How forest age impacts on net primary productivity: Insights from future multi-scenarios

Forest net primary productivity(NPP)constitutes a key flux within the terrestrial ecosystem carbon cycle and serves as a significant indicator of the forests carbon sequestration capacity,which is closely related to forest age.Despite its significance,the impact of forest age on NPP is often ignored in future NPP projections.Here,we mapped forest age in Hunan Province at a 30-m resolution utilizing a combination of Landsat time series stack(LTSS),national forest inventory(NFI)data,and the relationships between height and age.Subsequently,NPP was derived from NFI data and the relationships between NPP and age was built for various forest types.Then forest NPP was predicted based on the NPP-age relationships under three future scenarios,assessing the impact of forest age on NPP.Our findings reveal substantial variations in forest NPP in Hunan Province under three future scenarios:under the age-only scenario,NPP peaks in 2041(133.56TgC·yr^(−1)),while NPP peaks three years later in 2044(141.14TgC·yr^(−1))under the natural development scenario.The maximum afforestation scenario exhibits the most rapid increase in NPP,with peaking in 2049(197.95TgC·yr^(−1)).However,with the aging of the forest,NPP is projected to then decrease by 7.54%,6.07%,and 7.47%in 2060,and 20.05%,19.74%,and 28.38%in 2100,respectively,compared to their peaks under the three scenarios.This indicates that forest NPP will continue to decline soon.Controlling the age structure of forests through selective logging,afforestation and reforestation,and encouraging natural regeneration after disturbance could mitigate this declining trend in forest NPP,but implications of these measures on the full forest carbon balance remain to be studied.Insights from the future multi-scenarios are expected to provide data to support sustainable forest management and national policy development,which will inform the achievement of carbon neutrality goals by 2060.

An overview of the “Three-North” Shelterbelt project in China

The ＂Three-North＂ Shelterbelt is the largest and most distinctive artificial ecological engineering project in China. It has been conducted since November 25, 1978 in the ＂Three-North＂ （i.e., Northeast China, North China and Northwest China） regions. In this study, the background and the essential benefits of the ＂Three-North＂ Shelterbelt project are summarized. The basic status and future development of the ＂Three-North＂ Shelterbelt project are also studied. As well, we tried to discuss the problems existing in the current shelterbelt system and the strategies to conduct this ecological project rationally.

A PROJECT OF SUSTAINABLE UTILIZATION OF FOREST RESOURCES SUPPORTED BY GIS

This paper, with the help of GIS, analyzes the structure characteristics, dynamic process and factors which result in failure of forest resources sustainable development in Tayuan Forest Farm, Da Hinggan Mountains, finds that there are big problems either in quantity or in Planning for forest resource development, and puts forward a project for its forest resources sustainable utilization. From the analysis, this paper is going to find an available develoment project for forest resourees sustainabe utlization for the forest farm, and also provides the proection and management of forest resources and the strategy of sustainable forestry development with scienndc foundation.

A system dynamics model for billion trees tsunami afforestation project of Khyber Pakhtunkhwa in Pakistan:Model application to afforestation activities

As part of the global effort to plant billion trees,an afforestation project is launched in Pakistan in Khyber Pakhtunkhwa(KP)province to conserve existing forests and to increase area under forest cover.The present study is designed to build a Systems'model by incorporating major activities of the Billion Tree Tsunami Afforestation Project(BTTAP)with special focus on afforestation activities to estimate the growth in forest area of KP.Availability of complete dataset was a challenge.To fix the model,the raw data taken from the project office has been utilized.Planning Commission Form 1-Phase I&II helped us with additional information.We relied on the data available for one and half period of the project as rest of the data is subject to the completion of the project.Our results show that the project target to enhance area under forest differs from the target to afforest area under the project.The system dynamics'model projection shows that the forest area of KP would be 23.59 million hectares at the end of the BTTA project,thus having an increase of 3.29%instead of 2%that has been initially proposed.However,the results show that the progress to meet the target in some afforestation classes is slow as compared to other categories.Farm forestry,plantation on communal lands and owners'plantation need special focus of the authority.Deforestation would affect 0.02 million hectares area of the project.The model under study may be used as a reference model that can be replicated to other areas where billion tree campaigns are going on.

Predicting equations of main factors affecting regional climate in the"Three-North" Protective Forest Area

The relationship between the change of forest resources and climatic factor in the, “Three-North” region of China were studied in this paper. The predicting equations of climatic factor (dependent variable) with regional independent variable (longitude, latitude and altitude) and stand independent variable (forest coverage rate), were developed by extensively using the linear and nonlinear regression methods. With these models, we can calculate the ecological benefit of Shelter-belt forest.

Designing a Citizen Science Project for Forest Landscapes: A Case from Hofmann Forest in Eastern North Carolina

Citizen science is a participatory research design that utilizes both non-professional researchers and professional researchers to collect, analyze, and disperse data. Citizen scientists seek to discover answers and draw solutions to scientific questions. The Hofmann Open Water Laboratory (HOWL) project, established in 2016, focuses its collaborative-based efforts in eastern North Carolina. HOWL citizen scientists monitor water quality, and quantity, that flows on and off the Hofmann Forest. HOWL provides opportunities to citizen scientists and gathers data to meet the project outcomes, which include understanding the importance of Hofmann Forest in the inner coastal plain of North Carolina, building science education skills for citizen science participants, and enhancing community relationships between the forest and citizens. This article outlines several approaches for developing citizen science projects in a forest context, drawing on experiences from HOWL. The paradigm can be used to meet the needs of any forest landscape’s research and management goals, while employing a participatory research approach. The guidelines present suggestions for productive and enduring processes for citizen engagement and project sustainability. Each project will need participants to set goals, build a diverse collaboration, and establish on-going evaluation processes to determine successful and failed components that ensures the project moves forward effectively. The citizen science efforts near the Hofmann Forest in Eastern North Carolina provided an excellent case study of the development of citizen science on the forest and adjacent lands. HOWL attempts to meet participant and socio-ecological outcomes, such as encouraging public action in natural resource and forest management, as well as enhancing scientific knowledge and skills. The project helps synthesize our experiences in this effort and the social science literature, providing reasonable guidelines for those seeking to establish their own citizen science efforts within a forest context.

Effectiveness Evaluation of the Construction of the Natural Forest Resources Protection Project in Haikou Forest Farm of Kunming

The current situation about the natural forest resources protection project in Haikou Forest Farm of Kunming on the protection of forest resources, forest fire prevention, forest administration resource management, forest pests, and money management was briefed. Achievements made in the implementation of natural forest protection project in Haikou Forest Farm were analyzed, and problems existing in the project as well as corresponding countermeasures were expounded.

SWOT Analysis of Forest Carbon Sink Projects in Yunnan Province and Recommendations for Enhancing Competitiveness

Using the SWOT analysis method,this paper analyzed the internal strengths,weaknesses,external opportunities and threats of forest carbon sink projects in Yunnan Province.It found that Yunnan Province has strengths in economic environment and practical experience,weaknesses in social participation,project scale and carbon sink talents,opportunities in international climate environment,domestic policies,etc.,and threats in project crediting period and forest resource protection,etc.In view of these,Yunnan Province can change the participation mode of forest carbon sink projects,adopt appropriate trading methods,get familiar with the relevant rules of forest carbon sink projects,strengthen the publicity and research of forest carbon sink theory,strengthen the management of carbon sink forests and expand forest carbon sink projects to enhance the market competitiveness of the Yunnan forest carbon sink projects.

Monitoring and Evaluation of Benefits of Project of Returning Farmland to Forests in Henan Province

The project of returning farmland to forest has been implemented and consolidated in Henan Province for 20 years.At present,it is in a critical transition period when the previous round of project of returning farmland to forests has completed and a new round of project of returning farmland to forests has started.Henan Province took counties(cities)with different representations as sample counties for monitoring the benefits of project of returning farmland to forests(key monitoring areas in Henan Province),and monitored social and ecological benefits every year,and has obtained real and scientific monitoring data.

Coastal Protection Forest Construction Project

China’s coastal line starts at the Yalu River in Liaoning in the north and ends at the Beilun River mouth in Guangxi. It is 18,000 kilometres long and crosses 11 provinces, municipalities and autonomous regions, including Liaoning, Hebei, Tianjin, Shandong, Jiangsu, Shanghai, Zhejiang, Fujian, Guangdong, Guangxi and Hainan. In 1988, the Chinese government outlined the Coastal Protection Forest System Construction Project and defined the coastal line of 11 provinces as the main construction line. The project aims at developing a

Analysis of Factors Influencing Forest Carbon Sequestration Project in Guangdong Province and Recommendations

Through designing questionnaires for farmers in the project area,the understanding and utilization of carbon sink forests were surveyed. In the form of stratified sampling,150 representative forest farmers were selected from the project area. Through the survey,it found that many factors hindered the progress of forest carbon sequestration project in Guangdong Province. Besides,the implementation of this project was influenced by both natural and social factors. As to the natural factors,natural disasters for the forest carbon sequestration project in Guangdong Province mainly include typhoons,rainstorms,landslides and mudslides. The social factors of the forest carbon sequestration project in Guangdong Province mainly include the weak willingness of forest farmers to participate,the low awareness of forest farmers for forest carbon sinks,the single and insufficient source of afforestation funds,and the single afforestation model. In order to better implement the forest carbon sequestration project,Guangdong Province can take measures such as strengthening the publicity on forest carbon sinks,expanding channels of funds,organizing forest carbon exchange training courses,and diversifying the afforestation models.

Project to Protect Natural Forests

Gungjor County in Qamdois situated on the middlesection of the Jinsha-jiang River,on the upperreaches of the Yangtze Riverand in the northern part ofHenduan Mountains.Foreststhere total 220,198 hectares,and the forested area totals60,791 hectares.They com-bine to function as a naturalscreen on the Yangtze’s upperreaches.

多源多特征集成的南水北调工程丹江库区湿地时空格局演变

丹江口水库是中国南水北调工程的关键水源区。随着城镇化发展以及大坝二次建设,库区湿地生态系统变化显著,亟需湿地生态科学监测。以丹江库区为例,依托Google Earth Engine(GEE)平台,首先采用已有土地覆盖数据集生成湿地样本集,其次整合Landsat影像、DEM等数据构建多源特征集合,并基于Jeffries-Matusita(JM)距离进行特征优选,使用随机森林(RF)算法实现了1985~2023年丹江库区湿地制图。结果表明:①本文提出的样本采集流程可有效提高样本质量,为长时序分类样本采集提供参考;②湿地分类特征优选后特征数由37个减为27个,分类总体精度变化不大,优选后的特征应用于丹江库区湿地分类的平均总体精度(OA)以及平均数量和分配分歧指数(QADI)分别为89.53%和0.0802,说明特征优选有效减少信息冗余,提高影像分类效率;③1985~2023年,丹江库区湿地面积呈波动增加趋势,从1985年的17839.85 ha扩大到2023年的28872.48 ha,面积增长38.12%。总体来说,丹江库区湿地生态系统呈现出逐步恢复和优化的良好态势。

社会资本与林农林业碳汇项目参与——基于交易费用经济学视角

作为林地最主要的经营主体,林农的参与是林业碳汇项目开发的首要环节。考虑到中国“关系型”社会的特征以及由此产生的交易费用问题,基于交易费用经济学视角,结合社会资本理论剖析林农参与林业碳汇项目的内在机理,同时利用宁陕县微观农户调研数据分析社会网络、社会信任与社会规范是否会影响林农林业碳汇项目参与决策并检验社会资本变量发挥作用的条件,研究表明:89%的样本林农参与了林业碳汇项目,显现出了较高的参与水平;Logit模型结果表明强关系网络、人际信任、制度信任、惩罚机制与互惠行为变量均对林农林业碳汇项目参与具有显著促进作用,而弱关系网络变量并不会影响到林农的林业碳汇项目参与决策;调节效应模型的结果则表明林农的合作社社员身份可以显著地增强社会资本各维度对林农林业碳汇项目参与的正向影响。

东北天然林资源保护工程成效评估及热点区域识别

东北地区天然林资源保护工程的实施,改善了生态环境,提高了生态系统服务能力,对东北地区生态系统服务也起到了积极促进作用。为了更直观的反映东北地区天保工程的实施成效,研究基于长时间序列的遥感监测数据集-土地利用数据,采用InVEST模型和RUSLE模型对1990—2020年天保工程实施前后东北地区和天保工程区生态系统服务变化进行定量评估分析并采用Getis-Ord Gi∗指数识别热点区域。结果表明:(1)东北地区1990—2020年城乡/工矿居民用地和耕地面积分别增加25.37%,12.15%,水域减少21.42%,草地减少14.02%,未利用土地和林地分别减少8.41%,5.34%。(2)1990—2020年东北地区和天保工程区土壤保持量分别增加了95.81×106 t、24.05×10^(6) t,碳储量分别减少了7.49×10^(8) tC、3.92×10^(8) tC,水源涵养量分别增加了177.51×10^(9) m^(3)、58.65×10^(9) m^(3)。(3)东北地区的极显著热点区域主要分布内蒙古地区东北部、黑龙江省北部、吉林省东部和辽宁省东部。随着天保工程的实施,极显著热点区域显著增加,且范围与天保工程高度重合。研究拟为后续东北地区林业政策和生态工程的实施提供科学的参考依据。

农户碳汇林经营意愿与行为一致性研究——基于效益认知和受益认知的分析

基于效益认知和受益认知视角,研究农户的碳汇林经营意愿与行为,利用Logit模型对浙江省林业碳汇项目实施地区149户农户行为数据及附近非碳汇项目实施地区370户农户意愿数据进行实证分析。结果表明,效益认知和受益认知对农户碳汇林经营意愿与行为的影响存在明显差异。在效益认知方面,生态、社会效益认知均能显著提高农户的碳汇林经营意愿,而农户的碳汇林经营行为仅受社会效益认知影响;在受益认知方面,农户的碳汇林经营意愿同时受到受益金额和受益方式的影响,而拓展到行为时,两种因素的影响减弱。建议加大碳汇项目宣传和碳汇政策普及,制定合理的补贴标准及补贴途径,充分调动参与农户的碳汇林经营积极性。

赛罕乌拉林草交错区典型生态系统土壤理化性质对比

为分析退耕林地、自然草地、农田3种植被管理方式对土壤理化性质的影响,识别不同植被修复模式下土壤理化性质的差异,本研究以内蒙古赛罕乌拉林草交错区自然草地、退耕林地、农田3种典型植被类型为研究对象,通过对比分析3种植被类型下0 cm、10 cm、20 cm、40 cm、60 cm深度土壤容重、含水量、粒径比等物理属性以及全氮、全磷、全钾、碱解氮、速效磷、速效钾养分元素含量,结合元素含量之间的相关性分析,结果发现:1)农田土壤存在明显的犁底层,犁底层之下养分元素含量迅速下降;2)草地土壤pH值低、有机碳含量高,农田pH值最高、有机碳含量低,退耕林地浅层土壤有机碳含量少,其土壤理化性质呈现出居于农田与自然草地之间的特征;3)农田土壤除速效磷、全钾等指标高于自然草地外,其他养分含量均低于自然草地。本研究表明,自然草地、退耕林地和农田是在相同土壤母质基础上,因经营管理方式差异而产生的土壤理化性质差异,草地的有机质含量最高、农田最低,土壤有机碳含量对于其他养分元素含量具有关键作用。因此,林草交错区生态系统固碳功能对于防风固沙等其他生态功能发挥具有决定作用,退耕还草有利于土壤养分元素的恢复,退耕还林工程还应注重林冠下方草本灌木生物量及物种多样性的恢复。

基于可见光谱特征波长提取和分类算法的柑橘黄龙病快检研究

柑橘黄龙病(HLB)是由亚洲韧皮杆菌引起的一种严重病害,目前无法根治。其防控具有重要意义和经济价值。当前利用健康和患病叶片的光谱差异对其进行诊断显示了良好的应用前景。因患病叶片在叶绿素反射区及O—H伸缩振动区的可见光谱与健康叶片存在显著差异,而可见光谱检测在采集和数据处理方面具有成本低、简便的优势,研究可见光谱的黄龙病快速检测方法具有可行性和重要意义。为了减少光谱数据冗余和计算量,实现精准的黄龙病的早期鉴别以及降低黄龙病相似病症的误诊率,采集了黄龙病患病地区共160个叶片样本。经qPCR测定分别将其分类标定为健康、轻度疾病、重度疾病和缺镁症四类。根据叶片样本在可见光波段450~800 nm的反射光谱特征,通过S-G平滑以及降采样等预处理光谱数据后,为了优选出尽可能囊括光谱特征信息的特征波长,分别使用遗传算法(GA)、连续投影算法(SPA)以及竞争自适应重加权采样法(CARS)对采集到的可见光谱数据进行特征波长提取和降维优选出特征波长,进一步降低模型复杂度,提高预测精度。综合泛化能力及检测速度的考量,在定性判别分析模型的选择中采用训练速度快,分析准确率高的最小二乘支持向量机(LS-SVM)以及随机森林(RF)对两种变量筛选算法降维后的数据进行分类判别。通过对不同的模型的验证优选,筛选出最佳的快检方案。对比发现,在建立的模型中,SPA-RF模型与其他模型比较,对于训练集和测试集的判别准确率分别达到了100%和97.5%。结果表明,连续投影算法以及随机森林的组合分类模型可以很好地实现黄龙病早期的病理鉴别,同时也能够很好地识别出黄龙病病叶与其他相似病症的差异,为柑橘黄龙病快速检测及防治提供了一种方法依据。

湖南省权益类森林生态产品价值实现的问题与对策

权益类森林生态产品是一类需要政府赋权和确权并通过市场实现生态价值的生态产品,具有不完全的排他性和竞争性特征,依靠政府与市场共同作用实现生态价值。湖南省探索开发了林业碳汇项目、集体林权、林权抵押贷款等三种权益类森林生态产品,取得了积极成效,但依然在运行机制、配套政策等方面存在亟待解决的问题。政府应当采取优化林业碳汇项目开发、推动集体林权交易监管协同、打通林权抵押贷款通道等举措,推动权益类森林生态产品价值实现。

长白山北坡施业区植被变化及其驱动力分析

【目的】检测长白山北坡植被的变化趋势,分析植被分布与不同因素之间的关系以及森林干扰的变化情况,以期更加全面地揭示天然林资源保护工程前后研究区植被的变化情况,为评价天然林资源保护工程实施效果及制定植被资源恢复措施和生态环境保护政策提供科学依据。【方法】基于Google Earth Engine(GEE)地理数据分析云平台,使用1987—2020年的Landsat遥感数据,采用归一化植被指数(NDVI)、归一化燃烧率(NBR),结合Sen-Theil趋势分析、Mann-Kendall检验、地理探测器和LandTrendr变化检测算法,分析了白河林业局的植被覆盖时空分布特征及变化趋势,结合年均温、年平均降水量、海拔、坡度、林种和森林类型数据,研究了不同因子对植被覆盖空间分布特征的影响,并进一步分析了不同年份的森林干扰情况。【结果】1)1987—2020年研究区总体NDVI呈现提高趋势,在2000年大部分地区呈现不显著下降的趋势,而天保工程实施后研究区NDVI整体呈现上升趋势,尤其是初期提高趋势最为显著;2)温度和降水量对于NDVI空间分布的解释力最强,其次是森林类型和海拔;3)1987—2020年研究区的年干扰面积总体呈现出波动下降的趋势。2000年前森林干扰较为频繁,2000年开展天然林资源保护工程后森林干扰面积明显下降,且森林干扰主要发生在研究区中部以及北部部分区域,南部的落叶针叶林区域在研究时间内未观察到明显的干扰现象。【结论】近30年来长白山北坡植被总体呈现改善趋势,且天然林资源保护工程在植被改善以及降低干扰方面均发挥了重要作用。