East Asian Forests Research Articles

Survival dynamics of stick insect and the impact of environmental factors on natural fungal infection during the rainy season.

Phasmatodea, commonly known as stick insects, are recognized as noteworthy pests globally, impacting agriculture and forest ecosystems. Among them, the outbreak of Ramulus mikado has emerged as a notable concern in East Asian forests. Recently, Metarhizium phasmatodeae has been identified as utilizing stick insects as hosts. We have observed evidence of this entomopathogenic fungus infecting stick insects. Given the increase in these occurrences during the rainy period, this study investigated the relationship between the survival of R. mikado and the M. phasmatodeae infection during the rainy seasons of 2022 and 2023. We collected stick insects in two representative forests of the Republic of Korea and examined insect survival, fungal infection, and various environmental factors. No infections were detected in specimens collected in June before the rainy season, but from July onwards, both the mortality of R. mikado and the fungal infection substantially increased. By the last sampling date of each year, 75% (2022), 71.4% (2023) of the specimens were infected, and over 90% of the total individuals succumbed as a result. Fungi isolated from deceased R. mikado were successfully identified as M. phasmatodeae using morphological and taxonomic approaches. Various statistical analyses, including principal component analysis and modeling, revealed a robust association between fungal infection and the survival of stick insects. The results highlight the correlation between mass deaths of stick insects and fungal infection, particularly during the summer rainy season. These findings offer valuable insights for forecasting R. mikado population in the upcoming year and developing effective pest control strategies.

Differences in spatial niche of terrestrial mammals when facing extreme snowfall: the case in east Asian forests

BackgroundRecent climate changes have produced extreme climate events. This study focused on extreme snowfall and intended to discuss the vulnerability of temperate mammals against it through interspecies comparisons of spatial niches in northern Japan. We constructed niche models for seven non-hibernating species through wide-scaled snow tracking on skis, whose total survey length was 1144 km.ResultsWe detected a low correlation (rs < 0.4) between most pairs of species niches, indicating that most species possessed different overwintering tactics. A morphological advantage in locomotion cost on snow did not always expand niche breadth. In contrast, a spatial niche could respond to (1) drastic landscape change by a diminishing understory due to snow, possibly leading to changes in predator-prey interactions, and (2) the mass of cold air, affecting thermoregulatory cost and food accessibility. When extraordinary snowfall occurred, the nonarboreal species with larger body sizes could niche shift, whereas the smaller-sized or semi-arboreal mammals did not. In addition, compared to omnivores, herbivores were prone to severe restriction of niche breadth due to a reduction in food accessibility under extreme climates.ConclusionsDietary habits and body size could determine the redundancy of niche width, which may govern robustness/vulnerability to extreme snowfall events.

On a fi nding of the weevil Magdalis margaritae Barrios (Coleoptera, Curculionidae: Magdalini) in Kemerovo city, Russia, and func-tioning of the plantations of the Siberian elm, Ulmus pumila L., in the herbivores exchange between european and eastern palaearctic forest massifs with participation of elms

In July 2013, an Eastern Palaearctic weevil Magdalis margaritae Barrios, developing on Ulmus pumila , was found for the rst time in Kemerovo City, West Siberia. Findings of this and other coleopterous phytophages of Ulmus pumila in the centre of southern Siberia presume possible role of the Ulmus pumila plantings as a corridor for herbivores and, probably, pathogens exchange between European and East Asian forest massifs with participation of their endemic Ulmus species.

Patterns of compound-leaf form and deciduous-leaf habit across forests in China: Their association and key climatic factors

Leaf form (compound vs. simple) and habit (evergreen vs. deciduous) are key functional traits of trees to adapt to various climates and are vital in determining plant response to climate change. However, their association and climatic determinants remain uncertain, especially in East Asian forests in the largest monsoon region on earth. To fill these knowledge gaps, we compiled a dataset comprising 42 intact forests and over 2200 angiosperm tree species across China (spanning 30 latitudes and 47 longitudes). The geographical and climatic patterns of leaf form and habit were analyzed. The association between compound leaf and deciduousness was tested for tropical, subtropical and temperate climatic zones. We found that both the percentage of compound leaf (CT%) and deciduous tree species (DT%) increased with latitude and decreased with mean annual precipitation (MAP). For all forests, DT% was negatively related to mean annual temperature (MAT), whereas CT% was not. Nevertheless, both DT% and CT% increased with increasing MAT in the tropics, possibly owing to the high vapor pressure deficits (VPD) and canopy water deficits associated with high temperatures. A positive linear relationship between CT% and DT% was found across all forests and within different climatic zones except for temperate, and the intercept of the regression line was significantly higher in the tropics than in the subtropics. Overall, as supported by principal component analysis, deciduousness was negatively associated with both temperature and precipitation, while CT negatively with precipitation only across zones and positively with temperature in the tropics. Different relationships in different climatic zones suggest potentially different selective forces. Our findings provide novel insights into the linkage between leaf form and habit, as well as how climate shapes the landscape of broadleaf forests, which has important implications regarding the response of forest composition to climate change.

Recent advances in the understanding of ecosystem processes at eddy covariance CO&lt;SUB&gt;2&lt;/SUB&gt; flux sites in East Asian forest ecosystems: a review

Recent advances in the understanding of ecosystem processes at eddy covariance CO&lt;SUB&gt;2&lt;/SUB&gt; flux sites in East Asian forest ecosystems: a review

Estimation of six leaf traits of East Asian forest tree species by leaf spectroscopy and partial least square regression

To elucidate the potential of hyperspectral remote sensing for estimating the functional leaf traits in East Asian forests, we investigated the utility of leaf spectroscopy and partial least square regression (PLSR) models for 141 tree species distributed widely across cool temperate to tropical climate zones in the Pacific region. In 14 forests in Japan, Thailand, and Malaysia, leaf samples at various developmental stages (young, mature, and senescent) were collected from two plant functional types (deciduous and evergreen species). The target leaf traits were leaf mass per unit area and concentrations of nitrogen (N), carbon (C), total phenol, cellulose, and lignin. The leaf reflectance at visible-short wave infrared spectral reflectance from 400 nm to 2395 nm was measured at 3–10-nm intervals (351 bands) using a spectral radiometer. First, we compared the performance of the PLSR models in terms of dry mass (DM) -based concentration and leaf area (LA) –based concentration. Then, we investigated the applicability of the models based on the different plant functional types and leaf developmental stages of the training dataset. Finally, we evaluated the minimum number of spectral bands needed for stable performance of the PLSR model by changing the used bands in accordance with the variable importance of projection (VIP) and equal interval resampling.The coefficient of determination (R2) was higher and the normalized root mean square error (NRMSE) tended to be lower for all chemical trait concentrations expressed based on LA than for those based on DM, except for the case of leaf N. Plant functional type in the training data affected the applicability of the estimation model strongly. The estimation error increased when the functional type in the training dataset differed from that of the target tree species. In the PLSR model calibrated using datasets of evergreen tree species, the NRMSEs of the six traits were 8.0–12.6% for evergreen tree species but 10.4–21.1% for deciduous tree species. A similar trend was observed in the model calibrated for deciduous tree species. The model calibrated using both functional types showed intermediate accuracy for both types of tree species (NRMSE = 5.3–13.5%). The developmental stage of training data also affected the model performance, and the model calibrated using all of the stages showed better estimation accuracies for young and senescent leaves than the model calibrated from the data of mature leaves alone.The equal interval resampling provided better estimation accuracy than the case using the threshold of the VIP value although the model performance tended to be diminished with the reduction of input waveband in both methods. Using at least 104 bands with equal interval removal at a 20-nm interval confers similar performance of the PLSR model compared to the model with full wavebands. This study is the first to describe the potential of leaf spectroscopy for trait estimation of East Asian forest tree species, and our findings suggest that training datasets of typical functional types and varied developmental stages are important for estimation of leaf traits through the several biomes distributed widely in East Asia.

Global forest carbon uptake due to nitrogen and phosphorus deposition from 1850 to 2100.

Spatial patterns and temporal trends of nitrogen (N) and phosphorus (P) deposition are important for quantifying their impact on forest carbon (C) uptake. In a first step, we modeled historical and future change in the global distributions of the atmospheric deposition of N and P from the dry and wet deposition of aerosols and gases containing N and P. Future projections were compared between two scenarios with contrasting aerosol emissions. Modeled fields of N and P deposition and P concentration were evaluated using globally distributed insitu measurements. N deposition peaked around 1990 in European forests and around 2010 in East Asian forests, and both increased sevenfold relative to 1850. P deposition peaked around 2010 in South Asian forests and increased 3.5-fold relative to 1850. In a second step, we estimated the change in C storage in forests due to the fertilization by deposited N and P (∆Cν dep ), based on the retention of deposited nutrients, their allocation within plants, and C:N and C:P stoichiometry. ∆Cν dep for 1997-2013 was estimated to be 0.27±0.13PgCyear-1 from N and 0.054±0.10PgCyear-1 from P, contributing 9% and 2% of the terrestrial C sink, respectively. Sensitivity tests show that uncertainty of ∆Cν dep was larger from P than from N, mainly due to uncertainty in the fraction of deposited P that is fixed by soil. ∆CPdep was exceeded by ∆CNdep over 1960-2007 in a large area of East Asian and West European forests due to a faster growth in N deposition than P. Our results suggest a significant contribution of anthropogenic P deposition to C storage, and additional sources of N are needed to support C storage by P in some Asian tropical forests where the deposition rate increased even faster for P than for N.

Impacts of human farm activities on tropical deforestation and climate change: interactive statistical models

The tropical rainforests are essential for sustainable development of earth's ecosystem. The rainforests are rich storehouse of biodiversity, natural pharmaceutical products, source of sustained water resources and manage microclimate of their region. The forest regimes in Amazonian, Congo basin and South East Asian forest regions are under constant threat of degradation. The carbon dioxide concentration in the earth's atmosphere has reached the highest ever seen by the human beings to 400 ppm level and mean surface temperature of earth has increased by 1°C in last 50 years. This study explores statistical relations for rainforest remaining in the earth and carbon dioxide concentration in the earth's atmosphere as function of widespread human farm activities such as soya bean, corn and palm oil production as factors. The response surface methodology is used to analyse data from year 2000 to 2013 which shows that rate of world tropical rainforest degradation and CO2 concentration in the earth's atmosphere increases with increase in world soy, corn and palm production and mathematical models predicting these relations were developed.

Quantifying the role of fire in the Earth system – Part 2: Impact on the net carbon balance of global terrestrial ecosystems for the 20th century

Abstract. Fire is the primary form of terrestrial ecosystem disturbance on a global scale. It affects the net carbon balance of terrestrial ecosystems by emitting carbon directly and immediately into the atmosphere from biomass burning (the fire direct effect), and by changing net ecosystem productivity and land-use carbon loss in post-fire regions due to biomass burning and fire-induced vegetation mortality (the fire indirect effect). Here, we provide the first quantitative assessment of the impact of fire on the net carbon balance of global terrestrial ecosystems during the 20th century, and investigate the roles of fire's direct and indirect effects. This is done by quantifying the difference between the 20th century fire-on and fire-off simulations with the NCAR Community Land Model CLM4.5 (prescribed vegetation cover and uncoupled from the atmospheric model) as a model platform. Results show that fire decreases the net carbon gain of global terrestrial ecosystems by 1.0 Pg C yr−1 averaged across the 20th century, as a result of the fire direct effect (1.9 Pg C yr−1) partly offset by the indirect effect (−0.9 Pg C yr−1). Post-fire regions generally experience decreased carbon gains, which is significant over tropical savannas and some North American and East Asian forests. This decrease is due to the direct effect usually exceeding the indirect effect, while they have similar spatial patterns and opposite sign. The effect of fire on the net carbon balance significantly declines until ∼1970 with a trend of 8 Tg C yr−1 due to an increasing indirect effect, and increases subsequently with a trend of 18 Tg C yr−1 due to an increasing direct effect. These results help constrain the global-scale dynamics of fire and the terrestrial carbon cycle.

Reliability and resolution of the coexistence approach — A revalidation using modern-day data

The coexistence approach (CA) is widely used to reconstruct palaeoclimates for the Cenozoic. Most published CA analyses relied on climate data for nearest living relatives (NLRs) stored in the Palaeoflora database (PFDB). Here, we used more than two-hundred modern relevés (taxon lists of forest stands) from North American, Caucasian and East Asian forest regions in order to test the ability of CA/PFDB to estimate palaeoclimate. Since only data for mean annual temperature (MAT) are publicly available from the PFDB, we concentrated on this climate parameter. Two criteria were tested: ‘resolution’ and ‘reliability’ of CA/PFDB analyses. The CA assumes that for a given climate parameter (e.g. MAT; mean annual precipitation; coldest month mean temperature etc.) the interval shared by all or nearly all NLRs for a fossil assemblage is best describing the past climatic conditions. Narrow, i.e. well-resolved, intervals are desirable, since they describe most precisely the climate. Our results show that CA/PFDB is unable to reliably reconstruct the actual climates of most of the relevés analysed. CA/PFDB performed best for lowland and mid-altitude stands with MAT of ca. 13–16°C, while producing remarkably incorrect results for warmer lowland stands and cooler stands at higher elevations. This is mainly due to generally incorrect entries of MAT ranges of NLRs in the PFDB. Using corrected MAT tolerances, the reconstructed, low-resolved intervals (3°C in exceptional cases, typically 5–10°C) fall within the actual climates. Hence, only dramatic climate changes are likely to be captured in a CA analysis. This renders the coexistence approach useless for the quantitative reconstruction of palaeoclimate and calls for alternative approaches of investigating past climates by means of fossil plants.

Ecomorphology, differentiated habitat use, and nocturnal activities of Rhinolophus and Hipposideros species in East Asian tropical forests

We investigated the wing morphology and foraging distributions of sympatric Rhinolophus and Hipposideros species by acoustic sampling, measuring wing parameters, and observing bats in different settings of tropical East Asian forests, to evaluate their flexibility in habitat use and edge sensitivity. R. formosae and H. terasensis were more abundant at edges/in open habitats and shared the highest overlap, with R. formosae displaying the greatest breadth in habitat use, whereas R. monoceros had a higher abundance and feeding efficiency in forest interiors with a continuous canopy. H. terasensis was significantly larger and had higher wing loading and aspect ratio than R. formosae and R. monoceros, while R. formosae had higher wing loading but a lower aspect ratio than the smaller-sized R. monoceros. Shrubs and herbs were higher at sites where bats were captured than at those without bat captures, and R. monoceros and R. formosae were associated with greater canopy and ground coverage, respectively. R. monoceros always foraged while flying at lower heights close to the herb/shrub layers, while H. terasensis and R. formosae used perching to different extents, with R. formosae preferably using fly-catching techniques and appearing farther from the path in open forests rather than in forest interiors. Our results indicate that differences in wing parameters account for the different degrees of flexibility in habitat use, yet the deviations of call frequency from the expected values in R. formosae and H. terasensis suggest additional adaptations accounting for their flexibility in exploring habitats.

Spatial variations in evapotranspiration over East Asian forest sites. I. Evapotranspiration and decoupling coefficient

Evapotranspiration (ET) is not only a vital component of water budget, but also plays an important role in the energy budget of the earth-atmospheric system, ultimately driving many regional and global scale climatological processes. This paper describes the ET characteristics and factors controlling ET across the 17 forest sites in East Asia (2°S to 64°N latitude). ET was measured using the eddy covariance technique at each site. Daytime dry-canopy data for the growing season were used in this study. Growing season mean ET gradually decreased as latitude increased, with a range of 4.4 to 1.2 mm d−1. The growing season mean decoupling coefficient (Ω) ranged from 0.42 to 0.11 across the studied sites. At low-latitude forest sites, Ω was close to 0.50, indicating that the bulk surface was partially decoupled from the atmosphere and ET was strongly controlled by net radiation and vapour pressure deficit. At high-latitude forest sites, Ω was low (∼0.12), indicating that the bulk surface was well coupled to the atmosphere and ET was mainly controlled by surface conductance. The value of Ω was determined mainly by the ratio of aerodynamic conductance to surface conductance across the studied forests of East Asia.

Spatial variations in evapotranspiration over East Asian forest sites. II. Surface conductance and aerodynamic conductance

Evapotranspiration over forest surfaces is mainly constrained by environmental and forest structural components through their influence on surface conductance (Gs) and aerodynamic conductance (Ga). Tower based eddy covariance data from 16 forest sites in East Asia (2°S to 64°N) were used to examine the sensitivity of Matsumoto and Nakai models for predicting Gs and Ga, respectively. Daytime dry-canopy data for the growing season were used in this study. Comparisons between model predictions and observed Gs and Ga showed good agreement, suggesting that the models were suitable for predicting Gs and Ga with reasonable accuracy. However, the model for Gs was unable to predict Gs accurately when soil water content was low (∼10%). In this circumstance, effective soil water content and a more comprehensive method for modelling the soil water content function must be used. Gs in East Asia was largely depended on vapour pressure deficit and secondarily on soil water content. Ga was largely affected by leaf area index compared with stand density.

Effect of Topography and Soil on the Distribution of under Canopy Trees of Garcinia (Guttiferae) in Lowland Forest of Peninsular Malaysia

The distribution and aggregation of species in tropical forests is known to have certain preferences based on the edaphic factors such as topography types and soil series and this study was carried out to see the distribution of 16 Garcinia species in lowland dipterocarp forest in Pasoh Forest Reserve with those edaphic factors. Even though there have been many studies in large scale areas with a larger group of species to see the relationship of edaphic factors with species distribution, very few studies have been carried out on individual species especially for under-canopy or lesser known species. Garcinia is an under-canopy tree species in tropical South East Asian forests with no commercial values but mostly known because of their edible fruits. Based on published topography and soil series maps in 50 ha plot, the preferences of Garcinia trees were analysed and calculated. Results showed that Garcinia trees could be found on all types of topography and soil but most trees are distributed very well on the flatland and well-drained alluvium soils rather than other areas. The least number of stems found are in the top (highest) topography and poorly-drained (prone to flood) alluvium soil. However, at species level, there are significant preferences of each Garcinia species on the different type of topography and soil. This shows that different type of topography and soil play significant effect on the distribution of Garcinia trees in tropical lowland forest.

Did glacials and/or interglacials promote allopatric incipient speciation in East Asian temperate plants? Phylogeographic and coalescent analyses on refugial isolation and divergence in Dysosmaversipellis

To explore the evolutionary consequences of climate-induced fluctuations in presently fragmented temperate forest habitats in continental East Asia we investigated the phylogeography and demographic history of the temperate-deciduous forest endemic Dysosma versipellis from disjunct montane sites in Central-Southeast China. Based on a survey of chloroplast (cp) DNA sequence variation, our analyses show that this perennial herb consists of morphologically indistinguishable western and central/eastern cpDNA lineages. Coalescent analyses under the ‘isolation with migration’ (IM) model support an ancient (Mid-Pleistocene) divergence between these lineages, with the western lineage having persisted without significant population growth in a long-term refuge just east of the Tibetan (Qinghai-Xizang) Plateau. In contrast, for the central/eastern lineage, we found strong evidence for population expansion from a refuge located south of the middle and lower reaches of the Yangtze River, and likely coinciding with the last or penultimate interglacial, followed by considerable population isolation and divergence in situ over (at least) the latest glacial–interglacial cycle. In line with recent evidence from palaeomodeling of East Asian forest biomes, our results suggest that the same vicariance factor, i.e. climate-induced eco-geographic isolation through (a)biotic displacement of temperate-deciduous forested habitats, promoted the divergence of D. versipellis lineages and populations at different spatial–temporal scales and over glacial and interglacial periods. Thus, there is no evidence that populations of D. versipellis merged at lower elevations during the last glacial(s). As such, D. versipellis accords with the premise that Late Quaternary refugial isolation is likely to have enhanced allopatric (incipient) species formation of temperate plants in East Asia.

Aspidistras, amphipods and Oz: Niche opportunism between strangers in a strange land

The subterranean flowers of Aspidistra in their natural habitat of moist temperate East Asian forests are reportedly pollinated by terrestrial amphipods. Seed set by cultivated plants growing in Adelaide, South Australia, suggests that a pollinator shift has occurred and the results show that despite their different origins, the apparently highly specialized pollination system of the Asian Aspidistra can be accomplished by an introduced eastern Australian amphipod, Arcitalitrus sylvaticus . Pollination is possibly also achieved by cosmopolitan collembolans that feed on pollen inside the floral chambers. It appears that by providing subterranean floral chambers, Aspidistra potentially exploits the cryptic, fugitive behavior of soil or litter-dwelling invertebrates. This supports the theory of asymmetrical pollination where an apparently specialized flower is pollinated successfully through the generalized behavior of its pollinators.

South East Asian Forest Fires: Haze over ASEAN and International Environmental Law

Review of European Community & International Environmental LawVolume 7, Issue 2 p. 202-208 South East Asian Forest Fires: Haze over ASEAN and International Environmental Law Simon S. C. Tay, Simon S. C. TaySearch for more papers by this author Simon S. C. Tay, Simon S. C. TaySearch for more papers by this author First published: 17 December 2002 https://doi.org/10.1111/1467-9388.00147Citations: 6AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume7, Issue2July 1998Pages 202-208 RelatedInformation