A GIS-based method for the reconstruction of the late eighteenth century forest vegetation in the Prignitz region (NE Germany)

Our goal was to reconstruct the late eighteenth century forest vegetation of the Prignitz region (NE Germany) at a scale of 1:50,000. We also wanted to relate the historical forest vegetation to the actual and potential natural vegetation. For these purposes, we selected 15 woody species and transferred relevant data found in historical records from various sources together with the recent localities of (very) old individuals belonging to these woody species into ArcView GIS. Following multi-step data processing including the generation of a point density layer using a moving window with kernel estimation and derivation of vegetation units applying Boolean algebra rules together with information on site conditions, we derived 17 forest communities corresponding to the potential natural vegetation. We were able to reconstruct the historical forest vegetation for 90% of the forest area ca. 1780. Only two of the 17 forest communities covered large parts of the forested area. The oak forest with Agrostis capillaris covered about 44% of the total forest area, and alder forests on fenland made up about 37%. Oak-hornbeam forests with Stellaria holostea comprised slightly less than 6% of the forest area, while all other forest communities comprised less than 1%. The historical forest vegetation is more similar to the potential forest vegetation and quite different from the actual forest vegetation because coniferous tree species currently cover approximately two-thirds of the actual forest area. The most beneficial result of this study is the map of high-resolution historical vegetation units that may serve as the basis for various further studies, e.g., modelling long-term changes in biodiversity at the landscape scale.     

森林经营对土壤动物影响研究进展

森林经营是实现森林可持续发展的根本途径,土壤动物是森林生态系统的重要组成部分,可对森林经营及其带来的变化及时做出反应。为了探讨土壤动物对森林经营措施的响应,归纳总结了森林经营理念的发展以及森林经营对土壤动物影响的文献资料。结果表明森林经营主要通过对地上结构和微环境的改变对地下土壤动物的群落组成、分解功能及生物指示功能等方面产生影响。在今后研究中应加强森林经营对土壤动物连续长期的动态影响研究,同时利用现代研究技术与方法深入探讨森林经营对土壤动物影响的机制研究。     

Tropical deforestation and species endangerment: the role of remote sensing

Initial results of a pilot study to link remotely-sensed information on tropical forest loss to field-based information on species endangerment are reported here. LANDSAT multispectral scanner (MSS) imagery from 1973 and 1988 were used to estimate net forest removal (29% of forest area), regrowth (7% of forest area, including possible artifactual errors), and forest edges in Mabira Forest in southeastern Uganda during the 15-year period. Of the forest remaining, the percentage that was heavily disturbed increased from 18% to 42%. This change in forest density was observable with the MSS imagery. The total forest edge-to-area ratio (including edges interior to the forest boundary) increased by 29% over the period. Although four distinct types of closed tropical forest, based on structure or dominance, could be recognized on the ground, the types could not be distinguished by differences in spectral reflectance in the four MSS bands. Closed tropical forest could be readily distinguished from exotic conifer plantations, banana plantations, and other non-forest vegetation types. Field measurements in Mabira and other Ugandan rain forests, and in rain forest isolates on the Atherton Tableland of North Queensland, are being made to relate changes in forest fragmentation to resulting changes in species abundance, structural form of the forests, and morphological diversity of target populations. Possible applications of conservation biology theory and modeling to these data are briefly discussed.     

新疆野苹果居群年龄结构及郁闭度研究

对新疆巩留与新源2地的新疆野苹果居群年龄结构及郁闭度进行测定和分析,旨在为新疆野苹果资源的保护保存提供依据。结果表明,在随机选取的200个单株中,巩留居群Ⅰ级幼树为0,而且Ⅱ级小树数量也极少,仅2株,只占1%,年龄级构成有下降性特征,存活曲线呈断点凸型,故年龄结构应属老衰类型,郁闭度为0.47;新源居群有Ⅰ级幼树,10株占5%,Ⅱ级小树达26株占13%,年龄级构成有稳定中略有上升的特征,存活曲线呈弧形凸型,故年龄结构应属稳定类型,郁闭度为0.80。上述结果显示,巩留新疆野苹果居群破坏严重,亟待加强保护,而新源新疆野苹果居群保存较完好。     

Vegetation community and factors that affect the woody species composition of riparian forests growing in an urbanizing landscape along the Chao Phraya River,central Thailand

Improved knowledge of the environmental factors that affect woody composition is urgently required for species conservation in riparian zones of urbanizing landscapes. We investigated the environmental factors influencing tree abundance and regeneration in diverse forest types growing in the riparian area of an urbanizing landscape along the Chao Phraya River. We established 252 0.1-ha circular plots in remnant forest patches along 372 km of the river. Cluster analysis was applied to classify the forest types. The relationships between environmental variables and tree abundance were assessed with ordination analysis, and generalized linear models were used to assess seedling/sapling abundance. The cluster analysis revealed five forest types, including floodplain forest with three sub-forest types, swamp forest, and mangrove forest. The ordination indicated that tree abundance in the floodplain forest was positively affected by distance to the ocean and the proportion of forested area. Swamp forest was positively influenced by the proportion of urbanized area and mean rainfall. Mangrove forest was negatively related to distance to the river. Seedling/sapling abundance of the dominant species in the floodplain forests was positively affected by lowland plain topography and negatively affected by the proportion of urbanized area, whereas swamp and mangrove forest species were positively influenced by the proportion of urbanized area and estuarine topography. Mature tree density influenced seedling/sapling abundance of all forest types. Tree abundance and regeneration of the riparian landscape was prevented by the urbanized area, floodplain, estuarine topography, and mature tree densities in remnant forests. These results suggest that remnant forest patches of conserved riparian forests along the urbanized landscape of the Chao Phraya River must be protected and the factors determining their colonization must be considered to enhance restoration practices.     

北京地区低价值林改造浅谈

在对低效林概念进行总结的基础上,将北京地区林分划为低价值林,阐述了低价值林改造的效益,分析了北京地区低价值林形成的原因,同时结合当地实际情况提出了几点合理化建议。     

新时期森林经理学科的发展与改革简

论述我国森林经理的发展历程，探讨新时期森林经理学科在林业可持续发展中的作用，分析现阶段森林经理发展中存在的问题，提出重振森林经理学科、促进森林科学经营的若干改革建议。     

Landscapes as continuous entities: forest disturbance and recovery in the Albertine Rift landscape

Kibale National Park, within the Albertine Rift, is known for its rich biodiversity. High human population density and agricultural conversion in the surrounding landscape have created enormous resource pressure on forest fragments outside the park. Kibale presents a complex protected forest landscape comprising intact forest inside the park, logged areas inside the park, a game corridor with degraded forest, and forest fragments in the landscape surrounding the park. To explore the effect of these different levels of forest management and protection over time, we assessed forest change over the previous three decades, using both discrete and continuous data analyses of satellite imagery. Park boundaries have remained fairly intact and forest cover has been maintained or increased inside the park, while there has been a high level of deforestation in the landscape surrounding the park. While absolute changes in land cover are important changes in vegetation productivity, within land cover classes are often more telling of longer term changes and future directions of change. The park has lower Normalized Difference Vegetation Index (NDVI) values than the forest fragments outside the park and the formerly logged area—probably due to forest regeneration and early succession stage. The corridor region has lower productivity, which is surprising given this is also a newer regrowth region and so should be similar to the logged and forest fragments. Overall, concern can be raised for the future trajectory of this park. Although forest cover has been maintained, forest health may be an issue, which for future management, climate change, biodiversity, and increased human pressure may signify troubling signs.     

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.     

Urbanization increases the range,but not the depth,of forest edge influences on Pinus sylvestris bark pH

The influence of forest edge on Pinus sylvestris bark pH was evaluated in urban and suburban pine forests in Yekaterinburg (South Taiga subzone, Central Urals, Russia). The measurements was conducted in 18 transects (rows of 6–10 sample plots arranged in pairs along a 100–260 m line perpendicular to the forest boundary); 12 transects (110 plots) were located in the urban forest and 6 transects (58 plots) in the suburban forest. All the characteristics studied (degree of urbanization, distance from forest boundary, and type and age of boundary), were found to have a significant effect on the pH of P. sylvestris bark. Bark alkalinization increased on average by 0.2 to 0.5 pH units above background along a gradient from the forest interior to the forest edge. In urban forests, the edge influence was about twice greater (0.6–0.8 pH units) than in suburban forests (0.2–0.3 pH units), while the depth ranged between 70 and 160 m. Little variation in the depth of the edge influence observed due to transect characteristics, and no differences were noted due to degree of urbanization. The range of the edge influence was cumulative over the time that had elapsed since forest fragmentation and highway construction. The results show that urban airborne dust pollution affects southern taiga pine forests to a depth of about 100 to 150 meters from forest boundary. This circumstance is important to take into account when planning the locations of the borders of forests, roads, residential and social areas.     

Development of urban forest policy-making toward governance in the Republic of Korea

This research attempts to analyze the emergence and development of urban forest policies at the national and local levels in the Republic of Korea. The Policy Arrangement Approach (PAA) is applied as an analytical frame to analyze changes in the urban forest policies of the central and local governments. The PAA offers four dimensions that can be used to describe and analyze the policy process: actors, power, rules of the game and discourse. The research findings indicate that a discourse on sustainable development in which the social functions of forests are taken into account substantially contributed to the creation of urban forest policies. This discourse contributed to the activities of actors and their power relationships and to the introduction of new rules relating to Korean urban forest management. In addition to public actors, private actors have also participated in creating and managing urban forests. Various partnerships among actors were formed for urban forest management. Civil society exercised its power to design and manage urban forests through increased voluntary participation. The legislation relating to urban forests functioned as a framework for urban forest policies at the national and local levels. Agreements acted as new rules governing the relationships among the actors who were involved in urban forest management. In conclusion, the four dimensions of policy arrangements relating to urban forest policy, and the interconnections among these dimensions, elucidate the emergence and dynamic development of urban forest management in the direction of governance at the national and local level in the Republic of Korea. In particular, discourse about forests was a substantive dimension of policy arrangements, and it influenced changes in the identity of the participating actors and their power. The discourse contributed to the establishment and development of rules for urban forest management. Thus this research provides strong evidence that the PAA helps understand dynamic changes of urban forest policy-making toward governance.     

Historical influence of man on the riparian dynamics of a fluvial landscape

Man's influence, over the last three centuries, has gradually influenced the dynamics of forest cover along the valley of the Garonne, a seventh order river in Southern France. The vegetation cover of the floodplain depends on topographical levels which govern the frequency and duration of submergence during flooding. Along the valley, forest patches vary from a continuous ribbon of riparian wood along the river to a mosaic of groves towards the upland terraces. In the floodplain, the forest dynamics are influenced by floods, appear to be reversible, and are subject to dominant allogenic processes. On the contrary, forest dynamics on the terraces, which are not influenced by floods, are irreversible and subjected to dominant autogenic processes. Since the end of the 17th century, the structure of riparian woods has been modified by navigation and agriculture leading to a fragmentation of forest cover in the floodplain. Modern agriculture and urbanization have accentuated these tendencies by modifying the hydrologic regime of the river. These historical changes result in a fragmentation of forest cover and a substitution of species in the riparian zone, the forest dynamics being still reversible in the floodplain.     

A systematic review of the relationship between urban forest quality and socioeconomic status or race

The quantity of urban forests in cities is critical for biodiversity conservation and human health, and is known to be distributed unequally. Increasingly, the quality of urban forests are also being recognised as shaping the benefits they provide. Previous studies and reviews have demonstrated that the quality of urban green spaces is associated with patterns of inequality as measured by socio-economic status and race (in the U.S). This study extends this body of knowledge to urban forests by systematically reviewing the urban forest literature (that explicitly study the urban forest) exploring the relationship between urban forest quality and both socio-economic status and race. Two academic databases (SCOPUS and Web of Science) were systematically searched. A total of 2012 papers were screened and 21 articles were included in this study. Almost all studies (20/21) found evidence of inequality, with at least one significant association between measures of urban forest quality and socio-economic status or race. However, 6 studies found contrasting patterns, with lower socioeconomic status areas having higher urban forest quality. There was variation in the type of ‘urban forest’ studied, and variation in the ways both urban forest quality and socio-economic status were measured, making inter-study comparisons difficult. Interestingly, the literature was geographically diverse, and future research could continue to focus on countries in Africa, South America and Asia with diverse needs for and uses of urban forests. In conclusion, this review finds evidence for inequity in the distribution of urban forest quality. Future research that more clearly describes the urban forests being studied and that explores sociocultural variation in perceived quality would allow better generalisation and understanding of forest quality patterns.     

Landscape perception by forest understory birds in the Atlantic Rainforest: black-and-white versus shades of grey

Even among forest specialists, species-specific responses to anthropogenic forest fragmentation may vary considerably. Some appear to be confined to forest interiors, and perceive a fragmented landscape as a mosaic of suitable fragments and hostile matrix. Others, however, are able to make use of matrix habitats and perceive the landscape in shades of grey rather than black-and-white. We analysed data of 42 Chiroxiphia caudata (Blue Manakin), 10 Pyriglena leucoptera (White-shouldered Fire-eye) and 19 Sclerurus scansor (Rufous-breasted Leaftosser) radio-tracked in the Atlantic Rainforest of Brazil between 2003 and 2005. We illustrate how habitat preferences may determine how species respond to or perceive the landscape structure. We compared available with used habitat to develop a species-specific preference index for each of six habitat classes. All three species preferred old forest, but relative use of other classes differed significantly. S. scansor perceived great contrast between old forest and matrix, whereas the other two species perceived greater habitat continuity. For conservation planning, our study offers three important messages: (1) some forest specialist species are able to persist in highly fragmented landscapes; (2) some forest species may be able to make use of different anthropogenic habitat types to various degrees; whereas (3) others are restricted to the remaining forest fragments. Our study suggests species most confined to forest interiors to be considered as potential umbrella species for landscape-scale conservation planning.     

塞罕坝机械林场林内景观对公众健康恢复性效果的影响因素研究

森林是理想的恢复场所,营建良好的森林环境对公众健康的恢复具有重要意义。以塞罕坝机械林场落叶松林为研究对象,基于40个调查样地,通过设计量表并采用数理统计分析方法,对林内景观进行恢复性评价与美景度评价,探索恢复性效果、美景度与林分结构指标的关系。研究结果表明,落叶松纯林和落桦混交林的恢复性效果无显著性差异（P>0.05）,但不同样地间恢复性效果差异较大,恢复性效果的均值和标准差分别为7.126和25.123。恢复性效果与美景度之间呈极显著相关性（P<0.01）;恢复性效果和美景度与平均树高、密度呈极显著相关（P<0.01）;与郁闭度、下木高度、胸径变异系数呈显著相关（P<0.05）。     

Impacts of selective logging on tree diversity across a rainforest landscape: the importance of spatial scale

Selective logging of tropical forests imposes spatial pattern on the landscape by creating a mosaic of patches affected by different intensities of disturbance. To understand the ecological impacts of selective logging it is therefore necessary to explore how patterns of tree species composition are affected by this patchy disturbance. This study examines the impacts of selective logging on species composition and spatial patterns of vegetation structure and tree diversity in Sabah, Borneo. We compare tree diversity between logged and unlogged forest at three scales: species richness within plots, species turnover among plots, and total species richness and composition of plots combined. Logging had no effect on tree diversity measured at the smallest scale. Logged forest had a greater rate of species turnover with distance, so at a large spatial scale it supported more tree species than the relatively homogeneous unlogged area. Tree species composition also differed significantly between the two types of forest, with more small dipterocarps and large pioneers in logged forest, and more large dipterocarps in unlogged forest. Our results emphasize the importance of sampling at a sufficiently large scale to represent patterns of biodiversity within tropical forest landscapes. Large areas of production forest in SE Asia are threatened with conversion to commercial crops; our findings show that selectively logged forest can retain considerable conservation value.     

Landscape composition is the strongest determinant of bird occupancy patterns in tropical forest patches

Context

Biodiversity in tropical region has declined in the last decades, mainly due to forest conversion into agricultural areas. Consequently, species occupancy in these landscapes is strongly governed by environmental changes acting at multiple spatial scales.

Objectives

We investigated which environmental predictors best determines the occupancy probability of 68 bird species exhibiting different ecological traits in forest patches.

Methods.

We conducted point-count bird surveys in 40 forest sites of the Brazilian Atlantic forest. Using six variables related to landscape composition and configuration and local vegetation structure, we predicted the occupancy probability of each species accounting for imperfect detections.

Results

Landscape composition, especially forest cover, best predicted bird occupancy probability. Specifically, most bird species showed greater occupancy probability in sites inserted in more forested landscapes, while some species presented higher occurrence in patches surrounded by low-quality matrices. Conversely, only three species showed greater occupancy in landscapes with higher number of patches and dominated by forest edges. Also, several species exhibited greater occupancy in sites harbouring either larger trees or lower number of understory plants. Of uttermost importance, our study revealed that a minimum of 54% of forest cover is required to ensure high (> 60%) occupancy probability of forest species.

Conclusions

We highlighted that maintaining only 20% of native vegetation in private property according to Brazilian environmental law is insufficient to guarantee a greater occupancy for most bird species. We recommend that policy actions should safeguard existing forest remnants, expand restoration projects, and curb human-induced disturbances to minimise degradation within forest patches.

     

Studying the spatial evolutionary behavior of urban forest patches from the perspective of pattern-process relationships

Urban forest dynamics can influence the provision of ecosystem services provision. Considerable research has been conducted to understand how these dynamics respond to urbanization, from individual patches to entire landscapes. However, most of these are cross-sectional studies based on landscape metrics, and research using a process-based perspective in this context is scarce. In this study, we present a “pattern-process” analytical framework to quantify the evolutionary behavior of urban forest patches. We combine this framework with land cover classification data based on high-resolution remote sensing images (< 1 m) from 2002, 2013, and 2019 to detect the dynamic characteristics of four processes of forest patches in Beijing urban areas. These dynamic characteristics include: size distribution, aggregation and fragmentation, transfer, and self-stabilization. The results showed that 1) the average size of the patches in the study area is increasing, and patches larger than 50 m² have a more positive influence on the process of patch structure evolution, 2) patch fragmentation shifts with the direction of urban sprawl, 3) transfer between urban forest and bare land is increasing, and 4) urban forest network construction positively enhances the stability of patches. This framework can provide a useful basis for understanding the spatial and temporal evolution of urban forest landscapes during urban development and contribute to the sustainable management of urban forests.     

基于CiteSpace可视化分析的我国新一轮退耕还林工程发展脉络及展望

为进一步发掘新一轮退耕还林工程的研究热点及趋势,以新一轮退耕还林为主题,基于2012-2022年CNKI平台中的数据库,取300条样本,运用CiteSpace可视化分析的方法,深入解析我国新一轮退耕还林相关研究,包括研究机构合作网络、作者合作网络、关键词聚类图谱、关键词时区图谱和关键词突现图谱等方面。结果表明：(1)有关退耕还林的相关文献数量呈现先增加后下降的趋势。(2)有关我国新一轮退耕还林的研究文献主要围绕“后续产业”“农户收入”“生态效益”等问题展开,高频关键词显示新一轮退耕还林需要转变发展方式,要向高质量、可持续发展的方向转变,一味地扩大生态林规模并不可取。(3)退耕还林研究以对社会经济状况与初期退耕还林措施的综合改进分析为始发点,逐渐转变为以社会经济和生态效益的相互交织并存,并逐渐向以生态效益为主题逐步细分进行发展。所以,科研理念、方法之间的交融与并行以及怎样继续巩固和拓展退耕还林成果,如何合理的扩大退耕还林规模、保障农村环境安全、提高退耕农户增收,成为了今后科学研究发展的重要关键。     

Designating a greenbelt around the city of Riga, Latvia

Latvian legislation demands that forest protection belts are established around all cities and towns. The main goal of a protection belt is to provide suitable opportunities for recreation to urban dwellers and to minimise any negative impacts caused by urban areas on the surrounding environment. Legislation states the main principles to be adopted, which include the maximum area of protection belts, their integration in territorial development plans and restrictions placed on forest management activities. The largest part of the forest area around Riga is owned by the municipality of Riga, which, as a result, has two competing interests: to satisfy the recreational needs of the inhabitants of Riga, and to maximise the income from its property. In order to compile sufficient background information to solve this problem, the Board of Forests of Riga Municipality initiated the preparation of a proposal for the designation of a new protection belt.The proposal was based on the development and application of a theoretical framework developed during the 1980s. The analysis of the recreational value of the forest (5 classes of attractiveness) was carried out based on categories of forest type, dominant tree species, dominant age, stand density, distance from urban areas and the presence of attractive objects. Information was derived from forest inventory databases, digital forest maps and topographic maps. Additional information was digitised and processed using ArcView GIS 3.2. Local foresters were asked about the recreation factors unique to different locations, such as the number of visitors and the main recreation activities. From a recreational point of view and taking into account legal restrictions and development plans for the Riga region, it was proposed to create three types of zones in the forest: a protection belt, visually sensitive areas and non-restricted areas.