Identifying practical indicators of biodiversity for stand-level management of plantation forests

Testing indicators of biodiversity for plantation forests

Planted forests of Sitka spruce, a non-native species from north-west America, are the major forest type in Great Britain and Ireland. Standard management involves even-aged stands, rotations of 40–50 years and a patch clear-felling system with artificial regeneration. However, forest policies support managing these forests for multifunctional objectives with increased diversity of species composition and stand structure. Continuous cover forestry (CCF) is an alternative silvicultural approach used to provide such diversity, but the amount of CCF forest is under 10% of the forest area, and less in Sitka spruce forests; This paper reviews research carried out in the last two decades to support the implementation of CCF in Sitka spruce planted forests; Stand structures and microclimate favouring natural regeneration are understood. Harvesting systems have been adapted for use in CCF stands, a single-tree growth model has been calibrated, comparative costs and revenues have been determined, and operational trials established. The interaction between thinning and wind stability in irregular stands is problematic, together with the lack of suitable species for growing in mixture with Sitka spruce; Introduction of an alternative silvicultural approach may take decades and must overcome technical challenges and cultural resistance.

Uneven-aged management of conifer plantations is proposed as a way to increase the value of these forests for the conservation of bird diversity. To test this assumption, we compared the impact of four common silvicultural systems on bird communities, defined by cutblock size (large in even-aged silvicultural systems/smaller in uneven-aged silvicultural systems) and tree species composition (spruce/beech) in the Belgian Ardenne where beech forests have been replaced by spruce plantations. The abundances of bird species were surveyed in young, medium-aged and mature stands in 3–5 forests per silvicultural system (66 plots in all). The effect of silvicultural systems on bird species richness, abundance and composition were analysed both at the plot and at the silvicultural system levels. In plots of a given age, beech stands were richer in species. The composition of bird species at the plot level was explained by stand age and tree composition, but weakly so by stand evenness. For the silvicultural systems, bird species richness was significantly higher in even-aged and in beech forests, and bird species composition depended on the silvicultural system. This study emphasises the importance of maintaining native beech stands for birds and suggests that uneven-aged management of conifer plantations does not provide a valuable improvement of bird diversity comparatively with even-aged systems.

Ground flora communities in temperate oceanic plantation forests and the influence of silvicultural, geographic and edaphic factors

In the absence of native forests, non-native plantation forests have been identified as having an important function in conserving native biodiversity world-wide, including fungal biodiversity. The non-native tree species Sitka spruce (Picea sitchensis (Bong.) Carrière) is now the most abundant tree species in forests in Ireland and Britain, and these forests have been the focus of recent research into their ability to conserve native biodiversity. We conducted an analysis using data from macrofungal surveys from Sitka spruce forests in its native (Vancouver Island, Canada) and non-native (Ireland and Britain) range. Also included in all analyses were data for macrofungal diversity from other native tree species forests in each of the three regions. A total of 630 macrofungal species from seven forest types were analyzed, including 122, 247, and 70 species from Irish, British, and Vancouver Island Sitka spruce forests, respectively. In all three regions, notwithstanding differences in the ages of the sites surveyed in each region, the Sitka spruce forests were found to have species richness similar to that of the other forests types investigated. The communities of the Sitka spruce forests were clearly different in each of the regions, with only 17 species shared among Sitka spruce forests in all three regions. Overall, we found that Sitka spruce plantations in Ireland and Britain could provide a complementary ecosystem for native macrofungi, acting as a suitable forest type for many macrofungi in the absence of native forests. By encouraging the development of old-growth conditions in some plantations, along with the conservation of already existing seminatural forests in Britain and Ireland, we believe the best situation for macrofungal conservation can be achieved.

Identifying key actors, barriers and opportunities to lead a transition towards sustainable forest management: an application to the Basque Country, Spain

Proportions of a pine nurse influences overyielding in planted spruce forests of Atlantic Europe

The need to monitor trends in biodiversity raises many technical issues. What are the features of a good biodiversity index? How should trends in abundance of individual species be estimated? How should composite indices, possibly spanning very diverse taxa, be formed? At what spatial scale should composite indices be applied? How might change-points--points at which the underlying trend changes--be identified? We address some of the technical issues underlying composite indices, including survey design, weighting of the constituent indices, identification of change-points and estimation of spatially varying time trends. We suggest some criteria that biodiversity measures for use in monitoring surveys should satisfy, and we discuss the problems of implementing rigorous methods. We illustrate the properties of different composite indices using UK farmland bird data. We conclude that no single index can capture all aspects of biodiversity change, but that a modified Shannon index and the geometric mean of relative abundance have useful properties.

Forest plantations are expanding worldwide. The primary objective of plantations is to grow trees to produce various wood products. Other than wood, forest plantations also provide a multitude of environmental, economic and social benefits. Their development facilitates the rehabilitation of degraded sites and helps in the protection of natural environments. However, various environmental impacts are associated with the establishment of forest plantations - site degradation, biodiversity loss, effect on water quality and quantity and risks of pests and diseases. Specific to this study, writers in plantation forestry have raised the issue of the displacement effect of plantations to the natural forests. They said that forest plantations complement natural forests; they do not substitute. The plantation policy of the Philippines was formulated to supply the wood requirement of the forest industries and to rehabilitate degraded and marginal lands. In the establishment of plantations, large areas of the natural forests were affected. The study aims to analyse the displacement effect of plantations on the native dipterocarp forests. Analysis of the problem is important to define the role of forest plantations in the forestry sector. The research is divided into two major components: analysis of plantation policies and evaluation of policy implementation. In order to analyse the problem, four research questions are developed. The discussion is a focussed synthesis of relevant literature, public documents and the author's personal observations. The analysis of data gathered from project files archived in the Forest Management Bureau and in the regional offices of the Department of Environment and Natural Resources in the Philippines is a major part of the study. Result of the analysis show that early plantation policies and their modifications allowed the conversion of degraded and healthy native dipterocarp forests into industrial plantations. Most plantation projects were former timber concessions. In order to encourage the active participation of the private sector, the policy combined the management of natural forests and plantations in one management agreement. Plantation developers were given the incentive to log natural forests while growing tree crops. The environmental impacts of plantation projects were not properly assessed. Under the previous policy, plantations were not considered as environmentally critical projects. In the Philippines, the sustainability of plantations is poorly understood. The development of industrial plantations did not ease the pressure to log the natural forests. The combined production from plantations and natural forests was insufficient to meet the domestic demand. Results further show that the level of development of plantation projects was very low. Most projects are still categorised as grasslands and brushlands. Only a small area of plantations was established. However, because of the continuous depletion of the natural forests, it is projected that plantations will gradually expand and will play a significant role in the Philippine forestry sector. The sustainability of plantations is a major issue. Plantation management is entirely different from the management of natural forests. While plantations provide substitute wood products, they also introduce a new ecosystem. The replacement of native forests with plantations does not conform with the international principles in sustainable forest management. This thesis has identified five policy recommendations to promote the sustainable management of plantations in the Philippines. Key words: forest plantations, displacement effect, sustainability

to Planted Forests.- Planted forests: views and viewpoints.- Sustainable management of planted forests: some comparisons between Central Europe and the United States.- The Nature and Uses of Planted Forests.- Planted forests of the wet and dry tropics: their variety, nature, and significance.- Eucalypt plantations.- Douglas-fir planted forests.- Loblolly - the pine for the twenty-first century.- Planted forests: poplars.- The need for planted forests and the example of radiata pine.- Four common myths about plantation forestry.- Multiple purpose forests and the national forest system.- Sustainable plantations of high-yield Eucalyptus trees for production of fiber: the Aracruz case.- Trees outside forests: agro-, community, and urban forestry.- Forests planted for ecosystem restoration or conservation.- Technical and Social Considerations for Planted Forests.- How can we feign sustainability with an increasing population?.- Applications of biotechnology for forest regeneration.- Vulnerability of planted forests to biotic and abiotic disturbances.- Environmental impacts of forest monocultures: water use, acidification, wildlife conservation, and carbon storage.- On the sustainable productivity of planted forests.- Private forest investment and long-run sustainable harvest volumes.- International expectations for sustainable forestry: A view from the U. S. forest industry.- The potential of high-yield plantation forestry for meeting timber needs.- Case Studies of Planted Forests.- Planted forests, agriculture, and the environment - a perspective.- Multiple rotation yields for intensively managed plantations in the Amazon basin.- Sustainable management of native and exotic plantations in Australia.- Radiata pine plantations in Chile.- Small-scale planted forests in Zululand, South Africa: An opportunity for appropriate development.- Sustainability issues in Switzerland's forests.- Ecosystem management and plantation forestry: New directions in British Columbia.- Ideology and culture in the Oregon country: The landscapes of a planting society.- The integration of planted and natural forests in a regional landscape.- Epilogue.

Rationale and methods for conserving biodiversity in plantation forests

There is increasing interest worldwide in managing forests to maintain or improve biodiversity, enhance ecosystem services and assure long-term sustainability of forest resources. An important goal of forest management is to increase stand diversity, provide wildlife habitat and improve forest species diversity. We synthesize results from natural spruce forests in southeast Alaska and suggest strategies for managing Sitka spruce plantations in other parts of the world to benefit biodiversity and enhance a variety of forest ecosystem services. We also discuss the roles of fungi in increasing both biological and structural diversity in Sitka spruce forests. New silvicultural systems that use partial cutting in older spruce forests could alleviate some of the problems associated with conventional even aged management and increase both stand structural diversity and biodiversity. We found that mixed red alder-conifer stands in Alaska provided more heterogeneous structures than the pure conifer stands that typically develop after clearcutting. Well-planned silvicultural systems that include broadleaved species such as alder or birch could provide trees for timber production, improve wildlife habitat and a variety of other ecosystem services that are often compromised in young pure conifer forests.

Sitka spruce (Picea sitchensis (Bong.) Carr.), is the most common tree species in UK’s commercial forests. Tree species diversification of the UK’s commercial forests is currently occurring to make them more resilient to new pests and pathogens and climate change. The potential ecosystem implications of this transition are poorly understood. Our aims are to, (i) list the biodiversity known to be supported by Sitka spruce as this has not been collated previously, and (ii) assess the changes, in both ecosystem functioning and biodiversity supported, if Sitka spruce forests are diversified with any of 34 other tree species. Using records from across the UK, we identified 564 species that use the Sitka spruce trees as a living space or for feeding. Most of these associated species were non-specialist and found on a wide range of other trees. Data from an extensive literature review showed that diversification with broad-leaved trees would potentially result in faster nutrient cycling and litter decomposition with potential implications for carbon storage in the litter layer. Diversification with Oak (Quercus petraea/robur (Matt.) Liebl.), sycamore (Acer pseudoplatanus L.), Scots pine (Pinus sylvestris L.), birch (Betula pendula/pubescens Roth), beech (Fagus sylvatica L.), and Norway spruce (Picea abies (L.) H. Karst.) provide the greatest biodiversity benefits both through supporting the biodiversity found on Sitka spruce and additional biodiversity thought to be absent on Sitka spruce. However, except for sycamore, none of these tree species will grow in long-term intimate mixed stands with Sitka spruce. Therefore, we propose that diversification of Sitka spruce plantations should be carried out as ‘blocky mixes’, i.e. small blocks of single tree species, with tree diversity occurring within a management unit, as a pragmatic approach to support timber production and provide biodiversity benefits. However, the optimal size and spatial arrangement of such blocks requires further assessment.

Climate warming is projected to affect hydrological cycle in forest ecosystems and makes the forest-water relationship more controversial. Currently, planted forests are gaining more public attention due to their role in carbon sequestration and wood production relative to natural forests. However, little is known about how the global patterns and drivers of water yield and water-use efficiency (WUE) differ between planted and natural forests. Here, we conduct a global analysis to compare water yield and WUE in planted and natural forests using 946 observations from 112 published studies. The results showed that global average water yield coefficient was 0.29 for planted forests and 0.34 for natural forests. Planted forests exhibited lower water yield coefficient (p < 0.05) in three climatic regions (arid, dry subhumid, and humid regions), but higher (p < 0.01) WUE only in arid region, compared with natural forests. Both water yield coefficient and WUE in planted forests were significantly lower (p < 0.05) than that in natural forests for stand characteristic groups (stand density, average tree height, leaf area index [LAI], and basal area). Additionally, stand density within the ranging between 1000 to 2000 stem ha-1 can maximize the water yield and WUE in planted and natural forests. Water yield coefficient in planted forests was primarily controlled by the factors related to tree growth (i.e., tree height, DBH), while that of natural forest mainly affected by stand structure (i.e., LAI, stand density, DBH). WUE in planted forest was more sensitive to climate than in natural forests. This work highlights the critical role of natural forests in water supply and the importance of tree species selection and stand management (e.g., stand density adjustment) in plantations in future forest restoration policies and climate change mitigation.

Following the publication of the Millennium EcosystemAssessment (MEA, 2005), there has been increasing interest in evaluating the state of different ecosystems, the range and categories of services these systems provide, their effects upon human well-being, and the consequences of direct and indirect anthropogenic impacts. The framework provided by the MEA’s categories of ecosystem services (ES:, i.e. provisioning, regulating, cultural and supporting services) can be used to explore the role of forests in a wider landscape, as well as to examine the effects at a finer scale and the way ES provision from forests is affected by management actions (Eustafor and Patterson, 2011). There are overlaps between this framework and the concepts of sustainable forest management (SFM) that have underpinned forest policy for at least the last two decades. The multifunctional management strategies developed through SFM may be compromised by economic valuations involved with ES (Quine et al., 2013). There is a recognized need for research that examines the links between ecological systems such as forests and social institutions and management practices both over space and through time in order to improve methods of ecosystem governance (Carpenter et al., 2009). This ongoing dialogue around ES and their value to society presents forest managers with the major challenge of describing, assessing and delivering the various benefits that forest ecosystems provide. These benefits will vary with different types of forest ecosystem and the ways in which they are managed. One forest type of major importance in the northern Hemisphere comprises those forests dominated by spruce (Picea) species which occur both as natural forest systems (e.g. in North West America, Europe and North East Asia) and as plantation forests (e.g. the British Isles, Western Europe). These forests provide a wide range of ES such as biodiversity, recreation, timber, water quality, carbon sequestration and landscape. Planning and implementing multifunctional forest management in spruce-dominated forests is challenging because of the trade-offs and synergies between ES. There is a lack of understanding of appropriate silvicultural and funding measures that will enhance or sustain the provision of different services yet maintain forest resilience in the face of projected climate change and allow for the impacts of biotic and abiotic risks. In an attempt to address this range of issues, a conference was held in Edinburgh, Scotland, UK in October 2012 with the aim of providing a forum where researchers and practitioners could present and discuss new findings on the provision of ES in forests given changing societal demands and uncertainty over future climatic conditions. The main aim of the conference was to see how the concepts promulgated by the MEA and national initiatives such as the UK National Ecosystem Assessment (UKNEA, 2011) could be translated into effective strategic, tactical and operational forest management regimes. Spruce-dominated forests were used as a ‘model’ system to evaluate concepts capable of application across a much wider range of forest ecosystems. The meeting was organized by Forest Research (the research Agency of the Forestry Commission) under the auspices of the International Union of Forest Research Organizations (IUFRO) research group on the ‘Silviculture and Ecology of Spruces’ (group 1.01.08). Scotland was chosen as the venue because of the importance of planted forests of introduced spruce species such as Sitka spruce (Picea sitchensis (Bong.) Carr.). The meeting was attended by 92 delegates from 15 countries. The participants included research scientists from different disciplines, practicing forest managers and policy makers, as well as representatives of sector stakeholders. The conference was structured around a number of themes, providing an overview of forests and their management using an ES framework. These themes included consideration of the ecology and silviculture of spruce forests in different parts of the world, an examination of spruce forest management and the delivery of specific ES, and the way abiotic and biotic risks including climate change could affect the management of spruce forests for ES. The papers and posters presented covered a wide range of aspects relevant to ES provision in spruce-dominated forests including: biodiversity in planted forests, biotic and abiotic risks that may influence management practice, the development of mixed species stands in spruce forests, impacts of management upon carbon stocks in spruce forests, and the role of decision support tools in evaluating trade-offs in the provision of different ES. A number of operational case studies were presented to illustrate how forest managers were adapting their silvicultural regimes to sustain or enhance the provision of particular ES. Most of the presentations are available as