Ways to Improve Low-Benefit Black Locust Forests in Loess Plateau

This paper presents a general standard for the low-benefit black locust （Robinia pseudoacacia L.） torests m Loess Plateau based on defining the concept of “tri-low forest”, and emphasizes the major factors which result in low-benefit black locust, such as, lack of soil moisture of forest and nutrient, breaching the principle of matching tree species to sites, and high density of forests. Based on different characteristics of low-benefit forests, following the principle of “adjusting measures to local conditions, giving priority to ecological benefits, assisting with economic benefits”, the authors put forward some technical ways to reform low-benefit black locust forests, for example, taking measurements of collecting runoff and storing water, lowering the forest density, introducing mixed forests and transforming species, directive breeding and so on.

Perspective of Chinese Forest Carbon Absorption Trade Based on Low-Carbon Economy

The paper analyzes the basis of forest carbon trade including the feasibility of carbon absorption trade,main body,platform and standard.The purposes of capital of carbon absorption trade is introduced.Caron absorption trade capital can be used to resettle ecological migrants,absorb employment,build forest and increase fund,increase local income,enhance forest science and technology development and launch environmental proportion.The perspective of developing forest carbon absorption trade is pointed out and the practical problems of developing forest carbon trade need to be solved.For example,the property problem of forest resources,value calculation problem of forest resources and sustainable development of forest.

Mapping Glitches of Juniper Forests in Lebanon under Natural Conditions and Anthropogenic Activities

In 1965, the first forest map of Lebanon was produced. It is the oldest spatial distribution representation of junipers. Landcover maps of 2002 and 2010 are the most detailed spatial distribution that spatially shows forests. Juniper forests are found in Lebanon as mainly as clear to low density coverage. High-density juniper forests are rarely found and only on Mount-Lebanon. Juniper forests are also mixed with oaks on the Eastern flank of Mount-Lebanon. Mapping juniper forests have demonstrated high degree of complexity, especially because of their low density and being mixed. The spatial representation of juniper forests was compared between the 1965 forest map and the landcover maps of 2002 and 2010. GIS environment was used to extract juniper forests from all maps. The degree of matching between juniper forests was investigated regarding the total area and spatial overlapping. Juniper forests were examined to their spatial locations, comparing the three maps. Spatial changes and anthropogenic effect were obtained, using Google Earth facilities. Google earth had satellite images acquired since 2014. Landcover maps of 2002 and 2010 have spatially matched forest map of 1965 by about 90% and 50% respectively. Spatial coverage of juniper forests were about 12,000, 26,000 and 28,000 ha on the 1965 forest map, landcover maps of 2003 and 2010 respectively. Anti-Lebanon juniper forests were not well represented on both landcover maps. Anthropogenic activities were mainly agriculture that affected juniper forests. Cultivations have replaced about 2% of the spatial coverage of 1965 Juniper forests. Quarries and urban existed inside juniper forests but in very limited areas. Juniper forests delineation did not completely match neither between the available maps, nor to the ground. Some juniper forests were not spatially represented on all maps or existing maps represented only portion of juniper forests. Juniper forest mapping requires more consideration and field investigation. High spatial resolution satellite images are among the solutions but delimiting juniper would require extensive fieldwork and specific remote sensing treatments. Being centuries old forests and characterized by High Mountain elevations, these important conifer forests are needed to be mapped with higher accuracy for better statistics and conservation.

On Exploration and Evaluation of Forest Ecotourism Resources in Shangsi County of Guangxi,China

Forest ecotourism resources in Shangsi County were investigated,explored and screened for the qualitative and quantitative analysis of resource units,physiographic landscape resources and forest eco-resources of the local area elaborated,characteristics of its forest ecotourism resources summarized as "having an excellent location,great development potential and high development value".Basic laws of forest ecotourism resources in Shangsi County were obtained through resource investigation,exploration and analysis,development and utilization of forest ecotourism resources further studied,and suggestions proposed to facilitate the sustainable development of forest ecotourism resources in Shangsi County.

Impact of a Low Severity Fire on Soil Organic Carbon and Nitrogen Characteristics in Japanese Cedar Soil, Yamagata Prefecture, Japan

Slash and burn practices are widely used around the globe with different degrees of success which are mostly related to the impact of fire on soil properties. In Japan slash and burn practises, known as Yakihata, have a long history and are still used in Yamagata Prefecture today. The purpose of this study was to determine the impact of a low severity controlled fire underneath Japanese cedar (Cryptomeria japonica) on brown forest soil (Cambisol). Japanese Cedar is the dominant species among plantations in Japan. We measured organic carbon and nitrogen content as well as changes in carbon (δ13C) and nitrogen (δ15N) stable isotope composition in a steep west facing slope under heavy precipitation (~2600 mm/a) and heavy snowfall (~3 to 4 m/a). The accumulation of Ctotal and Ntotal at the bottom of the slopes was remarkably higher at the slash and burned site than in the control forest site. After slash and burn δ15N isotopes in the slope in general became significantly lighter than in the control forest while the δ13C did not show any significant difference between the two sites except at the bottom of the slopes where δ13C was heavier in the forest. The results show that Ctotal and Ntotal values as well as the isotopes ratios of C and N change with decreasing elevation in the forest as well as in the burned site being consistent with leaching and erosion. The changes in soil nitrogen and carbon isotopes at the bottom of the slope appear to be related to the transport of material with different isotopic composition from the upper slope. The effect of the low severity fire (as part of the slash and burn practice) on soil organic carbon and nitrogen movement was enhanced by the steepness of the slopes and the high precipitation of Shonai region.

The global rainforest mapping project JERS-1: a paradigm of international collaboration for monitoring land cover change

The Global Rainforest Mapping (GRFM) project was initiated in 1995 and, through a dedicated data acquisition policy by the National Space Development Agency of Japan (NASDA), data acquisitions could be completed within a 1.5-year period, resulting in a spatially and temporally homogeneous coverage to contain the entire Amazon Basin from the Atlantic to the Pacific; Central America up to the Yucatan Peninsular in Mexico; equatorial Africa from Madagascar and Kenya in the east to Sierra Leone in the west; and Southeast Asia, including Papua New Guinea. To some extent, GRFM project is an international endeavor led by NASDA, with the goal of producing spatially and temporally contiguous Synthetic Aperture Radar (SAR) data sets over the tropical belt on the Earth by use of the JERS-1 L-band SAR, through the generation of semi-continental, 100m resolution, image mosaics. The GRFM project relies on extensive collaboration with the National Aeronautics and Space Administration (NASA), the Joint Research Center of the European Commission (JRC) and the Japanese Ministry of International Trade and Industry (MITI) for data acquisition, processing, validation and product generation. A science program is underway in parallel with product generation. This involves the agencies mentioned above, as well as a large number of international organizations, universities and individuals to perform field activities and data analysis at different levels.

Application of LiDAR Data for Hydrologic Assessments of Low-Gradient Coastal Watershed Drainage Characteristics

Documenting the recovery of hydrologic functions following perturbations of a landscape/watershed is important to address issues associated with land use change and ecosystem restoration. High resolution LiDAR data for the USDAForestServiceSanteeExperimentalForestin coastalSouth Carolina,USAwas used to delineate the remnant historical water management structures within the watersheds supporting bottomland hardwood forests that are typical of the re- gion. Hydrologic functions were altered during the early1700’s agricultural use period for rice cultivation, with changes to detention storage, impoundments, and runoff routing. Since late1800’s, the land was left to revert to forests, without direct intervention. The resultant bottomlands, while typical in terms of vegetative structure and composition, still have altered hydrologic pathways and functions due to the historical land use. Furthermore, an accurate estimate of the watershed drainage area (DA) contributing to stream flow is critical for reliable estimates of peak flow rate, runoff depth and coefficient, as well as water and chemical balance. Peak flow rate, a parameter widely used in design of channels and cross drainage structures, is calculated as a function of the DA and other parameters. However, in contrast with the upland watersheds, currently available topographic maps and digital elevation models (DEMs) used to estimate the DA are not adequate for flat, low-gradient Coastal Plain (LCP) landscape. In this paper we explore a case study of a 3rd order watershed (equivalent to 14-digit hydrologic unit code (HUC)) at headwaters of east branch of Cooper River draining to Charleston Harbor, SC to assess the drainage area and corresponding mean annual runoff coefficient based on various DEMs including LiDAR data. These analyses demonstrate a need for application of LiDAR-based DEMs together with field verification to improve the basis for assessments of hydrology, watershed drainage characteristics, and modeling in the LCP.

森林结构差异对大兴安岭森林小流域径流情势和退水特征的影响

径流情势和流域退水是反映水文过程至关重要的指标,除气候因素外,主要受到下垫面和流域水文地质特征的影响。利用准配对流域法,对比大兴安岭地区森林结构不同的2个小流域(老爷岭流域、圣诞村流域),排除气候和地形地貌的干扰,探究森林结构变化对流域径流情势及退水过程的影响。结果表明:老爷岭流域的全年洪峰历时比圣诞村流域延长5 h、平均洪峰滞时推迟2 h,洪峰径流量、变异系数均无显著差异。随着森林平均蓄积量、树种组成、郁闭度等森林结构指标的提高,老爷岭流域(森林结构综合指数较高)较圣诞村流域(森林结构综合指数低)的枯水径流时间低4 h,平均枯水径流深提高0.65 mm(是圣诞村流域3倍),平均枯水径流变异系数低33%,且流域间差异均达到了极显著水平(P<0.01)。通过退水分析,结果表明:老爷岭流域和圣诞村流域退水系数(k)的均值分别为16.9、8.5 d,退水常数(α)均值分别为0.909 4、0.862 6,老爷岭流域的平均退水时间比圣诞村流域延缓了8.4 d。该地区流域水文特征受森林植被变化的影响明显,森林结构复杂、森林质量高的老爷岭流域枯水径流量高并且稳定,退水过程更慢,水源涵养功能更好。

改进TDM-LoRa低功耗森林火灾监测预警系统

针对目前森林火灾监测系统成本高、功耗大、维护复杂的缺点,提出一种基于改进TDM-LoRa设计的低功耗森林火灾监测预警系统.系统以STM32系列微处理器为节点控制核心,LoRa-SX1278芯片为通信模块,并使用增量传输和改进时分复用通信机制,有效降低节点能耗,从而延长监测节点和汇聚节点寿命.试验结果表明,数据信息在发射功率为20 dBm、传输速率为1.2 kbit·s^(-1)的情况下,节点在3500 m范围内实现的丢包率仅为7.2%;在使用2600 mA·h的电池、数据采集上传间隔时间为30 min的情况下,单个节点有效工作时间理论可达90.7个月,实现无中继远距离低功耗森林环境监测数据的采集.

考虑多扰动因子的含光伏电源低压台区漏电故障检测

针对含光伏电源的低压配电台区剩余电流检测易受多重因素干扰,难以实现漏电故障精准检测的问题,提出了一种基于随机森林算法的计及剩余电流扰动因子含光伏电源的低压配电台区漏电故障检测方法。通过多角度挖掘分析剩余电流扰动因子,利用剩余电流偏差法定量分析剩余电流扰动因子对剩余电流的影响,分析计及剩余电流扰动因子的漏电故障频域特性,构建了多维故障特征向量与特征数据集,建立了基于随机森林算法的漏电故障检测模型。通过仿真模型进行仿真分析与验证,结果表明所提方法可高精度检测漏电故障,与常用方法相比,所提方法的故障检测准确率和稳定性更高、抗干扰能力更强。

低覆盖草地叶面积指数遥感估算方法

有效估算低覆盖草地叶面积指数(LAI),对监测低覆盖草地生长状况、优化完善草地管理具有重要意义。以往针对草地叶面积指数的研究大多集中于中高覆盖度草地,对低覆盖草地的研究相对较少。利用谷歌地球引擎(GEE),基于Landsat-8卫星数据提取所需特征变量,通过特征变量与叶面积指数的相关性及其在模型中的重要性进行特征优选,确定模型最佳变量个数,以此构建机器学习模型,探寻适合在低覆盖区草地估算叶面积指数的方法。结果显示,基于相关性特征优选的梯度提升回归树模型(r-GBRT)在低覆盖草地估算叶面积指数的效果较好,测试集的R 2为0.686,均方根误差(RMSE)为0.101。结果表明,基于特征优选构建的机器学习模型在低覆盖条件下估算草地叶面积指数方面具有较好的应用价值。

蒙古栎低质林改造后2010—2023年林地土壤质量的综合评价及未来6a土壤质量变化趋势预测——以2009年改造的蒙古栎低质林为例

在黑龙江省大兴安岭林区的加格达奇林业局翠峰林场174林班,以蒙古栎(Quercus mongolica)低质林为例,2009年进行不同采伐带宽度的顺山皆伐,每条采伐带设置在近似相同海拔高度,皆伐带带长均为300 m,带宽分别为6、10、14、18 m,采伐后在每种采伐带分别补植了西伯利亚红松(Pinus sibirica)、兴安落叶松(Larix gmelinii)、樟子松(Pinus sylvestris),共设置12个不同改造样地;2010—2023年,测定12个不同改造样地的7个土壤养分指标(有机质质量分数、全氮质量分数、全磷质量分数、全钾质量分数、速效氮质量分数、速效磷质量分数、速效钾质量分数),应用模糊综合评价法、主成分分析法对土壤质量进行综合评价;结合2010—2023年对样地土壤养分质量评价结果,采用非线性自回归外部输入(NARX)神经网络模型预测2024—2029年各样地的土壤养分质量状况,分析未来6 a土壤养分质量变化趋势。结果表明:2023年测定的改造样地的土壤养分质量,91.67%的改造样地满足功能标准。补植樟子松样地中,只有采伐宽度为14 m的样地土壤养分质量相对稳定,其他采伐宽度的样地土壤养分质量状态不稳定。在2024—2029年,除了采伐宽度为10、18 m宽带中补植樟子松的样地以及采伐宽度为14 m宽带中补植西伯利亚红松的样地土壤养分不稳定外,其他样地未来6 a总体看土壤养分质量均较好,为Ⅰ级。构建的评价模型框架,可为低质林改造样地土壤养分质量综合评价及预测提供技术支持,弥补了土壤观测的数据盲区。

低温胁迫下林木的生理响应特征

低温严重危害了林业生产,是影响林业发展的重要自然灾害。目前,关于低温胁迫下林木的生理响应特征方面的研究已经取得了一定进展。本文综述了低温胁迫下林木的生理响应特征,旨在为深入研究林木的抗寒机制提供参考。研究表明,低温胁迫会使林木对其光合作用、叶绿素含量和黄酮类物质的含量进行调节以应对低温胁迫。具体而言低温会降低光合作用的速率,这是由于低温抑制了酶的活性,减缓了气孔开放和CO_(2)的吸收速率,进而降低了光合作用的效率。这种降低可能导致植物生长速度减缓,产量下降。另外,低温会引发叶绿素含量的变化,但具体的变化趋势和程度仍存在差异。研究表明低温胁迫会降低或促进叶绿素的合成和积累。此外,低温胁迫也会促使林木合成和积累更多的黄酮类物质,以增强其抗寒能力和应对低温压力的能力。这些化合物具有抗氧化作用,可以减轻低温引起的氧化损伤,保护细胞的完整性。综上所述,林木的光合作用、叶绿素含量和黄酮类物质的变化在低温胁迫条件下发生了改变。未来的研究可以通过利用更加精密的技术手段,深入探究林木在低温环境下的分子机制,以加深对林木抗寒机制的理解并为改良林木品种、提高抗寒性能以及增加林业产量提供更多的参考。

环境意识对低碳森林食品购买意愿的影响——基于中介和调节效应的实证分析

基于Ologit回归模型对559份消费者的问卷调查数据进行回归分析,探讨消费者环境意识对低碳森林食品购买意愿的影响机制。实证结果显示:环境意识正向影响消费者对森林食品的消费意愿;碳标签作为判断低碳消费的重要标准之一,消费者对碳标签产品的认知在环境意识对低碳森林食品购买意愿关系中具有中介效应;低碳产品信任度正向调节了环境意识对低碳森林食品购买意愿的影响。据此,提出了加强对消费者的低碳教育,培养消费者的生态环境意识;普及碳标签相关知识,加深消费者对碳标签产品的认知与理解;增强消费者对低碳产品的信任水平,助力消费者生活绿色转型的对策建议。

汉江兴隆水利枢纽下游近坝河段枯水位下降及成因分析

汉江兴隆水利枢纽运行后,坝下游近坝段枯水位较建坝前下降明显,500~800 m^(3)/s流量下,2021年较运行前坝下水位累计下降2.47~2.55 m,对工程安全及效益发挥带来不利影响。基于水文、断面、水下地形等观测资料,对枯水位下降的原因进行深入剖析。结果表明,兴隆水利枢纽的拦沙作用有限,皇庄以上沙量减少是兴隆以下河床冲刷加剧的重要原因,高水调平导致的年内枯水上滩几率下降和航道整治护滩工程是强冲刷过程中“滩淤槽冲”的核心因素。坝下游河段枯水河槽冲刷及汉口最低水位下降是造成兴隆近坝段枯水位下降的直接原因。随机森林算法分析显示,对兴隆坝下水位变化影响最大的因素为兴隆站输沙率的锐减。此外,航道整治工程、河床边界条件对枯水位下降也有十分重要的驱动作用。兴隆坝址及下游河段的河床组成偏细,2012-2022年虽然河床剧烈冲刷,但床沙组成没有出现粗化的现象,预计河床仍将继续冲刷下切,枯水位尚未达到稳定状态。

安徽省薄壳山核桃低产林形成原因与改造技术

薄壳山核桃果实营养丰富,收益期长,在安徽省已形成较大规模的种植,成为农民脱贫致富的重要途径。但由于建园不规范、品种混杂、栽培管理粗放等原因,出现了一批低产林。该文系统分析了安徽省内薄壳山核桃低产林形成的原因,并提出相应的技术改造措施,以提升其产量与质量,推动安徽省薄壳山核桃产业良性发展和壮大,助力乡村振兴。

不同带间距固沙林带间植被与土壤特性变化

在科尔沁沙地敖汉旗沙区,通过评估不同带间距低覆盖度固沙林对土壤及植被的影响,旨在提出更适宜当地条件的带间植被恢复与土壤发育的配置结构模式,为科尔沁沙地人工造林提供科学依据。对3种不同带间距的赤峰杨固沙林带间植被群落多样性、土壤理化性质及其相关性进行了研究。结果表明:不同带间距赤峰杨固沙林带间植被与土壤恢复有明显影响,植被恢复与土壤恢复是相辅相成的。(1)在调查的3种不同带间距的行带式固沙林中,随着带间距的增加,带间植被的物种多样性呈增加趋势,各物种多样性指数的变化趋势比较为:带间距25 m>16 m>10 m>等株距对照样地;(2)土壤含水量、孔隙度及土壤养分(有机碳、碱解氮、速效磷、速效钾)含量比较为:带间距25m>16m>10m>等株距对照样地;土壤容重比较为:带间距25 m<16 m<10 m<等株距对照样地;(3)在不同带间距赤峰杨固沙林中,土壤发育和植被恢复是相互促进的,物种多样性指数与土壤的各项理化性质存在不同程度的显著(P<0.05)或极显著(P<0.01)相关,但与速效钾的相关性不显著。低覆盖度赤峰杨固沙林带间距的大小对带间土壤理化性质、植被恢复有明显的影响,增大带间距,能有效促进土壤发育、促进带间植被生长,25m的带间距,更有利于土壤的发育和带间草本植被生长。

“双碳”目标下巍山县桉树低效林改造路径探索

为改善林分结构,开发林地生产潜力,提高林分质量和效益水平,促进林草产业高质量发展,实现绿色低碳发展目标,修复森林生态系统,建设生态文明,促进林业可持续发展,巍山县需尽快对桉树低效林实施改造。通过实地调查、对桉树低效林进行评判后,针对巍山县桉树林分现状与立地条件,提出基于生态优先、适地适树、统筹规划、循序渐进的原则,对桉树低效林进行综合改造。提出了分别对桉树用材林和林化工业原料林采取间伐、调整树种、更替等多种改造方式和带状改造、林冠下更新等措施,优化森林结构,提高森林质量,增加林地产出率和森林资源总量,增强森林碳汇功能。

基于随机森林算法的低压系统漏电检测技术研究

随着低压配电系统规模及用户需求量迅速增加,用户线路与家庭电气设备漏电故障频发,极易发生人体触电及电气火灾事故。剩余电流保护器作为检测低压漏电故障的常用手段,近年来因线路(或设备)存在对地泄漏电流而频频误动,极大降低了保护设备投运率与可靠性。为此,本文提出一种基于随机森林(random forest,RF)算法的低压配电系统漏电检测技术,为最大程度贴近真实漏电故障场景,充分考虑实际故障场景存在的正常泄漏电流过大、故障邻近支路负荷投切频繁等干扰因素以获得贴近真实故障场景的原始剩余电流数据;通过对原始剩余电流数据进行数据预处理,分析掌握剩余电流的频域与时域特性并利用傅里叶变换算法提取时频域特征,完成低压系统漏电检测模型的建立与训练;在施加多种干扰因素情况下对漏电检测模型进行深度测试,其漏电故障的检测准确率可达99.97%,实现了多种干扰因素情况下的低压配电系统漏电故障检测;最后将支持向量机(support vector machine,SVM)算法、K最近邻(K-nearest neighbor,KNN)算法与本文基于RF算法的漏电故障检测模型的准确性进行对比,以此验证了基于RF算法的低压系统漏电检测模型的准确性与可行性。

基于多维特征与随机森林的低压用电安全隐患预警方法

故障电弧作为低压用电常见安全隐患,因存在隐蔽性和随机性,导致难以在故障前夕有效感知,现有保护方法通常于故障发生后采取措施,容易造成电气火灾发生。针对这些问题,提出基于多维特征与随机森林的低压用电安全隐患预警方法。首先,搭建真型实验平台复现多种负载故障电弧真实场景,采集实验数据进行去噪、归一化和样本化等预处理;接着分析故障前、后波形变化情况,进而实行特征有效性分析,提取多维与故障相关程度较高的特征值,提高特征普适性。然后,搭建随机森林模型并进行超参数优化,以最小化节点信息熵为目标完成模型训练,提升模型整体性能和学习效率。最后,通过实验验证表明,所提方法在多种不同负载运行工况下预测准确率可高达99.4%以上,且预测准确率高于4种主流分类预测模型。