Forest In Japan Research Articles

Isolation and characterization of microsatellites from a cicada, Yezoterpnosia nigricosta (Hemiptera: Cicadidae), distributed in subarctic and cool temperate forests.

The cicada Yezoterpnosia nigricosta (Hemiptera: Cicadidae) is distributed in subarctic and cool temperate forests in Japan, China and the Russian Far East. Due to its limited and isolated distribution at higher altitudes in cool temperate forests on the main island of Japan, especially in the central and southern areas, this species is listed as a threatened or near-threatened species on the Red List of 12 prefectures in Japan. Moreover, there are concerns about the impacts of climate change on the species' distribution and population demography. In this study, seventeen microsatellite markers were developed for Y. nigricosta, and marker suitability was evaluated using 32 individuals from two populations in Nagano prefecture (central Japan) and Hokkaido, a northern island of Japan. The number of alleles, expected heterozygosity and fixation index at each locus were 1-15 (mean = 4.294), 0.000-0.914 (mean = 0.519) and -0.225-0.456 (mean = 0.108), respectively. Furthermore, there was moderate genetic differentiation between the two populations (FST = 0.111, F'ST = 0.237). These markers will be useful to evaluate the genetic structure and to infer population demographic history of Y. nigricosta populations, which can contribute to population genetics studies of this species.

Spatial Distribution of Sea Salt Deposition in a Coastal Pinus thunbergii Forest

We investigated the sea salt deposition process on the soil in a coastal black pine (Pinusthunbergii Parlatore) forest in Japan with reference to sea salt scavenging by the forest canopy and the following washout by precipitation. We collected throughfall and soil-infiltration water along transects crossing the coastal forest and measured the water chemistry—electric conductivity, pH, major cations (NH4+, Na+, K+, Mg2+, and Ca2+), major anions (Cl−, SO42−, NO2−, NO3−, and PO43−), and total organic carbon—at 10-m intervals on the survey transects. Leaching of base cations from surface soil kept lower acidity of soil water in the evergreen broadleaf forest, whereas soil infiltration water was acidified in the soil surface in the P. thunbergii forest. Hot spots of sea salt deposition on the soil surface were observed at hollows of the ground surface, slope-facing coastal line, or sites with an abrupt increase in height where the canopy faces the coast. However, the edge effect in sea salt scavenging was not evident in the juvenile stand at the forest edge, which had a height of <5 m. The sea salt deposition was only evident in the coastal black pine forest with canopy height >10 m.

Rain-induced bioecological resuspension of radiocaesium in a polluted forest in Japan

It is the conventional understanding that rain removes aerosols from the atmosphere. However, the question of whether rain plays a role in releasing aerosols to the atmosphere has recently been posed by several researchers. In the present study, we show additional evidence for rain-induced aerosol emissions in a forest environment: the occurrence of radiocaesium-bearing aerosols in a Japanese forest due to rain. We carried out general radioactive aerosol observations in a typical mountainous village area within the exclusion zone in Fukushima Prefecture to determine the impacts and major drivers of the resuspension of radiocaesium originating from the nuclear accident in March 2011. We also conducted sampling according to the weather (with and without rain conditions) in a forest to clarify the sources of atmospheric radiocaesium in the polluted forest. We found that rain induces an increase in radiocaesium in the air in forests. With further investigations, we confirmed that the fungal spore sources of resuspended radiocaesium seemed to differ between rainy weather and nonrainy weather. Larger fungal particles (possibly macroconidia) are emitted during rainy conditions than during nonrainy weather, suggesting that splash generation by rain droplets is the major mechanism of the suspension of radiocaesium-bearing mould-like fungi. The present findings indicate that radiocaesium could be used as a tracer in such research fields as forest ecology, meteorology, climatology, public health and agriculture, in which fungal spores have significance.

Impact of reduced ozone concentration on the mountain forests of Mt. Tateyama, Japan

The central mountainous area of Japan is affected by air pollutant emissions from nearby countries such as China and Korea. Sharp increases in the consumption of fossil fuels in the early 21st century, associated with rapid industrialization in China, resulted in long-range transport of pollutants from East Asia and increases in the harmful effects of pollution. However, the air pollutants emissions have decreased since 2006, when air pollution countermeasures were implemented in China. Furthermore, climatic patterns during 2008–2013 reduced tropospheric ozone concentrations around Japan. Such major changes in the social and climatic environment may have had a significant impact on forests. To investigate this, long-term forest monitoring data obtained at Buna-daira (1190 m a.s.l.), Buna-zaka (1090 m a.s.l.) and Arimine (1350 m a.s.l.) were analyzed. Buna-daira and Buna-zaka forests face the continental side of Mt. Tateyama in Toyama Prefecture. In both stands, the girth growth rate of Fagus crenata was found to have increased after 2008; however, such a tendency was not detected at Arimine, which is surrounded by mountains. The growth rates of Cryptomeria japonica, a conifer resistant to air pollution, were found to remain unchanged or decrease. Here, regional long-range transport of air pollution (including ozone and sulfur oxide) has been demonstrated to influence mountain forests in Japan. In particular, recent decreases in regional air pollution may be an important factor controlling increases in F. crenata, likely through changes in interspecific relationships between species sensitive to and tolerant of air pollution.

Two new deer truffle species, Elaphomyces marmoratus and Elaphomyces fuscus spp. nov., from a secondary forest in Japan

Abstract We describe two new species of deer truffle, Elaphomyces marmoratus and E. fuscus spp. nov., collected from a secondary forest dominated by Quercus serrata, in Tokyo, Japan. Both species have morphological similarities to E. muricatus and E. granulatus; however, the former has a gleba without a purplish color and the latter has reticulated ascospores more closely resembling E. asperulus. Molecular phylogenetic analyses also support the assignment of these specimens as new species. ITS rDNA homologies with known species were low (

Causes and consequences of reduced human intervention in formerly managed forests in Japan and other countries

In Japan, abandonment of forest management and underuse of forest resources are substantial challenges to environmental protection and sustainable wood production, while in many other countries, leaving a forest untouched may be perceived as positive for conserving the forest. This study thus analyses the scientific knowledge landscape on the causes and consequences of reduced human intervention in formerly managed forests and compares differences between Japan and other countries. Advanced search rules in the bibliographic databases returned 188 publications [35 for Japan and 153 for other countries] related to reduced human intervention in formerly managed forests. Reduced human intervention in formerly managed forests occurred in developed countries in the mid-twentieth century because of socio-economic changes and was primarily directed by small-scale private landowners, causing structural homogenisation, stand ageing, and canopy closure, often followed by the consequences of decreasing biodiversity and ecosystem services in Japan and other countries. In Japan, heavy dependency on wood imports at the expense of biodiversity and ecosystem services and the impending need for harvesting abundant mature forests due to the unbalanced tree age distribution possibly enhanced the recognition and urgency of underuse as a threat to biodiversity and wood security, while in other countries, multiple management objectives of diverse landowners probably dispersed the recognition of underuse. Although less recognised in other countries, the absence of forest management can pose a risk to biodiversity and ecosystem services. Hence, reactivating forest management in underused private forests can be a cost-effective precautionary approach against possible damage from underuse-induced ecosystem disservices. Policy implications for sustainable forest management in underused private forests are discussed from a perspective beyond conventional private ownership.

Intraspecific variation in spring leaf phenology and duration of leaf expansion in relation to leaf habit and leaf size of temperate tree species

Spring leaf phenology has been intensively studied in temperate deciduous broad-leaved tree species, but the phenology of evergreen broad-leaved tree species has seldom been focused on. Evaluation of the difference in spring leaf phenology between coexisting deciduous and evergreen species is essential to predict their responses to climate change. In this study, spring leaf phenology was investigated for the 12 deciduous and 12 evergreen broad-leaved species coexisting in a warm-temperate forest in Japan, based on the predictions that selection pressure for earlier leaf production in spring results in less intraspecific variation in phenology at a given timing (SDmax) and a shorter duration of leaf expansion in deciduous than in evergreen species. In contrast to this prediction, SDmax did not differ between deciduous and evergreen species and was not related to leaf area or LMA. On the other hand, the duration of leaf expansion was longer in evergreen than in deciduous species, and was positively correlated with LMA. The leaves of greater LMA required longer periods of leaf expansion, probably due to a higher cost of and/or more conservative leaf development in the face of herbivory. As a consequence, the timing of full leaf expansion was delayed not only by later budburst (approximately two weeks) but also by a longer duration of leaf expansion (approximately two weeks) in evergreen than in deciduous broad-leaved species, which would probably influence the productivity of newly emerging leaves in spring.

Seasonal and annual fluctuations of deer populations estimated by a Bayesian state-space model.

Deer overabundance is a contributing factor in the degradation of plant communities and ecosystems worldwide. The management and conservation of the deer-affected ecosystems requires us to urgently grasp deer population trends and to identify the factors that affect them. In this study, we developed a Bayesian state–space model to estimate the population dynamics of sika deer (Cervus nippon) in a cool-temperate forest in Japan, where wolves (Canis lupus hodophilax) are extinct. The model was based on field data collected from block count surveys, road count surveys by vehicles, mortality surveys during the winter, and nuisance control for 12 years (2007–2018). We clarified the seasonal and annual fluctuation of the deer population. We found a peak of deer abundance (2010) over 12 years. In 2011 the estimated deer abundance decreased drastically and has remained at a low level then. The deer abundance gradually increased from April to December during 2013–2018. The seasonal fluctuation we detected could reflect the seasonal migration pattern of deer and the population recruitment through fawn births in early summer. In our model, snowfall accumulation, which can be a lethal factor for deer, may have slightly affected their mortality during the winter. Although we could not detect a direct effect of snow on population dynamics, snowfall decrease due to global warming may decelerate the winter migration of deer; subsequently, deer staying on-site may intensively forage evergreen perennial plants during the winter season. The nuisance control affected population dynamics. Even in wildlife protection areas and national parks where hunting is regulated, nuisance control could be effective in buffering the effect of deer browsing on forest ecosystems.

Integration of Multi-Sensor Data to Estimate Plot-Level Stem Volume Using Machine Learning Algorithms–Case Study of Evergreen Conifer Planted Forests in Japan

The development of new methods for estimating precise forest structure parameters is essential for the quantitative evaluation of forest resources. Conventional use of satellite image data, increasing use of terrestrial laser scanning (TLS), and emerging trends in the use of unmanned aerial systems (UASs) highlight the importance of modern technologies in the realm of forest observation. Each technology has different advantages, and this work seeks to incorporate multiple satellite, TLS- and UAS-based remote sensing data sets to improve the ability to estimate forest structure parameters. In this paper, two regression analysis approaches are considered for the estimation: random forest regression (RFR) and support vector regression (SVR). To collect the dependent variable, in situ measurements of individual tree parameters (tree height and diameter at breast height (DBH)) were taken in a Japanese cypress forest using the nondestructive TLS method, which scans the forest to obtain dense and accurate point clouds under the tree canopy. Based on the TLS data, the stem volume was then computed and treated as ground truth information. Topographic and UAS information was then used to calculate various remotely sensed explanatory variables, such as canopy size, canopy cover, and tree height. Canopy cover and canopy shapes were computed via the orthoimages derived from the UAS and watershed segmentation method, respectively. Tree height was computed by combining the digital surface model (DSM) from the UAS and the digital terrain model (DTM) from the TLS data. Topographic variables were computed from the DTM. The backscattering intensity in the satellite imagery was obtained based on L-band (Advanced Land Observing Satellite-2 (ALOS-2) Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2)) and C-band (Sentinel-1) synthetic aperture radar (SAR). All satellite (10–25 m resolution), TLS (3.4 mm resolution) and UAS (2.3–4.6 cm resolution) data were then combined, and RFR and SVR were trained; the resulting predictive powers were then compared. The RFR method yielded fitting R2 up to 0.665 and RMSE up to 66.87 m3/ha (rRMSE = 11.95%) depending on the input variables (best result with canopy height, canopy size, canopy cover, and Sentinel-1 data), and the SVR method showed fitting R2 up to 0.519 and RMSE up to 80.12 m3/ha (rRMSE = 12.67%). The RFR outperformed the SVR method, which could delineate the relationship between the variables for better model accuracy. This work has demonstrated that incorporating various remote sensing data to satellite data, especially adding finer resolution data, can provide good estimates of forest parameters at a plot level (10 by 10 m), potentially allowing advancements in precision forestry.

Effects of aerosol dynamics and gas–particle conversion on dry deposition of inorganic reactive nitrogen in a temperate forest

Abstract. Dry deposition has an impact on nitrogen status in forest environments. However, the mechanism for the high dry-deposition rates of fine nitrate particles (NO3-) observed in forests remains unknown and is thus a potential source of error in chemical transport models (CTMs). Here, we modified and applied a multilayer land surface model coupled with dry-deposition and aerosol dynamic processes for a temperate mixed forest in Japan. This represents the first application of such a model to ammonium nitrate (NH4NO3) gas–particle conversion (gpc) and the aerosol water uptake of reactive nitrogen compounds. Thermodynamics, kinetics, and dry deposition for mixed inorganic particles are modeled by a triple-moment modal method. Data for inorganic mass and size-resolved total number concentrations measured by a filter pack and electrical low-pressure impactor in autumn were used for model inputs and subsequent numerical analysis. The model successfully reproduces turbulent fluxes observed above the canopy and vertical micrometeorological profiles noted in our previous studies. The sensitivity tests with and without gpc demonstrated clear changes in the inorganic mass and size-resolved total number concentrations within the canopy. The results also revealed that within-canopy evaporation of NH4NO3 under dry conditions significantly enhances the deposition flux of fine-NO3- and fine-NH4+ particles, while reducing the deposition flux of nitric acid gas (HNO3). As a result of the evaporation of particulate NH4NO3, the calculated daytime mass flux of fine NO3- over the canopy was 15 times higher in the scenario of “gpc” than in the scenario of “no gpc”. This increase caused high contributions from particle deposition flux (NO3- and NH4+) to total nitrogen flux over the forest ecosystem (∼39 %), although the contribution of NH3 was still considerable. A dry-deposition scheme coupled with aerosol dynamics may be required to improve the predictive accuracy of chemical transport models for the surface concentration of inorganic reactive nitrogen.

High-heat Effects on the Physical and Chemical Properties of Soil Organic Matter and Its Water-soluble Components in Japan's Forests: A Comprehensive Approach Using Multiple Analytical Methods.

Wildfires that expose the soil organic layer to high heat levels can alter soil organic matter (SOM), which includes water-soluble organic matter (WSOM) components. Various evaluation methods were used to characterize and quantify the effects of high heat levels on SOM and WSOM, including ion chromatography, thermogravimetry-differential thermal analysis (TG-DTA), colorimetry, elemental analysis, pyrolysis-gas chromatography-mass spectrometry using tetramethylammonium hydroxide (TMAH-py-GC/MS), total organic carbon (TOC) analysis, three-dimensional excitation-emission matrix (3DEEM) spectroscopy, and high-performance size-exclusion chromatography. In this study, we applied each of these evaluation methods using soil samples that were collected from broadleaf, coniferous, and bamboo forests and peatland in Japan and exposed to different initial high heat levels. Based on the TG-DTA results, the remaining mass in select soil samples markedly decreased when reheated to approximately 200°C. Comparatively, the TMAH-py-GC/MS results indicated a drastic change in SOM composition and the production of low molecular organic components (<C10) at this temperature. The TOC analysis results also indicated a significant increase in the proportion of WSOM. Colorimetry and elemental analysis results indicated that the soil color was dependent upon the initial heating temperature and was related to the H/C and O/C atomic ratios. The results of this study can form the basis for future similar studies for accurately characterizing and quantifying the heat effects on soil, and the effects of increasing wildfires due to climate change.

Influence of fine root traits on in situ exudation rates in four conifers from different mycorrhizal associations.

Plant roots can exude organic compounds into the soil that are useful for plant survival because they can degrade microorganisms around the roots and enhance allelopathy against other plant invasions. We developed a method to collect carbon (C) exudation on a small scale from tree fine roots by C-free filter traps. We quantified total C through root exudation in four conifers from different microbial symbiotic groups (ectomycorrhiza (ECM) and arbuscular mycorrhiza (AM)) in a cool-temperate forest in Japan. We determined the relationship of mass-based exudation rate from three diameter classes (<0.5, 0.5-1.0, and 1.0-2.5mm) of the intact root system with root traits such as morphological traits including root diameter, specific root length (SRL), specific root area (SRA), root tissue density (RTD) and chemical traits including root nitrogen (N) content and C/N. Across species, the mass-based root exudation rate was found to correlate with diameter, SRA, RTD, N and C/N. When comparing mycorrhizal types, there were significant relationships between the exudation and diameter, SRL, SRA, root N and C/N in ECM species; however, these were not significant in AM species. Our results show that relationships between in situ root exudation and every measured trait of morphology and chemistry were strongly driven by ECM roots and not by AM roots. These differences might explain the fact that ECM roots in this study potentially covaried by optimizing the exudation and root morphology in forest trees, while exudation in AM roots did not change with changes in root morphology. In addition, the contrasting results may be attributable to the effect of degree and position of ECM and AM colonization in fine root system. Differences in fine root exudation relationships to root morphology for the two types of mycorrhizae will help us better understand the underlying mechanisms of belowground C allocation in forest ecosystems.

Nitrogen source utilization in co-existing canopy tree and dwarf bamboo in a northern hardwood forest in Japan

Understory dwarf bamboo mitigated soil N competition with co-existing canopy oak trees by foraging in deeper soils and increasing dependence on N forms that differ from those used by canopy trees. Nitrogen (N) competition among co-existing plant species utilizing different mycorrhiza types was explored through the investigation of N sources of oak trees and dwarf bamboo. Vertical distribution of fine roots, soil N pools, δ15N of leaves, and possible soil N sources and nitrate reductase activity (NRA) were all quantified. The fine roots of canopy trees were more concentrated in the surface soils than roots of the understory dwarf bamboo. Soil NH4+ and extractable organic N (EON) content (based on unit weight) decreased from the organic horizon (O horizon) to the deep soils, the size of the NH4+ pool per unit volume increased with soil depth, and the EON was approximately constant. Soil NO3− was not detected at any soil depth or was not significant in value, while NO3− captured by ion-exchange resin (IER) buried at a 10 cm soil depth and net nitrification were observed via laboratory incubation at all soil depths. The δ15N of the NH4+ and EON pools increased with soil depth and the δ15N of NO3− of IER was lower than that of other N forms, except for the δ15N of NH4+ in the O horizon. Furthermore, root NRA tended to be lower in canopy trees than in the understory, implying lower dependency on NO3− by canopy trees. The pattern of root distribution and mycorrhizal fungi association of the understory vegetation (as well as the high root NRA) suggested that dependence on N in deeper soils was higher in understory plants than in canopy trees. These findings indicate that understory vegetation mitigates soil N competition against co-existing canopy trees via the use of alternative N sources.

Synthesis of L-Band SAR and Forest Heights Derived from TanDEM-X DEM and 3 Digital Terrain Models for Biomass Mapping

In this study, we compared the accuracies of above-ground biomass (AGB) estimated by integrating ALOS (Advanced Land Observing Satellite) PALSAR (Phased-Array-Type L-Band Synthetic Aperture Radar) data and TanDEM-X-derived forest heights (TDX heights) at four scales from 1/4 to 25 ha in a hemi-boreal forest in Japan. The TDX heights developed in this study included nine canopy height models (CHMs) and three model-based forest heights (ModelHs); the nine CHMs were derived from the three digital surface models (DSMs) of (I) TDX 12 m DEM (digital elevation model) product, (II) TDX 90 m DEM product and (III) TDX 5 m DSM, which we developed from two TDX–TSX (TerraSAR-X) image pairs for reference, and the three digital terrain models (DTMs) of (i) an airborne Light Detection and Ranging (LiDAR)-based DTM (LiDAR DTM), (ii) a topography-based DTM and (iii) the Shuttle Radar Topography Mission (SRTM) DEM; the three ModelHs were developed from the two TDX-TSX image pairs used in (III) and the three DTMs (i to iii) with the Sinc inversion model. In total, 12 AGB estimation models were developed for comparison. In this study, we included the C-band SRTM DEM as one of the DTMs. According to Walker et al. (2007), the SRTM DEM serves as a DTM for most of the Earth’s surface, except for the areas with extensive tree and/or shrub coverage, e.g., the boreal and Amazon regions. As our test site is located in a hemi-boreal zone with medium forest cover, we tested the ability of the SRTM DEM to serve as a DTM in our test site. This study especially aimed to analyze the capability of the two TDX DEM products (I and II) to estimate AGB in practice in the hemi-boreal region, and to examine how the different forest height creation methods (the simple DSM and DTM subtraction for the nine CHMs and the Sinc inversion model-based approach for the three ModelHs) and the different spatial resolutions of the three DSMs and three DTMs affected the AGB estimation results. We also conducted the slope-class analysis to see how the varying slopes influenced the AGB estimation accuracies. The results show that the combined use of the PALSAR data and the CHM derived from (I) TDX 12 m DEM and (i) LiDAR DTM achieved the highest AGB estimation accuracies across the scales (R2 ranged from 0.82 to 0.97), but the CHMs derived from (I) TDX 12 m DEM and another two DTMs, (ii) and (iii), showed low R2 values at any scales. In contrast, the two CHMs derived from (II) TDX 90 m DEM and both (i) LiDAR DTM and (iii) SRTM DEM showed high R2 values &gt; 0.87 and 0.78, respectively, at the scales &gt; 9.0 ha, but they yielded much lower R2 values at smaller scales. The three ModelHs gave the lowest R2 values across the scales (R2 ranged from 0.39 to 0.60). Analyzed by slope class at the 1.0 ha scale, however, all the 12 AGB estimation models yielded high R2 values &gt; 0.66 at the lowest slope class (0° to 9.9°), including the three ModelHs (R2 ranged between 0.68 to 0.69). The two CHMs derived from (II) TDX 90 m DEM and both (i) LiDAR DTM and (iii) SRTM DEM showed R2 values of 0.80 and 0.71, respectively, at the lowest slope class, while the CHM derived from (I) TDX 12 m DEM and (i) LiDAR DTM showed high R2 values across the slope classes (R2 &gt; 0.82). The results show that (I) TDX 12 m DEM had a high capability to estimate AGB, with a high accuracy across the scales and the slope classes in the form of CHM, but the use of (i) LiDAR DTM was required. On the other hand, (II) TDX 90 m DEM was able to achieve high AGB estimation accuracies not only with (i) LiDAR DTM, but also with (iii) SRTM DEM in the form of CHM, but it was limited to large scales &gt; 9.0 ha; however, all the models developed in this study have the possibility to achieve higher AGB estimation accuracies at the 1.0 ha scale in flat terrains with slope &lt; 10°. The analysis showed the strengths and limitations of each model, and it also indicates that the data creation methods, the spatial resolutions of datasets and topographic features affects the effective spatial scales for AGB mapping, and the optimal combinations of these features should be chosen to obtain high AGB estimation accuracies.

Climate responses of ring widths and radial growth phenology of Betula ermanii, Fagus crenata and Quercus crispula in a cool temperate forest in central Japan

Climate responses of radial growth of major hardwood species growing in a cool temperate forest in Japan were clarified by dendrochronological analysis combining the phenology observation of radial growth. To better understand which climate factors limit the radial growth of major hardwood species growing in a cool temperate forest in Japan, we clarified the phenology of radial growth and developed ring width residual chronologies for Betula ermanii, Fagus crenata and Quercus crispula at Takayama, an LTER research site located in central Japan. We inspected stem tissue for division of cambial cells in the early stage of wood formation and examined the cumulative radial growth by the wounding method. The onset of cambial cell division in Q. crispula was observed to be about 2 weeks earlier than in the other species. Wood formation in the final part of the tree ring occurred approximately 1 month earlier in B. ermanii than in the other species. The correlation analysis was performed between chronologies and moving averages of 31-day climate data with a 1-day lag. The periods which revealed significant correlations with climate factors were categorized into the previous growing season, previous autumn, just before the current growing season and current growing season according to their characteristic responses and the phenology of wood formation and leaves. The negative correlations between ring width of all the species and mean and minimum temperatures of previous year’s autumn, when the growth ending of ring width and leaf coloring occurred, suggested that temperature may have affected the respiration rate and/or prolonged the start of leaf fall, resulting in variations of radial growth through the consumption of photosynthetic products. On the other hand, different responses to climate were observed among species during the other phenological periods.

Trends and issues of landscape ecological studies on range expansion of bamboo forests in Japan -perspective for sustainable use of bamboo forests-

Trends and issues of landscape ecological studies on range expansion of bamboo forests in Japan -perspective for sustainable use of bamboo forests-

“The Dynamics of People and Ecosystems2: History and Future of Forests in Japan” written by SUZUKI Maki, SAITO Haruo, NISHIHIRO Jun, and MIYASHITA Tadashi (Book Review)

“The Dynamics of People and Ecosystems2: History and Future of Forests in Japan” written by SUZUKI Maki, SAITO Haruo, NISHIHIRO Jun, and MIYASHITA Tadashi (Book Review)

Leaf defense capacity of Japanese elm (Ulmus davidiana var. japonica) seedlings subjected to a nitrogen loading and insect herbivore dynamics in a free air ozone-enriched environment.

Japanese elm (Ulmus davidiana var. japonica) is a native species in cool-temperate forests in Japan. We investigated growth, physiological reactions, and leaf defense capacity of Japanese elm seedlings under nitrogen (N) loading (45.3 kg N ha-1 year-1) and seasonal insect dynamics in a free-air ozone (O3)-enriched environment (about 54.5 nmol O3 mol-1) over a growing season. Higher leaf N content and lower condensed tannin content in the presence of N loading and lower condensed tannin content in elevated O3 were observed, suggesting that both N loading and elevated O3 decreased the leaf defense capacity and that N loading further enhanced the leaf quality as food resource of insect herbivores. Two major herbivores were observed on the plants, elm leaf beetle (Pyrrhalta maculicollis) and elm sawfly (Arge captiva). The peak number of observed insects was decreased by N loading. Visible foliar injury caused by N loading might directly induce the reduction of number of the observed elm sawfly individuals. While elevated O3 slightly suppressed the chemical defense capacity, significantly lower number of elm leaf beetle was observed in elevated O3. We conclude that N loading and elevated O3 can alter not only the leaf defense capacity of Japanese elm seedlings but also the dynamics of elm leaf beetle and sawfly herbivores.

Quantitative comparison of flowering phenology traits among trees, perennial herbs, and annuals in a temperate plant community.

PremiseFlowering phenology may differ among life forms due to the costs and benefits to attract pollinators, dependence on outcross pollination, and resource availability in their habitats. However, few studies have compared flowering phenology among life forms within a community and described flowering phenology at the individual, species, and community levels.MethodsWe recorded flowering events for individuals of insect‐pollinated trees, perennial herbs, and annuals from spring to summer of 2016 and 2017 in a warm‐temperate forest in Japan. To compare phenological variables including mean and variance of flowering length, we standardized the number of observed individuals for each species and tested differences in variables, considering the phylogenetic relationships among species.ResultsTotal flowering length in trees (9–50 d) was significantly shorter than perennial herbs (27–113 d) or annuals (22–89 d), but mean flowering length was not significantly different among them. Flowering length variance was significantly smaller and intraspecies synchrony significantly higher in trees than in perennial herbs and annuals. At the community level, flowering times largely overlapped among successively flowering species, but interspecies synchrony was positive for all life forms.ConclusionsShorter total flowering length and higher intraspecific synchrony in trees are explained by a modified pollinator attraction hypothesis suggesting that selection favors higher intraspecific synchrony because it promotes between‐individual movement of pollinators. At the community level, positive interspecific synchrony for all life forms supports the hypothesis that flowering times tend to converge among species.

Plant trait database for Cryptomeria japonica and Chamaecyparis obtusa (SugiHinoki DB): Their physiology, morphology, anatomy and biochemistry

AbstractCryptomeria japonica (sugi) and Chamaecyparis obtusa (hinoki) are major Japanese timber species whose plantation area accounts for 44 and 25%, respectively, of the plantation forests in Japan. Physiology, anatomy and ecology of the species have been intensively studied for this half century, which now forms a huge stock of information. These data, however, were scattered in diverse sources, including papers, bulletins of research institutes, reports of other kinds and books, and were presented in nonstandardized, diverse styles in each source. This paper provides a database (SugiHinoki DB) that compiles 177 plant traits of sugi and hinoki from 364 primary sources published since 1950. The compiled traits include physiological, morphological, anatomical and biochemical features that are recognized as relevant to life history strategies, vegetation modeling and global change responses. Collected data have been obtained under different environmental conditions, for plants with different ages and for organs with a different age or different position, which provide information of within‐species variation for a given trait. Each data entry is accompanied by detailed ancillary information describing the site of measurement, stand of measurement and detailed measurement conditions, which help users account for data variations as a consequence of phenotypic plasticity and genetic variations and to filter data. To provide data in a consistent format, the data and the ancillary information were standardized, and units were converted. After data compilation, outliers were detected by calculating interquartile range for each trait per each species. As of August 2019, SugiHinokiDB contains 24,683 data entries (16,410 for sugi, 8,273 for hinoki). As sugi and hinoki are major plantation species in Japan, the data mostly came from study sites in Japan (from Hokkaido in the north to Yakushima island in Kyushu to the south) but were also obtained from arboretums or plantation forests in Taiwan, Korea and China. Data were largely obtained from plants in plantation forests but also from plants in natural forests and under experimental conditions. The improved availability of trait data offered by SugiHinokiDB provides new research opportunities, such as the intensive parameterization of vegetation models for a more accurate prediction of climate change impacts.