Estimating the production and mortality of fine roots using minirhizotrons in a Pinus densiflora forest in Gwangneung,Korea

The aim of this study was to estimate fine root production （FP） and fine root mortality （FM） at 0-10, 10-20, and 20-30 cm soil depths using minirhizotrons in a 75-year-old Pinus densiflora Sieb. et Zucc. forest located in Gwangneung, Korea. We developed the conversion factors （frame cm-2） of three soil depths （0.158 for 0-10 cm, 0.120 for 10-20 cm, and 0.131 for 20-30 cm） based on soil coring and minirhizotron data. FP and FM were estimated using conversion factors from March 26, 2013 to March 2, 2014. The annual FP and FM values at the 0-30 cm soil depth were 3200.2 and 2271.5 kg ha-1 yr -1, respectively. The FP estimate accounted for approximately 17 % of the total net primary production at the study site. FP was highest in summer （July 31-September 26）, and FM was highest in autumn （September 27-November 29）. FP was positively correlated with seasonal change in soil temperature, while FM was not related to that change. The sea- sonality of FP and FM might be linked to above-ground photosynthetic activity. Both FP and FM at the 0-10 cm depth were significantly higher than at 10-20 and 20-30 cm depths, and this resulted from the decrease in nutrient availability with increasing soil depth. The minirhizotron approach and conversion factors developed in this study will enable fast and accurate estimation of the fine root dynamics in P. densiflora forest ecosystems.

Forest structure and carbon dynamics of an intact lowland mixed dipterocarp forest in Brunei Darussalam

Tropical forests play a critical role in mitigating climate change because they account for large amount o terrestrial carbon storage and productivity.However,there are many uncertainties associated with the estimation o carbon dynamics.We estimated forest structure and carbon dynamics along a slope（17.3°–42.8°）and to assess the relations between forest structures,carbon dynamics,and slopes in an intact lowland mixed dipterocarp forest,in Kuala Belalong,Brunei Darussalam.Living biomass,basa area,stand density,crown properties,and tree family composition were measured for forest structure.Growth rate,litter production,and litter decomposition rates were also measured for carbon dynamics.The crown form index and the crown position index were used to assess crown properties,which we categorized into five stages,from very poor to perfect.The living biomass,basal area and stand density were 261.5–940.7 Mg ha-1,43.6–63.6 m2ha-1and 6,675–8400 tree ha-1,respectively.The average crown form and position index were 4,which means that the crown are mostly symmetrical and sufficiently exposed for photosynthesis.The mean biomass growth rate,litter production,litter decomposition rate were estimated as11.9,11.6 Mg ha-1a-1,and 7.2 g a-1,respectively.Biomass growth rate was significantly correlated with living biomass,basal area,and crown form.Crown form appeared to strongly influence living biomass,basal area and biomass growth rate in terms of light acquisition.However,basal area,stand density,crown properties,and biomass growth rate did not vary by slope or tree family composition.The results indicate that carbon accumulation by tree growth in an intact lowland mixed dipterocarp forest depends on crown properties.Absence of any effect of tree family composition on carbon accumulation suggests that the main driver of biomass accumulation in old-growth forests of Borneo is not species-specific characteristics of tree species.

The effect of fertilization on early growth of konara oak and Japanese zelkova seedlings planted in a harvested pitch pine plantation

We determined a suitable amount of fertilizer for konara oak（Quercus serrata） and Japanese zelkova（Zelkova serrata） planted in a harvested pitch pine（Pinus rigida） plantation. Two-year-old bare-root seedlings of konara oak and one-year-old containerized seedlings of Japanese zelkova were planted in April 2011. Three plots were established for each tree species to evaluate each of three fertilization applications. Solid compound fertilizer（N：P：K = 3：4：1） was applied yearly in three amounts（control： no fertilization, F1： 180 kg ha-1, and F2：360 kg ha-1）, every May from 2011 to 2013. We measured the root collar diameter and height, and analyzed the compartmental N and P concentrations. Compartmental N concentrations of konara oak and Japanese zelkova were not consistent based on amount of fertilization. However,the compartmental P concentrations of konara oak and Japanese zelkova were significantly different in the order of F2, F1, and control. Although the differences in growth of konara oak appeared after 3 years of fertilization,Japanese zelkova showed differences after only 2 years of fertilization owing to differences in seedling type. Growth of konara oak was affected by fertilization at F1 and F2 in2013. However, growth of Japanese zelkova was affected only at F2. Nutrient demand of Japanese zelkova appeard to be higher than that of konara oak, at least during the early growing period. Results from this study could be practically used in harvested pitch pine plantations to determine appropriate fertilization regimes.

Selecting and applying quantification models for ecosystem services to forest ecosystems in South Korea

There is growing interest in using ecosystem services to aid development of management strategies that target sustainability and enhance ecosystem support to humans. Challenges remain in the search for methods and indicators that can quantify ecosystem services using metrics that are meaningful in light of their high priorities. We developed a framework to link ecosystems to human wellbeing based on a stepwise approach. We evaluated prospective models in terms of their capacity to quantify national ecosystem services of forests. The most applicable models were subsequently used to quantify ecosystem services. The Korea Forest Research Institute model sat- isfied all criteria in its first practical use. A total of 12 key ecosystem services were identified. For our case study, we quantified four ecosystem functions, viz. water storage capacity in forest soil for water storage service, reduced suspended sediment for water purification service, reduced soil erosion for landslide prevention service, and reduced sediment yield for sediment regulation service. Water storage capacity in forest soil was estimated at 2142 t/ha, and reduced suspended sediment was estimated at 608 kg/ ha. Reduced soil erosion was estimated at 77 m^3/ha, and reduced sediment yield was estimated at 285 m^3/ha. These results were similar to those reported by previous studies. Mapped results revealed hotspots of ecosystem services around protected areas that were particularly rich in bio- diversity. In addition, the proposed framework illustrated that quantification of ecosystem services could be sup- ported by the spatial flow of ecosystem services. However, our approach did not address challenges faced when quantifying connections between ecosystem indicators and actual benefits of services described.

Assessing vulnerability of forests to climate change in South Korea

This study demonstrated a framework to assess vulnerability of forests to climate change. We focused on how alterations of temperature and precipitation might affect forest type distributions and carbon-related functions. In particular, our framework considered three sectors of forest type distribution, net primary production, and soil carbon storage. Future projections were derived from mechanistic models for South Korean forests under the A1 B scenarios of the intergovernmental panel on climate change. Forest type distributions were simulated by the Hydrological and thermal analogy group model, while the MAPSS and CENTURY1 models estimated forest carbon flux/storage. We quantified normalized vulnerability indices for each sector. Our results indicate that the overall vulnerability of forest type distribution is greater in the west central regions and southeastern inlands. The vulnerabilities of carbon flux/storage show that net primary production of South Korean forests is relatively less susceptible to climate change, but a highly vulnerable area of soil carbon storage mainly spreads from the west central to the south east region. The spatio-temporal vulnerability map with a synoptic overview from this study might be useful for policy makers in preparing adaptive measures and identifying management priorities.

Short-Term Effects of Experimental Warming and Precipitation Manipulation on Soil Microbial Biomass C and N, Community Substrate Utilization Patterns and Community Composition

Soil microorganisms are major drivers of soil carbon(C) cycling;however,the response of these microorganisms to climate change remains unclear.In the present study,we investigated how 18 months of multifactor climate treatments(warmed air temperature by 3℃ and decreased or increased precipitation manipulation by 30%) affected soil microbial biomass C and nitrogen(N),community substrate utilization patterns,and community composition.Decreased and increased precipitation significantly reduced microbial biomass C by 13.5% and 24.9% and microbial biomass N by 22.9% and 17.6% in unwarmed plots,respectively(P<0.01).Warming enhanced community substrate utilization by 89.8%,20.4%,and 141.4% in the natural,decreased,and increased precipitation plots,respectively.Particularly,warming significantly enhanced the utilization of amine and carboxylic acid substrates among all precipitation manipulation plots.Compared with the natural air temperature with natural precipitation treatment,other treatments affected fungal community richness by -0.9% to 33.6% and reduced the relative abundance of the dominant bacterial and fungal groups by 0.5% to 6.8% and 4.3% to 10.7%,respectively.The warming and/or precipitation manipulation treatments significantly altered Zygomycota abundance(P<0.05).Our results indicate that climate change drivers and their interactions may cause changes in soil microbial biomass C and N,community substrate utilization patterns,and community composition,particularly for the fungal community,and shifts in the microorganism community may further shape the ecosystems function.

Soil compression influences the avoidance behavior of Allonychiurus kimi(Collembola)to cadmium and copper

The behavior of soil organisms inhabiting soil pore spaces can be influenced by soil compression,which can affect their avoidance behavior to pollutants.In this study,we aimed to evaluate the effect of soil compression on the avoidance behavior of Allonychiurus kimi(Collembola)to heavy metals cadmium and copper.Initially,to assess the applicability of the avoidance test guideline of the International Organization for Standardization(ISO)developed for Folsomia candida,we investigated the avoidance behavior of A.kimi to cadmium and copper in an artificial soil with a loose structure(bulk density of 0.25 g cm^(-3)),the porous texture of which was sufficiently loose to enable A.kimi to move between pore spaces.The effect of soil compression on the avoidance behavior of A.kimi to both metals was evaluated in compressed soil(bulk density of 0.64 g cm^(-3))with a uniformly compressed soil surface,and avoidance behavior was investigated at 24-h intervals over a 120-h period.Given that A.kimi is unable to burrow into compressed soil,the compressed soil test can minimize the effects of differences in soil factors,such as soil porosity and bulk density,on the behavior of this collembolan.In the artificial soil,a statistically significant avoidance behavior of A.kimi was observed at cadmium and copper concentrations greater than 50 and 200 mg kg^(-1),respectively,thereby indicating the applicability of the ISO avoidance test guidelines for A.kimi.When compared at the same exposure time point,the avoidance response to both metals in compressed soil was less sensitive than that in uncompressed soil.In addition,we observed differences in the effects of metals on avoidance response in the compressed soil over time,with the effect of cadmium increasing with time and the effect of copper showing the opposite trend.Overall,we found that soil compression can affect the avoidance behavior of A.kimi to cadmium and copper,and we discussed the advantages and limitations of using compressed soil for assessments of pollutant toxicity.

Estimation of effective plant area index for South Korean forests using LiDAR system

Light Detection and Ranging(LiDAR) systems can be used to estimate both vertical and horizontal forest structure.Woody components,the leaves of trees and the understory can be described with high precision,using geo-registered 3D-points.Based on this concept,the Effective Plant Area Indices(PAIe) for areas of Korean Pine(Pinus koraiensis),Japanese Larch(Larix leptolepis) and Oak(Quercus spp.) were estimated by calculating the ratio of intercepted and incident LIDAR laser rays for the canopies of the three forest types.Initially,the canopy gap fraction(GLiDAR) was generated by extracting the LiDAR data reflected from the canopy surface,or inner canopy area,using k-means statistics.The LiDAR-derived PAIe was then estimated by using GLIDAR with the Beer-Lambert law.A comparison of the LiDAR-derived and field-derived PAIe revealed the coefficients of determination for Korean Pine,Japanese Larch and Oak to be 0.82,0.64 and 0.59,respectively.These differences between field-based and LIDAR-based PAIe for the different forest types were attributed to the amount of leaves and branches in the forest stands.The absence of leaves,in the case of both Larch and Oak,meant that the LiDAR pulses were only reflected from branches.The probability that the LiDAR pulses are reflected from bare branches is low as compared to the reflection from branches with a high leaf density.This is because the size of the branch is smaller than the resolution across and along the 1 meter LIDAR laser track.Therefore,a better predictive accuracy would be expected for the model if the study would be repeated in late spring when the shoots and leaves of the deciduous trees begin to appear.

Changes in the distribution of South Korean forest vegetation simulated using thermal gradient indices

To predict changes in South Korean vegetation distribution,the Warmth Index(WI) and the Minimum Temperature of the Coldest Month Index(MTCI) were used.Historical climate data of the past 30 years,from 1971 to 2000,was obtained from the Korea Meteorological Administration.The Fifth-Generation National Center for Atmospheric Research(NCAR) /Penn State Mesoscale Model(MM5) was used as a source for future climatic data under the A1B scenario from the Special Report on Emission Scenario(SRES) of the Intergovernmental Panel on Climate Change(IPCC).To simulate future vegetation distribution due to climate change,the optimal habitat ranges of Korean tree species were delimited by the thermal gradient indices,such as WI and MTCI.To categorize the Thermal Analogy Groups(TAGs) for the tree species,the WI and MTCI were orthogonally plotted on a two-dimensional grid map.The TAGs were then designated by the analogue composition of tree species belonging to the optimal WI and MTCI ranges.As a result of the clustering process,22 TAGs were generated to explain the forest vegetation distribution in Korea.The primary change in distribution for these TAGs will likely be in the shrinkage of areas for the TAGs related to Pinus densiflora and P.koraiensis,and in the expansion of the other TAG areas,mainly occupied by evergreen broad-leaved trees,such as Camellia japonica,Cyclobalanopsis glauca,and Schima superba.Using the TAGs to explain the effects of climate change on vegetation distribution on a more regional scale resulted in greater detail than previously used global or continental scale vegetation models.

Characteristics of greenhouse gas emissions from rice paddy fields in South Korea under climate change scenario RCP-8.5 using the DNDC model

Understanding the greenhouse gas(GHG)emission from rice paddy fields is essential to come up with appropriate countermeasure in response to global warming.However,GHG emissions from paddy fields in South Korea are not well characterized.The objectives of this study were to estimate the carbon dioxide(CO_(2))and methane(CH_(4))emissions from rice paddy fields in South Korea,under the Representative Concentration Pathway 8.5(RCP-8.5)climate change scenario using the DNDC(i.e.,DeNitrification-DeComposition)model at 1-km^(2)resolution.The performance of the model was verified with field data collected using a closed chamber,which supports the application of the model to South Korea.Both the model predictions and field measurements showed that most(>95%)GHG emissions occur in the cropping period,between April and October.As a baseline(assuming no climate change),the national sums of the CO_(2)and CH_(4)emissions for the 2020 s and 2090 s were estimated to be 5.8×10^(6)and 6.0×10^(6)t CO_(2)-equivalents(CO_(2)-eq)year^(-1)for CO_(2)and 6.4×10^(6)and 6.6×10^(6)t CO_(2)-eq year^(-1)for CH_(4),respectively,indicating no significant changes over 80 years.Under RCP-8.5,in the 2090 s,CH_(4)emissions were predicted to increase by 10.7×10^(6)and 14.9×10^(6)t CO_(2)-eq year^(-1),for a 10-or 30-cm tillage depth,respectively.However,the CO_(2)emissions gradually decreased with rising temperatures,due to reduced root respiration.Deep tillage increased the emissions of both GHGs,with a more pronounced effect for CH_(4)than CO_(2).Intermittent drainage in the middle of the cropping season can attenuate the CH_(4)emissions from paddy fields.The findings of this work will aid in developing nationwide policies on agricultural land management in the face of climate change.

Soil depth- and root diameter- related variations affect root decomposition in temperate pine and oak forests

Aims Assessment of factors regulating root decomposition is needed to understand carbon and nutrient cycling in forest ecosystems.the ob-jective of this study is to examine the effects of soil depth and root diameter on root decomposition and to analyze the relationship of root decomposition with factors such as soil environmental conditions and initial litter quality.Methods two decomposition experiments were conducted in natural pine(Pinus densiflora)and oak(Quercus serrata)forests over a 2-year period using the litterbag technique.For the soil depth experiment,216 litterbags containing fine roots(∅=0-2 mm)were buried at 0-10-,10-20-and 20-30-cm soil depths.Soil properties and soil enzyme activities and microbial biomass at each soil depth were analyzed.For the root diameter experiment,216 litterbags containing roots 0-1-,1-2-and 2-3-mm in diameter were buried at 10-cm soil depth.the initial litter qualities(carbon(c),nitrogen(N),calcium(ca)and phosphorus(P)concentrations)for each of the root diameter classes were analyzed.Litterbags were retrieved after 3,6,12 and 24 months in each forest type.Important Findingsthe root decomposition rate was significantly altered by soil depth and root diameter.After 2 years,the root decay constant at 0-10-cm depth(pine:0.35 and oak:0.41)was significantly higher than that at 10-20-cm(0.31 and 0.37)and 20-30-cm(0.32 and 0.33)depths in the P.densiflora and Q.serrata forests.Enzyme activities and microbial biomass declined with soil depth,which may be associated with decreasing soil moisture and organic matter.the decay constant for the 0-1-mm roots(pine:0.32 and oak:0.37)was higher than that of 1-2-mm(0.29 and 0.33)and 2-3-mm roots(0.26 and 0.33)for the P.densiflora and Q.serrata forests.Difference in initial P concentration and c/N ratio among the different diameter roots were linearly related with root decomposition.In particular,the increasing c/N ratio with root diameter resulted in decreases in the decomposition rate.these results indicate the surface soil microbial activities and initial c/N ratio of root litter as important drivers of c dynamics in temperate pine and oak forests.

Effect of open-field experimental warming on the leaf phenology of oriental oak (Quercus variabilis) seedlings

Aims An open-field warming experiment enables us to test the effects of projected temperature increase on change in plant phenology with fewer confounding factors and to study phenological response to temperature ranges beyond natural variability.This study aims to(i)examine the effect of temperature increase on leaf unfold-ing and senescence of oriental oak(Quercus variabilis Blume)under experimental warming and(ii)measure temperature-related parameters used in estimating phenological response to tempera-ture elevation.Methods Using an open-field warming system with infrared heaters,we increased the air temperature by~3℃ in the warmed plots compared with that of the control plots consistently for 2 years.Leaf unfolding and senescence dates of Q.variabilis seedlings were recorded and temperature-related phenological parameters were analysed.Important Findings The timing of leaf unfolding was advanced by 3-8 days(1.1-3.0 days/℃)and the date of leaf senescence was delayed by 14-19 days(5.0-7.3 days/℃)under elevated air temperatures.However,the cumulative degree days(CDD)of leaf unfolding were not significantly changed by experimental warming,which suggest the applicability of a constant CDD value to estimate the change in spring leaf phe-nology under 3℃ warming.Consistent ranges of advancement and temperature sensitivity in spring phenology and delayed autumn phe-nology and proposed temperature parameters from this study might be applied to predict future phenological change.

基于温度指数-温暖指数和最冷月低温对韩国森林植被分布变化的模拟

利用温暖指数（WI）和最冷月平均最低气温（MTCI）预测韩国森林覆盖和植被分布的变化.为模拟气候变化引起的植被分布变化,利用过去30年（1971-2000年）的气候数据和第5代NCAR和PennState Mesoscale模型（MM5）计算得到IPCC特别报告中A1B情景下的未来气候数据.WI和MTCI是非常重要的热量指标,它们与植物获得的有效热量和抗寒能力密切相关,树种的最适分布范围也受这两种热量指标的影响.为获得树种的热量相似组合（TAG）,将树种分布范围的WI和MTCI配置于二维网格图上,然后根据处于相似WI和MTCI范围的树种划为同一TAG.通过聚类分析产生出17种用于解释韩国森林植被分布的TAG.预测结果显示,未来几年韩国境内的WI和MTCI分布将向右上方移动.同时发现,与Pinusdensiflora和P.koraiensis等种类有关的热量相似组合的面积将会缩小,而常绿阔叶树（如Camellia japonica,Cyclobalanopsis glauca）占优势的热量相似组合的面积将扩大.与过去使用的全球或大陆尺度的植被模型相比,针对TAG的过程分析能够更明确地解释气候变化在区域尺度上的影响.

利用激光雷达数据估算韩国森林有效植被面积指数

雷达系统能够同时探测森林的水平结构和垂直结构,结合地面控制点还可以高精度地描绘森林中的树干、树冠及林下植被.基于此理念,通过计算雷达激光束被拦截的比例估算红松(Pinus koraiensis)、日本落叶松(Larix leptolepis)和栎类(Quercus sp.)的有效植被面积指数(PAIe).从冠层表面或冠层内部反射的雷达数据中利用k-均值聚类方法提取林隙分数(GLIDAR),根据比尔-朗伯吸收定律和GLIDAR计算PAIe.结果显示,利用雷达数据推算的红松、日本落叶松和栎类的PAIe与实际测量的PAIe之间的相关系数分别为0.82,0.64和0.59.不同树种之间雷达测量值与实测值之间相关性的差异,主要来自于叶片与枝条数量的不同.如果没有树叶,激光雷达的脉冲只能由枝条反射,然而枝条的大小往往小于激光雷达的分辨率(1m),所以与长满树叶的枝条相比,光秃的枝条反射雷达脉冲的几率非常小.因此,若在春季末期树叶出现后进行此类研究,估算的准确度将有所提高.