Biomass carbon sinks in Japanese forests: 1966-2012

The role of forests in absorbing atmospheric carbon has beenrecognized under the Kyoto Protocol, which allows signatorycountries to use forests as a mitigation option. Although severalstudies have estimated carbon stock changes in Japanese forests,most only estimate changes up to 1995 or ignore carbon stockchanges in natural forests. This study is the first attemptto estimate carbon stock changes in Japanese forests from 1966to 2012, to coincide with the final year of the Kyoto Protocol'sfirst commitment period. Forest area and growing stock datawere analysed. Then, two models for predicting the change inforest area and growing stock were developed. Results showedthat most natural forest loss resulted from conversion to plantationforest. The total above-ground and below-ground carbon stockin Japanese forests has been estimated to have increased from1114.8 TgC in 1966 to 2076.0 TgC in 2012, representing an increaseof 20.9 TgC year^-1 over the same period. During the first commitmentperiod of the Kyoto Protocol (2008–2012), annual carbonsinks were estimated at 20.1 TgC, of which 76.9 per cent weresequestered in plantation forests. Of the 20.1 TgC year^-1, eligiblecarbon sinks are estimated at 10.2 TgC or 78.7 per cent of themaximum or capped amount as allowed under the Marrakesh Accord.Although further effort is needed so that the capped amountof 13 TgC year^-1 could be achieved, this study suggests thatcarbon sinks through forest management could be used to offsetindustrial carbon emissions.     

Q10 values of soil respiration in Japanese forests

Q₁₀ is the most important index of soil respiration, and is essential for accurate prediction of soil carbon response to global warming. The response of soil carbon storage is an issue on global and regional scales. In this study, published Q₁₀ values of soil respiration in Japanese forests were examined (n = 44). The Q₁₀ values ranged from 1.30 to 3.45, and the mean value was 2.18 (SD = 0.61, median = 2.02). These results were slightly lower than those of global compilations. The number of studies of Q₁₀ values is still lacking, especially with regard to those in managed forests, those in northeast Japan, and those using modern measurement techniques such as infrared gas analysis. For accurate prediction of soil carbon dynamics and storage in Japanese forests, more such studies are required.     

Biomass and production of fine roots in Japanese forests

To better understand the control of fine-root dynamics in Japanese forests, we reviewed studies conducted in Japan on fine-root biomass and production. Most of the data on fine-root biomass were obtained for conifer plantations in limited regions; the average fine-root biomass of dominant trees ranged from ∼50 g m₋₂ for Pinus species (n = 3) to ∼600 g m₋₂ for Cryptomeria japonica (n = 4) and Chamaecyparis obtusa (n = 3). These values are comparable with or less than those reported for other temperate forests mainly in North America or Europe. Information on fine-root production in Japanese forests remains limited. Fine-root production accounted for ∼30% of the net primary productivity in two deciduous forests, but similar data was not reported for coniferous forests in Japan. In Japanese forests, slope position is a key parameter controlling fine-root biomass that is greater on upper slopes than on lower slopes, probably because soil resource availability decreases upslope. Studies in manipulated soil environments (e.g., removing throughfall to simulate drought) also suggested that fine-root biomass and production were greatly affected by altered soil environments. Physiological control of fine-root dynamics was recently discussed via anatomical analyses of Chamaecyparis obtusa. Findings from Japanese studies generally support data on fine-root biomass and production obtained from other temperate regions. Further attempts to elucidate the influence of slope position (soil resource availability) on fine-root production would be useful to gain a more detailed understanding of the fine-root dynamics in Japanese forests.     

Interspecific interactions of ungulates in European forests: an overview

Mammalian herbivores vary in the degree to which they browse, graze and cause physical disturbance, and so vary in the effects they have on the structure and composition of forest ecosystems. To create predictive models of the interactions of forest ecosystems with herbivore communities, an appreciation of the interactions between the species of herbivore themselves is necessary. This paper reviews interspecific interactions of ungulates, methods used in studying them, and seeks to identify areas to which future research should be directed in the context of European forest systems. Methods that have been used to provide information on interactions include: comparative resource studies, niche theory, physiological and anatomical analyses, modeling and foraging theory, and population studies. The most commonly reported types of interactions appear to be competition and facilitation. Behavioural and social interactions between species are potentially important, but evidence for these is scarce and often anecdotal. It is suggested that there may be considerable potential for ungulates to interact in European forests which are often significantly altered from their natural state. Future research should aim at refining the theoretical understanding of interspecific interactions, particularly between ungulates with different feeding ecologies. The roe deer (Capreolus capreolus) has a major impact on forest ecosystems and is increasing its range throughout Europe. However, there is evidence that it may be displaced or out-competed by a number of ungulate species, and it is suggested as being research priority to quantify these effects.     

Nitrogen dynamics across silvicultural canopy gaps in young forests of western Oregon

Silvicultural canopy gaps are emerging as an alternative management tool to accelerate development of complex forest structure in young, even-aged forests of the Pacific Northwest. The effect of gap creation on available nitrogen (N) is of concern to managers because N is often a limiting nutrient in Pacific Northwest forests. We investigated patterns of N availability in the forest floor and upper mineral soil (0–10 cm) across 6–8-year-old silvicultural canopy gaps in three 50–70-year-old Douglas-fir forests spanning a wide range of soil N capital in the Coast Range and Cascade Mountains of western Oregon. We used extractable ammonium (NH₄⁺) and nitrate (NO₃⁻) pools, net N mineralization and nitrification rates, and NH₄⁺ and NO₃⁻ ion exchange resin (IER) concentrations to quantify N availability along north-south transects run through the centers of 0.4 and 0.1 ha gaps. In addition, we measured several factors known to influence N availability, including litterfall, moisture, temperature, and decomposition rates. In general, gap-forest differences in N availability were more pronounced in the mineral soil than in the forest floor. Mineral soil extractable NH₄⁺ and NO₃⁻ pools, net N mineralization and nitrification rates, and NH₄⁺ and NO₃⁻ IER concentrations were all significantly elevated in gaps relative to adjacent forest, and in several cases exhibited significantly greater spatial variability in gaps than forest. Nitrogen availability along the edges of gaps more often resembled levels in the adjacent forest than in gap centers. For the majority of response variables, there were no significant differences between northern and southern transect positions, nor between 0.4 and 0.1 ha gaps. Forest floor and mineral soil gravimetric percent moisture and temperature showed few differences along transects, while litterfall carbon (C) inputs and litterfall C:N ratios in gaps were significantly lower than in the adjacent forest. Reciprocal transfer incubations of mineral soil samples between gap and forest positions revealed that soil originating from gaps had greater net nitrification rates than forest samples, regardless of incubation environment. Overall, our results suggest that increased N availability in 6–8-year-old silvicultural gaps in young western Oregon forests may be due more to the quality and quantity of litterfall inputs resulting from early-seral species colonizing gaps than by changes in temperature and moisture conditions caused by gap creation.     

Multifunctionality of mountain forests and economic evaluation

Mountain forests provide many functions, producing useful services to the man—in order to make decisions concerning their management it is necessary to evaluate them properly, taking into account expectations from individuals and society. To this purpose, different methods can be used, some of which are based on economic–monetary evaluations; by contrast, others allow choices to be made according to a set of priorities, using suitable indicators. Decisions concerning the management of forests may imply trade-offs between their different functions. They can also make some individuals better off and some worse off. Therefore, methods and techniques taking into account these different aspects are needed. Evaluating multifunctionality therefore represents a challenge involving manifold aspects, economical, technical, social and efficient methods should be chosen, which may be easily used.     

Review of study on mineralization, saturation and cycle of Nitrogen in forest ecosystems

Nitrogen is one of the most important elements that can limit plant growth in forest ecosystems. Studies of nitrogen mineralization, nitrogen saturation and nitrogen cycle in forest ecosystems is very necessary for understanding the productivity of stand, nutrient cycle and turnover of nitrogen of forest ecosystems. Based on comparison and analysis of domestic and international academic references related to studies on nitrogen mineralization, nitrogen saturation and nitrogen cycle in recent 10 years, the current situation and development of the study on these aspects, and the problems existed in current researches were reviewed. At last, some advices were given for future researches.     

Nitrogen leaching in response to increased nitrogen inputs in subtropical monsoon forests in southern China

Dissolved inorganic nitrogen (DIN) (as ammonium nitrate) was applied monthly onto the forest floor of one old-growth forest (>400 years old, at levels of 50, 100 and 150 kg N ha⁻¹ yr⁻¹) and two young forests (both about 70 years old, at levels of 50 and 100 kg N ha⁻¹ yr⁻¹) over 3 years (2004–2006), to investigate how nitrogen (N) input influenced N leaching output, and if there were differences in N retention between the old-growth and the young forests in the subtropical monsoon region of southern China. The ambient throughfall inputs were 23–27 kg N ha⁻¹ yr⁻¹ in the young forests and 29–35 kg N ha⁻¹ yr⁻¹ in the old-growth forest. In the control plots without experimental N addition, a net N retention was observed in the young forests (on average 6–11 kg N ha⁻¹ yr⁻¹), but a net N loss occurred in the old-growth forest (−13 kg N ha⁻¹ yr⁻¹). Experimental N addition immediately increased DIN leaching in all three forests, with 25–66% of added N leached over the 3-year experiment. At the lowest level of N addition (50 kg N ha⁻¹ yr⁻¹), the percentage N loss was higher in the old-growth forest (66% of added N) than in the two young forests (38% and 26%). However, at higher levels of N addition (100 and 150 kg N ha⁻¹ yr⁻¹), the old-growth forest exhibited similar N losses (25–43%) to those in the young forests (28–43%). These results indicate that N retention is largely determined by the forest successional stages and the levels of N addition. Compared to most temperate forests studied in Europe and North America, N leaching loss in these seasonal monsoon subtropical forests occurred mainly in the rainy growing season, with measured N loss in leaching substantially higher under both ambient deposition and experimental N additions.     

Nitrogen cycling following mountain pine beetle disturbance in lodgepole pine forests of Greater Yellowstone

Widespread bark beetle outbreaks are currently affecting multiple conifer forest types throughout western North America, yet many ecosystem-level consequences of this disturbance are poorly understood. We quantified the effect of mountain pine beetle (Dendroctonus ponderosae) outbreak on nitrogen (N) cycling through litter, soil, and vegetation in lodgepole pine (Pinus contorta var. latifolia) forests of the Greater Yellowstone Ecosystem (WY, USA) across a 0-30 year chronosequence of time-since-beetle disturbance. Recent (1-4 years) bark beetle disturbance increased total litter depth and N concentration in needle litter relative to undisturbed stands, and soils in recently disturbed stands were cooler with greater rates of net N mineralization and nitrification than undisturbed sites. Thirty years after beetle outbreak, needle litter N concentration remained elevated; however total litter N concentration, total litter mass, and soil N pools and fluxes were not different from undisturbed stands. Canopy N pool size declined 58% in recent outbreaks, and remained 48% lower than undisturbed in 30-year old outbreaks. Foliar N concentrations in unattacked lodgepole pine trees and an understory sedge were positively correlated with net N mineralization in soils across the chronosequence. Bark beetle disturbance altered N cycling through the litter, soil, and vegetation of lodgepole pine forests, but changes in soil N cycling were less severe than those observed following stand replacing fire. Several lines of evidence suggest the potential for N leaching is low following bark beetle disturbance in lodgepole pine.     

Assessing the diversity of dung beetle assemblages utilizing Japanese monkey feces in cool-temperate forests

Ecological investigation of the distribution and composition of dung beetle species utilizing feces of wild mammals has rarely been attempted, especially in cool-temperate forests. In this study we recorded and evaluated the community structure of dung beetle species utilizing feces of Japanese monkeys (Macaca fuscata) by conducting a macro-scale inventory survey in the northeastern Shirakami Mountains, located in the northernmost part of mainland Japan. Moreover, to assess the effect of human-induced forest disturbance on species assemblages in this cool-temperate area, we also carried out field sampling using pitfall traps baited with monkey feces in primary forests, secondary forests, and coniferous plantations, during every season except winter. Our findings were: (1) 14 dung beetle species comprising eight dwellers and six tunnelers utilized monkey feces; (2) Aphodius eccoptus was the core species in dung beetle assemblages attracted to the feces during spring and summer; (3) the frequency of occurrence of every species was extremely high in spring; and (4) human-induced forest disturbance did not increase species richness or biomass in cool-temperate forests.     

财务指标法在工业人工林栽培经济评价中的应用

本文以几个方面用财务指标法对工业人工林的发展进行了科学的论证，以使工业人工林在有限的土地上得到最大的效益。     

城市森林对小气候的调节及其功能价值评估

分析了广州市城市森林调节小气候的功能及其价值。结果表明:城市森林降低城市热岛效能晴天2.37℃,雨天2.0℃,增加空气湿度11%,这些带网片点结构的城市森林使得广州市热岛效应分布呈小而窄的断续分布,而不是大而集中的连续分布;降低紫外线指数日平均为2.23,降低辐射量热值日平均为6.10 MJ.m-2;使舒适天数增加36.36%,较舒适天数增加28.57%,而稍不舒适天数减少8.38%,稍闷热天数减少21.42%,闷热天数减少67%;城市森林改善小气候的功能价值包括降低热岛效应价值1 254 125.52×104元.a-1,增加空气湿度价值932 479.20×104元.a-1,共计2 186 604.72×104元.a-1。     

马尾松成熟林采脂量及效益分析

利用47年生马尾松成熟林,分别对3个径级组的产脂量和3个不同密度未采脂林的生长量进行了研究。结果表明:随着密度增加,胸径、树高和材积年均增量皆呈减少趋势,但差异不显著;随着径级组增加,单日产脂量、产脂力和矫正产脂力呈增大趋势,且差异皆显著;采脂林与未采脂林比较,生长量差异皆显著,说明采脂对生长有较大负向影响。综合分析采脂与木材收益,可知采脂林总体收益更高。本研究可为马尾松大径材林的定向培育提供技术支撑。     

Recruitment limitation in forests: Lessons from an unprecedented mountain pine beetle epidemic

Since the mid-1990s the forests of central British Columbia have undergone an unprecedented Mountain Pine Beetle (Dendroctonus ponderosae Hopkins) (MPB) epidemic that has resulted in extensive mortality of canopy lodgepole pine (Pinus contorta var. latifolia Engelm.). This study investigated how seed-source availability, seedbed substrate, overstory structure, and time since MPB attack interact to affect post-MPB seedling recruitment of the dominant tree species of these forests. In addition to post-MPB recruitment, these forests may be regenerated by trees established in the understory prior to MPB disturbance. Accordingly, we examined abundance and patterns of all regeneration less than 130 cm tall. We found post-MPB recruitment was sparse. Subalpine fir (Abies laciocarpa (Hook.) Nutt.) comprised the majority of the post-MPB recruitment. It increased with local parent tree basal area and increased strongly with proximity to a major seed source. This resulted in a patchy distribution for subalpine fir post-MPB regeneration. Lodgepole pine post-MPB recruitment was limited by overstory shading. Recruitment of pine decreased as the total overstory basal area increased. Interior spruce (Picea glauca × engelmannii) post-MPB recruitment was similarly limited by total overstory basal area. Seedbed substrates were uniform and dominated by moss. Substrate type distribution did not change as time since MPB disturbance increased. The overall low post-MPB recruitment observed was likely due to a lack of disturbance to the moss-dominated forest floor. Moss is known to be a poor substrate in northern forests. The distribution of all regeneration less than 130 cm tall showed the same trends as the post-MPB regeneration. We believe the post-MPB seedling recruitment dynamics of these forests was not substantially changed from conditions prior to MPB disturbance. There was no pulse of regeneration up to 10 years post-MPB disturbance. Unless this changes, future stand structure will be dominated by the seedling bank established prior to the MPB epidemic. Subalpine fir dominated the seedling bank (68%) and post-MPB recruitment (94%). This suggests that MPB-disturbed forests are undergoing a substantial shift in landscape-level species composition.     

Strategy for implementing silvicultural practices in Japanese plantation forests to meet a carbon sequestration goal

The strategy for implementing silvicultural practices in Japanese plantation forests was examined to achieve a carbon uptake of 13.0 Mt-C year^–1, which was capped by the Marrakesh Accords, during the first commitment period, 2008–2012. The plantation forests that implemented silvicultural practices in the period 1990–2012 (FM plantation forests) were identified in compliance with the hypothesized identification rules, and carbon uptake in the forests was estimated using a simple model composed of simulation and optimization components on the assumption that whole plantation forest is classified into only two groups. Furthermore, parametric analysis was conducted to investigate the relationships among three factors: (1) the average annual harvesting volume (including thinning) in plantation forests during the first commitment period, (2) the total area of FM plantation forests in 2012, and (3) the average annual amount of carbon to be sequestered in FM plantation forests during the first commitment period. The results imply that young stands have to be prioritized in implementing silvicultural practices under any harvesting plan and carbon sequestration goal, and that FM plantation forests sequestered 8.0–10.5 (Mt-C year^–1) carbon in inverse proportion to the harvesting volume of 21.0–14.0 million m³ year^–1 (log volume), assuming that most of the plantation forests were incorporated into them.     

邵阳市森林生态系统净化大气的功能价值估算

以湖南省邵阳市为研究对象,采用生产成本法、影子价格法、替代工程法等,估算了邵阳市森林净化大气服务功能价值。研究结果表明:邵阳市森林生态系统净化大气功能的总价值为81.98×108元.a-1,其中森林固定CO2的价值为24.06×108元.a-1,释放O2的功能价值为11.4×108元.a-1,净化SO2的功能价值为0.61×108元.a-1,滞尘功能价值为40.09×108元.a-1,过滤净化空气的功能价值为5.82×108元.a-1。研究结果可为邵阳市生态环境保护和管理经营,核算绿色GDP以及森林资源的生态价值量化提供科学依据。     

国外松地理种源试验林效果分析

经过对美国美森耐公司赠送的25个优良种源与浙江省马尾松混合种及火炬松种源，在东阳市境内7年的试验，试验结果表明：国外松优良种源间树高、胸径、材积存在显著的遗传变异，但树形、针叶差异不显著，并以速生丰产（树高、胸径、材积）为目标，初步筛选出MG-1，CT-3，MG-5，CT-4，MG-2，MG-4，MG-6等7个优良种源。     

Small-scale planted forests in Zululand,South Africa: an opportunity for appropriate development

Forestry in South Africa is sharply divided between commercially driven private enterprise which controls 1.3 million ha of plantation forests, and government and nongovernment organizations which promote a variety of social forestry programs. One area of crossover is that of small-scale (1–2 ha) commercial woodlots being promoted by private timber companies as an additional source of fiber for their pulpmills, but grown and managed by individual farmers. Inputs, such as plants and fertilizers, as well as expertise in the form of extension foresters, are provided by the company, whereas the farmers supply the land and the labor. The company guarantees to buy the timber at the time of harvest. Under such arrangements, the risk is spread between the farmers and the company; the farmers assume most of the risks of production, and the company takes on the marketing risks. The possibilities for appropriate and sustainable development do exist under such a program, but issues involving both ecological and social sustainability must be addressed. This paper suggests that four key characteristics are needed to achieve appropriate development in Zululand. These characteristics are participation, flexibility, empowerment, and commitment. When compared to the current arrangement, the company would have to make a fundamental paradigm shift to achieve these goals. However, the long-term support of the farmers, and ultimately more fiber in the mills, would be the reward. This revised version was published online in June 2006 with corrections to the Cover Date.