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To identify the soil carbon stock changes from croplands/grasslands to forestlands in Japan, we compared the soil carbon stock of a cropland/grassland with that of an adjacent forestland at 22 different sites. With respect to a 0–30-cm depth basis, the soil carbon stock in the cropland/grassland was the same as that in the forestland; however, it was less than that in the forestland when an equivalent mass approach was used. The ratio of the soil carbon stock in the forestland to that in the cropland/grassland was 1.11 on average, which is comparable with previous mass-corrected paired sampling studies. The ratio was affected by two factors: tree age and current vegetation. Mean annual temperature, mean annual precipitation, phosphate absorption coefficient, litter quantity, and former land use did not affect the ratio. According to a comparison with the results of a paired study for deforestation, the application of the reciprocal of the soil carbon stock ratio of deforestation to the ratio of afforestation was slightly overestimated. Further studies are necessary to establish a general conclusion. Some previous studies, including those involving non-mass-corrected data, are possibly biased, and more studies using the paired sampling method with equivalent mass basis must be conducted to provide the general factor for soil carbon stock change in the future.

Few long-term fertilization experiments have been performed in forests, even though the effects of nitrogen (N) addition on soil microbial biomass are a cause for concern. Our objective was to examine the effects of repeated fertilization for 36 years on soil microbial biomass in two forest stands. We measured soil chemical properties and microbial biomass carbon (C) and N in soils in fertilized and non-fertilized plots in a birch stand (Betula maximowicziana Regel) and a fir stand (Abies sachalinensis Fr. Schmidt). We also performed lime amendments and a 21-day laboratory incubation, and measured microbial biomass to clarify the effects of acidification due to fertilization. Soil pH was significantly lower in fertilized plots in both stands, and soil microbial biomass C and N were lower (significantly so in the fir stand) in the fertilized plots after 36 years of repeated fertilization. In the laboratory incubation, lime amendment did not significantly affect the microbial biomass C, N, or C:N ratio, despite an increase of about 1 unit in soil pH. Our results therefore indicate that factors other than soil pH also have important effects on soil microbial biomass in repeatedly fertilized forest stands.

Stress fractures are a limitation for athletes not only in sports performance but in activities of daily living. Thus, preventing them is crucial. In female athletes, a triad of symptoms including low energy availability, functional hypothalamic amenorrhea and osteoporosis are considered risk factors for stress injuries, but biomarkers predictive of these outcomes are not available. Here, we evaluated 56 female university athletes and found that 13 had a history of stress bone injuries. Logistic regression analysis demonstrated that dysmenorrhea including amenorrhea, but not reduced food intake or body weight loss, was significantly associated with stress injuries. When we subdivided subjects into stress fracture and non-fracture groups, we found that serum levels of creatine kinase (CK) and lactic acid dehydrogenase (LDH) were significantly higher in the fracture group, while osteocalcin and uncarboxylated osteocalcin (ucOC), which are bone forming parameters, significantly decreased. Low vitamin D levels are associated with stress fractures, but serum vitamin D levels were higher in fracture compared to non-fracture subjects. We followed up 32 subjects for one year, and three exhibited new stress injuries during that period. A history of stress fracture history is significantly associated with experiencing a new stress fracture. We also found that subjects with new fracture performed significantly greater exercise activity than did non-fracture subjects. Taken together, our data indicate that increased serum CK and LDH and decreased serum osteocalcin and ucOC are biomarkers of stress injuries, and evaluating these markers along with dysmenorrhea, stress fracture history or high sports activity could predict future stress fractures in female athletes.

Weed control, which is commonly achieved by herbicides, is important in successfully establishing short-rotation coppice (SRC) of willow. In this study, we examined agricultural mulch film as a means of effective weed control and the influence of cutback practice (coppicing the first year&rsquo, s shoot growth in the winter following planting) on biomass production in boreal Hokkaido, Japan. One-year-old cuttings from two clones each of Salix pet-susu and S. sachalinensis were planted in double-rows at a density of 20,000 plants ha&minus, 1. All plants were harvested three growing seasons after cutback. Average oven-dried biomass yield was 5.67 t ha&minus, 1 yr&minus, 1 with mulching, whereas it was 0.46 t ha&minus, 1 in the unmulched control with a weed biomass of 4.13 t ha&minus, 1, indicating that mulching was an effective weed control. However, weeds grew vigorously on the ground between mulch sheets and their dry biomass amounted to 0.87 t ha&minus, 1. Further weeding between the mulch sheets enhanced the willow biomass yield to 10.70 t ha&minus, 1 in the treatment with cutback. In contrast, cutback even reduced the willow yield when there were weeds between the mulch sheets. This negative effect of cutback on the willow yield resulted from nutrient competition with weeds, there was similar leaf nitrogen content and dry biomass per unit land area for the weeds and willows combined in the control and mulching treatments. These results suggest that growing SRC willow is feasible in boreal Hokkaido if combined with complete weed control and cutback, and is facilitated by using mulch film.

Japanese forests were exposed to multiple sources of radioactive contamination. To acquire scientific guidance on forest management planning, it is crucial to understand the long-term radiocesium (

Although harvester–forwarder systems have high work productivity and are safe for the operators, they can cause environmentally detrimental soil compaction and rutting that potentially reduces futu...

Although forestry plantations dominate landscapes in many parts of the world, effects of plantation forestry on various ecosystem services (ESs) remain unknown. Here, we modeled 10 forest ESs as functions of forest type (natural forest vs. plantation), stand age, and environmental covariates to systematically evaluate ESs of plantation landscapes in central Japan. Our models showed that although three ESs including biodiversity conservation and amenity service are greatly reduced by replacing natural forests with plantations, other ESs show small changes or even increase when stand age is accounted for. Five ESs increase and four decrease with stand age in both forest types. Model application to the study area in the past 60 years suggested that many ESs were greatly reduced when or immediately after vast plantations were established. Two ESs (biodiversity conservation and amenity service) have not sufficiently recovered despite forests’ reaching maturity. ESs dependent on early-successional stage showed precipitous recent declines. Scenario analysis suggests that increasing timber production while avoiding harvesting steep slopes would not increase landslide susceptibility. Furthermore, restoration of natural forests in flat areas near roads would greatly improve biodiversity conservation and amenity services. Landscape management will determine whether plantations deliver net benefits to current and future generations.

Two morphological variants of Terminalia alata (Combretaceae) differed in leaf flushing phenology and spatial distribution in a Cambodian deciduous forest. The hairy-type trees displayed leaf exchange behavior in the middle of the dry season. The glabrous type flushed new leaves 3 months after the wet season started. The leafless period of the hairy type was estimated to be

In order to investigate how the depth to which a cutting is inserted into the ground influences biomass of short-rotation coppice willows, 1-year-old cuttings from three clones each of Salix pet-susu and Salix sachalinensis were planted and harvested after two-seasons growth under natural conditions. All cuttings were 20 cm long, with either 18 or 10 cm below ground level (referred to as deep planting [DP] and shallow planting [SP], respectively, hereafter). Aboveground dry biomass from DP was 40% greater than from SP, although root biomass did not differ between the two treatments and shoot number per cutting was lower for DP than SP. The roots of the DP cutting were found deeper in the soil than those of SP cutting, suggesting that sustained soil water supply resulted in the higher aboveground biomass.

Japanese forests were exposed to multiple sources of radioactive contamination. To acquire scientific guidance on forest management planning, it is crucial to understand the long-term radiocesium (137Cs) distribution (and redistribution) over time. To obtain robust evidence of the residual global fallout of 137Cs (137Cs-GFO) after a few decades, we determined 137Cs-GFO inventory in forest soil at 1171 soil pits of 316 plots evenly spaced across Japan from 2006 to 2011, shortly before the Fukushima Dai-ichi Nuclear Power Plant accident. The activity concentration measurements were performed using a NaI well-type scintillation counter. The average (±SD) 137Cs-GFO in forest soil (0–30 cm from the surface) of the National Forest Soil Carbon Inventory (NFSCI) sampling plots uniformly extracted from the entire country was estimated to be 2.27 ± 1.73 kBq m−2 (n = 316) as of Oct. 1, 2008. A high nationwide spatial variation was found in 137Cs-GFO, where relatively high 137Cs-GFO was found along the Sea of Japan compared with the total annual precipitation. We also obtained a reconstructed decay-corrected cumulative 137Cs-GFO dataset from the fallout observatories as the initial 137Cs-GFO. The cumulative 137Cs-GFO of fallout observatories averaged 2.47 ± 0.95 kBq m−2 (n = 39) as of Oct. 1, 2008 and displayed spatial variation similar to that in forest soil. To identify whether 137Cs-GFO remains in forest soil across Japan, we examined a general linear mixed-effect model comparing 137Cs-GFO between forest soil and the observatory under normalized annual precipitation and region. The model did not indicate a significant difference, but relatively lesser 137Cs-GFO was found in forest soil, where the least-squares mean of 137Cs-GFO in forest soils was 79.1% of that of the observatory. The variation in 137Cs-GFO in forest soils within NFSCI sampling plots was 1.4 times greater than that among plots. The high spatial variation in 137Cs-GFO within a 0.1-ha plot strongly suggested the redistribution of 137Cs-GFO within the forest catchment. The vertical distribution pattern of 137Cs-GFO across three depth layers indicated that the 137Cs-GFO redistributions were likely attributed to the movements of sediments and mass. Moreover, when extracting soil pits assumed to have the least soil disturbance from the vertical distribution pattern, no significant difference in 137Cs-GFO was observed between forest soil and observatory data. These findings provide important insights into the stability of 137Cs-GFO in the forest ecosystem. Considering the potential hotspot where 137Cs-GFO can accumulate deeper in the soil (>30 cm in depth), most 137Cs-GFO has remained in the forest for decades. Our study offers microscale heterogeneous 137Cs-GFO distribution in forests for ensuring long-term forest management planning necessary for both the long-term migration and local accumulation of 137Cs in forests.

The water balance of tropical dry deciduous forests is less well understood than some other forest ecosystems. To help close this knowledge gap, we separately measured the evapotranspiration from the whole ecosystem (ETW), transpiration (TR) and interception loss (IL) from overstory trees, and evapotranspiration from the understory vegetation (ETU) in a tropical dry deciduous forest in Cambodia. It was found that ETW was equivalent to 73.7% of rainfall (P) at the annual scale. In the dry season, ETW corresponded to 120.1% of P, which indicates the utilization of soil water replenished during the wet season. The sum of transpiration estimated by the thermal dissipation (TD) method with the original coefficient (TRG), IL, and ETU was smaller than ETW, except for the middle of the dry season, due to an underestimation of TRG. Although recently reported calibration coefficients can reasonably correct TRG, future calibrations of the TD method are highly recommended for the precise evaluation of single-tree-scale transpiration in tropical dry forests. The annual contribution of the understory vegetation to ETW (ETU/ETW) was 34.6%, leading to the conclusion that the understory vegetation cannot be ignored when trying to gain a comprehensive understanding of the hydrologic cycle in tropical dry forests. The seasonal variations in ETU/ETW were mainly controlled by the leaf area index (LAI) of overstory trees, resulting from the overall stability of ETW and decreasing trend of ETU with increasing LAI in the wet season, with the opposite holding true in the dry season, i.e., decreasing ETW with the decline of LAI and less variations of ETU. Thus, LAI influenced both the seasonality and the annual contribution in ETU/ETW, exerting a notable influence on hydrological cycling in this forest.

We developed an empirical model to estimate aboveground carbon density with variables derived from airborne Light Detection and Ranging (LiDAR) in tropical seasonal forests in Cambodia, and assessed the effects of LiDAR pulse density on the accurate estimation of aboveground carbon density. First, we tested the applicability of variables used for estimating aboveground carbon density with the original LiDAR pulse density data (26 pulse m−2). Aboveground carbon density was regressed against variables derived from airborne LiDAR. Three individual height variable models were developed along with a canopy density model, and three other models combined canopy height and canopy density variables. The influence of forest type on model accuracy was also assessed. Next, the relationship between pulse density and estimation accuracy was investigated using the best regression model. The accuracy of the models were compared based on seven LiDAR point densities consisting of 0.25, 1, 2, 3, 4, 5 and 10 pulse m−2. The best model was obtained using the single mean canopy height (MCH) model (R 2 = 0.92) with the original pulse density data. The relationship between MCH and aboveground carbon density was found to be consistent under different forest types. The differences between predicted and measured residual mean of squares of deviations were less than 1.5 Mg C ha−1 between each pulse density. We concluded that aboveground carbon density can be estimated using MCH derived from airborne LiDAR in tropical seasonal forests in Cambodia even with a low pulse density of 0.25 pulse m−2 without stratifying the study area based on forest type.

In the context of their role in global climate change, changes in soil carbon stocks resulting from land use conversions from forest to agricultural lands (cropland and grassland) and subsequent agricultural activities were investigated with data from a total of 46 soil sampling sites across Japan (28 cropland and 18 grassland sites). Collection of soil sample pairs from forest land and adjacent agricultural land converted from forest land allowed derivation of the soil carbon change factor (SCCF; ratio of soil carbon stock in the agricultural land to that in the forest land at the time of soil sampling). Depth-based SCCFs for a fixed depth of 0–30 cm were 23% greater than mass-based SCCFs determined by the equivalent soil mass approach, in which soil carbon stocks in all replicated samples from forest land and agricultural land were calculated for different depths but equal masses of the soil mineral fraction. The overestimation of SCCFs by the depth-based approach was more pronounced in Andosols, particularly in croplands on Andosols, because soil bulk densities in forest lands were much lower than those in croplands on Andosols. The mass-based SCCFs for croplands (upland fields and orchards) and grasslands (pasture land and grazing land) after deforestation were 0.741 ± 0.259 (a 25.9 ± 25.9% decrease in soil carbon stocks after an elapsed time of 2–85 years) and 0.858 ± 0.212 (a 14.2 ± 21.2% decrease after an elapsed time of 26–81 years), respectively. Therefore, conversions from forest land to cropland or grassland resulted in a significant carbon loss from most soils in Japan. Soil carbon stocks in cropland converted from forest land declined as the elapsed time after deforestation increased although the uncertainty was large. Of the environmental variables, soil type (Andosols versus non-Andosols) and tillage frequency during cultivation had little impact on mass-based SCCFs; however, the SCCFs decreased with higher mean annual air temperature at the sites.

AIM To develop a Japanese version of the short-form FAMCARE Scale (Ornstein, 2015) for family caregivers of terminal cancer patients at home. METHODS The survey was conducted with 316 family caregivers of terminal cancer patients at home selected as eligible participants in 11 major regions in Japan (the Tokyo metropolitan area, and the prefectures of Tochigi, Ibaraki, Saitama, Chiba, Kanagawa, Nara, Hyogo, Kagawa, Ehime, and Saga). Construct validity was confirmed using a confirmatory factor analysis, and the Caregiver Quality of Life Index-Cancer (CQOLC) scale was administered to assess criterion-related validity. RESULTS A total of 120 family caregivers provided valid responses. The mean±standard deviation of the age of the family caregivers was 64.6±12.0 years, and 91 (75.8%) were female. A factor analysis of the results showed that the Japanese version of the 10-item and 5-item short-form FAMCARE Scale was a unidimensional construct, and a confirmatory factor analysis demonstrated a goodness of fit index of 0.910 and 0.972, an adjusted goodness of fit index of 0.835 and 0.916, a comparative fit index of 0.968 and 0.992, and a root mean square error of approximation of 0.095 and 0.081, respectively. The Cronbach's α coefficients of the 10- and 5-item scales were 0.95 and 0.93, respectively. The scale scores were significantly correlated with the family caregiver's quality of life (CQOLC) (10-item r=0.304, P

We investigated the capabilities of a canopy height model (CHM) derived from aerial photographs using the Structure from Motion (SfM) approach to estimate aboveground biomass (AGB) in a tropical forest. Aerial photographs and airborne Light Detection and Ranging (LiDAR) data were simultaneously acquired under leaf-on canopy conditions. A 3D point cloud was generated from aerial photographs using the SfM approach and converted to a digital surface model (DSMP). We also created a DSM from airborne LiDAR data (DSML). From each of DSMP and DSML, we constructed digital terrain models (DTM), which are DTMP and DTML, respectively. We created four CHMs, which were calculated from (1) DSMP and DTMP (CHMPP), (2) DSMP and DTML (CHMPL), (3) DSML and DTMP (CHMLP), and (4) DSML and DTML (CHMLL). Then, we estimated AGB using these CHMs. The model using CHMLL yielded the highest accuracy in four CHMs (R2 = 0.94) and was comparable to the model using CHMPL (R2 = 0.93). The model using CHMPP yielded the lowest accuracy (R2 = 0.79). In conclusion, AGB can be estimated from CHM derived from aerial photographs using the SfM approach in the tropics. However, to accurately estimate AGB, we need a more accurate DTM than the DTM derived from aerial photographs using the SfM approach.

We measured the sap flux densities of 12 deciduous trees in a tropical dry deciduous forest with high seasonality of available water located in Cambodia and evaluated the seasonal trends in transpiration and leaf phenology. For all trees, the minimum transpiration was recorded in the middle of the dry season, and almost all trees restarted transpiration before the first monsoon rain. The occurrence of the ‘paradox’ of leaf phenology was confirmed. During the dry season, transpiration was controlled by leaf phenology and decreased with an increase in the duration of the leafless period. In contrast, during the wet season, daily changes in transpiration were determined by changes in evaporative demand. Transpiration during the dry season accounted for more than 30% of the annual total among trees, and at the stand scale, the dry season contribution was 38%. The dry season transpiration was not negligible for the water balance in this ecosystem. The soil water condition in the shallow layer, where the main root system is located, was not the source of transpiration during the dry season. This implied that the root probably extended to a deep layer and absorbed water. The relationships between the mean canopy stomatal conductance and vapour pressure deficit revealed that most trees were isohydric. Isohydric behaviour controlling stomatal openness to avoid xylem hydraulic failure was also confirmed at the stand scale and was advantageous for these trees, allowing them to continue transpiring under the high evaporative demand during the dry season. Copyright © 2015 John Wiley & Sons, Ltd.

Ground-layer vegetation in abandoned woodlands of the Northern Hemisphere is rapidly declining because of overshading and an overabundance of ungulate herbivores; these changes may be affecting belowground ecosystems. An effective countermeasure is to restore ground-layer vegetation by establishing deer exclosures immediately after creating canopy gaps. However, such measures disturb belowground processes (e.g., decelerate decomposition rates and decrease soil water content) and may cause further disintegration of the whole system. To estimate the combined effects of gap creation and exclosure installation, we established a 2 × 2-factorial experiment (including gap creation, exclosure installation, both methods, and a control) in warm-temperate secondary woodlands. After five years, we studied ground vegetation, litter cover, soil–water physics, abundance of litter-dwelling invertebrates, and litter decomposition in each experimental plot. A significant increase in ground vegetation was found in gap-and-exclosure plots and gap-and-deer plots, although the increase in the latter was limited to approximately half of that in the former; in contrast, no significant increase was found in the control or canopy-and-exclosure plots. The abundance of litter-dwelling invertebrates was significantly reduced by gap creation, although this effect was offset by installation of exclosures in gaps. Fine porosity and water holding capacity of topsoil were reduced by gap creation, but these negative effects were mitigated by exclosures installed in gaps. Meanwhile, coarse porosity and water permeability of topsoil were not affected by gap creation; they tended to be increased by exclosure installation both in gaps and under the canopy. Litter decomposition tended to be delayed in the gap-and-deer plot, although this effect was temporary; exclosure installation slightly increased decomposition rates, but this effect was limited. These results show the possibility of restoring belowground dynamics in abandoned forests by creating small canopy gaps and establishing ungulate exclosures. This mixture of interventions should increase habitat heterogeneity in these forests and help prevent biological homogenization while mitigating long-term negative effects of gap creation on belowground ecosystems.

Litter plays key roles in forest ecosystems, and forest degradation is likely to spur a further decline in leaf litterfall inputs to forest soils. However, the effects on physicochemical surface-soil properties remain largely unknown, especially in seasonal tropical forest ecosystems. We initiated a litterremoval manipulation experiment in a Cambodian lowland evergreen forest undergoing intensive selective logging. Litter removal performed for 2 and 4.4 years respectively triggered an increase in bulk density and decrease in surface-soil carbon (C) and nitrogen (N) contents to 67 and 73% of the original levels, respectively. After only 2 years of treatment, bulk density rose to very high value (>1.40 Mg m) likely preventing further soil compaction, while the C and N reduction effects lasted over 2 years. Greater soil compaction occurs in stands with a smaller initial bulk density. However, C (N)-rich soils did not necessarily lose a greater relative proportion of C (N) than C (N)-poor soils. Although N remained above C following the litter removal, conservative trends in the C:N ratio suggested a limited capacity for N retention. Together, our data suggest that shifts in leaf litter inputs in response to localized human disturbances may have rapid and lasting consequences on physicochemical surface-soil properties; possibly accelerated by a tropical climate. Moreover, a speedy recovery to an adequate litter supply, at least before reaching the upper soil compaction limit, is essential to conserve forest ecosystems. Discipline: Soils, fertilizers and plant nutrition Additional key words: bulk density, carbon, forest degradation, nitrogen, soil compaction

Although information about the hydrologic and ecological features of lowland evergreen forests in central Cambodia has been collected since the beginning of the 21st century, measurements of the transpiration process remain very limited. This paper describes the differences detected in transpiration (q) and crown-level stomatal conductance (GS) between Calophyllum inophyllum (which undergoes successive leaf exchange) and Drypetes sp. (which performs irregular leaf exchange) (hereafter referred to as Calophyllum and Drypetes, respectively), and the analysis of these differences in consideration of their contrasting leaf phenologies. We evaluated q using sap f low measurements and obtained daily GS values. Calophyllum and Drypetes had high and low periods between which q and GS differed significantly. Within high/low periods, smaller scatter in the plot of GS versus vapour pressure deficit (D) was found in Calophyllum compared to Drypetes. For a given value of D, q in high periods was 1.3 and 1.9 times larger than in low periods for Calophyllum and Drypetes, respectively. The smaller scatter for Calophyllum was the result of relatively constant physiological activity that was maintained by successive leaf fall. For both species, high periods were recorded after remarkable leaf-fall events; thus, our current data implied that leaf phenology is one of the most important factors affecting transpiration. Discipline: Forestry and forest products Additional key words: leaf phenology, riparian zone, sap flux density, transpiration, vapour pressure deficit

Tipping-bucket flow meter and rain gauge (TBFM/TBRG) are widely used for the measurement of gross rainfall (GR), throughfall (TF), and stemflow (SF) to evaluate the amount of interception loss (I). However, TBFM/TBRG cannot measure the inflow rate during tipping and underestimates the inflow rate. To correct this systematic bias, 33 total calibrations were conducted for five types of TBFM/TBRG in the laboratory. The tipping time increased with the bucket volume, and the underestimation during one tip was higher for TBFM/TBRG of larger capacity. With the use of the scaled actual inflow rate and the actual volume of a single tip from the measured static volume of a single tip when the inflow rate is zero, the common calibration curves were obtained as quadratic equations for each of the five types within an error range of ±3%. We measured GR and TF by using TBRG and TBFM with a resolution of 0.2 mm and measured SF by TBRG with a single-tip static volume of 15.7 cm3 in a Japanese temperate coniferous forest (TCF) and a Cambodian tropical deciduous forest (TDF). At both sites, the calibration curves needed to be applied to obtain GR, TF, and SF on an event scale with an underestimation degree of less than 3%. Without applying any calibrations, the higher rainfall intensities in TDF caused larger underestimations of GR, TF, and SF and larger overestimations of I compared with results for TCF. On an annual scale, the degree of overestimation of I relative to GR (ΔI/GR) was 1.2% in TCF and 3.5% in TDF, and ΔI/I was at least 10% at both sites. Copyright © 2012 John Wiley & Sons, Ltd.

As a feasibility study for applying a simplified method to estimate CO2 emissions from deforestation and forest degradation in tropical forests, we estimated the nationwide forest tree biomass carbon stock using data from 100 permanent sampling plots (PSPs) set by the Forestry Administration, Cambodia in seasonal forests in Cambodia. Averaged tree carbon stocks and SE-Standard error were at 158.8 ± 7.3 Mg C ha-1 for evergreen and semi-evergreen forests and 55.2 ± 6.9 Mg C ha-1 for deciduous forests in 1998 (the first census) and for the second census in 2000-2001, 163.8 ± 7.8 Mg C ha-1 and 56.2 ± 6.7 Mg C ha-1, respectively. The averaged tree biomass carbon stock differed significantly between the two forest types. Using the forest cover for 2006 and the averaged carbon stock for 2000-2001, the national-level forest tree carbon stock in the early to mid-2000s was estimated at 824.2 ± 39.2 Tg C for evergreen forests and 263.9 ± 31.3 Tg C for deciduous forests, and 1,088.1 ± 50.2 Tg C in total. By repeating this calculation for all forest areas by remote sensing and averaged tree carbon stock via ground-based measurement with PSPs, we could monitor the total tree carbon stock in nationwide forests in Cambodia. We also presented the possible reasons for uncertainty related to the present tree biomass carbon stock of forests and recommendations in order to improve the accuracy of the carbon stock using PSP systems in Cambodia.

Forest soils in the basalt region of Southeast Asia are important natural resources, due to their high agricultural potential and high capacity for carbon sequestration. To characterize the physicochemical properties and the components of the soil organic carbon of forest soils in the basalt region, five evergreen sites (E1–5) and one deciduous forest site (D1) were selected in Cambodia at elevations ranging from 132 to 908 m. The components of the soil organic carbon of each site were separated using a density fractionation approach, i.e. high(≥ 1.6 g cm−3) and low( 600 m), were strongly weathered and characterized by a lower pH, a lower level of exchangeable bases, and a more reddish color than the other evergreen forest soils. The soils of sites E3 and E4, located on a hillside and at the base of a hill, respectively, had a high soil effective cation exchange capacity in the B horizons compared to those at sites E1–2 and E5. The soil of site E5 in the isolated basalt region had characteristics resembling those in sites E1–2 except for its high exchangeable aluminum content. The site D1 soil on a hillside was relatively young and shallow, and black in color. The carbon stock in the six forest sites (0–30 cm in depth) was 40.8– 113.7 Mg C ha−1 for high-density fractions and 3.3–7.6 Mg C ha−1 for low-density fractions, respectively. The differences in vegetation types (deciduous vs. evergreen forests), mean annual temperature and free aluminum contents among forest sites were considered factors affecting the carbon content and carbon to nitrogen (C/N) ratio of high-density fractions. It was considered that the variously weathered parent materials, regulated by the relative position in the basalt plateau, were responsible for the gradient of soil morphology and soil nutrient conditions and characterized the soil carbon stock in the study area. Discipline: Forestry and forest products Additional key words: tropical monsoon forest * Corresponding author: e-mail jtori@affrc.go.jp Received 29 May 2012; accepted 19 September 2012.

We studied the relationships among the soil C stock in tropical monsoon forests, the type of forest, and the environmental factors in the lower Mekong basin in Cambodia. We analyzed nine soil profiles in evergreen and deciduous forests growing over sedimentary rock and basalt. Evergreen forest soils tended to have a larger C stock than deciduous forest soils within geological formations. In evergreen and deciduous forest soils, carbon stocks were 56.9 ± 30.0 (mean ± SD) and 34.9 ± 23.5 Mg C ha-1, respectively, in the 0- to 30-cm depth range, and 108.7 ± 53.0 and 53.2 ± 30.4 Mg C ha-1, respectively, in the 0- to 100-cm depth range. Soil C stock was highly positively correlated with soil water content in the dry season, which is likely affected by the openness of the forest canopy and by soil clay content.

We examined non-destructive methodologies for practicalities in monitoring anthropogenic greenhouse gas (GHG) emissions from tropical dry-land forest under the influence of various forms of human intervention. Spaceborne SAR withstood comparison with Landsat ETM+ in land cover classification of degraded tropical forest. For measurement of carbon stock and GHG flux per unit land area, the gain-loss method requires both growth rate and removal rate of forest carbon stock. However, the latter has rarely been obtained in tropical forest. For the stock-difference method, permanent sampling plot data can be used to estimate mean carbon stock per unit land area of each forest type. For cyclic land use that includes a clear-cutting stage such as slash-and-burn agriculture, chronosequential changes in carbon stock can be predicted by determining the time and spatial-distribution of cleared land. Changes in forest biomass by logging, storm-damage, etc., may be identified by monitoring the presence and diameter of the crowns of overstory trees. We developed five equations containing the parameter for crown diameter for estimating tree biomass. Overstory height can be a parameter for estimating ecosystem carbon stock of various plant communities, and forest height can be measured by airborne and spaceborne sensors, etc. Generic equations containing the parameter for overstory height are available for estimating community biomass of tropical and subtropical forests. PALSAR has an advantage over other remote systems by enabling frequent sensing and semi-direct biomass estimation using backscattering coefficients. However, no reasonable remote sensing methods exist for monitoring the amount of carbon loss by forest conversion and logging in forests with high biomass. To compensate for the faults of the present PALSAR methodologies and to enable practical and frequent monitoring of all types of forests by humans, it is vital to devise a new methodology to detect changes in high-biomass forests.

平成20年5月から12月にかけて，九州大学病院皮膚科と関連病院皮膚科に通院中の，そう痒性皮膚疾患を有する患者107例(平均年齢は52.1±19.0歳，男女比=45 : 62)を対象として，少なくとも1 週間のベシル酸べポスタチン投与後に，そう痒の改善と日中の眠気，夜間の睡眠，服用に適した錠剤の色と形状，満足度などについてアンケート調査を行った。日中のそう痒の改善は全体で88.6％，夜間のそう痒の改善は89.5％で，疾患別にみると蕁麻疹群(日中 : 94.3％，夜間 : 97.1％)は湿疹・皮膚炎群(日中 : 87.2％，夜間 : 89.4％)に比べて有意に改善していた(P

The Reducing Emissions from Deforestation and Forest Degradation in Developing Countries (REDD) initiative requires accurate estimates of carbon stock changes in forested areas. However, estimating carbon emissions from stumps of various heights left by illegal loggers is difficult. To remedy this problem, we examined two methods of estimating diameter at breast height (DBH) from a reference diameter observation measured at any stump height. The one-reference diameter (OD) observation model estimates DBH from a single diameter observation using empirical coefficients derived mainly from emergent dipterocarp trees. The two-reference diameter (TD) observation model estimates DBH from two diameter observations and assumes a logarithmic relationship between diameter and height. Prediction data to establish the models were collected in Cambodian lowland evergreen forests that are undergoing intensive illegal logging of emergent dipterocarp trees for timber. The OD model performed better than the TD model in predicting DBH and is extremely practical, as it requires only a single diameter observation. Validation data previously collected in the Southeast Asian tropical forests established the general validity of the OD model. This study may improve the reliability of the REDD scheme by providing a reliable method to assess carbon emissions from Southeast Asian tropical forests.

Development pressure has led to serious deforestation on the Indochina Peninsula. Particularly rapid defor-estation has occurred in easily accessible lowland areas, and it is thus important to accumulate knowledge about these forests immediately. We measured evapotranspiration rates for a lowland dry evergreen forest in Kampong Thom Province, central Cambodia, using the energy balance Bowen ratio (EBBR) method based on meteorological data collected from a 60-m-high observation tower. Daily evapotranspiration was higher during the dry season than during the rainy season of the Asian monsoon climate. The seasonal variation in evapotranspiration generally corresponded to the seasonal difference in the vapor pressure deficit. A multi-layer model was used to simulate the seasonal variation in evapotranspiration. The multilayer model also reproduced the larger evapotranspiration rate in the dry season than in the rainy season. However, observed values substantially exceeded model-calculated results during certain periods at the beginning of the dry season and in the late dry season. Moreover, during the rainy season, the model tended to overestimate evapotranspiration. The differences between these observed and simulated values may have been caused by seasonal characteristics of photosynthesis and transpiration in the lowland dry evergreen forest that were not considered in the model simulation.

The nitrogen status of forest ecosystems can be represented by the net nitrification potential (NNP) of the forest soils. Prediction of NNP using a small number of soil properties is a practically useful tool for forest management planning. Artificial neural networks (ANN) have recently become popular tools in forest modeling because they eliminate certain difficulties in handling forest data, such as the nonlinear relationships and non-normality. This study aimed to develop an ANN model to predict NNP that required a few soil properties as possible for input data. The ANN model was fitted to field data using the ridge-stabilized Gauss–Newton method, with a subset of methods to prevent excessively high weights that are likely to cause over-fitting. We collected surface mineral soil samples from 56 locations in temperate forest ecosystems of central Japan. We measured NNPs on a per area basis (Mg N km −2 ) using aerobic laboratory incubation at 30 °C for 4 weeks. The ANN-based model using data on only two soil properties (the C:N ratio and the maximum water-holding capacity) provided the best prediction of NNP. The ANN-based model’s success results from its incorporation of (1) the nonlinear relationship between the C:N ratio and NNP and (2) the hierarchical control of NNP, which is governed primarily by the C:N ratio and secondarily by soil moisture conditions. The simplicity of the model greatly enhances its practical value in forest management planning.

The seasonality of forest leaf area index and photosynthetic activity is an important element of ecosystem function. The ecohydrological models representing water and carbon fluxes in tropical forests need regional-scale spatial information on forest leaf phenology. We aimed to evaluate the utility of the National Oceanic and Atmospheric Administration (NOAA)/Advanced Very high resolution radiometer (AVHRR) imagery for monitoring evergreen and deciduous forest phenology in lowland Cambodia. The temporal sequences of the normalized difference vegetation index (NDVI) data were constructed from ten-day composite imagery acquired from May 2001 to April 2002. A local maximum fitting (LMF) technique that combined time-series filtering and local curve-fitting techniques was used to extract cloud-free data. With this approach, different phenology between evergreen and deciduous forests was clearly observed during the dry season: Deciduous forests exhibited marked and spatially uniform loss and (later) gain in new leaf area, whereas evergreen forests showed lesser and spatially/temporally heterogeneous changes in leaf phenology. A significant finding was that about 30% of evergreen forests shed detectable quantities of leaves at two times during a dry season (i.e., in the early, and late, dry season). In summary, the capability of composite NOAA/AVHRR NDVI data sets processed with the LMF technique was established as a viable approach for monitoring heterogeneous forest phenology at regional scales during the tropical dry season, although it is apparent that further improvements in cloud clearing are required if the approach is to be useful also in the wet season.

This study of a water cycle was conducted in an evergreen forest located in the Mekong River Basin in central Cambodia. At the observation site, we measured the dynamics of the spatial distribution of groundwater levels. The groundwater movement was analyzed two-dimensionally using boundary conditions and parameters that had been observed in the field. The climate in the research area is dominated by two seasons, which occur annually: a rainy and a dry season. The groundwater levels are generally high during the rainy season and low during the dry season. Groundwater levels were measured along a stream, which flowed through the study site. The streambed was visible at the head of the stream in January. At the next downriver well point, the streambed appeared in March. Finally, it became visible at all well points in April, meaning that surface runoff had disappeared temporarily and instead flowed underground during the ensuing dry period. Groundwater levels of the studied lateral flow perpendicular to the stream that seeped and infiltrated into the stream were 1.2–2.5 m deep (in April), which was the lowest level recorded for the year. During that period, the depth of the groundwater of the studied lateral flow fell by as much as 56 mm per month. In addition, the lateral flow groundwater infiltrated into groundwater of the stream during that period. The groundwater level fluctuation was estimated based on a two-dimensional analysis of lateral flow perpendicular to the stream using a numerical simulation model with soil physical parameters and observed boundary conditions. The observations of ground water fluctuations were well reproduced. Deep seepage of groundwater was estimated using a uniform boundary condition that allowed efflux through the bottom, estimated as being approximately 30 mm per year. The simulated deep seepage rate was considered plausible considering other hydrological components such as soil water storage fluctuation.

In this study, we measured evapotranspiration in an evergreen broadleaf forest watershed in the Kampong Thom Province of central Cambodia with the aid of a 60-m high meteorological observation tower. The main vegetation species at the study site were Myristica iners and Vatica odorata. The mean tree height in the upper crown layer at the study site was 27·2 m, and the maximum tree height was 45·1 m. A heat balance method, which incorporated the Bowen ratio, was used to calculate the energy balance above the forest canopy; this value was subsequently used for the calculation of evapotranspiration. All the equipment necessary for the measurement of meteorological variables was installed in the observation tower. Data were collected during two distinct sampling periods: October 2003, in the late rainy season, and March 2004, in the middle of the dry season. Daily variations in evapotranspiration were strongly correlated with the measured amount of net radiation above the canopy layer. On the basis of our measurements, the mean evapotranspiration levels of the forest watershed during the late rainy season and the middle of the dry season were 4·3 and 4·6 mm/day, respectively. No significant differences in soil moisture were observed between the middle of the dry season and the late rainy season, probably due to the shallow depth of the water table. The results of this study suggest that the high levels of evapotranspiration recorded during the middle of the dry season reflect the presence of sufficient soil moisture (derived from the shallow water table) and a high vapour-pressure deficit. Copyright © 2008 John Wiley & Sons, Ltd.

森林の適切な管理を行うためには，森林域からの窒素負荷を簡便かつ広域的に推定する手法が必要である．そのため，矢作川流域の森林域1,340 km2を対象とし，森林土壌から渓流水を通じて流出する窒素負荷の可能性を，以下の3つの過程で推定した．1）森林表層鉱質土壌（0-5 cm）の窒素無機化・硝化速度を室内培養法で測定する．2）立地環境特性から流出窒素ポテンシャル（培養期間中の硝酸態窒素生成量を面積あたりに換算；Mg N・km-2）を予測する多変量回帰モデルを作成する．3）モデルに既存のGISデータを入力して，流域全体の流出窒素ポテンシャルを推定する． さらに，広域的な水質予測を行うため，簡易蒸発散量推定式を用いたGISモデルによって年流出量（mm・yr-1）を推定した．実測流入量と比較して，流出量推定モデルの精度を検証した．最後に，広域的な水質予測の指標としての渓流水窒素濃度ポテンシャル（流出窒素ポテンシャル/年流出量；mg N・L-1）を推定した．既往の渓流水窒素濃度測定値と比較して，本稿で試みた手法が広域的な傾向を再現できることを確認した．

前立腺癌が疑われ，生検前にMRI検査が施行された91症例中37症例に癌が認められた。生検をコントロールとしてMRIの診断能を検討するとaccuracy 0.84，sensitivity 0.95，specificity 0.76であった。拡散強調画像が撮像できた26症例 (前立腺癌14症例) においてapparent diffusion coefficient (ADC) 値とprostate specific antigen (PSA) 値は有意に逆相関を認めた。正常辺縁域の平均ADC値は1.51±0.20×10-3mm2/sec，正常中心域の平均ADC値は1.47±0.12×10-3mm2/sec，前立腺癌部の平均ADC値は0.97±0.23×10-3mm2/secであり正常辺縁域と前立腺癌部においてp