Natural Mongolian Pine Forests in the Great Xing＇an Mountains,Northeast China

Based upon 134 reltves, the vegetation of the forests with Mongolian pine (Pinus sylvestris var. mongolica) of the Great Xing‘an Mountains in the northeast China was classified into 3 communities, 7 types and 4 subtypes by numerical cluster analysis. 1) The Pinus sylvestris var. mongolica-Populus davidiana-community was found on relatively dry sites. It was subdivided into a Quercus mongolica-type, consisting of a Adenophora tetraphylla subtype, a Pulsatilla dahurica subtype, and a pure type; 2)The Pinus sylvestris var. mongolica-Rhododendron dauricum-community occurred on medium dry sites. It included a Calamagrostis angustifolia type, consisting of a Cladonia arbuscula subtype, a pure subtype, and a Rubus idaeus-type; 3) The Pinus sylvestris var.mongolica-Ledum palustre-community was found on periodically wet sites. It included a Picea koraiensis type, a Vaccinium uliginosum type, and a pure type.     

Post-fire habitat restoration of sables during winter season in northern slope of the Great Xing＇an Mountains

Habitat loss and fragmentation have been associated with the decline of endangered species. In 1987, a catastrophic fire in the northern Great Hing＇an Mountains of China, where the main habitat of sables （Martes zibellina） is located, aggravated the loss and fragmentation of the forest landscape. Due to restricted distribution and low population density, sables were listed in the national first-grade protected species in China. The objective of this paper was to identify to what extent the habitat of sables had been restored 13 years after the fire. Based on the behavioral data, which came from field survey information by radio-tracking, GPS （Global Positioning System） and forest inventory data, suitability habitat maps were derived using the Ecological Niche Suitability Model （ENSM）. In addition, the habitat structure was analyzed with selected landscape indices. Although forest cover mostly had been restored by 2000, the results indicated that, compared to the pre-fire situation, the areas of suitable habitat had been reduced significantly, especially those of less suitable, marginally suitable and moderately suitable designation. Fragmentation was aggravated, and suitable patches were found to be further isolated with the exception of those in most suitable areas. The ratio of the patch perimeter to area in unsuitable, moderately suitable and suitable areas decreased, while the ratios within other suitability types increased. Moreover, the percentage of soft boundaries decreased slightly, which can influence the redistribution of sables. The results above indicated that the suitable habitat had deteriorated, and the restoration of the sables＇ habitat remained to be done.     

Effects of selection cutting on the forest structure and species diversity of evergreen broa-leaved forest in northern Fujian, southern China

The short-term effects of selection cutting of different intensities on the forest structure and species diversity of evergreen broad-leaved forest in northern Fujian Province were investigated and analyzed. The results showed that selection cutting of low and medium intensities caused little variation in the forest structure. After cutting, the dominant species retained their leading status in the community. However, the community structure changed significantly following selection cutting of high and extra-high intensities; the status of the dominant species of the community declined dramatically. Some tree species began to disappear from the sampling plots. Except for extra-high intensity cutting, the diversity of tree species did not change significantly for the other three cutting intensities. However, the evenness of the stands was very different among the four kinds of cutting plots. For low and medium intensity selection cutting, the evenness declined slightly. For extra-high intensity selection cutting, the evenness increased to some extent, which might be due to a more even distribution of tree species after cutting. Cutting operations resulted in some adverse reactions to development of arborous species diversity of evergreen broad-leaved forest, particularly serious damage to the forest canopy. But the rational selection cuttings, which may benefit the restoration and maintenance of species diversity over a long period and may come about from the variations in environmental factors such as sunlight, temperature and humidity.     

Evaluation of regeneration potential of Pinus koraiensis in mixed pine-hardwood forests in the Xiao Xing’an Mountains, China

Large scale harvest of Korean pine(Pinus koraiensis) seeds as a food product in the mixed Korean pine-hardwood forest of northeastern China poses a serious threat to the sustainability and restoration of this endangered regional ecosystem.Seed collection over past decades greatly reduced the seed bank and subsequent seedling and sapling recruitment,and impacting a wide array of granivorous animals that rely on the pine seeds.We surveyed Korean pine seeds,including solid seeds(SS),insect consumed seeds(ICS) and other(animal) consumed(OCS) kernels,of the seed bank(forest floor and the top 10 cm of mineral soil),the seedlings and saplings from 1 m 2 sample plots in five forest types in Liangshui Nature Reserve(LNR) of the southern Xiao Xing’an Mountains in northeastern China to provide accurate information for assessing the Korean pine regeneration potential.The average number of pine seeds in the seed bank were 11.2 seeds/m 2,9.1 seeds/m 2,4.6 seeds/m 2,1.1 seeds/m 2,and 0.2 seeds/m 2 in Korean pine-basswood forest,mixed Korean pine-hardwood forest,mixed conifer-hardwood forest,white birch forests,and oak forests,respectively.In the first three forest types,percentages of SS(potentially viable seeds) were 11.2%,3.5% and 27.8%,respectively.The percentages of ICS(not viable seeds) were consistent at around 35%.The higher but variable percentages of OCS(not viable seeds) indicated high seed predation in these forests.Compared with other studies,we recorded higher percentages of seed damage,probably due to our survey approach and the increased depth of seed bank sampled in our study.Depletion of pine seeds in the seed bank greatly reduced seedling and sapling recruitment.Densities of pine seedlings varied from about 180 trees/ha in the mixed Korean pine-hardwood forest to about 5,400 trees/ha in the mixed conifer-hardwood forests and showed a high degree of spatial variation.Saplings were rare in the mixed Korean pine-hardwood forest,but ranged in the thousands in other forests.Large scale pine seed harvest has seriously threatened the sustainability of the mixed Korean pine-hardwood forest ecosystem.Scaling down the seed harvest or supplemental planting of pine saplings are urgently needed to maintain the health of the existing Korean pine forests and to restore this endangered ecosystem.     

The effect of fire disturbance on short-term soil respiration in typical forest of Greater Xing’an Range,China

We investigated the effect of fire disturbance on short-term soil respiration in birch （Betula platyphylla Suk.） and larch （Larix gmelinii Rupr.） forests in Greater Xing’an range, northeastern China for further understanding of its effect on the carbon cycle in ecosystems. Our study show that post-fire soil respiration rates in B. platyphylla and L. gmelinii forests were reduced by 14%and 10%, respectively. In contrast, the soil heterotrophic respiration rates in the two types of forest were similar in post-fire and control plots. After fire, the contribution of root respiration to total soil respiration was dramatically reduced. Variation in soil respiration rates was explained by soil moisture （W） and soil tem-perature （T） at a depth of 5 cm. Exponential regression fitted T and W models explained Rs rates in B. platyphylla control and post-fire plots （83.1% and 86.2%） and L. gmelinii control and post-fire plots （83.7%and 88.7%）. In addition, the short-term temperature coefficients in B.     

Effect of fire intensity on active organic and total soil carbon in a <Emphasis Type="Italic">Larix gmelinii</Emphasis> forest in the Daxing’anling Mountains,Northeastern China

Studying contents and seasonal dynamics of active organic carbon in the soil is an important method for revealing the turnover and regulation mechanism of soil carbon pool. Through 3 years of field sampling and lab analysis, we studied the seasonal variations, content differences, and interrelationships of total organic carbon (TOC), light fraction organic carbon (LFOC), and particulate organic carbon (POC) of the soil in the forest areas burned with different fire intensities in the Daxing’anling Mountains. The mean TOC content in the low-intensity burned area was greater than that in the unburned area, moderate-intensity, and high-intensity burned areas in June and November (P < 0.05). LFOC and POC in the low-intensity burned area were greater than that in either moderate-intensity or high-intensity burned areas, with significant differences in LFOC in September and November (P < 0.05). A significant difference in LFOC between the unburned and burned areas was only found in July (P < 0.05). However, the differences in POC between the unburned and burned areas were not significant in all the whole seasons (P > 0.05). Soil LFOC and POC varied significantly with the seasons (P < 0.05) in the Daxing’anling Mountains. Significant linear relationships were observed between soil TOC, LFOC, and POC, which were positively correlated with soil nitrogen and negatively correlated with soil temperature in the Daxing’anling Mountains.     

大兴安岭北坡火烧迹地森林郁闭度恢复及其影响因子分析

1987年发生在大兴安岭北坡的特大火灾造成了森林资源的巨大损失,其森林景观恢复一直是人们关注的热点.本研究选取与森林生产力具有密切联系的郁闭度因子作为研究对象,以 ArcView、ArcGIS等地理信息系统软件为研究平台,采用1987年和2000年两期森林资源二类调查数据,对郁闭度、火烧强度、抚育类型、地形因子等进行分级,通过数据叠加,探讨了森林郁闭度格局的恢复状况以及火烧强度、更新类型、地形因子对郁闭度恢复的影响.结果显示:2000年郁闭度等级构成与1987年火前相比发生了明显变化,无林地以及高郁闭度等级比重明显下降,较低郁闭度等级比重显著上升;火烧强度是影响火后恢复的初始因子,火烧强度与郁闭度等级呈负相关;更新措施短期内对郁闭度恢复影响不显著,但可以缩短森林演替的周期,对未来针叶林群落生产力恢复具有重要促进作用;地形因子中坡度对郁闭度恢复影响最为明显,其次为坡位,坡向影响最弱.     

Discussions on forest recovery in the burned area in Daxing’anling forest region

The disastrous fire occurred in northern area of Daxing’anling forest region on May 6, 1987, destroyed a large area of forests. The broad-leaved tree species, such as poplar, birch had regenerated in a great quantity after the fire, but the coniferous species such as larch and scotch pine had difficult to regenerate naturally, This paper put forward that the coniferous forest could be recovered by the planting method of effect strip and effect islet based on the principle of borderline effects and by making full use of the condition of broad-leaved trees.     

林火迹地森林恢复研究进展

森林火灾后如何恢复被破坏的森林是人们面临的一个非常重要的问题。本文回顾了国内外火烧迹地森林恢复的研究概况,从种群、群落、生态及景观四个尺度上概括了该领域研究的主要方法;总结了在森林恢复的研究方面采用的地理信息系统和遥感等先进技术和方法,并探讨了林火迹地森林植被恢复的对策及发展趋势。参38。     

The effect of forest fire on streamflow in Daxing’an Mountains

Based on the data obtained by single watershed experiment, the changes in streamflow by forest fire had been studied. The results showed the most forest fire in Daxing’an Mountains in 1987 resulted in the increase of annual runoff in the initial stage, snowmelt runoff reduced in May. The relationship between precipitation and streamflow was closed. The changes in streamflow relied more on the precipitation.     

洞庭湖区防浪林林分林冠结构的研究

对洞庭湖区河洲、滩地上的不同林龄的旱柳、杨树防浪林、芦苇林进行了标准地调查,选取标准株(地),对其茎杆、枝条、叶片的空间分布进行了测定,通过对其差异进行比较分析,旨在间接测定不同防浪林的防浪效益的差异。     

Short-term effects of forest restoration management on non-symbiotic nitrogen-fixation in western Montana

Forest restoration treatments involving selection harvest and prescribed fire have been applied throughout the Rocky Mountain West with only a limited understanding of how these treatments influence plant community composition and soil processes. Forest restoration treatments, especially those involving fire, have the potential to reduce N capital on site. Unfortunately there has been only limited effort to investigate the effects of forest restoration treatments on forest ecosystem N inputs, especially free living N-fixation in soil and woody residues. Recent studies have highlighted the potential for decaying woody roots to serve as hot spots for N-fixation. The fire and fire surrogates (FFS) study site at Lubrecht Experimental Forest in Western Montana provided a unique opportunity to investigate the effect of restoration treatments on N-fixation. We set out to examine how prescribed fire, selection harvest, and a combination of both influence free living N-fixing bacteria that colonize decomposing woody roots, mineral soil, and soil crusts. Soil, root, and soil crust samples were collected from replicated treatment plots in August 2005 and soil samples were recollected in May 2006 just following snowmelt. Acetylene reduction assays were run on all samples, and extractable inorganic N and potentially mineralizable N (PMN) were measured in mineral soil. While restoration treatments caused an increase in dead roots associated with stumps and fire killed trees, N-fixation rates were nearly non-existent in these root systems. Nitrogen-fixation rates were not significantly influenced by treatments in decomposing woody roots or in mineral soil, but were slightly greater (P < 0.10) in soil crusts when the control stand was compared to treated plots. Nitrogen-fixation rates were also greater in mineral soil than in roots. Soil collected in August exhibited greater rates of N-fixation than soil collected in May which we attributed to higher moisture and an increase in available N following spring thaw. Average rates of free living N-fixation across the treatment plots at Lubrecht were low (0.26 kg N ha⁻¹ year⁻¹), but over time we estimate that these sources, along with the sparse population of symbiotic N-fixing plants and wet N deposition, would replenish soil N lost through fire or harvesting in approximately 40–100 years.     

关于中国吉林省林业建设的思考

This paper reviews various forestry practices in Jilin Province, China. The authors emphasize the rich natural diversity of Jilin and the need to focus research efforts on understanding the potential of native species to meet the needs of land-management agencies involved in forest resource exploitation and ecological restoration. The native species of China hold great potential, and deserve more research attention, for meeting these needs. The introduction and testing of exotic species should be dbne only under rigorous scientific testing and after comparison with native species prior to operational introduction into forestry in order to avoid unwanted ecological consequences, including potential problems with alien invasives and pest introductions. The authors also emphasize the need to maintain viable （e.g., genetically diverse and reproductively fit） natural populations of native species in order to protect China＇s valuable natural diversity and maintain the potential of native species to function as future seed sources for local forest and ecological restoration activities.     

大兴安岭北坡火后紫貂冬季生境恢复研究

由自然和人为原因引起的生境丧失与生境破碎化已严重影响到野生动物的生存。大兴安岭北坡是国家一级保护动物紫貂(Marteszibellina)的主要分布区,1987年发生在这里的特大森林火灾造成了森林景观的严重破碎化,紫貂的生存面临极大的威胁。本文的研究目的是为了确定火灾13年后,紫貂冬季生境的恢复程度。首先根据紫貂对冬季生境的喜好选取对其生存影响较大的生态因子,结合数字化林相图,利用地理信息系统软件ArcGIS编制火烧前后的生境适宜性类型图。然后选取相关的景观格局指标,对火灾烧前后的生境格局进行对比分析。结果显示:尽管火后采取了一系列的森林恢复措施,但紫貂冬季适宜生境仍有大幅度减少,特别是中等适宜生境类型减少最为明显。适宜生境破碎化加剧,隔离度增加。适宜生境斑块的形状趋于简单,软边界比重有所增加。以上结果表明,与火前相比,紫貂生境明显恶化,需要较长的时间恢复。图4表5参41。     

内蒙古大兴安岭北部原始林区森林火灾应急资源储备与调度研究

【目的】为更好地开展原始林区森林灭火工作,保护内蒙古大兴安岭北部原始林区森林生态资源。【方法】对内蒙古大兴安岭重点国有林管理局下辖的22个林业局,3个自然保护区的应急资源储备情况进行了整理,同时对北部原始林区森林火灾发生的时间规律和空间规律分别进行了分析,在此基础上采用ArcGIS软件,对内蒙古大兴安岭重点国有林管理局森林火灾应急资源的空间分布状况与内蒙古大兴安岭北部原始林区近5年森林火灾发生的空间分布状况进行了叠加分析,依据叠加分析的结果对内蒙古大兴安岭重点国有林管理局森林火灾应急资源空间分布的合理性进行了评判。【结果】叠加分析结果显示,目前内蒙古大兴安岭北部原始林区周边林业局森林火灾应急资源空间配置存在区域集聚以及北部原始林区附近应急资源配置不足等不合理问题。在对内蒙古大兴安岭重点国有林管理局森林火灾应急资源储备情况整理分析的基础上,创新性地提出了以应急物流系统所需时间最少和费用最小为目标进行优化的森林火灾应急资源分配模型。【结论】最后通过实例证明,该模型可以优化森林火灾应急物流系统中资源配置体系,为应急资源的合理调配提供了指导,对于实现科学决策指挥,保护北部原始林区森林生态资源具有一定的现实意义。