CO2 flux measurements at a mature Gmelin larch stand in Central Siberia, Russia (64 degrees 16'N, 100 degrees 12'E, 250m a.s.l.). The measurements were conducted during one growing season (June-early September in 2004). CO2 uptake was initiated in early June and increased sharply until late June, which was closely related to the phenology of the larch trees (i.e., bud-break and needle flush). Maximum half-hourly net CO2 uptake was similar to 6 mu mol m(-2) s(-1). Maximum daily net uptake of similar to 2 g C m(-2) day(-1) occurred at the end of June and in mid-July. Cumulative net uptake was 76-78 g C m(-2), indicating that the mature larch forest acted as a net sink for CO2 during the growing season (91 days). In comparison with other boreal forests, however, the magnitude of net CO2 uptake and night-time release of the forest, and cumulative net CO2 uptake were lower. We suggest that lower net ecosystem CO2 uptake of the study stand was primarily associated with low leaf area index.

DOI： 10.1007/s00704-007-0337-x

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Language：Japanese   Publisher：日本森林学会  

DOI： 10.11519/jjsk.53.0_68

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

An analysis was performed of the climatic responses of the radial growth of Larix gmelinii (Rupr.) Rupr. at two sites-both of which included contrasting north- and south-facing slopes-in Tura, central Siberia, with the development of ring width and maximum-density chronologies for each slope. Both residual and standard chronologies of ring widths were positively correlated with temperature from late May until mid June on all four slopes. By contrast, standard chronologies of ring widths were negatively correlated with precipitation during the winter (from October to April) and in May on the north-facing slope at site 1 and on the south-facing slope at site 2 respectively. The negative correlations with precipitation during the winter and in May on some of the slopes suggested that delayed snowmelt in early spring might inhibit the radial growth of L. gmelinii, and the effects of snow are likely to vary with topography. Both residual and standard chronologies of maximum densities were positively correlated with temperature in early July on all four slopes. Maximum densities were also positively correlated with precipitation during summer of the previous year on all the slopes. These suggest that no major differences exist in terms of responses of maximum density to climatic factors between the north- and south-facing slopes.

DOI： 10.1007/s11284-006-0062-4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

We present results of individual-based root system measurement and analysis applied for Larix gmelinii trees growing on the continuous permafrost region of central Siberia. The data of root excavation taken from the three stands were used for the analyses; young (26 years old), mature (105 years old), and uneven-aged over-mature stand (220 years old). In this article, we highlight two topics: (1) factors affecting spatio-temporal pattern of root system development, and (2) interactions between aboveground (i.e., crown) and belowground (i.e., root) competition. For the first topic, the detailed observation of lateral roots was applied to one sample tree of the overmature stand. The tree constructed a superficial (&lt; 30 cm in depth) and rather asymmetric root system, and each lateral root expanded mainly into elevated mounds rather than depressed troughs. This indicated that spatial development of an individual root system was largely affected by microtopography (i.e., earth hummocks). For these lateral roots, elongation growth curves were reconstructed using annual-ring data, and annual growth rates and patterns were compared among them. The comparison suggested that temporal root system development is associated with differences in carbon allocation among the lateral roots. For the second topic, we examined relationships between individual crown projection area (CA) and horizontal rooting area (RA) for the sample trees of each stand. RA was almost equal to CA in the young stand, while RA was much larger (three or four times) than CA in the mature and overmature stands. Two measures of stand-level space occupation, crown area index (aboveground: CAI; sum of CAs per unit land area) and rooting area index (belowground: RAI; sum of RAs), were estimated in each stand. The estimates of RA1 (1.3-1.8 m(2) m(-2)) exceeded unity in all stands. In contrast, CAI exceeded unity (1.3 m(2) m(-2)) only in the young stand, and was much smaller (&lt; 0.3 m(2) m(-2)) in the two older stands. These between-stand differences in RAI-CAI relationships suggest that intertree competition for both aboveground and belowground spaces occurred in the young stand, but only belowground competition still occurred in the two older stands. Based on this finding, we hypothesized that competition below the ground may become predominant as a stand ages in L. gmelinii forests. Methodological limitations of our analysis are also discussed, especially for the analysis using the two indices of space occupation (CAI, RAI).

DOI： 10.1007/s10310-006-0259-y

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

An analysis was performed on the climatic responses of the radial growth of Larix gmelinii (Rupr.) Rupr. on contrasting north-facing and south-facing slopes in Tura, central Siberia. We developed chronologies of tree-ring width for four plots, designated as north-upper, northlower, south-upper, and south-lower. Both residual and standard chronologies of tree-ring widths exhibited a significant positive correlation with temperature from the end of May until early June in all four plots. The chronologies of ring width did not reveal any major difference in the response to temperature among the four plots. The standard chronologies of ring widths on the north-facing slope were negatively correlated with precipitation during the winter (October-April) and in early and mid-May, whereas the residual chronologies did not reveal clear relationships with precipitation during the winter and May. The significant correlation between ring width and temperature from the end of May until early June indicates that temperatures in springtime play a significant role in the radial growth of L. gmelinii. The negative correlations between standard chronologies of tree-ring width and precipitation in the winter and in May on the north-facing slope indicate that lowfrequency fluctuations in snowfall have negative effects on the radial growth. However, these effects vary and depend on the microscale topography.

DOI： 10.1007/s10086-006-0837-9

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Language：Japanese   Publisher：一般社団法人日本森林学会  

We analyzed the species and densities of established tree with height&amp;ge;1.3 m in 59 conifer plantations and 41 reforestation-abandoned sites after clear cutting (i.e. clear-cut sites) on Kyushu Island. Natural or secondary broad-leaved forests (i.e. broad-leaved forests, n=l7) were also investigated for the purpose of comparison. Based on these field data, we developed prediction models for tree establishment. Mean densities of trees established in both plantations and clear-cut sites were lower than in broad-leaved forests, especially for species dominating the canopy layer of natural forests, such as Fagaceae. The coefficients of determination of the prediction models were larger for a group of pioneer tree species than for all pooled species in both plantations and clear-cut sites. Major factors affecting tree establishment were different between the plantations (slope inclination) and the clear-cut sites (altitude and slope direction) , although stand age (including years after clear-cutting) affected tree establishment most in both sites. Basic site information (e.g. altitude) and stand description data (e.g. stand age) were useful for the prediction. The accuracy of the prediction model was improved by grouping tree species with similar growth and/or regeneration characteristics.

DOI： 10.4005/jjfs.88.482

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

The individual growth of tree diameter at breast height (dbh) is analyzed in an even-aged plantation of Cryptomeria japonica from stand age of 45 to 94 years, to examine how the growth of individual trees has been affected by the changes in spacing resulting from thinning operations. At any age, a significant proportion (0.37-0.46) of the variation in dbh growth during a 5-11-year period was explained by dbh at the beginning of the period, probably due to greater leaf mass of larger trees. Next, either one-sided or two-sided competition was added to the model, by calculating the basal area (BA) of neighboring trees around each tree within a given radius or BA for trees having larger dbh than the focal tree within the radius. After preliminary analyses, a radius of 8 m was selected as the critical range for tree competition. Although both types of competition explained a significant proportion (0.09-0.43) of growth variation, one-sided competition was not significant at ages greater than 54 years. Based on the model at 45 years of age, the initial deviation of growth rate for each tree from the predicted rate was calculated and added to the models as a third variable. This raised the coefficient of determination up to 0.50-0.74. These findings have practical significance for forest plantation management, particularly for controlling the growth of standing trees via thinning, to produce high-quality timber in the future.

DOI： 10.1007/s10310-005-0175-6

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We analyzed the growth patterns of Thujopsis dolabrata var. hondai trees in an old plantation (161 years old), where no silvicultural treatments (e.g., thinning) have been conducted since the initial planting. The analysis focused on understanding individual growth under a long-term self-thinning process, and the stand-level stemwood production at the mature stage was evaluated. Nine canopy-layer trees and one suppressed tree were used for the analysis of annual increments in stem diameters, heights, and stemwood volumes for a given past year using the ring-width data. Both the diameter (at basal portion) and height of all the canopy-layer trees increased at similar rates during the early stage (i.e., 60-70 years after planting); however, after this period, only the height growth rates declined sharply. The annual growth rates of stemwood volume also simultaneously leveled off at the stand age of 40-60 years. Subsequently, the patterns diverged conspicuously, e.g., the growth rates were maintained or increased in some individuals, while it gradually decreased in the case of others until the present year. The divergence of growth pattern was likely to be triggered by intertree competition at several decades after the onset of canopy closure. The current stemwood production of the sample trees, including the suppressed one, was positively correlated with certain size parameters such as stem diameter at breast height and sap-wood area at a height of 4m. Based on the diameter-base allometry, the total stand stemwood production was estimated to be about 12.8 m(3) ha(-1) year(-1). This estimate was higher than those of some old natural T. dolabrata forests (2.0-8.6 m(3) ha(-1) year(-1)) that have been well managed by repetitive selection thinning. Furthermore, individual mean stemwood production of the study plantation (0.03 m(3) tree(-1) year(-1)) was within the range of these natural stands (0.01-0.05 m(3) tree(-1) year(-1)). These comparisons suggested that the old T dolabrata plantation still maintained a relatively high stemwood production potential despite the absence of artificial controls of tree density in the past. In terms of timber production, this fact implied that a rather long rotation (&gt; 100 years) can be applicable in the management of T. dolabrata plantations.

DOI： 10.1007/s10310-005-0193-4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

We examined size-mass allometry and biomass allocation of two larch species (Larix gmelinii (Rupr.) Rupr. and Larix cajanderi Mayer) that grow on the continuous permafrost regions in Siberia. Sample tree data (total n = 27) gathered from four mature stands (&gt; 100 years old) were employed for analysis. First, to determine good size predictor of biomass, site-specific allometric relationships (log-linear equation form) were derived between dry mass of four components (stem, branch, needle and coarse root; &gt;= 5 mm in diameter) and seven size variables; stem diameters (breast height, 30 cm height and crown base), sapwood areas (breast height and 30 cm height), and two combined-variables (tree height x dia-diameter). For all components, site-specific allometric equations based on breast-height diameter (D) always gave high correlations as those using other size variables. However, between-stand comparisons of the D-base site-specific allometry indicated that size dependency (i.e., regression slope) differed for stem mass. Besides, needle and coarse root mass for a given size (i.e., regression intercept) differed significantly among the four stands. These facts implied that D-base regression model was reliable for biomass estimation by site-specific allometry, but was not suitable for developing general (i.e., site-common) allometry. Second, to examine carbon allocation pattern, we estimated each stand biomass by applying corresponding site-specific D-base allometry. Stand total biomass ranged from 8.6 to 33.1 Mg ha(-1), and aboveground-total/coarse root biomass ratio (i.e., T/R) ranged from 1.5 to 2.6. The variation was mainly due to trade-offs between stem and root biomass. Average T/R was about 2.3 that was calculated for some reported L. gmelinii and L. cajanderi stands (n = 16), including our four stands. This average T/R was extremely small in comparison to that (5.1) of Scots pine (Pinus sylvestris L.) stands on the non- or discontinuous permafrost regions in Siberia. This finding strongly suggested that the two Larix species invested annual carbon gains largely into root growth. We discussed its ecological implications in relation to stand structure and permafrost soil-N conditions in the larch taiga ecosystem. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.foreco.2005.10.031

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS  

Fluxes of dissolved organic carbon (DOC) in forested watersheds underlain by permafrost are likely to vary with changes in climatic regime that increase soil moisture and temperature. We examined the effects of temporal and spatial variations in soil temperature and moisture on DOC fluxes from the forest floor of contrasting north- and south-facing slopes in central Siberia. DOC fluxes increased throughout the growing season (June-September) on both slopes in 2002 and 2003. The most favorable combination of moisture content and temperature (deepest active soil layer) occurred in September, and we believe this was the primary driver of increased DOC concentrations and flux in autumn. Total DOC flux for June-September was 12.6-17.6 g C(.)m(-2) on the south-facing slope and 4.6-8.9 g C(.)m(-2) on the north-facing slope. DOC concentrations in forest floor leachates increased with increasing temperature on the north-facing slope, but were almost unaffected by temperature on the south-facing slope. Our results suggest that water input in midseason from melting of ice or precipitation events is the primary factor limiting DOC production. Significant positive correlations between amounts of precipitation and DOC flux were found on both slopes. Dilution of DOC concentrations by high precipitation volumes was observed only for the forest floor leachates collected from the north-facing slope. Our results suggest that global warming will result in increased DOC production in forest floors of permafrost regions, and that precipitation patterns will play an important role in determining the magnitude of these changes in DOC flux as well as its interannual variability. However, the longer-term response of soils and DOC flux to a warming climate will be driven by changes in vegetation and microbial communities as well as by the direct results of temperature and moisture conditions.

DOI： 10.1139/X05-150

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：INST ARCTIC ALPINE RES  

On a gentle leeward slope in a snowy forest limit in northern Honshu Island, Japan, mechanical damage by snow settlement and creep on Abies mariesii trees buried below the snowpack was examined to detect signs of the snow-damage effect on future survival and crown development. Damage types were recorded based on direct observation of crowns in 1996, a year of high snow accumulation exceeding 4.5 m, and 1997, a year of moderate snow accumulation. Of 153 trees examined, 63% were damaged in 1996 and 15% were damaged in 1997. The most destructive damage type was breakage of stems &GE; 5 cm in diameter, which occurred on eight trees in 1996 and three in 1997, resulting in foliage loss and death of some trees. The prevalent damage type was branch tearing, at branch-stem junctions primarily within a height range of 4-6 In, which occurred on 171 branches in 1996 and 5 in 1997. Under snowy and windy conditions, stem breakage and branch tearing, caused by forces active within restricted layers of the snowpack, may reduce the future survival and crown development of A. mariesii buried below the snowpack in years of heavy snowfall.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：FERDINAND BERGER SOEHNE  

Deciduous coniferous taiga, larch (genus Larix) ecosystem is one of unique biomes in northeastern Eurasian Continent, where vast area of forest exists on continuous permafrost. We selected three representative sites for ecosystem research: 1) a forest near Yakutsk in Yakutian Basin, eastern Siberia (62N-129E), 2) a forest near Tura in central Siberian Plataeu (64N-100E), and 3) a forest tundra transition near Chersky in Kolyma lowland (69N-160E). We estimated C storage in both aboveground and belowground biomass, in forest floor, and in active layer as soil organic C and as carbonate-carbon. Soil organic C in active layer was the largest component in each site. Soils in Yakutsk and Tura showed carbonate-C accumulation in active layer, which might result from extreme continental climate with low annual precipitation. C storage in aboveground and belowground biomass varied among sites, however, ratios of above/belowground biomass C had a relatively narrow range from 1.1 to 1.5. High allocation rate of C to belowground part resulted from a kind of adaptation to effective nutrient acquisition under nutrient limited environment due to low soil temperature.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：INST ARCTIC ALPINE RES  

We examined the effects of snow avalanche on stand structure and the subsequent regeneration of subalpine Abies mariesii Mast forest in northern Japan, and discussed whether gap formation after avalanche disturbance leads to immediate seedling establishment or not. Tree size and age, tree-ring chronology, and seedling density were compared between, on, and around a relatively large avalanche path, which was created in the mid-1980s within Hachimantai National Park. On the avalanche path, only smaller and younger trees (height &lt;5 m, 50-100 yr old) escaped the mechanical damage of avalanche by leaning into the remaining snowpack, and old canopy trees were mostly killed by stem breakage. Tree size structure of the avalanche path, including both living and dead individuals, was relatively similar to that of nearby undisturbed forest, indicating that a mature stand (&gt;ca. 200 yr old) had been previously developed on the avalanche slope without large-scale disturbances in the past. Most of the surviving, younger trees showed abrupt growth release during the few years (1987-1989) after the avalanche event. However, densities of both post-avalanche (&lt; 15 yr old) and pre-avalanche (&gt; 15 yr old) seedlings were much lower on the avalanche path than in the nearby forest, especially at microsites covered with dense dwarf bamboo (Sasa kurilensis) shrub. The pre-avalanche seedlings on the avalanche path sharply increased annual height growth rates after the mid-1980s avalanche, but such positive growth response did not continue longer than 6 to 7 yr. These findings suggested that gap formation following the infrequent, large-scale avalanche disturbance did not necessarily lead to immediate seedling recruitment and/or further growth release of pre-avalanche seedlings. The constraint of seedling establishment was primarily explained by the lack of potential seed supply, and shading effect of the dwarf bamboo bush. Consequently, post-avalanche regeneration of the subalpine fir forest was likely to depend on the smaller individuals (2-5 m in height) that were able to avoid both the mechanical damage of avalanche and mortality from shading by the dwarf bamboo.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Spatial distributions of root systems of Larix gmelinii (Rupr.) Rupr. trees were examined in two stands in central Siberia: an even-aged stand (ca. 100 yrs-old) and a mature, uneven-aged (240-280 yrs-old) stand. Five larch trees of different sizes were sampled by excavating coarse roots (diameter &gt; 5 mm) in each stand. Dimensions and ages of all first-order lateral roots were measured. Micro-scale conditions of soil temperature and soil water suction ( each 10 cm deep) were also examined in relation to earth hummock topography (mound vs. trough) and/or ground floor vegetation types (moss vs. lichens). All larch trees developed superficial root systems, consisting of the aborted short tap root (10-40 cm in soil depth) and some well-spread lateral roots (n = 4-13). The root network of each tree was asymmetric, and its rooting area reached about four times the crown projection area. Lateral roots generally expanded into the upper soil layers of the mounds where summer soil temperature was 1-6degreesC higher than inside nearby troughs. Chronological analysis indicated that lateral root expansion started successively from lower to upper parts of each aborted tap root, and some lateral roots occurred simultaneously at several decades after tree establishment. The process of root system development was likely to be primarily linked with post-fire dynamics of rhizosphere environment of the permafrost soils.

DOI： 10.1023/A:1026175718177

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

To clarify the factors affecting the seedling establishment of the subalpine stone pine (Pinus pumila Regl.) from nutcracker-cached seeds, subsequently emerged seedlings were examined in two plots on Mt Akitakomagadake, northern Japan. The survivorship of older seedlings (2-20 years old) was also monitored during six seasons at nine different sites. In one plot with 18 caches, seed germination occurred between June and mid-July. During this period, nutcracker&apos;s retrieved the stored pine seeds from 16 caches and ate some seeds immediately. Simultaneously, this nutcracker behavior caused mechanical damage to newly emerging seedlings (e.g. uprooting and tearing off cotyledons). Such initial loss to in situ harvesting and mechanical damage accounted for 75% of the total seeds remaining in the caches. The number of established current seedlings sharply declined during the first 2 years, and the survival rate was 4.4% over four winters. Two major mortality factors were identified: uprooting by frost-heave soil disturbance in the spring of the second year and standing death by drought or other physiological stresses in early summer. In another plot with 13 caches, survivorship of newly emerged seedlings was also low (4.2%), but mortality was mostly due to summer drought, indicating that the frost-heave event was a site-specific disturbance factor. For older seedlings, survival rates reached approximately 90% even after six seasons and summer drought stress was a major mortality factor. My findings suggest that seedling recruitment of P. pumila was largely limited by both nutcracker disturbance and external disturbance (and/or stresses) at an early stage. However, after the critical first few years, pine seedlings were highly likely to survive and grow to the sapling stage despite the harsh environment of the high mountains.

DOI： 10.1046/j.1440-1703.2002.00505.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

We reconstruct the paleoclimatic background of buried peat layers formed around the 10th century, which occur in a snowpatch grassland in a snowy mountain in northern Japan. In the snowpatch grassland, peat accumulation is presently restricted by the presence of a summer snowpatch. Thus, the buried peat layers imply that the summer snowpatch around the 10th century was smaller than it has been in recent times. Climatic control of the year-to-year variation of the present snowpatch was examined based on a snowpatch survey and analysis of meteorological data. The observed snowpatch profiles suggested that winter wind speed played an important role in controlling summer snowpatch size. The buried peat layers indicate not only warming in the melt season, but also a possible weakened winter monsoon in the Medieval Warm Period. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0341-8162(02)00009-7

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Arctic and Alpine Research  

We examined effects of annual snowfall fluctuation on tree growth and establishment in a mature stand (ca. 200 yr old) of Japanese subalpine Abies mariesii Mast. near upper forest-limits at leeward site. Relatively tall and aged fir trees (&gt
5 m, &gt
100 yr old) retained various scars of past mechanical damage due to snow pressures, e.g., multiple-, tip dieback- and broken-stems, and canopy anomaly. Ring-width pattern analysis showed that these deformed trees mostly experienced abrupt growth reduction. Some events of such abrupt growth reduction occurred simultaneously just after winters with heavy snowfall (e.g., mid-1960s), indicating that the A. mariesii trees often suffered from snow damage due to settlement force of excess snowpack. Particularly, in snowy winters, mechanical breakage of branches was likely to occur intensively at the height of 1 to 3 m above the maximum snowpack level of normal snowfall winters (ca. 3 m). On the other hand, some aged, but suppressed, trees sharply enhanced their growth rates simultaneously after such period of the intensive snow damage. This indicated that the snow damage upon the relatively tall trees sometimes facilitated regeneration of nearby shaded-trees by creating small-scale gaps. The snow-induced disturbance events may have occurred at about 10-yr intervals during the last half of 20th century. Our findings suggested that population dynamics of A. mariesii near its upper forest-limit, especially located at leeward and snowy site, was closely affected by the repetitive events of snow damage following snowy winters: the event primarily acted as a major limiting factor for canopy development of individuals, and sometimes triggered growth of suppressed-trees.

DOI： 10.2307/1552471

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：National Research Council of Canada  

Feasibility was tested of estimating the total stem volume and aboveground biomass from data of only the largest trees in even-aged pure stands. We applied a method of fitting a size-distribution function to data that exclude information of smaller individuals in a stand and compared the predicted stem volume and aboveground biomass with those calculated with data of all living trees in the stand. The paired t test showed that the predicted values of the total stem volume and aboveground biomass were not different (p = 0.05) from those observed even if only the largest 10% of the trees were used for estimation with the -3/2 power distribution. Results were similar with the beta-type distribution
however, data from at least the largest 30% of the trees in the stand must be included. Absolute values of the relative error of the predicted total stem volume or aboveground biomass were generally in the range 10-20%, indicating that the present method is accurate enough to be used for calculation of these variables. However, there is systematic bias in the predictions of the total stem volume and aboveground biomass of a stand. Possible causes of the indicated biases and potential ways for improvement of the predictions were discussed.

DOI： 10.1139/x01-137

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Language：Japanese   Publisher：The Japanese Society of Snow and Ice  

1999年4月21日, 岩手県岩手郡松尾村籐七温泉付近の斜面で幅約100m長さ約300mの全層雪崩が発生した.雪崩が発生した斜面は谷地形の発達が悪い地すべり滑落崖で, アバランチシュートなどの常習的な雪崩の発生を示唆する地形は見られなかった.この雪崩は発生斜面における雪食地の拡大と堆積地における亜高山帯林の破壊という景観変化を伴っていた.空中写真判読と現地調査の結果, 同様の景観変化は八幡平の稜線部の鏡沼付近においても, 1986年頃に起きたことが明らかになった.これまで雪崩災害の報告が少かった八幡平地域においても, 頻度は低いものの比較的大規模な全層雪崩が発生していると考えられる.

DOI： 10.5331/seppyo.62.463

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS  

We assessed above- and belowground biomass and net primary production (NPP) of a mature Larix gmelinii (Rupr.) Rupr. forest (240-280 years old) established on permafrost soils in central Siberia. Specifically, we investigated annual carbon budgets in roots in relation to root system development and availability of soil resources. Total stand biomass estimated by allometry was about 39 Mg ha(-1). Root biomass (17 Mg ha(-1)) comprised about 43% of total biomass. Coarse root (greater than or equal to 5 mm in diameter) biomass was about twice that of fine roots (&lt; 5 mm). The aboveground biomass/root biomass ratio (T/R) of the larch stand was about unity, which is much less than that of other boreal and subalpine conifer forests. The proportion of fine roots in total root biomass (35%) was relatively high compared with other cold-climate evergreen conifer forests. Total NPP, defined as the sum of annual biomass increment of woody parts and needle biomass, was estimated to be 1.8 Mg ha(-1) year(-1). Allocation of total NPP to needle production was 56%. The proportion of total NPP in belowground production (27%) was less than for evergreen taiga forests. However, belowground NPP was probablyunderestimatedbecauserootmortalitywasexcluded.We conclude that L. gmelinii trees invested annual carbon gains largely into needle production or roots, or both, at the expense of growth of aboveground woody parts. This carbon allocation pattern, which resulted in the construction of exploitative root networks, appeared to be a positive growth response to the nutrient-poor permafrost soil of central Siberia.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：INST ARCTIC ALPINE RES  

Seedling establishment of Japanese stone pine, Pinus pumila, primarily depends on seed dispersal by Japanese nutcrackers (Nucifraga caryocatactes var, japonica). To assess how this mode of seed dispersal affects regeneration and habitat expansion of P. pumila, we mode held observations concerning foraging behavior of nutcrackers, past annual production of pine cones, and age structure of established pine seedlings. Nutcrackers used various microsites for feeding and removing the pine seeds, especially on bare ground or around rocks. The pine seedlings occurred mainly in open patches sparsely covered with dwarf woody shrubs in wind-exposed sites, suggested that the nutcrackers preferred such open patches for caching. Age structure of the seedlings (&lt;20 yr old) showed a clumped age distribution. Most of the younger pine seedlings (&lt;10 yr old) grew as clusters, averaging four to five in number per cluster. Past cone production, estimated using a cone scar technique, varied annually, with some remarkable poor-crop years during the recent 12 yr. However, extensive recruitment of the pine seedlings did not necessarily follow a mast year. Fluctuation of the seedling recruitment was closely related to annual changes in early summer precipitation rather than air-temperature, indicating positive effect of water supply on seed germination. Our findings suggested that regeneration success of P. pumila was limited for two reasons: (1) spatially due to site preference of nutcrackers for seed caching, i.e., open patches at windy sites near the seed source of mature pine scrubs; and (2) temporally by annual fluctuation in climatic factors, especially soil moisture availability. Consequently, nutcrackers do not seem to help the pines expand more widely in the Japanese subalpine region.

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Language：Japanese   Publisher：The Japanese Society of Snow and Ice  

This study shows the use of subalpine meadow soil stratigraphy to establish the time of disappearance of past snow patches. Growth periods of plants are too short in places where the snow disappears late in the season, such as at the centers of snow patches. Therefore, plant growth and the subsequent increase of organic content in the soil will indicate the disappearance of snow patches in early summer. Key tephras indicated that a series of buried peat layers on Mt. Zarumori in northeastern Japan accumulated after ca. 1200 yBP, and were buried after 915 AD, showing that the organic content in the surface soil increased ca. 1000yBP. The increase in carbon content probably indicates an increase in litter and stable surface condition. This was likely due to an early snow disappearance and longer snow-free period during the Medieval Warm Period. Snow disappearance before mid July is needed for the formation of buried peat, thus the buried peat layers on Mt. Zarumori probably indicate that the size of summer snow patch in 1000 yBP was smaller than those of recent snow patches.

DOI： 10.5331/seppyo.59.101

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Language：Japanese   Publisher：Japanese Forestry Society  

To clarify the influences of snow depth on the development of basal bending, the growth of tree heights and the breaking process of snow damage to understory trees in a two-storied type and three strip-cut types (strip widths of 10, 15, and 20 m) sugi (Cryptomeria japonica D. DON) stands cut in 1974 in a heavy snow-fall area, a monitoring investigation was made. The mean value of snow depth in a 20 m wide stand was the largest, followed by the two-stried stand, the 15 m wide stand, and the 10 m wide stand. It was confirmed that the stage of development of basal bending kept up with the growth of tree heights. It also was confirmed that basal bending and the growth of tree heights were much influenced by the annual changes of snow depth. The mean values of tree heights and basal bendings were large in the order of the 20 m wide stand, the 15 m wide stand, the 10 m wide stand, and the two-storied stand. The snow damage by the basal splitting of tree trunks occurred to several individuals in the 20 m wide stand, and it became clear that the annual rate of increase for basal bending of such individuals was well above the average rate of the stand. It became clear that partially heavy snow covered areas were formed by extreme snow drifting in the strip cut stand, and that this was the cause of the outbreak of snow damage.

DOI： 10.11519/jjfs1953.78.1_61

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Language：Japanese   Publisher：一般社団法人日本森林学会  

To clarify the influences of snow depth on the development of basal bending, the growth of tree heights and the breaking process of snow damage to understory trees in a two-storied type and three strip-cut types (strip widths of 10, 15, and 20m) sugi (Cryptomeria japonica D.DON) stands cut in 1974 in a heavy snow-fall area, a monitoring investigation was made. The mean value of snow depth in a 20m wide stand was the largest, followed by the two-stried stand, the 15m wide stand, and the 10m wide stand. It was confirmed that the stage of development of basal bending kept up with the growth of tree heights. It also was confirmed that basal bending and the growth of tree heights were much influenced by the annual changes of snow depth. The mean values of tree heights and basal bendings were large in the order of the 20m wide stand, the 15m wide stand, the 10m wide stand, and the two-storied stand. The snow damage by the basal splitting of tree trunks occurred to several individuals in the 20m wide stand, and it became clear that the annual rate of increase for basal bending of such individuals was well above the average rate of the stand. It became clear that partially heavy snow covered areas were formed by extreme snow drifting in the strip cut stand, and that this was the cause of the outbreak of snow damage.

DOI： 10.11519/jjfs1953.78.1_61

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Language：Japanese   Publisher：森林立地学会  

This study discussed the relationship between snow dynamics and ecological characteristics of trees on the snowy slope of Mt. Yakeishi, central the Oou mountain range, north east Honsyu, Japan. Most of dwarf-type formed deciduous broad leaved trees dominated on the lee ward slope against the winter seasonal wind. The snow folds and snow cracks caused by glide of snow cover extended over a wide area of the lee ward slope and also the debris of full-depth snow avalanches were observed at places. And the scars caused by the snow erosion distributed in the slope. On the other hand, numbers of pit and mound formations caused by uprooting of middle or large size stands were observed on the wind ward slope and the longitudinal shape of the slope showed uneven feature like a staircase. While the dominant tree species on the lee ward slope were Alnus pendula, Weigela hortensis, Fugus crenata and others, those on the wind ward slope were Fugus crenata, Hamamelis japonica var. obutusata, Acer japonicum and others. The stands on the lee ward slope were extremly small in the size and showed the groundlinglike form which had extraordinary large basal bending width in contrast to those on the wind ward slope. The basal bending width varied with each tree species and that of higher ranking dominant tree species was larger on the lee ward slope and smaller on the wind ward slope. It seems advantegeous to the tree species to adapt for the creep and glide pressure of snow on the lee ward slope and to adapt for the settlement force of snow on the wind ward slope for the survival of individuals. Fagus crenata dominated on the both slopes seems to be the species of high snow tolelance capacity adapted to the snow environment which excelled in the settlement force rather than the creep and glide pressur of snow cover. The regeneration style of the stand growing on the snowy slope depend chiefly upon sproutings on the lee ward slope while seedlings on the wind ward slope. The ecological characteristics of trees above mentioned are the reflex of the difference of snow environment, and not only the depth of snow but also the qualitative aspect of snow such as the variety of metamorphic process and the snow dynamics such as glide and avalanches play an important role in the snow environmental factor which affect the distribution of community.

DOI： 10.18922/jjfe.37.2_59

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Language：Japanese   Publisher：日本生態学会  

P. pumila grows in alpine regions from central Japan to E Siberia and generally forms dwarf scrub. The ecological features of P. pumila were reviewed, focusing especially on its dry matter production and process of regeneration. Based on the annual above-ground net production and gross production of the pine forest, the carbon allocation pattern and efficiency of energy fixation were discussed. The reproduction style of P. pumila is characterized by two different phases: seedling establishment as a result of seed dispersal by nutcrackers, and regeneration by layering in the mature trees. -from English summary

DOI： 10.18960/seitai.45.1_57

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL SCIENCE  

Aboveground net production rates of the subalpine stone pine (Pinus pumila) forests in central Japan were estimated by the summation method; net production was defined as the sum of annual biomass increment and annual loss due to death. In the two pine stands of different scrub heights, P1 (200 cm) and P2 (140 cm), aboveground biomass reached 177 and 126 ton ha-1, respectively. Leaf biomass was about 14 ton ha-1 in each stand. The estimates of aboveground net production during the 2 year period (1987-1989) averaged 4.1 and 3.7 ton ha-1 y-1 in P1 and P2, respectively, which were at the lowest among the pine forests in the world. Two indices of efficiency of energy fixation, that is, the ratio of net production to the total radiation during a growing season and the ratio of net production to total radiation per unit of leaf weight, were evaluated. Both efficiency indices for the two P. pumila stands fell in the range obtained for other Japanese evergreen conifer forests. This suggested that the low annual net production of the stone pine stands were mainly due to a limitation in the length of the growing season. The pine forests were also characterized by a small allocation (about 17%) of aboveground net production into biomass increment, in comparison with other evergreen conifer forest types. Annual net carbon gain in the P. pumila forests was suggested to be largely invested in leaf production at the expense of the growth of woody parts.

DOI： 10.1007/BF02347495

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：HERON PUBLISHING  

Seasonal shoot dynamics of Japanese mountain stone pine (Pinus pumila Regel.) growing at six sites with different altitudes and slope aspects on the Kiso mountain range in central Japan were investigated. The shoots followed a similar growth pattern at all sites; current shoots elongated rapidly during June and July, and the current needles grew during July and August. Final lengths of the current shoots and needles decreased with increasing altitude. Current-shoot lengths were also shorter at the windward sites than at the leeward sites. At all sites, leaf senescence occurred intensively between mid-August and mid-September. Needle longevity, i.e., the age of the oldest living needle attached to a shoot, increased with increasing altitude. Fascicle density, i.e., the number of current needle fascicles on a unit shoot length, was greater at higher altitudes and windward sites than at lower altitudes and leeward sites.
Seasonal dynamics of the P. pumila shoots were characterized by simultaneous replacement of old needles with new needles in the early autumn, thus avoiding any loss of canopy photosynthetic production during the growing season. Increases in needle longevity and fascicle density were associated with declining air temperature and increasing wind exposure. Needle longevity and fascicle density were characteristics of adaptive plasticity in P. pumila that prevent a reduction in growth potential in the stressful conditions of alpine regions.

DOI： 10.1093/treephys/13.1.41

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL SCIENCE  

Size, biomass and spatial distribution patterns of belowground woody organs of Pinus pumila trees were investigated. Dry weight estimates of five sample trees were between 14 and 36 kg tree-1. Belowground stems accounted for about 3 2 % of the total tree weight. However, the belowground stems had extensive barkless portions, indicating that the decomposition of dead belowground stems was an important source of organic matter in the soil. The basal diameters of adventitious roots tended to become smaller as their orginating positions neared the ground surface. It was suggested that P. pumila trees regenerate by successively producing adventitious roots from their buried stems and moving down the slope.

DOI： 10.1007/BF02347100

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer-Verlag  

Rates of net photosynthesis and dark respiration were measured for detached needles of Pinus pumila trees growing on the Kiso mountain range in central Japan in 1987. Dependency of photosynthesis on light and temperature was examined in relation to needle age and season. The light saturation point of net photosynthesis was lower in 3- and 4-yr-old needles than that in current (flushed in 1987), 1- and 2-yr-old needles. Pnmax, net photosynthetic rates at 1000 μmol m-2 s-1 and 15°C, of needles from 1- to 4-yr-old generally decreased with needle age. Pnmax of 1- to 4-yr-old needles became higher in August than in other months, and Pnmax of current needles did so in September. Current needles showed high respiration rates (at 15°C) only in August. Optimum air temperatures for net photosynthesis at 1000 μmol m-2 s-1 were between 10 and 15°C for current and 1-yr-old needles. The temperature coefficient of dark respiration rates was 2.3-3.3 for current needles from August to October, and 2.2 for 1-yr-old needles in mid-July. © 1990 the Ecological Society of Japan.

DOI： 10.1007/BF02347008

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer-Verlag  

Aboveground biomass and litterfall of Pinus pumila scrubs, growing on the Kiso mountain range in central Japan, were investigated from 1984 to 1985. The biomass of two research plots (P1 and P2) with different scrub heights was estimated by two methods, the stratified clip technique and the allometric method. Aboveground total biomass estimated by the latter method reached 181 ton d.w. ha-1 in P1 and 132 ton d.w. ha-1 in P2. Creeping stems contributed to about half of the total biomass. Although estimates of woody organs differed between the two plots, leaf biomass estimates were almost the same at 15.5 ton d.w. ha-1. The canopies of the two P. pumila scrubs were characterized by a large mean leaf area density of 5.0 m2 m-3. Despite this large area density, relatively moderate attenuation of light intensity was observed. Specific leaf area generally increased with reduced leaf height. Annual total litterfall was estimated to be 3.60 ton d.w. ha-1 yr-1 in P1 and 2.39 ton d.w. ha-1 yr-1 in P2. Annual leaf fall in both plots was approximately 2.0 ton d.w. ha-1 yr-1. Leaves fell mainly in early autumn. Annual loss rates of branches, estimated as the sum of annual branch litterfall and the amount of newly formed attached dead branches, were 0.29 ton d.w. ha-1 yr-1 in P1 and 0.37 ton d.w. ha-1 yr-1 in P2. © 1989 Ecological Society of Japan.

DOI： 10.1007/BF02346943

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Language：Japanese   Publisher：大日本山林会  

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DOI： 10.4005/jjfs.98.135

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

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DOI： 10.11519/jfsc.127.0_497

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DOI： 10.11519/jfsc.127.0_498

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Containerized tree seedlings are expected to exhibit high survivorship and good growth after outplanting; however, a unified consensus on the performance of containerized seedlings in Japan remains undetermined. To understand the universal properties of the performances of containerized seedlings after outplanting, the survival ratio and height and diameter growth rate of two stock types (containerized seedlings and bare-root seedlings) were estimated from 39 experiment sites covering five prefectures and five species and compared between stock types. The result of parameter estimation using hierarchal Bayesian models revealed that the median survival ratio of containerized seedlings across all species was 0. 96, which was not different from that of bare-root seedlings (0. 97). The estimated height and diameter growth rates were also similar between stock types. The sturdiness quotient (SQ, the ratio of height and diameter) was higher in containerized seedlings than in bare-root seedlings of all species immediately after outplanting. However, the difference in SQ between stock types diminished 1 year after outplanting. These results suggest that containerized tree seedlings generally show performances equivalent to those of bare-root seedlings after outplanting. Therefore, other properties of containerized seedlings, such as ease of cultivation and low-labor planting present more attractive advantages than those of good performance after outplanting.

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Language：Japanese   Publisher：日本治山治水協会  

DOI： 10.20820/suirikagaku.58.5_104

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

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DOI： 10.11519/jfsc.125.0_396

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DOI： 10.11519/jfsc.125.0_87

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Language：Japanese   Publisher：一般社団法人日本土壌肥料学会  

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DOI： 10.11519/jfsc.123.0.Pa111.0

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Other Link： http://id.nii.ac.jp/1141/00110477/

Language：Japanese   Publisher：Faculty of Science, Tohoku University  

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