Forest In Japan Research Articles

Sustainable management of planted landscapes: lessons from Japan

In Japan, 42 % of forests are planted forests, and most of them were established after World War II (1950–1980) to meet increased wood demands. Although Japanese planted forests are now reaching their planned harvest age, they have not been managed, and their restoration is now being discussed. Japanese foresters have not cut their own forests, and the country’s high wood demands have been met by imports during recent decades. The decline of young forests due to the stagnation of forestry activity is suggested to be partly responsible for the nation-wide decline in early-successional species, which is referred to as the “second crisis of biodiversity.” As a timber-importing nation, it is suggested that Japan has underused the nation’s own forests and has overused forests elsewhere. A revival of Japanese plantation forestry may contribute to the restoration of early-successional species because young planted forests are likely to provide suitable habitats. Furthermore, only 30 % of the current planted forests in Japan will be needed to meet the expected future domestic demand for lumber and plywood without imports. The remaining 70 % of the current planted forests may be restored to natural forests with or without harvesting. The history of Japanese planted forests suggests that some natural trees/forests should be retained, even in the landscapes that specialize in wood production, because part of the planted forests may be economically marginalized in the future, and their restoration to natural forests would then be needed.

Automated analysis of fine‐root dynamics using a series of digital images

AbstractInformation related to the growth of fine roots is important for understanding C allocation in trees and the mechanisms of C cycling in ecosystems. Observations using a camera or scanner embedded in the soil enabled us to obtain continuous images of fine‐root‐growth dynamics. However, these methods are still labor‐intensive because the image analysis has to be conducted manually. We developed an automated method for tracking movement or elongation of fine roots using a sequence of scanner images. We also show how data obtained with these methods can be used for calculating fine‐root behavior. Two A4‐size scanners were buried in a mixed forest in Japan and images were taken continuously from within the soil. We preprocessed these images by extracting the fine‐root area from the images and developed an automated calculation plug‐in we named A‐root for tracking growth movement of the tips of fine roots. A‐root and manual‐tracking results were compared using the same images. The results show the A‐root and manual‐tracking methods yielded similar levels of accuracy. The average growth rate of 17 fine roots tracked using the program was 0.16 mm h–1. The observation of the direction of growth in fine roots showed the direction may be influenced by the original root's growth where the fine roots branched, distribution of soil particles, other roots, and the force of gravity. The A‐root analysis also suggested there may be an interaction between speed of growth and changes in direction of growing fine roots.

Review of Plant Species Diversity in Managed Forests in Japan

The effects of conifer plantation management and forest fragmentation on plant species diversity in Japan were reviewed. While most studies have demonstrated that the practice of thinning in coniferous plantations can enhance species diversity of naturally regenerated trees, such as broad-leaved trees, some have shown that thinning reduces plant species diversity through the direct physical disturbance to forests. In addition, plant species diversity in plantations has also been shown to be dependent on the distance from seed sources. Extensive forest fragmentation due to land use changes has occurred, particularly in forests near urban and suburban areas. Although the number of species per unit area in abandoned coppice forests is not clearly related to the extent of forest fragmentation, most species attributes (such as rare species) are negatively influenced by forest fragmentation. Some of the forests owned by shrines and temples in urban areas are similar to island forests and are relatively well protected from human disturbance. To more clearly understand and evaluate changes in biodiversity through forest management, elucidating the interactions between management and plant species diversity, species composition, and the ecological traits of various species is therefore necessary.

Seasonal and interannual variation in net ecosystem production of an evergreen needleleaf forest in Japan

Carbon dioxide (CO2) flux was measured above the forest at the Fujiyoshida site on the northern slope of Mount Fuji in Japan in 2000–2008 using an eddy covariance technique. The forest mainly consists of Japanese red pine (Pinus densiflora) and Japanese holly (Ilex pedunculosa). The 9-year average of monthly mean net ecosystem production (NEP) ranged from −0.1…−2 day−1 in January to 2.5…−2 day−1 in May. The maximum net uptake was observed in May, although gross primary production (GPP) was highest in July. Variation in the leaf amount did not notably affect seasonal variation in GPP. This site was characterized by carbon uptake even in winter, if the meteorological conditions were conducive for photosynthesis and a resulting long period of carbon uptake. The 9-year averages of annual NEP, GPP, and ecosystem respiration (RE) were 388, 1,802, and 1,413…−2 year−1, respectively. The annual NEP was lowest in 2003 and highest in 2004 over the 9 years. Year-to-year variability of NEP mainly depended on air temperature and photosynthetically active radiation in summer, and the dependence of the deviation of annual NEP on that of GPP was greater than that of RE. Long-term observational data indicated that the carbon uptake ability at the study site was at a moderate level in comparison with other temperate humid evergreen forests around the world. These data also indicated that the site had a high carbon uptake ability compared with other deciduous forests in Japan because of the duration of carbon uptake.

Heterotrophic respiration causes seasonal hysteresis in soil respiration in a warm-temperate forest

To assess the effect of changes in organic litter stock on seasonal changes in heterotrophic respiration (RH), soil respiration (RS), and total ecosystem respiration (RE), we measured seasonal changes in leaf litter respiration (RLL) by the chamber method and estimated the seasonal change in total RH using the RothC model in a warm-temperate mixed deciduous–evergreen forest in Japan. Both RE and RS had seasonal hysteresis and were higher in spring than at the same temperature during autumn. Under warm and humid conditions, the rate of decomposition of newly supplied leaf litter in one year was high (60% loss). Consequently, RLL and RH were higher in spring after leaf drop, when more fresh material was available, than in autumn. In this study, 42 and 88% of the difference in RE and RS between spring and autumn (soil temperature 16–18°C) could be accounted for by the difference in RH, respectively, and 71% of the difference in RH could be accounted for by the difference in RLL. This study showed that seasonal changes in heterotrophic respiration (RLL and RH) could be a major factor in the seasonal hysteresis of RE and RS.

Insectivory by Five Sympatric Carnivores in Cool-Temperate Deciduous Forests

We studied insectivory by five carnivores—the Asiatic black bear (Ursus thibetanus), Japanese marten (Martes melampus), Japanese badger (Meles meles), red fox (Vulpes vulpes), and raccoon dog (Nyctereutes procyonoides)—in a cool-temperate deciduous forest in Japan. From May 2003 to April 2005, we assayed 373 fecal samples (91 from bear, 158 from marten, 43 from badger, 36 from fox, and 45 from raccoon dog) for insects. Each carnivore species consumed a variety of insect species, some preferentially. Bears preferred colonial insects like ants and wasps; martens ate a variety of forest insects, such as ground beetles and arboreal insects; badgers preferred forest ground beetles; foxes ate ground beetles and grassland insects; and raccoon dogs ate a variety of species. Dietary preferences may reflect the feeding strategy, behavior, or habitat preference of each carnivore species. Based on the habitat preferences of the insects, we could assign carnivores to particular microhabitats: bears and martens used forest in three dimensions, badgers inhabited forest in two dimensions, foxes used grassland and forest in two dimensions, and raccoon dogs inhabited grassland and forest in three dimensions. Identification of insects in feces may provide information on the dietary and habitat preferences of these carnivores.

Characteristics of canopy interception loss in Moso bamboo forests of Japan

AbstractIn recent years, Moso bamboo (Phyllostachys pubescens) forests have rapidly expanded in Japan by replacing surrounding coniferous and/or broadleaved forests. To evaluate the change in water yield from forested areas because of this replacement, it is necessary to examine evapotranspiration for Moso bamboo forests. However, canopy interception loss, one of the major components of evapotranspiration in forested areas, has been observed in only two Moso bamboo forests in Japan with relatively high stem density (~7000 stems/ha). There are, in fact, many Moso bamboo forests with much lower stem density. Thus, we made precipitation (Pr), throughfall (Tf) and stemflow (Sf) observations for 1 year in a Moso bamboo forest with stem density of 3611 stems/ha and quantified canopy interception loss (Ic). Pr and Ic for the experimental period were 1636 and 166 mm, respectively, and Ic/Pr was 10%. The value was approximately the same as values for the other two Moso bamboo forests and lower than values for coniferous and broadleaved forests. On the other hand, Tf/Pr and Sf/Pr for our forest (86% and 4%, respectively) were approximately 10% of Pr larger and smaller than values for the other two Moso bamboo forests. These results suggest that the difference in stem density greatly affects precipitation partitioning (i.e. Tf/Pr and Sf/Pr) but does not greatly change Ic/Pr. Copyright © 2012 John Wiley & Sons, Ltd.

Assessing the use of camera-based indices for characterizing canopy phenology in relation to gross primary production in a deciduous broad-leaved and an evergreen coniferous forest in Japan

Recent studies have reported that seasonal variation in camera-based indices that are calculated from the digital numbers of the red, green, and blue bands (RGB_DN) recorded by digital cameras agrees well with the seasonal change in gross primary production (GPP) observed by tower flux measurements. These findings suggest that it may be possible to use camera-based indices to estimate the temporal and spatial distributions of photosynthetic productivity from the relationship between RGB_DN and GPP. To examine this possibility, we need to investigate the characteristics of seasonal variation in three camera-based indices (green excess index [GE], green chromatic coordinate [rG], and HUE) and the robustness of the relationship between these indices and tower flux-based GPP and how it differs among ecosystems. Here, at a daily time step over multiple years in a deciduous broad-leaved and an evergreen coniferous forest, we examined the relationships between canopy phenology assessed by using the three indices and GPP determined from tower CO2 flux observations, and we compared the camera-based indices with the corresponding spectra-based indices estimated by a spectroradiometer system. We found that (1) the three camera-based indices and GPP showed clear seasonal patterns in both forests; (2) the amplitude of the seasonal variation in the three camera-based indices was smaller in the evergreen coniferous forest than in the deciduous broad-leaved forest; (3) the seasonal variation in the three camera-based indices corresponded well to seasonal changes in potential photosynthetic activity (GPP on sunny days); (4) the relationship between the three camera-based indices and GPP appeared to have different characteristics at different phenological stages; and (5) the camera-based and spectra-based HUE indices showed a clear relationship under sunny conditions in both forests. Our results suggest that it might be feasible for ecologists to establish comprehensive networks for long-term monitoring of potential photosynthetic capacity from regional to global scales by linking satellite-based, in situ spectra-based, and in situ camera-based indices.

The role of dung beetles as a secondary seed disperser after dispersal by frugivore mammals in a temperate deciduous forest

We studied the effects of dung beetles on the fates of endozoochorous seeds of five species (Prunus jamasakura, Prunus verecunda, Prunus grayana, Swida controversa, and Vitis coignetiae) in a temperate deciduous forest in Japan during 2004–2006. In field experiments using dung of the Asiatic black bear (Ursus thibetanus), we investigated the depths that dung beetles (Onthophagus atripennis, Onthophagus lenzii, and Phelotrupes auratus) buried seeds (4.8–6.8 mm diameter) and plastic markers (2 or 5 mm diameter), the levels of predation on buried and unburied seeds, and germination rates of seeds buried to different depths. All three species buried the 2-mm markers, but only P. auratus buried the seeds and 5-mm markers. There were seasonal differences in mean seed burial rates (range, 27–51%) and depths (range, 1–27 mm). Significantly more seeds were buried in June, July, and September than in August or October, and the mean burial depth was significantly deeper in June and July. Most seeds and markers were buried to a 3–6 cm depth. Germination of seeds that were positioned at depths of 1–4 cm was significantly greater than that of seeds left on the surface or buried at greater depths. Buried seeds were less likely to disappear than seeds at the surface, which may reflect differential predation. These results suggested that dung beetles, especially P. auratus, acted as a secondary seed disperser that affected the survival and distribution of seeds dispersed by a frugivore.

In situ examination of the relationship between various vegetation indices and canopy phenology in an evergreen coniferous forest, Japan

We examined the relationship between four vegetation indices and tree canopy phenology in an evergreen coniferous forest in Japan based on observations made using a spectral radiometer and a digital camera at a daily time step during a 4 year period. The colour of the canopy surface of Japanese cedar (Cryptomeria japonica) changed from yellowish-green to whitish-green from late May to July and turned reddish-green in winter. The normalized difference vegetation index (NDVI), enhanced vegetation index (EVI) and plant area index (PAI) showed no seasonality. In contrast, the green–red ratio vegetation index (GRVI) increased from March to June and then decreased gradually from July to December, resulting in a bell-shaped curve. GRVI revealed seasonal changes in the colour of the canopy surface. GRVI correlated more positively with the evaluated maximum photosynthetic rate for the whole forest canopy, A max, than did NDVI or EVI. These results suggest the possibility that GRVI is more useful than NDVI and EVI for capturing seasonal changes in photosynthetic capacity, as the green and red reflectances are strongly influenced by changes in leaf pigments in this type of forest.

Modeling of Stomatal Conductance for Estimating Ozone Uptake of Fagus crenata Under Experimentally Enhanced Free-air Ozone Exposure

We examined a performance of the multiplicative stomatal conductance model to estimate the stomatal ozone uptake for Fagus crenata. Parameterization of the model was carried out by in-situ measurements in a free-air ozone exposure experiment. The model performed fairly well under ambient conditions, with low ozone concentration. However, the model overestimated stomatal conductance under enhanced ozone condition due to ozone-induced stomatal closure. A revised model that included a parameter representing ozone-induced stomatal closure showed better estimation of ozone uptake. Neglecting ozone-induced stomatal closure induced a 20 % overestimation of the stomatal uptake of ozone. The ozone-induced stomatal closure was closely related to stomatal ozone uptake rather than accumulated concentrations of ozone exceeding 40 nmol mol−1. Our results suggest that ozone-induced stomatal closure should be implemented to stomatal conductance model for estimating ozone uptake for F. crenata. The implementation will contribute to adequate risk assessments of ozone impacts on F. crenata forests in Japan.

Endophytic fungi associated with leaves of Betulaceae in Japan

Diversity and species composition of endophytic fungi on leaves of 11 tree species in Betulaceae were studied, with reference to climatic, tree species, and seasonal variations. A total of 186 fungal isolates were obtained from 190 leaves collected in a subalpine forest, a cool temperate forest, and a subtropical forest in Japan, and were divided into 46 operational taxonomic units (OTUs) according to the base sequences of D1-D2 region of large subunit rDNA. The 2 most frequent OTUs were Muscodor sp. and Nemania sp. in Xylariaceae, followed by Gnomonia sp., Glomerella acutata , Apiosporopsis sp., Asteroma sp., and Cladosporium cladosporioides . The similarities of OTU composition in endophytic fungal assemblages on leaves of Betulaceae were generally low among the forests of different climatic regions. Fungal OTU compositions were relatively similar between 2 Betula species in the subalpine forest, whereas 7 tree species in the cool temperate forest were divided into 3 groups according to the similarity of endophytic fungal assemblages on the leaves, with 4 Carpinus species assigned into 2 of the 3 groups. The similarity of endophytic fungal assemblages between August and October was relatively high in the subalpine forest, whereas the seasonal changes were generally greater (i.e., the similarities among sampling dates were lower) in the cool temperate forest.

Crown exposure to light and tree allometry of 11 tree species in a snowy cool-temperate forest in Japan

Crown exposure to light (CE) and tree allometry were investigated for 11 species in a snowy cool-temperate secondary forest dominated by Fagus crenata and Betula ermanii in Japan. The 11 species differentiated horizontal and vertical light gradients for regeneration. CE was highly variable across species in small trees, but variation in CE decreased with increasing height. The 11 species were classified into three patterns of height-dependent change in CE in comparison to community-level trends, and rank reversal of CE with increasing height was not apparent. Allometric relationships between trunk diameter (D) and height (H) and between D and trunk length (L) differed little between trees of high and low CE within species. In contrast, slopes of the allometric relationships between D and H differed across species; species with larger maximum height (H max) were taller at a given D, as was noted in previous studies of warm-temperate and tropical forest trees. Differences in trunk angle among the species of different H max were the main factor generating the differences in allometric relationships between D and H in this forest. Trunk angle increased with increasing height in the species of large H max but decreased in those of small H max. Hence, allometric relationships between D and L were not related to H max. Since the species of small H max grow laterally and are easily covered in snow during winter while those of large H max grow vertically above snow cover, differences in trunk angle may reflect species mechanical properties.

Landscape image sketches of forests in Japan and Russia

With increased economic and tourism interests in both Japan and Russia, culturally different meanings of ‘forest’ need to be understood for future cooperative environmental management. In this study, we propose Landscape Image Sketching Technique as an original, practical methodology to externalise an individual landscape image as a scene sketch aiming to represent the viewer's fundamental way of seeing the landscape. To discuss different perceptions and interpretations of forests in a cultural framework, we conducted cross-national research in Japan and Russia. A total of 325 respondents were asked to make a landscape image sketch of an imaginary forest and to include keywords and text. The sketches were analysed by means of four aspects: ‘linguistic knowledge’, ‘spatial view’, ‘self-orientation’ and ‘social meaning', which were represented by landscape elements, the shape of elements, the subject's standpoint and the combination of the elements in the framework. As a result, landscape image sketches revealed differences between respondents in Japan and Russia. The typical landscape images of a forest were represented objectively, as aesthetic scenery in Russia and subjectively, as a practical place in Japan. The results suggested a fundamental difference in ways of seeing the landscape through individual perceptions rather than normative views on forests. This methodology for visualising ways of seeing a landscape can be useful in understanding different assumptions about environmental issues, not only for a global environmental discussion regarding each locality, but also for local environmental management and public participation.

Analysis of Vegetation Structure of Castanopsis sieboldii Forest in the Warm-temperate Zone, Korea

This study aims at classifying and analyzing the vegetation structure of Castanopsis sieboldii forest, one of the evergreen broad-leaved forests found under the warm-temperate climate of Korea. It is also compared with the ones of the Castanopsis sieboldii forest in Japan where most similar such forest of Korea, to find unique vegetation structures of the only Korean forest. Vegetation structure of Korean Castanopsis sieboldii forest was divided into two units at the level of community units both of Ardisia japonica-Castanopsis sieboldii community and Ardisio-Castanopsietum sieboldii association. The association carries similar type with the vegetation system of Japan, but any subunits differentiated with the Japan were found vary much. Hierarchical cluster analysis brings in similar result with the analysis on the vegetation structure as well.

Water condition control of in situ soil water repellency: an observational study from a hillslope in a Japanese humid‐temperate forest

AbstractTo evaluate the relationship between the moisture conditions and the water repellency of soil surfaces in situ, we periodically conducted field surveys for more than a year in a humid‐temperate forest in Japan. Measurements were made in four plots with varying soil physicochemical properties and under different topographic conditions across a hillslope. Each plot contained permanent quadrats with measurement points in a grid pattern. At each point, we measured the volumetric water content at 0‐ to 5‐cm depths and the water repellency at soil surfaces approximately twice a month. The repeated measurements enabled us to estimate the critical water content (CWC) below which soils repelled water at each point. We defined the representative CWC (RCWC) of a plot as the median of all CWCs in a plot and estimated the representative critical water potential (RCWP) on the basis of the RCWC using the water retention curve. The RCWC values differed among plots, but the corresponding RCWP values were similar (pF = 3.5–3.9). The relationship of the areal fraction showing water repellency against soil water potentials was similar across plots, but the relationship differed among plots against the soil moisture content. These results suggest that soil water potential is more indicative of the spatial occurrence of water repellency than moisture content on a hillslope where soil physicochemical properties vary. Plots located on ridge crests frequently exhibited lower water potentials and showed a higher areal fraction of water repellency, implying a greater chance of generating surface runoff by rainfall events. Copyright © 2011 John Wiley & Sons, Ltd.

Estimating Vertical Distribution of Vegetation Cover in Temperate Heterogeneous Forests Using Airborne Laser Scanning Data

Vertical structure is important for understanding forest environment, yet difficult to characterize, especially in temperate heterogeneous forests where the structure is complex. This study used data from a small-footprint airborne laser scanning (ALS) to estimate vegetation coverage in four stratum ranges in a warm temperate forest in Japan: >12 m, 8 - 12 m, 4 - 8 m, and 0 - 4 m in height. Field data were collected in 17 broad-leaved and 12 coniferous sample plots, consisting of the proportion of vegetation cover in each stratum range. The field and ALS measurements were conducted in summer, during leaf-on conditions. Using echo attributes (first, last, intermediate, and only), we calculated the vegetation coverage index (VCI) at 1-m height intervals. The cumulative sum of the VCI (CUMVCI) was then computed and compared with field observations. Linear regression analysis showed that the ALS data gave reasonable estimates of vegetation coverage in the upper two or three stratum ranges in broad-leaved stands, and in the upper two stratum ranges in coniferous stands. The model gave reproducible estimates until approximately 95% of the total returns had been applied. We conclude that ALS data can provide useful information on natural habitats in the management of warm temperate forest.

Developing a National-level System for Simulating the Forest Carbon Dynamics of Hinoki Planted Forests in Japan(ORAL SESSION,Followup and New Challenge for Coming Generations,The Second International Conference on FORCOM,Abstract Proceedings of FORCOM2011)

Developing a National-level System for Simulating the Forest Carbon Dynamics of Hinoki Planted Forests in Japan(ORAL SESSION,Followup and New Challenge for Coming Generations,The Second International Conference on FORCOM,Abstract Proceedings of FORCOM2011)

Characteristics of Pedon under Ten Nature Sanctuary Forests in Japan

Characteristics of Pedon under Ten Nature Sanctuary Forests in Japan

Contemporary Problems Relating to the Coastal Forest in Japan

Contemporary Problems Relating to the Coastal Forest in Japan