The decreased competition in expanding versus mature juniper woodlands is counteracted by adverse climatic effects on growth

World-wide deforestation is being reversed in Mediterranean continental areas, where abandonment of traditional practises favours the expansion of valuable habitats, like Juniperus thurifera woodlands. We hypothesised that pre-existing trees facilitate establishment in expanding woodlands, whereas in mature woodlands, competition leads to patch disaggregation. We compared the imprint of these processes on growth, demographic and spatial structure of expanding and mature J. thurifera woodlands. We selected plots where we geopositioned, aged and quantified the morphological characteristics of all trees. In the mature woodland, trees arranged in clumps and randomly in the expanding woodland. Competition negatively affected growth, was greater in the mature woodland and led to disaggregation of juvenile clumps. Differences in growth between the mature and the expanding woodland disappeared in climatically unfavourable years, suggesting that adverse climate constrains growth more in expanding than in mature woodlands. We suggest that change in the dispersal agents and a decrease of facilitation underlay differences in spatial patters between the expanding and the mature woodland. Observed effective recruitment in less than 30?years into the expanding woodland evidenced that propagule arrival and sapling survival do not constrain woodland expansion. Furthermore, growth of juveniles established in these new areas is favoured by reduced intra-specific competition. However, we expect growth in expanding woodlands to be negatively impacted by climate change. We conclude that under current global change scenario, conservation of J. thurifera woodlands is favoured by changes in land use, but greater frequency and severity of drier than usual episodes could hamper natural reforestation.     

Exploring for senescence signals in native scots pine (Pinus sylvestris L.) in the Scottish Highlands

The main aim of this project was to explore whether the pine trees in Glen Affric (GAF), one of the more extensive pine woodlands in the northern Scottish Highlands, are, on average, reaching a senescent stage which could ultimately be detrimental to the sustainability of the pine woodland in this region under present management conditions. This aim was realized by (1) comparing the mean stand age of the GAF trees to other pine woodlands around Scotland, (2) exploring whether there was a significant pre-death trend in ring-width series from naturally dead trees and (3) assessing whether a notable change in response of tree growth to climate was noted as a function of age which could indicate that trees were entering a state of senescence.     

人工诱导阔叶红松林改良土壤效果分析

文章通过比较不同类型红松针阔混交林和红松纯林的林分枯落物含量、土壤理化性质及土壤酶活性等性状可知,单位面积枯落物总量红松针阔混交林比红松纯林高40%~60%,其半分解的枯落物量均高于未分解的枯落物量,而红松纯林则相反;红松针阔混交林中枯落物的持水量较红松纯林高26%~75%,养分含量明显高于红松纯林;红松针阔混交林土壤理化性质及酶活性都明显优于红松纯林。     

Insights from behavioural economics for forest economics and environmental policy: Potential nudges to encourage woodland creation for climate change mitigation and adaptation?

Evidence from behavioural economics illustrates how cognitive factors can affect the preferences, values and choices of individual decision-makers. The evidence also shows how policy ‘nudges’ that account for the influence of cognitive factors can shift choices in socially desirable directions. Despite a wide range of potential applications, little research has been published to date applying behavioural economics in forestry. As an example of how behavioural economics could be used, this paper considers the potential for nudges in encouraging woodland creation to help meet climate change mitigation and adaptation goals. Although forests offer significant climate change mitigation and adaptation potential, land managers are often reluctant to create new woodlands, hindering accomplishment of national targets. Nudges could potentially help overcome the barriers. Disaggregating behavioural elements of woodland creation using the Stages of Change model, we identify a number of relevant intervention points at which nudges could be applied. It is argued that nudges may best be tailored towards different types of land manager taking account of differences in attitudes, motivations, circumstances and behaviour. To be effective, a combination with other policy instruments is likely to be needed. Pilot studies are recommended in determining which nudges are cost-effective. The paucity of existing studies drawing upon behavioural economics, or testing out nudges, points to this as a current frontier of both forest economics and policy, but can also be considered a frontier of environmental policy more widely. Developing a consistent valuation framework allowing for the social endogeneity of preferences and for optimization (or some other protocol) to be used in selecting policy options remains a fundamental challenge.     

Increasing connectivity in fragmented landscapes: An investigation of evidence for biodiversity gain in woodlands

Increasing connectivity is frequently proposed as an effective strategy to address biodiversity decline within fragmented habitats. Woodland habitats in Great Britain have been significantly reduced in area and are described as having ‘fragmented’ distribution. Many researchers have associated declines in woodland species with fragmentation. Currently, there is a concerted effort to increase connectivity (through increasing the number of physical links) between woodlands, often through the development of habitat networks, with the aim of increasing biodiversity. This aim is driven through rising interest in the role of landscape scale processes in biodiversity conservation and increasing concern of the fate of populations facing a predicted increase in habitat isolation through climate change.In this paper, the evidence behind the assumption that increasing connectivity will increase biodiversity is reviewed, together with the assumptions made during development of models that identify potential networks within which connectivity is to be increased. Gaps identified within the evidence base lead to the suggestion of new research areas that will provide a firm basis from which more informed evaluation of increasing connectivity for biodiversity gain can be developed. Alternative approaches to enhancing woodland biodiversity in fragmented landscapes are proposed.     

Edge type affects leaf-level water relations and estimated transpiration of Eucalyptus arenacea

While edge effects on tree water relations are well described for closed forests, they remain under-examined in more open forest types. Similarly, there has been minimal evaluation of the effects of contrasting land uses on the water relations of open forest types in highly fragmented landscapes. We examined edge effects on the water relations and gas exchange of a dominant tree (Eucalyptus arenacea Marginson & Ladiges) in an open forest type (temperate woodland) of south-eastern Australia. Edge effects in replicate woodlands adjoined by cleared agricultural land (pasture edges) were compared with those adjoined by 7- to 9-year-old eucalypt plantation with a 25m fire break (plantation edges). Consistent with studies in closed forest types, edge effects were pronounced at pasture edges where photosynthesis, transpiration and stomatal conductance were greater for edge trees than interior trees (75m into woodlands), and were related to greater light availability and significantly higher branch water potentials at woodland edges than interiors. Nonetheless, gas exchange values were only ～50% greater for edge than interior trees, compared with ～200% previously found in closed forest types. In contrast to woodlands adjoined by pasture, gas exchange in winter was significantly lower for edge than interior trees in woodlands adjoined by plantations, consistent with shading and buffering effects of plantations on edge microclimate. Plantation edge effects were less pronounced in summer, although higher water use efficiency of edge than interior woodland trees indicated possible competition for water between plantation trees and woodland edge trees in the drier months (an effect that might have been more pronounced were there no firebreak between the two land uses). Scaling up of leaf-level water relations to stand transpiration using a Jarvis-type phenomenological model indicated similar differences between edge types. That is, transpiration was greater at pasture than plantation edges in summer months (most likely due to greater water availability at pasture edges), resulting in significantly greater estimates of annual transpiration at pasture than plantation edges (430 vs. 343lm(-2)year(-1), respectively). Our study highlights the need for landscape-level water flux models to account for edge effects on stand transpiration, particularly in highly fragmented landscapes.     

集体林分权条件下的林地细碎化程度及与农户林地投入产出的关系——基于江西省8县602户农户调查数据的分析

以江西省8个县602户农户调查数据为基础,运用定量统计方法,分析集体林分权条件下的林地细碎化程度、农户投入水平及与林地产出的关系,以验证集体林权制度改革后的农户林地细碎化经营是否具有经济合理性.实证结果表明:以S指数衡量,江西省样本县林地细碎化的程度达到0.55,受访农户林地细碎化程度与地貌特征之间未出现明显的关联性;以户均数据衡量,受访农户从家庭收入中用于林业投资的比例维持在30％左右,且传统林业重点县的农户林业投入比例要明显高于非林业重点县.计量模型计算结果表明,S指数衡量的林地细碎化程度对农户林业投入和林地产出水平均构成负向影响趋势;曲线模型临界值分析表明,当农户林地细碎化程度低于0.23或高于0.69时,农户投资林业的积极性则随着林地细碎化程度高低呈现正向变化趋势,当林地细碎化程度低于0.22或高于0.67时,林地细碎化程度对林地产出水平表现为负向影响趋势.     

Effect of Peat-based Container Media on Establishment of Scots Pine,Norway Spruce and Silver Birch Seedlings after Transplanting in Contrasting Water Conditions

Abstract

Urban woodlands are the subject of complex decision-making that requires a strategic overview of the resource. This article contributes a national study of municipal woodland in Denmark. Data were collected among all Danish municipalities through a postal survey (with a response rate of 52%). As much as 83% of the woodland units were located within urban settlements or at their fringe, emphasising that municipalities are important urban woodland providers. Municipal woodland resources were typically divided into many separate units of varying size. On average, the responding municipalities owned 12.6 woodland units with an allocated area of 265 ha, resulting in a mean size of 21.5 ha. A general lack of management plans, and a significant drop in recreational facilities provided with decreasing woodland size indicate that the recreational use potential of small woodland units was largely overlooked. Municipal woodland units frequently bordered other woodland or nature areas of different ownership. Thus even small municipal woodlands can play a key role in the development of multifunctional green infrastructures in the urban landscape. Only municipalities with extensive woodland property had issued a woodland policy, and/or certified woodland management. This indicates a need for development of governance and strategic management instruments attractive to municipalities with limited woodland property.     

三种人工林的土壤碳密度动态研究

对木荷、尾叶桉、湿地松3种人工l林的土壤碳密度进行研究。结果表明：不同林分的土壤碳密度存在差异,木荷、尾叶桉、湿地松林地1999年的土壤碳密度分别为181.13t／hm^2、34.21t／hm。和100.35t／hm^2,2012年的分别为237.94t／hm^2、92.03t／hm^2和144.39t／hm^2,其大小排序为木荷林地〉湿地松林地〉尾叶桉林地,其中以乡土树种木荷林地的土壤有机碳密度最高。3种林地的土壤有机碳密度均显著增加,其中尾叶桉林地的增幅最大。     

Socialist and postsocialist land-use legacies determine farm woodland composition and structure: lessons from Eastern Germany

European agroecosystems host a variety of farm woodlands that act as primary determinants of biodiversity and ecosystem services. While woodland areas have been in decline worldwide, they have regionally increased, for example, in Eastern Germany. This study performs a quantitative and spatially explicit assessment of differences in species richness, diversity, and evenness as well as forest physiognomy and structure among Eastern German farm woodlands established during (1) the presocialist era (until 1945), (2) the socialist era (1945–1990), and (3) the postsocialist era (after 1990). Aerial imagery was used to allocate woodlands to one of the three eras, after which a forest inventory of 120 woodlands was performed. The results show substantial differences in forest composition and structure. Presocialist-era woodlands are composed of native (mean 96 %), deciduous (mean 94 %) tree species. Mean diameters and species richness values are high. Typical socialist woodland species are nonnative (mean 35 %) and/or coniferous (mean 51 %). Stands have a uniform, even-aged stand structure. Species richness/diversity indices are generally low. Postsocialist woodlands exhibit a high degree of variability. Percentages of nonnative (7 %) and coniferous (10 %) individuals are low. The findings suggest that socialist and postsocialist farmland and forest policies translated into distinct land-use legacies in the newly established farm woodlands, which differ considerably from the composition and structure of presocialist woodlands. We argue that forest conservation planning should actively consider land-use legacies, which are of particular relevance in the landscapes of Central and Eastern Europe, as these have undergone multiple, abrupt, and severe land-use transitions.     

Private Ownership and Public Good Provision in English Woodlands

There is increasing emphasis on multipurpose forestry within UK national and regional forest strategies, with the aim of co-delivering the social, environmental and economic benefits of woodlands. Private woodland ownership is also changing, with an increase in owners without a farming or forestry background. However, there is little substantive evidence relating to the motivations of private woodland owners and, in particular, their ability and willingness to deliver public goods. A qualitative study is adopted, using semi-structured interviews in three areas in England, to address this theoretical gap. Exploratory findings indicate that private woodland owners have a diverse range of objectives, motivations and management regimes which influence the potential for public good delivery. It is shown that some private woodland owners, such as those less motivated by economic return, may be better placed than others to deliver certain public goods; that conflicts can arise between the provision of recreation and nature conservation, especially in smaller woodlands; and that many private woodland owners are sceptical about becoming involved in grant schemes which may help foster public good provision in the private sector.     

Recent Changes in the Conservation Value of Woodlands in Rockingham Forest

Surveys of all woodlands within Rockingham Forest, Northants,in 1946 and 1972 show that, whilst the total area of woodlandremains almost unchanged, considerable changes have taken placein woodland distribution, management systems, crop species,and physiognomy. These changes are quantified and their impacton the value of the woodlands for wildlife conservation andfeatures of interest is assessed by reference to criteria relatedto the development of the woods. It is concluded that therehas been a substantial decline in the conservation value ofRockingham Forest woodlands, caused mainly by State forest policyand open-cast mining, and that this decline is likely to continue.     

黑龙江省西部丘陵漫岗区径流效益分析

本文通过观测 ,对黑土漫岗林网区不同林种的土壤结构及理化性质、树冠截留、树干截留、枯落物截留及地表径流、径流含沙量的测定 ,测定出在黑土漫岗林网区 ,有林地比无林地的径流效益值大 ,其中有林地以落叶松、小黑杨、天然栎林的径流效益值较大 ,以落叶松林的径流效益值最大 ,果树林的径流效益值较小     

THE USE OF A SPHERICAL RADIATION METER IN WOODLANDS

For measurements of the light climate in woodlands, conventionallight meters have a limited usefulness. The flat light-receivingsurface results in preferential sensitivity to radiation incidentin a direction normal to the surface; while barrier-layer cellsvary in sensitivity according to the light wavelength, and cannotat present be accurately calibrated to characterize the spectralvariation under a tree canopy. A new type of radiation meter, designed by E. C. Wassink andC. Van der Scheer and comprising two photocells with hemisphericalcovers, was compared with a flat meter in several woodland environments.It is shown to be less sensitive than the flat meter to changesin direction of light influx, and more sensitive to changesin light intensity due to cover type and ground vegetation.The influence of ground vegetation on the light intensity aboveit is assumed to be due to differences in light reflection bydifferent vegetation types. It is suggested that under a tree canopy the measurement oflight influx is of more value to the forester than an estimateof illumination at a surface, and that, when barrier-layer cellsare calibrated for use in woodlands, the emission spectrum ofthe standard light source should conform to the spectral curveof photosynthesis.     

Woodland vegetation and its implications for archaeological survey using LiDAR

Archaeological surveys in woodland have always been problematicand many woodlands contain an unrecorded archaeological resource.For other types of rural landscape, aerial photographs are oftenused to map archaeological features but woodland cover has alwaysimpeded such disclosure. Remote sensing methods are rapidlyevolving and are used both within forestry and archaeologicaldisciplines for a range of applications. This paper considersthe exciting application of the remote sensing technique ofairborne Light Detection and Ranging (LiDAR) to reveal archaeologicalevidence previously hidden below a woodland canopy. Our researchshows how different types of woodland canopy and understoreyvegetation greatly influence the effectiveness of the LiDARto perform these surveys. A simple, visual vegetation mappingassessment is tested and its ability to predict the potentialof the LiDAR considered. This work highlights the importanceof vegetation awareness when considering both a new LiDAR surveyfor a woodland, and when interpreting the data. Simple estimatesof LiDAR penetration of the woodland canopy and understoreyvegetation can be used to predict the effectiveness of a LiDARsurvey in disclosing archaeological evidence and aid the interpretationof results.     

Land-use legacy of historical tree harvesting for charcoal production in a semi-arid woodland

Historical processes may have longer lasting effects in arid forest and woodlands because of slow rates of succession. We investigated the influence of historical tree harvesting upon contemporary spatial dynamics of pinyon-juniper woodland in the western United States. Despite intensive and widespread harvesting of woodland by the charcoal industry during the late 19th century, the role of afforestation has seldom been addressed as a potential mechanism for the dramatic expansion of pinyon-juniper woodlands over the past century. Spatial models of disturbance processes are one way to ascertain effects of such historical influences. We developed a process-based spatial model to estimate the historical tree harvest pressure according to a parsimonious set of rules and constraints. The model used a convection-diffusion approach that incorporated the influences of topography, transportation, and mining production. We used a combination of field-surveyed, archaeological, historical, and GIS data sets to calibrate, validate, and compare the alternative mathematical models. Model results were consistent with the historical harvest evidence (AUC > 0.66), with high harvest intensity closer to the mining districts, quickly decreasing at the maximum distance of influence. Performance was improved by including the local terrain. Harvesting initially showed radial patterns emanating from the significant mining districts, and then gradually expanded northward with development of the railway system. Our spatial modeling approach provides a means to assess the pattern and magnitude of historical tree harvesting in semi-arid woodlands. The general approach can be applied to explore the importance of other historical disturbance and cultural processes, whose effects may no longer be evident, in forests and woodlands worldwide.     

Long-term approaches to native woodland restoration: Palaeoecological and stakeholder perspectives on Atlantic forests of Northern Europe

The long timeframes involved in woodland regeneration and adaptation introduce considerable uncertainty into management and conservation planning as most ecological datasets span only a small part of ecosystem dynamics. This is a particular concern in vulnerable habitats, such as Atlantic birch-oak woods in north-western Britain, where range edge populations are at risk from herbivory and climate change. This study combines historical palaeoecology and stakeholder observations to assess how multiple perspectives can inform existing models, expectations and goals for Atlantic woodland management. Long-term evidence for changing woodland composition addresses stakeholder uncertainties over the currently restricted distribution of oak, alder and hazel. Oak has remained a secondary component of birch-dominated woods and habitat definitions based on oak are too narrow to ensure sustainability. Birch has survived numerous periods of climatic and biotic adversity and shows the strongest positive response to historic reductions in grazing pressure. This has led to a pulse of regeneration since c. AD 1900, so current restoration efforts are taking place within the strongest period of woodland expansion in the last c. 500 years. Positive and negative cultural legacies are evident and intervention is considered a necessary restoration tool. Managed grazing at key stages of habitat development can support continued recruitment and regeneration. A more flexible and integrated management approach is recommended. Long-term ecology can provide direction and address uncertainties, while ecological and stakeholder evidence provide the detail necessary to develop effective management that incorporates ecosystem perspectives. This can help shape management strategies that balance possible conflicts over perceived short-term ‘damage’ to secure longer-term processes. Learning based on multiple temporal perspectives has the potential to contribute to conservation and restoration planning and practice. These principles are more widely applicable in adaptive management.     

General Management Principles for Nature Consrvation in British Woodlands

The management of British woodlands is partly determined bythe need to maintain wildlife and protect features of scientificinterest; but the requirements of nature conservation oftenconflict with other objectives of management. This paper summarisesthe fundamental objectives of nature conservation in Britishwoodlands, then proposes 15 principles which can form the basisof integrating nature conservation into woodland managementpolicies at all levels. Eleven woodland types are discussedas examples which demonstrate both their value for nature conservationand the application of the general principles. The forestryprovisions of the Plan for the Chilterns seem a successful localprecedent for this approach.     

Woodland Management and Public Good Outputs: Appraising the Trade-offs in English Woodlands

This paper examines the trade-offs between woodland management for timber and public good outputs in English woodlands. Recent evidence suggests that some public good values may be declining as a result of a lack of woodland management. Such under-management has been attributed to the decline in timber values and reduction in the productivity of woodlands and forests for timber products. It is argued that assessing the management needs of woodlands in order to enhance public good outputs presents a complex challenge and often depends on a variety of factors, including location, type of woodland, age, condition, substitutability and ownership motivation. However, in most instances a moderate level of management (whether for timber or otherwise) is likely to be beneficial for public good outputs.

Forestry in Nottinghamshire

Forestry in Nottinghamshire is best known for its historicalassociations with the old Royal Forest of Sherwood. The historyof the County's woodlands is described against the backgroundof its physical geography and human development. The part played by the Forestry Commission and other landownersin the past and present management of woodlands is described.The high population density of the County produces a numberof pressures on woodland but also provides a number of positivemanagement opportunities. The future development possibilities for forestry in the Countyare discussed with reference to these and other influences.