Effects of Thinning Intensity on Carbon Stocks and Changes in Larch Forests in China Northeast Forest Region

Thinning represents an important and frequently used silvicultural technique that improves forest wood products and has obvious effects on forest carbon stocks and stock changes. Here, we used the carbon budget model CBM-CFS3 to simulate the effects of thinning on carbon storage and changes in larch forest ecosystems under thirteen thinning scenarios. Simulation results demonstrate that strong thinning greatly reduces the biomass carbon density of larch forests compared to non-thinning forests. The minimum and maximum average biomass carbon density, respectively, were 30.3 tC ha^-1 and 47.8 tC ha^-1, a difference of 58% under set scenarios in the simulated time scale. The dead organic matter（including soil） carbon density increased in all thinned larch forests stands, compared with non-thinning stands, and the pattern of variation was opposite to that found for biomass carbon density. However, the total ecosystem carbon density of larch forests declined with thinning because the increase in dead organic matter carbon is insufficient to offset the loss of biomass carbon caused by thinning. Thus, strong thinning can transform larch forest ecosystems from carbon sinks into carbon sources. Future work should consider the carbon sequestered in wood materials acquired via thinning and their use as substitutes for other construction materials with less favorable lifecycle carbon footprints, such as steel, cement, aluminum and PVC.

A management planning system for even-aged and uneven-aged forests in northeast China

The most common scientific approach to numerical landscape-level forest management planning is combinatorial optimization aimed at finding the optimal combination of the treatment alternatives of stands. The selected combination of treatments depends on the conditions of the forest, and the objectives of the forest landowners. A two-step procedure is commonly used to derive the plan. First, treatment alternatives are generated for the stands using an automated simulation tool. Second,the optimal combination of the simulated treatment schedules is found by using mathematical programming or various heuristics. Simulation of treatment schedules requires models for stand dynamics and volume for all important tree species and stand types present in the forest.A forest planning system was described for Northeast China. The necessary models for stand dynamics and tree volume were presented for the main tree species of the region. The developed models were integrated into the simulation tool of the planning system. The simulation and the optimization tools of the planning system were described. The optimization tool was used with heuristic methods, making it possible to easily solve also spatial forest planning problems, for instance aggregate cuttings.Finally, the use of the system is illustrated with a case study, in which nonspatial and spatial management plans are developed for the Mengjiagang Forest District.

Forest phenological patterns of Northeast China inferred from MODIS data

The role of remote sensing in phenological studies is increasingly regarded as a key to understand large area seasonal phenomena. This paper describes the application of Moderate Resolution Imaging Spectroradiometer (MODIS) time series data for forest phenological patterns. The forest phenological phase of Northeast China (NE China) and its spatial characteristics were inferred using 1-km 10-day MODIS normalized difference vegetation index (NDVI) datasets of 2002. The threshold-based method was used to estimate three key forest phenological variables, which are the start of growing season (SOS), the end of growing season (EOS) and growing season length (GSL). Then the spatial patterns of forest phenological variables of NE China were mapped and analyzed. The derived phenological variables were validated by the field observed data from published papers in the same study area. Results indicate that forest phenological phase from MODIS data is comparable with the observed data. As the derived forest phenological pattern is related to forest type distribution, it is helpful to discriminate between forest types.

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

Based upon 134 rel関es, the vegetation of the forests with Mongolian pine (Pinus sylvestris var. mongolica) of the Great Xingan 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.

THE STRUCTURE AND DYNAMICS OF THE LAND RESOURCES SYSTEM IN THE FARMLAND SHELTER FOREST REGION IN THE NORTHEAST PLAIN

The structure and dynamics of land resources system in the shelter forest region in the Northeast Plain is discussed according to the remote sensing and statistical information from the typical profiles and spots. For agricultural utilization, the land resources system is made up of five components, i.e. man, land resources, water resources,climatic resources and barren land. The local economy depends heavily upon its land resources, especially farm land. Having been exploited for 50-60 years from the 1930s to 1980s, it has already changed from the reclaiming period into the declining period.There is no waste land to be reclaimed. Facing the increase of population and requirements and the decrease of farmland fertility, proper management of land resources is indispensable if local economic and living level is maintained. It is imperative to make artificial regeneration (highest input) for the land resources and to keep fine circle of thesystem. If only natural regeneration if relied, the system will be changed to vicious circle.

Responses of Grassland and Forest to Temperature and Precipitation Changes in Northeast China

Using the Normalized Difference Vegetation Index （NDVI） as an indicator of vegetation growth, we explored the characteristics and differences in the response to drought of five vegetation biomes in Northeast China, including typical steppe, desert steppe, meadow steppe, deciduous coniferous forest and deciduous broad-leaved forest during the period 1982 2009. The results indicate that growing season precipitation may be the primary vegetation growth-limiting factor in grasslands. More than 70% of the temporal variations in NDVI can be explained by the amount of precipitation during the growing season in typical and desert steppes. During the same period, the mean temperature in the growing season could explain nearly 43% of the variations in the mean growing season NDVI and is therefore a dominant growth-limiting factor for forest ecosystems. Therefore, the NDVI trends differ largely due to differences in the vegetation growth-limiting factors of the different vegetation biomes. The NDVI responses to droughts vary in magnitude and direction and depend on the drought-affected areas of the five vegetation types. Specifically, the changes in NDVI are consistent with the variations in precipitation for grassland ecosystems. A lack of precipitation resulted in decreases in NDVI, thereby reducing vegetation growth in these regions. Conversely, increasing precipitation decreased the NDVI of forest ecosystems. The results also suggest that grasslands under arid and semi-arid environments may be more sensitive to drought than forests under humid environments. Among grassland ecosystems, desert steppe was most sensitive to drought, followed by typical steppe; meadow steppe was the least sensitive.

Discussions on taxonomy of genus Betula in northeast China

Many researches have been carried out on the taxonomy of Betula in northeast of China, but the classification of species and subdivision of species had some divergences at all times, which led to a disorder for developing and utilizing resources of Betula. In this paper, species and subdivision of Betula were classified not only according to the wax sample of Betula but also the comprehensive taxonomy of population characters, geographical distribution, and the habitat. Theconclusion supported the Fu Pei-yuns?(1995) viewpoint of the taxonomy of Betula in the northeast of China. But B. mandshurica (Regel) Nakai should be considered as one single species, the name of B. platyphyla Suk.var phellodendroidesTung should be the synonym of B. platyphyla var platyphyla, and B. ermanii Cham.var.yingkiliensis liou et Wang should be incorporated into B. ermanii Cham. B. ovalifolia Rupr should not be regarded as a variety of B. fruticosa Pall. but as one single species.

Harnessing REDD+ opportunities for forest conservation and carbon stock enhancement in the Northeastern States of India

Forests have significant economic and ecological value as a provider of ecosystem services, being home to much of the world’s biodiversity and supporting the livelihoods of many people. Reducing emissions from deforestation and forest degradation in developing countries (REDD) is a critical component of the overall greenhouse gas emission reductions and now the significance of REDD+ (which is not only about reducing emissions but halting and reversing forest loss), in delivering climate change mitigation benefits along with co-benefits, is increasingly being recognized in global climate negotiations. Northeast India provides a tremendous potential for harnessing REDD+ activities with about 66% of the total geographical area of the region being covered by forests. This paper attempts to explore this potential besides estimating the area available for different options under REDD+ as well as the mitigation potential using COMAP model, overcoming limitations of existing studies or a lack of them. Within this, the status of forests and biodiversity along with drivers of deforestation in north east India are documented and an assessment of the potential for taking up reducing deforestation and degradation and enhancement of carbon stocks and afforestation is conducted both at the state as well as district level. It was found that northeastern states have been experiencing net forest loss during the last few years along with significant scale forest degradation, with Nagaland followed by Arunachal Pradesh offering maximum potential for “reducing deforestation” option under REDD and the total incremental annual mitigation potential of the four REDD+ activities in northeast India being 29.2 MtCO2 for 2030.

东北地区森林草原湿地生态系统外来入侵物种概况及对策

在对东北地区部分有害生物来源考证的基础上,筛选出56种外来入侵物种作为东北地区森林、草原、湿地生态系统的主要种类,并对其入侵特征进行分析。结果表明:原产地以北美洲种类最多,入侵东北种类总体呈不断增加势头,入侵途径以无意引入为主,入侵地以辽宁省种类居多,入侵生境在森林、草原、湿地生态系统均有代表性种类。进一步筛选出18种外来入侵物种作为东北地区森林、草原、湿地生态系统的重要种类,并对其重要性进行评述,根据每种在入侵过程的阶段性,分别提出防止入侵、阻止扩散和抑制危害的防控管理对策。针对完善入侵生物学理论提出3点建议,针对提升东北地区外来入侵物种防控能力提出4点建议。

东北地区森林旅游与养老产业耦合协调发展研究

运用综合指标评价法、耦合协调度模型分析2013—2022年东北地区森林旅游与养老产业之间的内在耦合关系演化及可能产生的原因。研究结果表明:东北地区森林旅游产业整体发展水平指数均值为0.4911,明显高于养老产业综合发展指数;东北地区森林旅游与养老产业耦合协调度整体偏低,两产业耦合协调度从濒临失调阶段转变为轻度失调阶段;省域范围内两产业耦合协调度存在明显的差异。因此,为提高森林旅游与养老产业发展水平,推进两产业向更高级别的产业系统协调发展,要转变发展理念,重视两产业的顶层设计与全局规划;以产业需求为引领,深化供给侧结构性改革;立足优势产业资源,推进产业优化协同并进。

栗山天牛在我国东北林区灾害成因分析

栗山天牛是栎树林的毁灭性蛀干害虫,近年来,由于栎树林具有的脆弱性、易感性,栎树林林分抗虫能力低下,栗山天牛灾害呈现加重趋势,其引发的栎树林生物灾害在我国东北地区已上升为重要灾害,给森林生态效益的发挥造成严重影响。因此,栗山天牛的防治是当前林业资源保护的重要任务之一。分析结果表明,栗山天牛灾害形成的内在原因是栗山天牛的K-生态对策。灾害形成的外在原因是承灾体天然次生栎林的脆弱性。同时由于防灾控灾措施不到位致使灾害持续加重。基于此,本文从灾害学的理论出发,对栗山天牛致灾因子的危害性、承灾体的脆弱性、孕灾环境的稳定性进行分析,指出了灾害的成因路径,从而为栗山天牛的灾害防控提供科学依据。

基于物质剥夺视角的森林依赖对相对贫困的影响研究--来自东北国有林区1350个职工家庭的经验证据

实现共同富裕,解决相对贫困问题是关键。森林资源丰裕地区往往因过度依赖森林资源而产生“资源诅咒”。文章基于东北国有林区1350个职工家庭的调查数据,首次构建森林依赖指数和物质剥夺指数体系,运用Logistic模型和Poisson模型实证检验森林依赖对职工家庭发生相对贫困和物质剥夺程度的影响,并进一步分析影响的代际差异。研究发现:(1)职工家庭的森林依赖程度、林业活动重要性和家庭资产对相对贫困发生以及物质剥夺程度均具有显著的影响,森林依赖程度、林业活动重要性和家庭资产每增加1单位,职工家庭发生相对贫困的概率分别上升225%、220%和下降5%,表明林业活动重要性是致贫的主要因素。(2)提高职工家庭人力资本水平、改善居住条件、提升家庭收入水平能够有效降低职工家庭陷入相对贫困以及物质剥夺维度增加的风险。(3)进一步分析显示,森林依赖对于新老两代职工家庭相对贫困的影响存在明显的代际差异。森林依赖对于老一代职工家庭发生相对贫困和物质剥夺程度的影响不显著,而对于新一代职工家庭均在1%的显著性水平上显著为正。两代系数相差1.26和0.03。据此得出政策启示:提高职工家庭在非林业部门的就业比例;改善职工家庭的生活及工作条件;加强对森林依赖程度高的新一代职工家庭拓展增收渠道的政策引导;建立识别相对贫困的动态监管体系。

Forest Dwellers’ Perception on Climate Change and Their Adaptive Strategies to Withstand Impacts in Mizoram, North-East India

We studied the perception of forest-dependent communities on climate change with its associated risk and their adaptation strategies in Mizoram, Northeast India. A total of 360 respondents (household heads) were randomly selected from 24 villages across the three different agro-climatic zones prevalent. The community perceived awareness of climate change phenomena in the region with a positive correlation between age, education and occupation of the respondents. The overall perception of climate change in temperature was medium (0.49), while low for change in precipitation (0.26) and seasonal durability (0.23). The community showed over-all low score of perception on risk of climate change (0.10) where risk on livelihood and socio-economic factors was higher than risk to environment or forest. Perception on impact of climate change was high for forest abi-otic ecological factors (0.66) and flora and fauna (0.62), while medium on livelihood of forest-dependent communities (0.44). The majority (more than 75%) of the respondents agreed that human beings are involved and responsible for climate change. Adoption of adaptive strategies to cope climate change ranged from 0.07 to 0.91, amongst which zero tillage, use of traditional knowledge, forest fire prevention, soil and water conservation techniques, agroforestry practices and social forestry are popular. However, rain water harvesting and investments for crop insurance were adopted on low scores clearly implied by the educational and socio-economic status of the farmers in the majority. The study brings out the knowledge and perceptions to climate change by forest-dependent communities and their adaptive strategies to cope had been assessed. The finding results seek the attention of researchers and policy makers to integrate technological and financial interventions in supporting farmer’s effort to cope with climate change with a long term objective for improving their livelihood and climate sensitive resources at the same time.

RELATIONSHIPS BETWEEN LARCH GROWTH AND FOREST SITE FACTORS

Dahurian larch (Larix gmelinii Rupr.) Rupr is one of the dominant species in bothnatural and man-made forests in northeast China.Effects of site factors,including topography,soilproperties and nutrient elements(P,Ca,K,Mg,Mn,Zn,Cu,Ag,Co and Ni)on the growth of larchwere analyzed in detail,qualitatively and quantitatively.The ordination technique was used to groupthe site factors and to classify sites for larch.Analysis indicated that height growth,diameter(DBH)and volume of the larch varied among site types and this will be of theoretical and practical signifi-canee in developing larch plantations.

Phytosociology of stratification in a lowland tropical rainforest occurring north of the Tropic of Cancer in Meghalaya, India

Stratification in lowland rainforests of Meghalaya,India,which represent the westernmost limit of the rainforests north of the Tropic of Cancer,was studied in horizontal and vertical planes to elucidate the patterns in stacking of species diversity and community attributes,and to draw comparisons with rainforests of‘Indo-Malaya’ecozone(biogeographical realm).All individuals≥10 cm GBH(girth at breast height)were enumerated in six transects of 10 m width and up to 500 m length covering 2.45 ha area.The stratification of whole assemblage of species in vertical plane is referred to as‘storey structure’(=height class distribution),which explains structural complexity.In horizontal plane,it is typically referred to as‘stand structure’(=girth class distribution),which explains structural heterogeneity.The stratification of an individual species in vertical plane is referred to as‘loftiness’and in horizontal plane,it is frequently referred to as‘population structure’.The stand structure was characterized by a negative exponential relationship or a reverse J-shaped curve,which is typical of a well regenerating forest stand.The storey structure was characterized by the low stature of the rainforest(<30 m),subtle layering in the canopy with dearth of discrete multi-stories,narrower widths of the stories and a thick understory.The cluster analysis and‘candlestick charts’showed that the dominant species spatially segregated in canopy height to profile three strata,viz.,an understory of juveniles and shrubs below 5 m,a middle-storey of intermediate trees between 5 and 15 m,and an overstory of large trees between 15 and 25 m.Emergent trees of a few species may reach up to 30 m.The individuals tended to scatter in increasingly wider range of height classes from a lower to the next higher girth class,creating a‘torchlight scatter’pattern,with a tendency to concentrate towards smaller height classes due to stochastic factors,which potentially influence vertical growth proportionate to diametric growth.In comparison to equatorial rainforests of Malaysia and seasonal rainforests of southwestern China,the rainforests of Meghalaya are short-statured at the geographic extremity of the occurrence of rainforest biome in Asiae Pacific region,owing to floristic composition,site quality factors,excessively higher quantities of rainfall and high differential of precipitation and potential evapotranspiration.Despite limited diversity of megaphanerophytes,these rainforests deserve concerted conservation efforts as they stack high diversity of meso-,micro-and nano-phanerophytes.

我国东北林区夏季森林生态系统服务功能对气候变化的响应研究

东北林区是我国最大的天然林区,森林覆盖率高,在吸收二氧化碳、水土保持、减缓气候变暖等方面发挥重要作用,是东北平原、华北平原的重要生态屏障。采用MODIS资料和逐日气象数据等长期观测数据资料,利用多种评估指标和方法,对2000—2021年夏季东北林区气象条件、净初级生产力、净生态系统生产力和植被覆盖度等生态参数以及土壤保持功能、水源涵养功能等生态服务功能进行了评价。结果表明:2000年以来,东北林区夏季降水和气温总体呈增加趋势,促进了森林生态恢复,植被覆盖度和净初级生产力平均每年分别增加0.3个百分点、3.0 gC/m^(2);夏季土壤保持功能稳步提升,平均每年涵养水量增加2.4 mm,土壤保持量增加1.4 t/hm^(2)。2000年以来,东北地区夏季降水量和涵养水量、土壤保持量呈显著正相关,表明夏季降水是影响东北森林水土保持服务功能的重要气候因子。本研究揭示了2000年以来气候变化对东北森林生态服务功能的影响,为切实保障森林生态建设的质量和效益的提升提供了气象依据。

东北国有林区林下生态产品价值实现模式

基于生态位理论,以东北国有林区林下生态产品为研究对象,从资源、环境、需求和技术生态位等方面分析林下生态产品价值实现的状况,认识改革前林下生态产品价值实现面临的瓶颈,提出改革后林下生态产品价值实现的模式:“原生态种养+林X”资源开发模式、“EODF+林下生态产品”市场转化模式、“景城一体+多核吸引”需求扩大模式及“区块链+林下生态产品”价值实现模式。

东北地区PM_(2.5)质量浓度遥感估算与时空分布特征

利用2014—2018年近地面观测PM_(2.5)质量浓度数据、MODIS 10 km气溶胶光学厚度(Aerosol Optical Depth,AOD)数据、ERA5再分析气象数据和DEM(Digital Elevation Model)数据,分别构建估算东北地区PM_(2.5)质量浓度的多元线性回归模型(Multiple Linear Regression,MLR)、线性混合效应模型(Linear Mixed Effects Model,LME)和随机森林模型(Random Forest,RF),利用十折交叉验证方法对3个模型进行精度评价。根据最优模型估算2009—2018年东北地区逐日PM_(2.5)质量浓度,结果表明:(1) 3种模型模拟的PM_(2.5)质量浓度与地面实测值间的相关系数R^(2)排序为RF>LME>MLR,RF模型整体精度最高。(2)不同季节、月份的RF模型模拟PM_(2.5)质量浓度与地面实测值间的R^(2)均高于0.93,通过RF模型估算东北地区的PM_(2.5)质量浓度是可行的;(3) 2009—2018年东北地区PM_(2.5)质量浓度呈先升后降的年际变化趋势,同时表现为冬季>春季>秋季>夏季的季节性变化特征;从空间分布上看,PM_(2.5)质量浓度由西南到东北逐渐降低,总体上辽宁>吉林>黑龙江。

进口资源约束下东北国有林区木材加工企业转型策略研究

在进口木材资源约束下,运用扎根理论分析东北国有林区木材加工企业以及伊春森工、吉林森工、龙江森工的部分林业局的转型策略。研究表明:停伐后东北国有林区受资源约束程度较两危时期有所缓解,但整体仍处于较高水平,木材加工企业过度依赖进口木材,企业经营成本与经营风险增加。从多元化发展、数字化发展、市场化发展角度分析企业转型路径,针对不同类型木材加工企业提出针对性建议。

东北森林生长季NDVI对昼夜不对称增温及降水变化的响应特征

【目的】东北地区森林面积广袤,是我国重要的生态屏障。本文旨在研究昼夜不对称增温的背景下,东北森林生长季NDVI变化及其对气候的响应,以期为东北地区林业建设与保护提供科学数据与指导。【方法】基于2000-2019年SPOT Vegetation NDVI数据、植被类型空间分布数据以及逐月降水、气温数据,应用趋势分析、Hurst指数、相关分析等方法,探究昼夜不对称增温的背景下东北森林生长季NDVI的时空演变规律,对气候因子的响应特征及未来变化趋势。【结果】(1)近20年东北森林生长季NDVI整体呈上升趋势,每10年增加0.035,其中混交林增加趋势最大,每10年增加0.037,阔叶林最小。东北森林以改善为主,占总面积55.59%,另有43.84%的森林保持基本不变,仅有0.57%的区域森林属于退化状态。(2)从整个生长季来看,NDVI受最低气温和降水影响显著,与最高气温关系不密切,同时生长季最低气温和降水呈明显增加趋势,最高气温无明显变化,一定程度上解释了在昼夜不对称增温的背景下,东北森林生长季NDVI增加;不同林型对气候响应不完全相同:3种森林类型中,针叶林生长主要受最低气温影响,阔叶林生长由降水和最低气温共同控制,混交林生长对降水最为敏感。(3)从逐月特征来看,生长季前期(4-5月)NDVI主要受最高气温和最低气温共同影响,旺盛生长期(6-8月)对降水敏感性较高,生长季末期(9-10月)受最低气温和降水共同控制;NDVI对降水、温度敏感性均呈现明显的时滞性特征。(4)利用Hurst指数对未来趋势进行分析,显示东北森林将由改善转为退化,有71.94%的森林将面临退化风险,尤其是中部和北部气候变化剧烈区域。【结论】白天和夜晚升温的不对称性和NDVI对最高、最低气温差异性响应特征,导致白天和夜晚温度对东北森林NDVI近20年变化具有不对称影响;2000-2019年东北森林生长季NDVI呈增加趋势,但未来面临退化风险。