森林凋落物分解影响因素的研究进展

凋落物是森林生态系统中重要的环节之一，作为连接地上部分和地下部分的纽带，对森林的生态功能不言而喻。而凋落物的分解是森林的枯枝落叶分解的养分回归土壤、补充土壤养分的过程。研究凋落物的分解及其影响因素可以掌握促进凋落物的因子，从而快速释放养分，起到保肥作用。关于影响森林凋落物的影响因素已经展开一系列的研究，但是尚缺乏系统总结，该研究归纳总结国内外相关文献，综述了影响森林凋落物的因素，分别为大气氮沉降、气候变化、自然灾害、人类干扰等因子，分析目前研究的不足并提出展望，以期为有效利用森林凋落物、提高森林生态功能提供参考依据。今后除了在以上方面进行研究之外，可在各因素之间的交互作用对凋落物分解的影响等加强研究。     

森林抚育间伐的直接效应分析

森林抚育间伐是森林生态系统经营中人类作用于森林的主要措施.针对抚育间伐对森林地上环境和土壤理化性质等方面的直接效应进行综述分析,并指出未来森林抚育间伐工作应从以下几个方面予以加强:森林实施分类经营管理；科学编制森林经营方案；转变间伐理念；森林抚育间伐进行长期定位研究.     

规范林业采伐技术 科学保护生态环境

森林采伐是指人类为获得木材和林产品而对森林进行的经营活动,这种重要的人为活动对森林生态系统产生较大的破坏作用,对森林生态系统的影响很大,林木的采伐、木材运输、集运材道路和机械设备等均可使森林植被和土壤不可避免地遭受不同程度的损害。本文在论述林业采伐作业对环境影响的基础上,具体探讨了林业采伐作业环保技术及对策,以期对日后此方面的研究提供一定的借鉴。     

解析森林经营对水土资源的保育作用影响

随着我国经济的快速发展,国家相关部门逐渐认识到了森林资源保护和利用的重要性,使得很多企业和个人都积极经营森林资源。这种森林经营活动不仅可以有效地保护树木和土壤,同时促进保护和控制水资源的污染,因此,森林经营在水土资源保护中具有十分重要的作用。对此做了深入分析,首先阐述了森林经营对水土资源的保育作用,然后分析了森林经营对水土资源保育的影响,最后介绍了森林经营对水土资源保育的有效对策。     

商品林木采伐管理制度对森林经营的影响

在进行森林经营的过程中,进行森林采伐是比较重要的一个环节,在现阶段,我国的森林采伐管理制度中,重要的一个内容就是采伐实施的限额制度,这个制度不但限制了森林经营者的经营权限,同时也对森林经营者行使森林的处理权造成了一定障碍。针对这种情况,本文主要研究讨论采伐限额制度对现阶段商品林木的采伐管理及森林经营的影响,并深入讨论制度改革的内容,从多个方面分析这一制度对森林经营的影响。同时,也根据在现实的森林经营中存在的问题提出相应的处理及应对措施,希望可以通过对这些问题的解决和处理,制定一系列的措施来保证森林经营的可持续性。     

凋落物分解酶的研究进展

森林凋落物分解是陆地生态系统物质循环和能量流动的重要环节,凋落物和土壤中的酶在凋落物分解过程中起着关键的调节作用.该研究综述了凋落物分解酶的生态学作用、种类以及影响酶活性的主要因素,为深入研究凋落物分解机理及其在森林可持续经营中的作用提供参考.未来该领域应注重全球变化背景下凋落物分解过程中酶的反馈调节机制探索,需将植物、凋落物和土壤作为一个整体,并结合新的检测技术和方法,对不同类型生态系统开展长期性、系统性的研究.     

五宝山国有林场分类经营的探讨与研究

经过长期的森林经营实践,对森林进行一定的功能分类已被普遍认同,在很多国家森林分类经营已经实行。但由于各国的森林状况、社会经济、人文理念等不同,其森林分类经营方式各有特点。总的看来,成功的森林经营管理,不仅取决于对森林进行合理的分类,重要的是在于森林分类之后的"分类式经营"。     

抚育采伐对林下天然更新及其环境的影响

抚育采伐是森林经营过程中人类作用于森林的主要措施。本文针对当前国内外森林抚育采伐对林分更新的影响进行了综述,重点探讨了抚育采伐对林分小气候、土壤环境和林下更新的影响。特别指出,在今后的森林经营过程中,应实施分类抚育采伐,加强群团状抚育采伐的研究。     

银川植物园城市森林生态系统服务功能评价

为确定城市森林生态系统服务功能,本研究以银川植物园为研究对象,调查统计银川植物园不同植被类型的涵养水源、固碳释氧、保育土壤、净化大气环境、保护生物多样性、积累营养物质、森林游憩等生态功能,并以货币的形式直观地展现森林服务功能的价值。研究结果表明,银川植物园森林生态系统服务功能总价值5524329.89元/年,各功能指标表现为森林游憩(33.66%)生物多样性保护(17.56%)固碳释氧(17.18%)保育土壤(13.46%)净化空气(13.20%)涵养水源(3.09%)积累营养物质(1.85%)。不同植被类型的平均单位面积生态服务功能价值排序差异明显。城市森林生态系统的多功能评价可以为银川植物园可持续发展与生态环境建设政策的制定提供科学依据,提高对森林生态效益和林业生态建设的认识,对进一步加快生态文明建设步伐具有重要意义。     

林业生态建设与可持续发展

森林的生态环境调节功能也越来越受到重视,林业不但是一个物质资料生产部门,同时也是生态公益功能生产部门。但是,在分类经营不能得到有效实施的情况下,对林业生态公益功能的认识只能停留在宣传上,还未能做到针对森林的公益功能采取有效的经营措施,也未能理顺受益与经营之间,投入与产出之间的关系,因此也直接影响到生态公益林经营和商品林经营两者之间的正常经营关系,使两者的主体功能都不能得到有效发挥。     

Vertebrate distributions relative to clear-cut edges in a boreal forest landscape

Clearcutting is the main method of harvesting boreal forests, to some extent mimicking natural disturbances by fire and wind-felling. Effects of clearcutting on vertebrate fauna in managed forests was examined by small mammal trapping in spring and autumn, winter censuses of mammal snow tracks and censuses of birds in spring and summer in one central and one edge (125 m) section of large clearcuts and mature forests, respectively. There was a separate clearcut fauna, at least on large clearcuts, that was well distinguished from the forest fauna. There was not any physiognomic ecotone but the forest fauna showed a marked edge effect with larger numbers of many species in the peripheral parts of the forest. In the forests examined, with a Western European bird fauna, there were no typical interior forest species, in contrast to northern taiga forests. The present forest species easily changed distributions seasonally and according to variations in snow conditions and food abundance. Such generalist species in the boreal forest will therefore vary considerably in local density according to landscape composition but will also show large-scale persistence. They may have been selected for as a result of man's restructuring of temperate and boreal landscapes, e.g. by forest management. Edge effects seem to arise for several reasons but will probably only apply to generalist species.     

塞罕坝不同植被类型地表土壤动物群落特征

为了解塞罕坝地区不同植被地表土壤动物群落特征,分别以白桦林、阔叶混交林、落叶松林、针阔混交林、云杉林、草甸为研究对象,于2017年7月采用陷阱法采集不同植被土壤动物并对其群落组成、结构及多样性进行分析。结果显示,6种植被样地中共获得土壤动物8 351头,隶属5纲19目96科186种,优势类群为盲蛛目、弹尾目、膜翅目、鞘翅目和双翅目。白桦林、落叶松林、阔叶混交林和针阔混交林土壤动物类群数均显著高于草甸和云杉林;落叶松林土壤动物个体数显著高于其他林分。各植被类型之间土壤动物Shannon-Wiener多样性指数和均匀度指数无显著差异。主成分分析和相关分析显示不同植被地表土壤动物的空间分布差异显著,且土壤动物个体数与林分内凋落物生物量、厚度、全氮、全磷、全碳含量及土壤容重呈极显著正相关。可见,塞罕坝地区不同植被类地表土壤动物群落组成和分布存在一定差异,地表环境因子是影响其组成的重要因素。     

Urbanization pressures on the natural forests in Turkey: An overview

Forests used to be the main field of interest for rural communities, but now they attract the attention of urbanites too. The forest–public relationship is important as forests protect water resources, preserve the soil and increase its productivity, provide positive effects on climate and health in general, and can be used for recreation and tourist purposes. This study aims at assessing how the current rapid urbanization process in Turkey affects forests. Urban requirements such as biomass for heating, education facilities, settlements, recreation, tourism and employment exert various pressures on the forest. In this study we assessed these pressures and suggest that forest legislations should be developed to respond to expectations of urbanites from forests, new recreation areas should be developed and urbanites’ interest in and knowledge of the forests should be increased, where all social groups including the forestry authority should work together.     

Geospatial methods provide timely and comprehensive urban forest information

Urban forests are unique and highly valued resources. However, trees in urban forests are often under greater stress than those in rural or undeveloped areas due to soil compaction, restricted growing spaces, high temperatures, and exposure to air and water pollution. In addition, conditions change more quickly in urban as opposed to rural and undeveloped settings. Subsequently, proactive management of urban forests can be challenging and requires the availability of current and comprehensive information. Geospatial tools, such as, geographic information systems (GIS), global positioning systems (GPS) and remote sensing, work extremely well together for gathering, analyzing, and reporting information. Many urban forest management questions could be quickly and effectively addressed using geospatial methods and tools. The geospatial tools can provide timely and extensive spatial data from which urban forest attributes can be derived, such as land cover, forest structure, species composition and condition, heat island effects, and carbon storage. Emerging geospatial tools that could be adapted for urban forest applications include data fusion, virtual reality, three-dimensional visualization, Internet delivery, modeling, and emergency response.     

Comparing climate-growth responses of urban and non-urban forests using L. tulipifera tree-rings in southern Indiana,USA

Urban forests have many positive effects on human health and recreation. However, urban areas can create stressful environments for native trees, leading to increased mortality and an altered ecosystem. Here, we compare growth variability and the climate response from old (>200 years) L. tulipifera growing in an urban forest in Bloomington, IN to surrounding non-urban sites in southern Indiana using dendrochronological techniques. We found that L. tulipifera growing in the urban forest responded similarly with small differences to climate compared to the non-urban sites. Radial growth from urban L. tulipifera had statistically similar correlation values with temperature, soil moisture, and precipitation compared to the trees in non-urban forests. Growth variability between the urban and non-urban L. tulipifera trees showed good agreement through time with the exception of the 20th century, where the urban forest experienced a stand-wide release from competition. Our results indicate that some urban forests may function similarly to non-urban forests from an ecological perspective. These findings suggest management practices from non-urban old-growth forest could be useful for management of rare urban old-growth forests.     

Expansion of gallery forest on Konza Prairie Research Natural Area,Kansas, USA

To determine the dynamics of the spatial extent of gallery forest on Konza Prairie Research Natural Area (KPRNA), aerial photographs taken over a 46 year time frame were digitized into an ARC-INFO Geographic Information System (GIS). A Global Positioning System (GPS) was used to collect ground control points to co-register the photographs for each year. Gallery forest areas for the three major drainage boundaries (Kings Creek, Shane Creek, and White Pasture) were analyzed to assess the uniformity of change in the landscape system. Results indicated that the total gallery forest area on KPRNA has increased in area from 157 ha in 1939 to over 241 ha in 1985. During this time, there was an increase in the total number of patches and a decrease in the mean size of forest patches. However, the rate of increase was not consistent over this time period, nor was it uniform from one drainage basin or stream order to another. Detailed spatial analysis of the forested area with a geomorphology and digital elevation model of Konza Prairie showed that in 1985, 58% of the forest was on alluvial/colluvial soil, yet only 15% of that soil type was forested. In addition, over 70% of the forest was on the 0–15% slope interval, but only 15–20% of that slope interval was forested. These results may be attributed to a variety of factors such as changing management practices (i.e., frequency of fires and herbicide spraying) and the temporal constraints on extent to which the gallery forest can expand across the landscape.     

国家森林公园建设发展情况及其空间格局

为探索国家森林公园建设发展情况并揭示其空间分布规律,本研究采用知识图谱及GIS空间技术对我国国家森林公园的研究进展和空间格局进行了可视化的探索分析.结果 显示:(1)国家森林公园、生态旅游、森林旅游、风景园林、生物多样性、自然保护区、评价、群落结构等是我国森林公园的历史研究热点领域.(2)我国国家森林公园总体呈现东密西疏的空间格局,东北区域及西南区域公园分布较为集中,青海及西藏地区相反.(3)1992-2017年期间国家森林公园的面积得到了更为显著的提升,黑龙江、西藏、新疆、内蒙古4省贡献的面积较多,天津、上海、宁夏、海南4省市对全国国家森林公园建设面积的贡献较小.西部地区国家森林公园的数量有待提升,宁夏、海南2省的国家森林公园总面积有较大理论拓展空间,未来可以加强国家森林公园动态监测评价、森林公园管理制度保障、森林公园建设成效评价、智慧森林公园等方面的研究,以此来推动全国森林公园的全面健康发展.     

辽东地区日本落叶松人工林土壤持水性能及其涵养水源功能研究

对辽东地区日本落叶松人工林林地土壤的持水性能进行了实测研究。结果表明:按不同林龄和不同坡向划分的林型,其土壤的物理性质、持水性能及其涵养水源方面都存在着显著差异。7种林型土壤容重排序为:荒地>幼龄林阳坡>幼龄林半阴坡>中龄林阳坡>中龄林阴坡>近熟林阳坡>近熟林阴坡。土壤孔隙度排序则表现为与容重相反。不同林型表层土壤的物理性质与林地凋落物之间存在着显著相关关系。林地土壤在持水性能和涵养水源方面表现为:近熟林阴坡>近熟林阳坡>中龄林阴坡>中龄林阳坡>幼龄林半阴坡>幼龄林阳坡>荒地。与无林荒地相比,可以看出日本落叶松人工林具有明显的涵养水源功能。     

Modeling height-diameter relationship for artificial monoculture Metasequoia glyptostroboides in sub-tropic coastal megacity Shanghai,China

Tree height is a key variable in forest monitoring studies and for forest management. However, tree height measurement is time consuming, and the recommended procedure is to use estimates from tree height (H) - diameter at breast height (DBH) models. Increasingly, H-DBH models are being developed for urban forests, providing tools to forest management and ecosystem services estimation. Here, we compared model forms and approaches for predicting H as a function of DBH and additional stand level covariates variables. Four model forms were evaluated: (i) basic models (which only used DBH as predictor variable); (ii) generalized models (which used DBH and other predictor variables based on the best basic model); (iii) a mixed-effects model based on the best basic model; and (iv) a mixed-effects model based on the generalized model. Several sampling designs aimed at minimizing height measurement were tested in terms of accuracy and applicability. Taking predicted accuracy and investigation cost into account, we recommend generalized non-linear mixed-effects model (NLME) when there were two or less tree height measurements taken in a given stand. The basic NLME model could be calibrated when there were 3 or more tree height measurements, depending on the required level of accuracy and investigation cost. Additionally, we first reported that soil pH as a covariate variable in H-DBH model and our generalized NLME model implied that the difference in the H-DBH relationship caused by pH varies among different stands. This finding may be attributable to differing biological properties of the similar alkaline tolerance species.     

Modeling the effects of forest harvesting on landscape structure and the spatial distribution of cowbird brood parasitism

Timber harvesting affects both composition and structure of the landscape and has important consequences for organisms using forest habitats. A timber harvest allocation model was constructed that allows the input of specific rules to allocate forest stands for clearcutting to generate landscape patterns reflecting the look and feel of managed landscapes. Various harvest strategies were simulated on four 237 km² study areas in Indiana, USA. For each study area, the model was applied to simulate 80 years of management activity. The resulting landscape spatial patterns were quantified using a suite of landscape pattern metrics and plotted as a function of mean harvest size and total area of forest harvested per decade to produce response surfaces. When the mean clearcut size was 1 ha, the area of forest interior remaining on the landscape was dramatically reduced and the amount of forest edge on the landscape increased dramatically. The potential consequences of the patterns produced by the model were assessed for a generalized neotropical migrant forest bird using a GIS model that generates maps showing the spatial distribution of the relative vulnerability of forest birds to brood parasitism by brown-headed cowbirds. The model incorporates the location and relative quality of cowbird feeding sites, and the relation between parasitism rates and distance of forest from edge. The response surface relating mean harvest size and total area harvested to the mean value of vulnerability to cowbird brood parasitism had a shape similar to the response surfaces showing forest edge. The results of our study suggest that it is more difficult to maintain large contiguous blocks of undisturbed forest interior when harvests are small and dispersed, especially when producing high timber volumes is a management goal. The application of the cowbird model to landscapes managed under different strategies could help managers in deciding where harvest activity will produce the least negative impact on breeding forest birds.