Article

Effects of partial cutting on logging productivity, economic returns and dead wood in boreal pine forest

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Abstract

Structural diversity of forests is important for biodiversity. In managed forests, structural diversity can be maintained by retaining living and dead trees, and by creating dead wood during logging operations. In Sweden, a small percentage of the trees is currently retained on each clear-cut. Since retention decreases revenues from forest harvesting, it is important to understand the consequences of retention for both forestry economy and biodiversity conservation. Thus, in this study we compared effects of retaining percentages ranging from 5% to 50% of the initial number of trees in 12 Scots pine-dominated stands in central Sweden. The retained trees in each stand consisted of equal proportions of green living trees, felled trees, high-cut trees and girdled trees. We estimated costs associated with tree retention and, as indicators of biodiversity conservation values, dead wood volumes, number of dead wood types, and dead wood diversity. We also estimated the damage caused by the logging operations on old dead wood. Revenue declined with increases in retention level, due mainly to associated reductions in harvested volumes, but partly to increases in logging costs. Both harvester and forwarder performance were lower at high than at low retention levels. The volume of dead wood increased with increases in retention level, since the number of retained trees killed per stand was proportional to the retention level. The number of dead wood types and dead wood diversity increased continuously up to the highest retention level of almost 50%. Moreover, old dead wood that was deemed particularly valuable for biodiversity was not destroyed at retention levels above 30%. In conclusion, dead wood destruction decreased with increasing retention level and costs increased proportionally to the retained volume. There were no signs of saturation of dead wood diversity as retention level increased. Therefore, mainly economic restrains will determine the retention level.

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... In particular regions, up to 79% of forest area are favorable for h 51 vester deployment [4]. Overall, Dvořák and Natov [5] productivity of forest machinery [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The accuracy of the analyses is increasing, as th 67 no longer rely on manual measurements and limited data, but rather on the abunda 68 data from the on-board forest machine systems [15,20]. ...
... Therefore, prior to any economic analysis, analyzing the operation of a machine is suggested, from which, economic costs are inferred. Many authors focused on predicting or explaining the productivity of forest machinery [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The accuracy of the analyses is increasing, as they no longer rely on manual measurements and limited data, but rather on the abundant data from the on-board forest machine systems [15,20]. ...
... Productivity of forwarders depends on factors such as mean volume of forwarded stem (mean stem volume; MSV), forwarding distance, terrain conditions, harvesting intensity and type, machine performance class, its bunk capacity, and others [1,5,[7][8][9][10][11]17,19,[21][22][23]. Forwarders with a bunk capacity up to 3 m 3 are able to forward from 2 to 4.1 m 3 /MH, whereas those with approximately 12 m 3 bunks typically forward between 7.1 and 20 m 3 /MH [1]. ...
Article
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Cut-to-length (CTL) operations are expanding in Central European bio-economies. However, they are costly, so efficiency must be maximized. The objective of this study was to analyze direct operational costs of three forwarders from the year 2006 until 2019. Annual amortization, services, materials, and personnel costs were analyzed and compared through ANOVA, trends were analyzed through linear regression. Forwarders LVS 5, John Deere 1010, and John Deere 1110E were deployed in coniferous forest stands with a mean stem volume between 0.10 and 0.84 m3/stem, forwarding distance between 261 and 560 m. The machines forwarded between 4045 and 34,604 m3 of timber per year, over operational times between 490 and 3896 MH (machine hours)/year, reaching machine utilization between 58% and 89%, machine productivity between 3.5 and 12.3 m3/MH, and costs between 20.95 and 84.39 €/MH. The most substantial were personnel costs (35 to 66% of the total costs), followed by materials (14.9–27.1%), amortization (12.5–15.7%), and services (3.3–22.1%). Differences between total operational costs per m3 of machines with different engine powers were not observed.
... While all measurements in the field of providing ecosystem services should be done cost-effectively for the sake of the landowner [37], works about the management of deadwood are scarce and focus on Scandinavia: Wikström and Eriksson [38], Ranius et al. [39], Jonsson et al. [40], Tikkanen et al. [41], Jacobsen et al. [42], Santaniello et al. [43] at the stand level, and Ekvall et al. [44] at the enterprise level. One decision support system ("Der Waldplaner" 31) includes a deadwood model that can show the effects of management on deadwood. ...
... The basic patterns of the results are reasonable. Higher costs with increasing deadwood amounts have been shown by other studies [43]. The authors present costs as net present values of 301 e ha −1 for 5 m 3 ha −1 of deadwood to around 2034 e ha −1 for 48 m 3 ha −1 of deadwood. ...
... This is caused by the different assumptions about the timber prices and the different growth conditions. While Santaniello et al. [43] calculate with average prices of 43.84 e m −3 for spruce, we assumed 83 e m −3 for sawlogs of diameter class 20 cm to 24 cm and 50 e m −3 for pulpwood. Furthermore, their study region is a low-productivity forest in Scandinavia while our results are derived from high-productivity forests in Central Europe. ...
Article
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Coarse woody debris (deadwood) serves as a dwelling space for many rare species, and is therefore a most important factor to ensure diversity in forest ecosystems. However, wood from forest ecosystems is also needed for construction and heating. Therefore, a forest enterprise has to simultaneously incorporate the provision of suitable habitats, as well as the production of wood into their long-term management plans. If the owner wants to fulfil such multiple objectives in an effective way, the providing of ecosystem services can be included in economic planning. Applying computer aided robust optimization techniques, we optimized the provision of deadwood for two exemplary enterprises in East Bavaria, Germany. The results show that high amounts of deadwood provision can cause severe opportunity costs for the forest owner. These costs highly depend on the tree species, the sorting strategy and the time horizon, in which the deadwood objective is reached. Low deadwood targets up to 5 m 3 ha −1 can be provided most cost-effectively with crown material, while higher targets (20 m 3 ha −1 and more) are better achieved with heavy timber grades or the provision of total trees. The novelty of our research is the inclusion of deadwood targets in a risk-considering optimization tool on enterprise level. Instead of calculating the economic loss of commercially not-used timber assortments we show a way of deriving the impact of such decisions at stand level on the economic performance of the whole forest enterprise. We were able to derive optimized opportunity costs. These costs can be used as guidelines for necessary incentives to encourage forest owners to incorporate the provision of deadwood into their management.
... In the long term, retention is expected to increase the amounts of old trees and dead wood in intensively managed forest landscapes (Roberge et al., 2015). Retention generates additional costs since it decreases the harvested timber volume, increases the harvesting costs (Santaniello et al., 2016), and has a negative effect on the wood production of the regenerated forest due to competition between the retained trees and the seedlings (Elfving and Jakobsson, 2006;Erefur, 2010). Tree retention can also affect carbon storage; for instance, Nunery and Keeton (2010) found that tree retention increased average carbon storage after logging. ...
... Within each retention group, half of the trees were left intact and half of them girdled to mimic fire damages. Among trees outside these groups, trees were cut and retained and high-cut stumps were created by cutting them at c. 3 m above ground (Santaniello et al., 2016). Thus, in every harvested stand, there were four categories of retained trees: 1) living trees, 2) girdled trees, 3) high-cut stumps and 4) cut trees left on the ground (Fig. 1). ...
... The site index for each stand (expressed as the expected dominant tree height, in this case pine tree, at 100 years of age) was estimated using the method based on site characteristics (altitude, latitude, field and bottom layer vegetation, water availability, and soil texture; according to H€ agglund and Lundmark, 1977). The location of the retained trees was determined from photos taken by an airborne drone camera (Santaniello et al., 2016). ...
Article
Boreal forests are an important source of timber and pulp wood, but provide also other products and services. Utilizing a simulation program and field data from a tree retention experiment in a Scots pine forest in central Sweden, we simulated the consequences during the following 100 years of various levels of retention on production of merchantable wood, dead wood input (as a proxy for biodiversity), and carbon stock changes. At the stand level, wood production decreased with increased retention levels, while dead wood input and carbon stock increased. We also compared 12 scenarios representing a land sharing/land sparing gradient. In each scenario, a constant volume of wood was harvested with a specific level of retention in a 100-ha landscape. The area not needed to reach the defined volume was set-aside during a 100-year rotation period, leading to decreasing area of set-asides with increasing level of retention across the 12 scenarios. Dead wood input was positively affected by the level of tree retention whereas the average carbon stock decreased slightly with increasing level of tree retention. The scenarios will probably vary in how they favor species preferring different substrates. Therefore, we conclude that a larger variation of landscape-level conservation strategies, also including active creation of dead wood, may be an attractive complement to the existing management.
... Effaråsen is now hosting a large research project, in which trees and dead wood, old and newly created, are retained in different amounts (see Santaniello et al. 2016 for further details). The research treatments were applied 12 months before the lichen sampling took place, and we assume only a negligible effect on lichen species during this short time. ...
... The amount of dead wood in terms of total area available for lichen colonization on different types of substrates was recorded in July-September 2013 (Santaniello et al. 2016). The coverage of wood dependent lichens and the amount and quality of dead wood was surveyed in September 2014. ...
Article
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In the original publication of the article, in Table 2 under the column “Observed frequency fire scars”, the values of species Mycocalicium subtile were published incorrectly as “1” and “0”. However, the values should be “0” and “1”.
... Effaråsen is now hosting a large research project, in which trees and dead wood, old and newly created, are retained in different amounts (see Santaniello et al. 2016 for further details). The research treatments were applied 12 months before the lichen sampling took place, and we assume only a negligible effect on lichen species during this short time. ...
... The amount of dead wood in terms of total area available for lichen colonization on different types of substrates was recorded in July-September 2013 (Santaniello et al. 2016). The coverage of wood dependent lichens and the amount and quality of dead wood was surveyed in September 2014. ...
Article
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Intensive forest management has led to a population decline in many species, including those dependent on dead wood. Many lichens are known to depend on dead wood, but their habitat requirements have been little studied. In this study we investigated the habitat requirements of wood dependent lichens on coarse dead wood (diameter >10 cm) of Scots pine Pinus sylvestris in managed boreal forests in central Sweden. Twenty-one wood dependent lichen species were recorded, of which eleven were confined to old (estimated to be >120 years old) and hard dead wood. Almost all of this wood has emanated from kelo trees, i.e. decorticated and resin-impregnated standing pine trees that died long time ago. We found four red-listed species, of which two were exclusive and two highly associated with old and hard wood. Lichen species composition differed significantly among dead wood types (low stumps, snags, logs), wood hardness, wood age and occurrence of fire scars. Snags had higher number of species per dead wood area than logs and low stumps, and old snags had higher number of species per dead wood area than young ones. Since wood from kelo trees harbours a specialized lichen flora, conservation of wood dependent lichens requires management strategies ensuring the future presence of this wood type. Besides preserving available kelo wood, the formation of this substratum should be supported by setting aside P. sylvestris forests and subject these to prescribed burnings as well as to allow wild fires in some of these forests.
... Instead, there is a heavy reliance on untested proxies for conservation costs." Apart from the investigations by Nordén et al. (2019) in restoration of deciduous preserves and set-asides, and a study by Santaniello et al. (2016) of effects on harvester productivity from different levels of tree retention, no studies have been found. ...
Thesis
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Forests provide a variety of ecosystem services and traditional forest management is largely based on the extraction of one product, wood. Multifunctional forestry, forest management aimed at benefitting multiple ecosystem services, has emerged as awareness has grown of other forest ecosystem services. Nature conservation management is a type of multifunctional forestry promoting ecosystem services other than harvest of wood, most commonly biodiversity and recreation. While the benefits of multifunctional forestry and nature conservation management is recognised, there are knowledge gaps regarding how to perform these operations. The overarching objective of this thesis is to increase knowledge and improve implementation of multifunctional forest operations in Sweden. This is addressed through four studies aiming at answering questions related to how forest operations can be implemented in multifunctional forestry. The findings indicate that many conservation values in forest land can be identified using commonly available GISdata. In most cases, nature conservation management operations are not complicated, but forest managers are disincentivised by conflicting goals and fear of high costs and criticism. The conclusion from detailed studies of operations is that costs in multifunctional operations are higher than conventional operations, but when the entire management system is analysed, effects on net revenues may be small. The general conclusion is that, in many cases, multifunctional forestry is not limited by the operations but rather a lack of clear goals and strategies for achieving goals and evaluating their attainment.
... The pattern of increased species diversity with increasing vegetation cutting occurs when cutting trees and shrubs exposes understorey vegetation to sunlight, which makes it grow more vigorously (Abella and Springer 2015). Although partial cutting is beneficial for the growth of plant species, cutting of vegetation on larger scales has a negative impact on plant diversity (Santaniello et al. 2016). Decreased species abundance with increasing grazing level has also been reported from other parts of the world, but only in arid conditions and not in moist conditions (de Bello et al. 2007). ...
Article
Elevational gradients are linked with different abiotic and biotic factors, which in turn influence the distribution of plant diversity. In the present study we explored the relative importance of different environmental factors in shaping species diversity and composition of vascular plant species along an elevational gradient in the Chamelia Valley, Api-Nampa Conservation Area in western Nepal. Data were collected from 2,000 to 3,800 m above sea level and analysed using a generalized linear mixed model (GLM) and non-metric multidimensional scaling (NMDS). We recorded 231 vascular plant species consisting of 158 herb species belonging to 55 families, 37 shrub species belonging to 22 families and 36 tree species belonging to 23 families. Species richness and species abundance significantly decreased with increasing elevation. However, species richness increased with the intensity of vegetation cutting. Species richness and abundance also increased with increased annual precipitation and mean annual temperature whereas species abundance decreased with grazing, soil phosphorus and nitrogen. NMDS ordination revealed that mean annual temperature and annual precipitation affect the composition of vascular plant species in opposite ways to elevation. Among the many anthropogenic disturbances, only grazing affected species composition. In conclusion, more than one environmental factor contribute to the shaping of patterns of vascular plant species distribution in western Nepal. Knowledge on species diversity, distribution and underlying factors needs to be taken into consideration when formulating and implementing conservation strategies.
... Logging Table 2 Experiments on retention forestry in Finland and Sweden. The Finnish experiments are located in the middle boreal biome and the Swedish experiment in the north boreal biome (Ahti et al. 1968 time (minutes per m 3 wood), opportunity costs, and deadwood diversity increased with an increasing retention level (Santaniello et al. 2016). Baseline data show that old hard pine wood is a valuable habitat for epixylic lichens (Santaniello et al. 2017a). ...
Article
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Retention approaches in forest management are today common in several North European countries, integrated into the clearcutting practice as a way to promote biodiversity and maintain ecosystem functions. Individual green trees and retention patches (tree groups) are retained at final harvest, and deadwood is left at site or created. Here, we review research on retention in Sweden, Finland, Norway, the Baltic States, and NW Russia, with special focus on biodiversity. Following the first publication in 1994, about 180 peer-reviewed articles have been published. We present results from a systematic search of the retention literature, separated into the following topics: buffer zones, retention patches, high stumps, other types of deadwood, European aspen Populus tremula, and cost-efficiency. Russian literature is synthesized separately since studies from this region have so far almost exclusively been published in the Russian language. Furthermore, we describe six ongoing large-scale, replicated experiments with varying retention levels, five in Finland and one in Sweden, and summarize their main results. Among main conclusions for practice from the literature and experiments are that retention patches as large as 0.5 ha and 10-m-wide buffers to watercourses are not enough to maintain pre-harvest species composition but survival of forest species is still larger than on conventional clearcuts. Deadwood on clearcuts may present important habitats to saproxylic species, including rare and red-listed ones and a prioritization of tree species per stand is recommended. We identify several important future research directions including switch of focus towards the landscape as well as the species population level. Surveys in parts of European Russia where retention has been unintentionally implemented already for a century would indicate possible future trajectories of biodiversity and their drivers in other regions of Northern Europe. A stronger link to ecological theory would help in study designs and in the formulation of predicted outcomes.
... Increasing retention results in higher amount and more diverse quality of CWD (Santaniello et al. 2016(Santaniello et al. , 2017b, and retention tree groups also add structural variation to managed forests (Kruys et al. 2013). The location (site type) and size (level of retention) of retention tree groups are important determinants of the muchneeded continuity of large-sized CWD for saproxylic species. ...
Article
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Intensive forest management has been applied in most Fennoscandian forests for a period of almost one felling rotation. This paradigm has produced even-aged and even-structured forests of different successional stages that cover about 90% of forest land. At the same time, wildfires have been nearly eliminated in most of the Fennoscandian nature. Consequently, hundreds of species are red-listed because of forest management. To support these species, forest management requires improvements. Variable retention forestry and habitat restoration have been suggested to mitigate negative effects of forest management on biodiversity, and these have been practiced to some extent during the past few decades. Here, we review experimental results on the effects of variable retention and two restoration measures (prescribed burning and artificial addition of coarse woody debris) on different species groups in Fennoscandia. Our key findings are as follows: (i) Many species respond positively to felling within a few years, apparently due to released and often ephemeral resources, such as fresh residue and stumps. Species associated with shady conditions are negatively impacted, but any retention supports many of these, and their species composition remains almost unaffected with 50–70% retention of the initial tree volume. (ii) These effects remain detectable for at least 10–30 years or, according to some studies, nearly 100 years, e.g., in polypore fungi. (iii) Initial effects of prescribed burning on most species groups (apart from pyrophiles) are negative, but within 10–15 years post-fire sites begin to support many rare and threatened deadwood-dependent species. Epiphytic lichens, however, remain negatively affected. (iv) Artificial addition of deadwood (mostly high stumps) supports a wide spectrum of deadwood-dependent species, but the species composition differs from that of naturally died trees. (v) Moisture and micro-habitat variation are crucial for forest species at harvested sites, at least in forests dominated by Norway spruce. We conclude that felling method as such is of little importance for threatened forest species, although retention mitigates many negative effects. These species require microclimatic continuity, and maintenance and active increase of legacies, such as deadwood of different qualities (species, downed/standing, snag/log/stump, decay stage), very old trees, and tree species mixtures.
... Niemistö et al. 2012; and purely conservational treatments (cf. Santaniello et al. 2016). Costs of NCM operations have not been examined in this study, but the interviewees indicated that costs vary widely, where complex NCM requires more resources and skills while some NCM is straightforward and costs are easily estimated. ...
Article
In Sweden, there is a lack of knowledge about nature conservation management (NCM) practices in voluntary set-aside forests. Estimates indicate that, for unknown reasons, only a small proportion of the NCM needed is carried out. The aims of this study are to (1) describe current practices for NCM of voluntary set-aside areas in Sweden and (2) identify factors affecting whether NCM of these areas is carried out. Twenty-seven semi-structured interviews were held with professional forestry practitioners and the responses analysed applying thematic analysis. NCM in Sweden generally has two main aims: (1) creation of dead wood and (2) promotion of domestic broadleaf tree species. Simplified, these aims are attained through removal of Norway spruce (Picea abies (L.) H. Karst.). The decision to implement NCM is influenced by few incentives and many barriers. Incentives include certification scheme obligations and commitment from dedicated individuals, while barriers include weak internal company incentives, the experienced or anticipated risk of high costs, and experienced or anticipated criticism from internal company experts or public actors. Based on the results, a set of managerial implications was drawn up, aimed at increasing the extent of NCM.
... However, monitoring for forest biodiversity and conservation should expand to include other important parameters such as deadwood type and situation (Lassauce et al., 2011). Deadwood volume and diversity of deadwood types can be enhanced by varying retention levels at the harvesting stage (Santaniello et al., 2016). For instance, methods of deadwood creation (e.g. ...
... The study area, Effaråsen, is located in the province of Dalarna in the southern boreal vegetation zone of Sweden (60°58'29''N, 14°01'55''E, mean altitude 385 m). Since 2012, Effaråsen is hosting a retention experiment, in which trees and dead wood, old and newly created, are retained in different amounts across 12 forest stands (Santaniello et al., 2016). The study area has an extension of about 140 ha. ...
Article
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The excessive simplification of forest structure associated with clear-cutting can carry risks for biodiversity. Tree retention is an alternative practice that maintains greater structural diversity, but its effects on climate change impacts relative to conventional harvesting are largely unexplored. By integrating field measurements from 12 forest stands with modelling approaches, we investigated the post-harvest effects on radiative forcing of tree retention in a Swedish boreal pine forest. In the near-term, impacts from carbon fluxes and surface albedo were of the same order of magnitude but with opposite sign (warming for carbon and cooling for albedo), with a net warming effect. In the long-term, the net effect turns to cooling, as the forest becomes a strong carbon sink. Retention had a significant effect on climate in the near-term, where differences between the various retention levels are more evident. At increasing tree retention, warming impacts from carbon fluxes tend to decrease, but cooling contributions from surface albedo are less pronounced. Balancing these effects, we find a net climate warming that increases with tree retention.
... This corresponds to the general patterns reported in the literature. Hautala et al. (2004) have reported large scarification-caused reductions for final fellings in Finland (65% of volume for all CWD and 88% for welldecayed CWD), while such reductions were insignificant in partial cuttings that retained more than 30% from trees (Santaniello et al., 2016). We recall that our pine shelterwood harvests retained ca. ...
Article
Shelterwood is commonly assumed to be a more nature-friendly silvicultural system than clear-cutting. However, dead-wood pools – a key characteristic of natural forest – have been seldom compared between these systems. We investigated how shelterwood harvesting influences the dynamics of different dead-wood fractions in Estonia, where the predominant forestry model is clear-cutting based but 'seminatural’ (using native tree species and, to a significant extent, natural regeneration). We measured dead-wood pools in 49 Scots pine-dominated stands (representing all shelterwood harvesting stages), and in 11 pine-dominated and 10 Norway spruce-dominated stands as before-after experiments (1st stage only). We analysed dead-wood amounts in relation to site conditions and the proportion of timber harvested, and we compared the shelterwood impacts with published estimates from Estonian clear-cuts. Fine woody debris (5–9.9 cm) increased with the harvest. The volume of coarse woody debris was 19–27 m³ ha⁻¹ in uniform shelterwood stands in pine forest (0–25 years after the first harvest); 63 m³ ha⁻¹ in strip shelterwood stands in spruce forest (immediately post harvest). In before-after experiments, post-harvest dead-wood amounts depended on fraction and harvesting intensity, which determines the balance between the input of new debris (logs; stumps) and the loss of pre-existing standing and downed dead trees. After the first shelterwood harvesting, dead-wood pools remained relatively stable, which contrasts with the large fluctuations after clear-cutting. In the long term, however, shelterwood did not sustain generally larger dead-wood pools than the clear-cutting system in seminatural forestry setting. The issue to be resolved in both types of regeneration cuttings is the near-complete loss of standing dead trees, which probably requires new harvesting techniques.
... This is because of the slow formation of kelos: it can be roughly estimated that after a clearcut it can take 500 to 1000 years before a kelo tree population and its dynamics are restored. Therefore, leaving some retention pine trees on clearcuts can be recommend as one possible way to enhance kelo tree recruitment in managed forests (Gustafsson et al. 2012;Santaniello et al. 2016). However, this may not be sufficient, as the formation of long- Fig. 8 Examples of different kelo structures contributing to forest structural and substrate diversity. ...
Article
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Background After their death, Scots pine trees can remain standing for decades and sometimes up to 200 years, forming long-lasting and ecologically important structures in boreal forest landscapes. Standing dead pines decay very slowly and with time develop into ‘kelo’ trees, which are characterized by hard wood with silvery-colored appearance. These kelo trees represent an ecologically important, long lasting and visually striking element of the structure of natural pine-dominated forests in boreal Fennoscandia that is nowadays virtually absent from managed forest landscapes. Methods We examined and mapped the amount, structural features, site characteristics and spatial distribution of dead standing pine trees over a ten hectare area in an unmanaged boreal forest landscape in the Kalevala National Park in Russian Viena Karelia. Results The mean basal area of dead standing pine trees in the forested part of the landscape was 1.7 m2∙ha−1 and the estimated volume 12.7 m3∙ha−1. From the total number of standing dead pine trees 65% were kelo trees, with a basal area of 1.1 m2∙ha−1 and volume of 8.0 m3∙ha−1, the remainder consisting of standing dead pines along the continuum between a recently dead tree and a kelo tree. Overall, standing dead pines were distributed throughout the study area, but there was a tendency towards spatial clustering up to
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Dead wood occurs in every forested ecosystem. Even if trees are harvested, some of their wood remains on site; for example, in the form of roots and branches. This wood from dead and dying trees plays a key role in ecosystem processes and functioning. Through the removal of wood, this dead-wood resource, in particular that of larger dimension, termed “coarse woody debris” (CWD), has become scarce in most managed forests. The term “debris” indicates that this resource was not valued, neither economically nor ecologically. The recognition that many species were threatened by low levels of this resource initiated a wave of research into the ecology of dead wood beginning in the 1970s to 1980s. It is now estimated that 20–40 percent of organisms in forested ecosystems depend, during some part of their life cycle, on wounded or decaying woody material from living, weakened, or dead trees. In addition to its habitat function, it has been recognized that dead wood plays important roles in carbon, nutrient, and hydrological cycles and is a key structural component influencing ecosystem processes such as erosion. Dead wood is a dynamic resource. Disturbances such as fires or windthrow as well as individual tree death and harvesting supply dead wood, which is subsequently decomposed. The most important species driving the decomposition process are fungi and insects. Together with a number of other species, including vertebrates, they form complex food webs of detritivores, fungivores, predators, scavengers, and parasitoids, including various symbioses. The high variability of dead wood in space and time makes its description challenging. In this article we describe this variability of dead wood, present dynamics of dead wood in unmanaged and managed forests, and characterize the decomposition of dead wood and point to its role in the carbon and nutrient cycles. An overview of the role of dead wood for ecosystem processes and as habitat is followed by a section on the effects of forest management on CWD and strategies to manage for dead wood.
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Retention forestry (RF) is a modified form of clear-cutting that has been introduced recently in several countries. It is intended to integrate the conservation of biodiversity with timber production and to maintain the provision of other ecosystem services by retaining important forest qualities, habitats and structures. In this study we seek to identify forces driving the conceptual development, acceptance and implementation of RF in Sweden by describing and investigating the RF debate among foresters and environmental NGOs from 1968 to 2003. Specifically, we seek to elucidate when RF was first proposed, the arguments for and against it, and pivotal trends in the debate. Our study is based on thorough systematic analysis of articles published in journals issued by two non-profit associations. Our data show that the development of RF in Sweden was driven by several interacting factors and we distinguish critical time periods, from strong debates and conflicts during the 1970s until the breakthrough of forestry certification at the turn of the millennium. We argue that historical analysis of the forces driving changes in forestry management is important for elucidating why changes occur and the dynamic nature of perceptions and uses of forest ecosystems in modern societies.
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Clearcutting has been identified as a main threat to forest biodiversity. In the last few decades, alternatives to clearcutting have gained much interest. Living and dead trees are often retained after harvest to serve as structural legacies to mitigate negative effects of forestry. However, this practice is widely employed without information from systematic before–after control-impact studies to assess the processes involved in species responses after clearcutting with retention. We performed a large-scale survey of the occurrence of logging-sensitive and red-listed bryophytes and lichens before and after clearcutting with the retention approach. A methodology was adopted that, for the first time in studies on retention approaches, enabled monitoring of location-specific substrates. We used uncut stands as controls to assess the variables affecting the survival of species after a major disturbance. In total, 12 bryophyte species and 27 lichen species were analysed. All were classified as sensitive to logging, and most species are also currently red-listed. We found that living and dead trees retained after final harvest acted as refugia in which logging-sensitive species were able to survive for 3 to 7 years after logging. Depending on type of retention and organism group, between 35% and 92% of the species occurrences persisted on retained structures. Most species observed outside retention trees or patches disappeared. Larger pre-harvest population sizes of bryophytes on dead wood increased the survival probability of the species and hence buffered the negative effects of logging. Synthesis and applications. Careful spatial planning of retention structures is required to fully embrace the habitats of logging-sensitive species. Bryophytes and lichens persisted to a higher degree in retention patches compared to solitary trees or in the clearcut area. Retaining groups of trees in logged areas will help to sustain populations of species over the clearcut phase. When possible, old logs should be moved into retention patches to provide a more beneficial environment for dead wood-dependent species. Our study also highlights the need for more before–after control-impact studies of retention forestry to explore factors influencing the survival of species after logging.
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Restoration fires are increasingly used as a conservation tool in Sweden to recreate forests with characteristics of previous forests that were periodically disturbed by fires and promote firedependent species. Restoration fires can result in large inputs of fresh dead wood, but there are risks of losing some of the existing, pre-fire dead wood. To assess these counteracting effects we studied the heterogeneity and availability of dead wood before and after three restoration fires in boreal Scots pine forests. Specifically, we studied volumes of stumps, high stumps, snags and logs. The fires decreased the total volume of pre-fire dead wood (23–41%) and consumed logs in late decay stages (26–54%) to a higher extent than logs in earlier stages. The input of new fresh dead wood after the fires exceeded losses of pre-fire dead wood and resulted in a net increase of dead wood in all three sites. The added dead wood consisted of fresh snags killed by the fires. Fire also affected log characteristics: reducing their vegetation coverage (60–98%), decreasing their ground contact (4–50%) and increasing their surface area of charred wood (>50%). Such changes have important consequences for the micro environmental conditions inside logs, but have been rarely studied in relation to restoration fires. Our results show that restoration fire causes changes in dead wood availability and characteristics of logs. The results imply that ideally stands with low abundance of rare and heavily decayed wood substrates should be burned to optimize dead wood values. Alternatively, management practices should include protection of these substrates during restoration fires.
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Retaining trees for conservation at final harvest is becoming increasingly common within forestry globally, especially connected to clearcutting. The main action is to leave single living and dead trees, tree patches and buffer strips, to benefit biodiversity and to enhance ecosystem functioning. We present the first national analysis of effects on structural components from applying the retention approach. In Sweden retention forestry has been practiced large-scale for about 25 years, prescribed by the law and a requirement in certification standards. By analyzing data from the Swedish National Forest Inventory we found that the volume of dead trees (⩾100 mm in diameter; single trees and trees in patches < 0.02 ha; data for larger retention patches not available) in stands 0–10 years old increased about 70% during the period 1997–2007, with a current average level of 8 m3 ha−1, and with a larger increase rate in this age class than in other forest ages. Retained living trees (⩾150 mm in diameter; single trees and trees in patches < 0.02 ha; data for larger retention patches not available) decreased in quantity from 1955 until the early 1980s, with lowest levels of about 5 ha−1 (excluding Pinus sylvestris, commonly used as a seed tree) and then increased, approximately reaching the 1950s level by 2007, with about 15 trees ha−1 on average. Large-scale application of the clearcutting practice is the probable cause of the decrease, whilst retention actions are the likely explanation for the increase during the last decades. Our study clearly shows that young forests have become structurally richer since the introduction of the retention approach in forestry. However, comparatively low amounts of dead wood in forests 0–10 years old compared to what is available in old forests imply loss at harvest and studies of possible mechanisms to explain this are needed. Our results can indicate possible changes in other parts of the world, where the retention approach has been introduced more recently.
Article
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Coarse woody debris (CWD) is an important component of temperate stream and forest ecosystems. This chapter reviews the rates at which CWD is added and removed from ecosystems, the biomass found in streams and forests, and many functions that CWD serves. CWD is added to ecosystems by numerous mechanisms, including wind, fire, insect attack, pathogens, competition, and geomorphic processes. Despite the many long-term studies on tree mortality, there are few published rates of CWD input on mass-area-1 time-1 basis. CWD is significantly transformed physically and chemically. Movement of CWD, especially in streams, is also an important but poorly documented mechanism whereby CWD is lost from ecosystems. Many factors control the rate at which CWD decomposes, including temperature, moisture, internal gas composition of CWD, substrate quality, size of CWD, and types of organisms involved. However, the importance of many of these factors has yet to be established in field experiments. CWD performs many functions in ecosystems, serving as autotrophic and heterotrophic habitat and strongly influencing geomorphic processes, especially in streams. It is also a major component of nutrient cycles in many ecosystems and is an important functional component of stream and forest ecosystems.
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We investigated the transformation of a large (135 000 ha) forest landscape in boreal Sweden from the end of the 19th century to the end of the 20th century. Historical documents were used to obtain quantitative data on fire influence, historical logging, the development of forest management, and the ecological changes of the forest landscape over the last century. The imprint of the fire-regenerated preindustrial forest is still discernible in the present landscape, although very important ecological structures; e.g., old trees and multiple-storied stands, have been removed and fundamental processes, e.g., forest fire, have ceased. The 19th century boreal forest landscape was shaped by recurrent forest fires and was characterized by continuous multistoried old-growth forest, containing also a deciduous component that no longer exists. Our data indicate that many of the interpretations of previous natural landscape properties used as base-line conditions in forest management must be seriously questioned. Historical records and their limitations when used for reconstruction of forest stand structure are discussed.
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In natural circumstances very old pine trees (Pinus sylvestris L.) usually die while still standing. At the time of their death the trees have reached up to 300–500 years of age, and while dead they may still stand for another 200–500 years or even more. Such long-ago died, debarked, standing pines are called in Finnish the 'kelo', and the term is here proposed for common usage. When the kelo trees finally fall down, they make up a niche for a number of highly specialized fungi. A list is given on typical such Basidiomycetes (polypores and corticiaceous fungi). The onset of forest cutting virtually eradicated that kind of substrate from Central European lowland forests, as well as from the Mediterranean, which resulted in large-scale disappearance of many spe-cialized fungi. Due to the slow development and extremely slow rate of decay of the kelo trees, also the fungi living on them seem to be slow in their colonization, needing a continuity in the supply of the substrate. Therefore scarce and random occurrence of dead standing pines will not suffice for the survival of fungi specialized to live on the kelo.
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In contemporary forest management, also of commercial forests, threshold values are widely used for consideration of biodiversity conservation. Here, we present various aspects of dead-wood threshold values. We review published and unpublished dead-wood threshold data from European lowland beech–oak, mixed-montane, and boreo-alpine spruce–pine forests separately to provide managers of European forests with a baseline for management decisions for their specific forest type. Our review of dead-wood threshold data from European forests revealed 36 critical values with ranges of 10–80m3ha−1 for boreal and lowland forests and 10–150m3ha−1 for mixed-montane forests, with peak values at 20–30m3ha−1 for boreal coniferous forests, 30–40m3ha−1 for mixed-montane forests, and 30–50m3ha−1 for lowland oak–beech forests. We then expand the focus of dead-wood threshold analyses to community composition. We exemplify the two major statistical methods applied in ecological threshold analysis to stimulate forest researchers to analyze more of their own data with a focus on thresholds. Finally, we discuss further directions of dead-wood threshold analysis. We anticipate that further investigations of threshold values will provide a more comprehensive picture of critical ranges for dead wood, which is urgently needed for an ecological and sustainable forestry. KeywordsThresholds-Conditional inference tree-Maximally selected rank statistic-Logistic regression-Bootstrapping-Variable selection
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Aim In a selected literature survey we reviewed studies on the habitat heterogeneity-animal species diversity relationship and evaluated whether there are uncertainties and biases in its empirical support. Location World-wide. Methods We reviewed 85 publications for the period 1960-2003. We screened each publication for terms that were used to define habitat heterogeneity, the animal species group and ecosystem studied, the definition of the structural variable, the measurement of vegetation structure and the temporal and spatial scale of the study. Main conclusions The majority of studies found a positive correlation between habitat heterogeneity/diversity and animal species diversity. However, empirical support for this relationship is drastically biased towards studies of vertebrates and habitats under anthropogenic influence. In this paper, we show that ecological effects of habitat heterogeneity may vary considerably between species groups depending on whether structural attributes are perceived as heterogeneity or fragmentation. Possible effects may also vary relative to the structural variable measured. Based upon this, we introduce a classification framework that may be used for across-studies comparisons. Moreover, the effect of habitat heterogeneity for one species group may differ in relation to the spatial scale. In several studies, however, different species groups are closely linked to 'keystone structures' that determine animal species diversity by their presence. Detecting crucial keystone structures of the vegetation has profound implications for nature conservation and biodiversity management.
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1. Priority effects have been hypothesized to have long-lasting impact on community structure in natural ecosystems. Long-term studies of priority effects in natural ecosystems are however sparse, especially in terrestrial ecosystems. 2. Wood decay is a slow process involving a high diversity of insect and fungus species. Species interactions that drive change in communities of insects and fungi during wood decay are poorly understood because of a lack of sufficient long-term studies. 3. In this paper, we followed the colonization and succession of wood-living insects and fungi on cut trees during 15 years, from tree death and onwards, in a boreal forest landscape. We test the long-term priority effects hypothesis that the identity and abundance of species that colonize first affect the colonization success of later-arriving species. We also hypothesize that species interact in both facilitative and inhibitory ways, which ultimately affect habitat quality for a red-listed late-succession beetle species. 4. Possible causal associations between species were explored by path analysis. The results indicate that one bark beetle species, Hylurgops palliatus, and one wood-borer species, Monochamus sutor, which colonized the wood during the first year after cutting, influenced the occurrence of a rare, wood-living beetle, Peltis grossa, that started to emerge from the stumps about 10 years later. The positive effects of Hylurgops palliatus and negative effects of M. sutor were largely mediated through the wood-decaying fungus species Fomitopsis pinicola. 5. The study shows that variable priority effects may have long-lasting impact on community assembly in decaying wood. The study also exemplifies new possibilities for managing populations of threatened species by exploring links between early, well-understood species guilds and late, more poorly understood species guilds.
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• To assess the sustainability of plantation forest management we compare two types of biodiversity indicators. We used the species richness of saproxylic beetles as a case study to test the “species” and “environmental” indicator approaches. We compared single species abundance or occurrence and deadwood volume or diversity as predictor variables. • Beetles were sampled with flight interception traps in 40 Maritime pine plantation stands. The volume and diversity of deadwood was estimated with line intersect and plot sampling in the same stands. Predictive models of species richness were built with simple linear or Partial Least Square regressions. • Deadwood variables appeared to be good predictors of saproxylic beetle richness at the stand-scale with at least 75% of variance explained. Deadwood diversity variables consistently provided better predictive models than volume variables. The best environmental indicator was the diversity of deadwood elements larger than 15 cm in diameter. • By contrast, the use of “species variables” appeared to be less relevant. To reach the quality of prediction obtained with “environmental variables”, the abundance or occurrence of 6 to 7 species — some of which are difficult to identify — had to be used to build the indicator.
Article
In the new edition of this book, Malcolm Hunter and new co-author James Gibbs offer a thorough introduction to the fascinating and important field of conservation biology, focusing on what can be done to maintain biodiversity through management of ecosystems and populations. Starting with a succinct look at conservation and biodiversity, this book progresses to contend with some of the subject’s most complex topics, such as mass extinctions, ecosystem degradation, and over exploitation. Discusses social, political, and economic aspects of conservation biology. Thoroughly revised with over six hundred new references and web links to many of the organizations involved in conservation biology, striking photographs and maps.
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Biological Diversity provides an up-to-date, authoritative review of the methods of measuring and assessing biological diversity, together with their application. The book's emphasis is on quantifying the variety, abundance, and occurrence of taxa, and on providing objective and clear guidance for both scientists and managers. This is a fast-moving field and one that is the focus of intense research interest. However the rapid development of new methods, the inconsistent and sometimes confusing application of old ones, and the lack of consensus in the literature about the best approach, means that there is a real need for a current synthesis. Biological Diversity covers fundamental measurement issues such as sampling, re-examines familiar diversity metrics (including species richness, diversity statistics, and estimates of spatial and temporal turnover), discusses species abundance distributions and how best to fit them, explores species occurrence and the spatial structure of biodiversity, and investigates alternative approaches used to assess trait, phylogenetic, and genetic diversity. The final section of the book turns to a selection of contemporary challenges such as measuring microbial diversity, evaluating the impact of disturbance, assessing biodiversity in managed landscapes, measuring diversity in the imperfect fossil record, and using species density estimates in management and conservation.
Chapter
Operational efficiency is defined as the efficient utilization and economical management of the resource (forest). The aim of operational efficiency with which this book is concerned is to economize the human activities in forestry. Human inputs or activities are manipulated to meet certain goals or objectives.
Article
Context Species distributions are influenced by habitat conditions and ecological processes at multiple spatial scales. An understanding of the importance of habitat characteristics at different spatial scales is important when developing biodiversity conservation measures. Objectives We investigated the effect of habitat characteristics or amount at three spatial scales on the occurrence of saproxylic (=dead wood-dependent) beetles. Methods Saproxylic beetles were sampled under the bark of dead wood in a managed forest landscape in central Sweden. We modelled the occurrence probability in dead wood items of 44 species (all species occurring in >2 % of the items), based on dead wood item characteristics, forest stand characteristics, and habitat connectivity (i.e. area of potentially suitable forest stands in the surrounding of each stand), using hierarchical Bayesian regression. Results For the majority of species, dead wood item characteristics (especially tree species and whether standing or downed) were more important than measured stand characteristics and habitat connectivity. Whether the stands were clear-cuts, mature forests, or reserves affected some species, whereas the stand-level amount of dead wood per hectare was not important for any species. Habitat connectivity improved the occurrence models for about a half of the species, but there were both positive and negative relationships, and they were generally weak. Conclusions Forest management should include creation and retention of a high diversity of dead wood to sustain habitat for all species. In a forest-dominated landscape, the spatial distribution of dead wood is of little importance for common saproxylic beetle species.
Article
To mitigate the negative impact of intensive forest management on biodiversity, several silvicultural measures are used in production forests. We studied the effect of two such treatments, green-tree retention and prescribed burning on epiphytic lichens 11 years after timber harvests in Scots pine (Pinus sylvestris) dominated forests of middle boreal Finland. Lichen assemblages were sampled from retained Scots pines and their dead wood legacies (snags and logs) below a height of 2 m. Twelve study sites were harvested with two retention levels (10 and 50 m(3)/ha) and six uncut old-growth sites were used as controls. Prescribed burning was applied to half of the sites immediately after harvest. A total of 42 and 65 lichen species was found in the burned (B) and unburned (UB) sites with 10 m(3)/ha retention, 41 and 74 in the B and UB sites with 50 m(3)/ha retention, and 63 and 80 in the B and UB controls respectively. Mean species richness per tree did not differ between the control and harvested sites at either retention level on any of the substratum types. However, microlichen species richness was significantly lower on harvested sites on both living trees and snags. The species richness of both micro- and macrolichens was lower on burned sites. In addition, the composition of lichen assemblages differed between burned and unburned sites. The negative effect of fire was significant for lichens growing on living trees and snags, but not on logs. We conclude that the retention of Scots pines is a successful measure for maintaining epiphytic lichen richness over a timescale of 11 years after harvest, and that roughly equal numbers of living trees and their dead wood legacies are needed to support the lichen species richness on harvested sites. Given that the negative effect of prescribed burning is relatively longer for lichens than for other wood-dependent organisms, burning should not be applied to stands with particularly rich lichen communities. However, these conclusions may have limitations as our inventory was limited to the lowermost part of tree trunks only. Hence inventories of whole trees are useful to assess the full effect of prescribed burning. Our results also imply that the specific impact of prescribed burning for specialist lichen species should be evaluated over a longer timescale.
Article
Retention forestry has been used for over 20 years to reduce the unfavorable impacts of intensive forest management on biodiversity. The assumed positive effects of retention trees, however, depend on the dynamics of trees in providing substrates or structures for forest-dwelling organisms. In 2000 an experimental study was established to investigate the effects of different retention levels (10 m3 ha−1 and 50 m3 ha−1) and fire on tree dynamics. In total, 2758 individually marked, initially living, retention trees were followed on 12 sites in eastern Finland over 10 post-harvest years. Over half (59%) of the total volume of the retention trees died during these initial 10 years, and burning resulted in much higher mortality (84% vs. 34% on unburned sites). At lower retention levels, retention trees did not provide continuity of habitat substrates since all trees died quickly. Fire shortened the tree availability, due to increased tree mortality. However, in higher retention levels, burned areas maintained diverse deadwood substrates for an extended period. Our study proved that tree retention can maintain the continuity of dead wood over early successional stages, if the level of retention is high enough. Fire, combined with higher retention level, created diverse assemblages of dead and living trees. At lower retention levels, however, the effect of fire can be too severe for maintaining living trees or continuity of diverse dead wood.
Article
Publisher Summary This chapter reviews the rates at which Coarse Woody Debris (CWD) is added and removed from ecosystems, the biomass found in streams and forests, and many functions that CWD serves. CWD is an important component of temperate stream and forest ecosystems and is added to the ecosystem by numerous mechanisms, including wind, fire, insect attack, pathogens, competition, and geomorphic processes. Many factors control the rate at which CWD decomposes, including temperature, moisture, the internal gas composition of CWD, substrate quality, the size of the CWD, and the types of organisms involved. The mass of CWD in an ecosystem ideally represents the balance between addition and loss. In reality, slow decomposition rates and erratic variations in input of CWD cause the CWD mass to deviate markedly from steady-state projections. Many differences correspond to forest type, with deciduous-dominated systems having generally lower biomass than conifer-dominated systems. Stream size also influences CWD mass in lotic ecosystems, while successional stage dramatically influences CWD mass in boat aquatic and terrestrial settings. This chapter reviews many of these functions and concludes that CWD is an important functional component of stream and forest ecosystems. Better scientific understanding of these functions and the natural factors influencing CWD dynamics should lead to more enlightened management practices.
Article
Bell System Technical Journal, also pp. 623-656 (October)
Article
The majority of the world's forests are used for multiple purposes, which often include the potentially conflicting goals of timber production and biodiversity conservation. A scientifically validated management approach that can reduce such conflicts is retention forestry, an approach modeled on natural processes, which emerged in the last 25 years as an alternative to clearcutting. A portion of the original stand is left unlogged to maintain the continuity of structural and compositional diversity. We detail retention forestry's ecological role, review its current practices, and summarize the large research base on the subject. Retention forestry is applicable to all forest biomes, complements conservation in reserves, and represents bottom-up conservation through forest manager involvement. A research challenge is to identify thresholds for retention amounts to achieve desired outcomes. We define key issues for future development and link retention forestry with land-zoning allocation at various scales, expanding its uses to forest restoration and the management of uneven-age forests.
Article
The availability of habitat for wood-dependent species has been greatly reduced in Fennoscandian boreal forests and hence the setting aside of forest land for conservation purposes is a common strategy. Here, we explore the biodiversity quality and conservation relevance of three categories of set-asides dominated by Norway spruce (nature reserves, woodland key habitats and retention patches, i.e. groups of living trees left on clear-cut areas) and a non set-aside forest category (old managed spruce forests) in a boreal forest region in central Sweden. The comparisons are based on surveys of (1) dead wood volumes, (2) diversity of dead wood types in terms of tree species, decomposition stage, diameter and presence of bark and (3) occurrence of saproxylic (i.e. wood dependent) beetles in Norway spruce, Picea abies. For saproxylic beetles, species richness, species composition and occurrence of red-listed species were compared. In total 180 dead wood types and 129 beetle species were found, 12 of which were red-listed. We found no significant difference between the forest categories in terms of total dead wood volume. However, the rarefied number of dead wood types was significantly greater in reserves and key habitats compared to retention patches. Woodland key habitats had significantly more beetle species than retention patches and old managed forests, as well as significantly more red-listed species than the retention patches. The species composition of retention patches, differed significantly from that of old managed forests and reserves, probably due to higher degrees of sun-exposure. We conclude that the conservation strategies explored in this study, provide valuable habitats and contribute differently to the preservation of old forests and saproxylic beetles. We would add that inventories, to identify conservation values, should be carried out prior to harvest of old stands and that measures should be taken accordingly to set-aside the parts of forest stands with the highest biodiversity values.
Article
Epiphytic lichen and bryophyte species composition, richness and diversity were surveyed on basal trunks of six common old-growth forest tree species, Picea abies, Pinus sylvestris, Betula pendula, Alnus incana, Salix caprea and Populus tremula, in two old-growth forest areas, one in southern and one in middle boreal Finland. The average species numbers per tree ranged from 18 (Picea) to 27 (Salix) in the southern and from 20 (Populus) to 31 (Salix) in the middle boreal area. A few widespread habitat-generalist species, such as the foliose lichens Hypogymnia physodes and Platismatia glauca, were most abundant on all the tree species, except Populus. Most other epiphyte species showed at least a slight preference for one or two tree species. Populus proved to have the most distinct flora characterized by the abundance of certain, rather specialized crustose lichens and bryophytes. The number of species that occurred on only one tree species was highest on Populus (9) in the southern and on Alnus (18) in the middle boreal area. Differences in bark acidity and structure were the most likely explanations for the differences between tree species in the epiphytic flora and diversity. Salix and Populus were the most important of the tree species studied for the conservation of epiphyte diversity in the boreal forests of Finland.
Article
Loss of old-growth forests and greatly reduced volumes of coarse dead wood in managed forests are the main reasons for the decline of many wood-inhabiting species in Europe and elsewhere. To assess the habitat requirements and extinction vulnerability of 13 polypore species associated mainly with spruce, their occurrences were recorded on 96 521 dead-wood objects in 331 stands along a regional gradient of forest utilization history across southern-middle boreal Finland. The substrates studied included a variety of tree species and dead-wood qualities investigated in both unmanaged and managed stands at different successional stages. Hierarchical logistic regression models were constructed to analyze the relationships between the occurrence probability of individual species and variables at the substrate, stand and regional scales. The substrate preferences of the polypore species studied overlapped, since most of them favored large-diameter spruce logs in mid-decay stages. However, only a few species were restricted to this substrate. Other species were able to use a wider range of host tree species and qualities of dead wood, including man-made substrates that are abundant in managed forests (logging residues and stumps). Species confined to logs had a significantly lower occurrence probability in regions with the longest and most intensive forest use history. Species less specialized in their resource use showed no decline or the opposite trend. Loss of threatened species is likely if the preservation of old-growth forests is not combined with conservation measures in managed forests. Increasing extraction of logging residues and stumps for biofuel may cause non-threatened species to decline by reducing substrate qualities utilized by them. The hierarchical models predicted a considerable part of the variation in Species' occurrence probabilities, and therefore provide powerful tools for setting quantitative targets for management.
Article
High stumps are often retained at clear cuttings to increase the abundance of habitat patches for saproxylic (wood living) insects. However, these high stumps constitutes a very uniform dead wood habitat which probably supports only a part of the saproxylic fauna. Therefore, we compared the saproxylic fauna of high spruce stumps with the fauna of long and short felled boles of spruce. We also investigated the associations between insect species and polypore fungi growing in the wood. All wood units were created at the same occasion on a clear cut in SW Sweden. The dominating species of bark beetles and longhorn beetles were surveyed in the first year after the cutting. Four years later, the fauna was sampled again by sifting bark samples and all species found were determined. In total we recorded six species early in the succession and 43 four years later. Two species were red-listed. Three out of five statistically tested early successional species had significant associations with some of the wood types, while the corresponding figures later in the succession were six of 15. Three of the 15 species in the late succession were also significantly associated with the presence of fruiting bodies of the polypore fungus Fomitopsis pinicola. We concluded that retaining felled wood in addition to high stumps may provide an important means of diversifying the dead wood substrates, which may in turn increase the number of saproxylic species on a site.
Article
We studied the immediate changes in pre-treatment coarse woody debris (CWD) after retention felling and mechanical site preparation (scarification) in mature Picea abies-dominated boreal forest. Retention felling and scarification were hypothetised to affect the amount of CWD. The disturbance caused to CWD was assumed to depend on species and decay class. Logs were inventoried before fellings, after fellings, and after scarification, estimating the damage percentage for each log. After felling, 7.8% of the total pre-treatment volume of CWD was destroyed in the felled area. After scarification, the decline from pre-treatment volume was 67.6% in the felled area. The amount of CWD decreased also inside the retention tree groups; in the 1st post-treatment season, 4.6% was destroyed of the pre-treatment volume and 20% in the 2nd season. Of the retained trees, 40% were uprooted by the end of the 2nd season. If the majority of the initial downed CWD is destroyed by scarification, as our results show, we can estimate that since scarification became a widely used regeneration method in the 1960s, at least from 4 to 6 million m3 of CWD has already been destroyed in Finland. The role of CWD as a key element for biodiversity in boreal forest is generally accepted, which has led to retention of trees in fellings instead of clear felling. We suggest that at least as important as leaving trees in order to maintain continuum in CWD and species diversity is to preserve existing CWD in fellings over the regeneration phase. This can be done using less destructive harvesting methods, reduced use of scarification and placing retention tree groups in patches with high amounts of CWD.
Article
The main problem when adapting forest management to mimic natural processes and structures is the lack of detailed knowledge about historical forest conditions. One way to refine these management goals is by local analysis of change in forest conditions over time. The aim of this investigation was to perform a retrospective regional gap analysis by using historical data. Forest surveys and cadastral maps from the 19th and 20th century were compared with a recent forest survey in a 170 km2 coniferous forest landscape in the middle boreal zone of Sweden. Changes in species composition, age distribution and landscape pattern were analysed at different spatial scales using a GIS. Spatio-temporal analyses were made to compare representative forest types. During the 20th century, clear-cutting has replaced fire as the most important factor influencing the landscape pattern. The old-growth forest is fragmented and the proportion is much lower than in other boreal forest landscapes. Since the 19th century, the landscape has changed from a matrix of forest older than 100 years to a highly fragmented landscape with only small patches of forest older than 100 years. Multi-aged stands have gradually been converted to even-aged stands. The gap analysis indicates a large deficit of multi-aged pine forest. Restoring this forest type requires large areas where Scots pine is allowed to naturally regenerate from seed trees on burned sites. Some trees need to grow to natural maturity (i.e. 200+ years) and die naturally. The restoration of deciduous forest should be directed towards mixed stands. Currently used models to describe the natural landscape are inadequate to use as basis for ecological landscape planning. We conclude that retrospective gap analysis can be used to refine goal setting in Swedish FSC-certification.
Article
The beetle (Coleoptera) fauna of old-growth spruce (Picea abies) forest was compared with that from managed mature and overmature forests in southern Finland. Samples were collected from 9–11 sample plots in each case using 10 window-flight traps in each stand. These yielded a total of 43,289 beetles and 553 species of which 232 were associated with dead wood. The species richness of these saproxylic species was significantly higher in old-growth forests than in managed forests, and had very significant positive correlations with most dead-wood variables. Seventy eight percent of the saproxylic species were more abundant in old-growth than in mature managed forests, and their assemblages in managed and old-growth forests were distinctive with almost no overlap. On the other hand, species richness and assemblages of non-saproxylic species did not differ between the managed and old-growth forests. Obviously these species do not require as much attention as saproxylic species when conservation measures are planned in managed forests. An increase in the general level of decaying wood would improve the situation of many declining saproxylic species. Although the species richness of Coleoptera as a whole was higher in overmature than in mature managed stands, the value of long-rotation stands in preserving species assemblages typical of old-growth forests may be limited.
Article
Changing silvicultural methods to improve habitat quality for forest organisms has become one of the main means to preserve forest biodiversity in Fennoscandia. In boreal forests, coarse woody debris (CWD) is an important substrate for red-listed species. In this study, we analyse cost-efficiency of five management measures taken in Swedish forestry, which aim at increasing CWD in managed forests: retention of living trees at harvest, artificial creation of high stumps, manual scarification at clear-cuts to avoid destruction of CWD, prolongation of the rotation period, and retention of naturally dying trees. For Norway spruce (Picea abies) stands in different parts of Sweden, we calculated the present value and predicted the amount of CWD that will be present if the same management method is used over a long time. To retain reasonable amounts of naturally dying trees was always inexpensive, and in central and northern Sweden it was more economical to retain them than to harvest them. Creation of high stumps was a cost-efficient method to increase the amount of CWD. Prolonging the rotation period was the most expensive way to increase CWD. We conclude that adopting several different measures to increase CWD in managed forests, as prescribed by certification standards today, is a good concept, but to be cost-efficient the focus should be on different measures for different parts of Sweden.
Article
Effective management of biodiversity in production landscapes requires a conservation approach that acknowledges the complexity of ecological and cultural systems in time and space. Fennoscandia has experienced major loss of forest biodiversity caused by intensive forestry. Therefore, the Countdown 2010 initiative to halt the loss of biodiversity in Europe is highly relevant to forest management in this part of the continent. As a contribution to meeting the challenge posed by Countdown 2010, we developed a spatially explicit conservation-planning exercise that used regional knowledge on forest biodiversity to provide support for managers attempting to halt further loss of biological diversity in the region. We used current data on the distribution of 169 species (including 68 red-listed species) representing different forest habitats and ecologies along with forest data within the frame of modern conservation software to devise a map of priority areas for conservation. The top 10% of priority areas contained over 75% of red-listed species locations and 41% of existing protected forest areas, but only 58% of these top priorities overlapped with core areas identified previously in a regional strategy that used more qualitative methods. We argue for aggregating present and future habitat value of single management units to landscape and regional scales to identify potential bottlenecks in habitat availability linked to landscape dynamics. To address the challenge of Countdown 2010, a general framework for forest conservation planning in Fennoscandia needs to cover different conservation issues, tools, and data needs.
  • Hunter Jr
  • M L Gibbs
Hunter Jr., M.L., Gibbs, J.P., 2007. Fundamentals of Conservation Biology,, Blackwell Publishing.
Succession of wood-inhabiting fungal communities. Diversity and species interactions during the decomposition of Norway spruce
  • E Ottosson
Ottosson, E., 2013. Succession of wood-inhabiting fungal communities. Diversity and species interactions during the decomposition of Norway spruce. Acta Universitatis agriculturae Sueciae 17 [Doctoral thesis].
Skogsbrukets arbetshästar, skördaren och skotaren trimmas ständigt
  • M Thor
Thor, M., 2014. Skogsbrukets arbetshästar, skördaren och skotaren trimmas ständigt. In: Thorsén, Å. (Ed.), Effektivare skogsbruk -ett långsiktigt miljöarbete. Skogforsk, Uppsala, pp. 29-31.
Forest Work Study Nomenclature. The Nordic Forest Study Council (NSR)
  • Anon
Anon., 1987. Forest Work Study Nomenclature. The Nordic Forest Study Council (NSR), Norwegian Forest Research Institute, Ås, ISBN 82-7169-210-0, pp. 83-99.
The creation of structural diversity and deadwood habitat by ring-barking in a Scots pine Pinus sylvestris plantation in the Cairngorms
  • J M Agnew
  • S Rau
Agnew, J.M., Rau, S., 2014. The creation of structural diversity and deadwood habitat by ring-barking in a Scots pine Pinus sylvestris plantation in the Cairngorms, UK. Conserv. Evid. 11, 43-47.
Basic data for productivity norms for extra-large single-grip harvesters in final felling. Redogörelse 2/2007 Skogforsk
  • T Brunberg
Brunberg, T., 2007. Basic data for productivity norms for extra-large single-grip harvesters in final felling. Redogörelse 2/2007 Skogforsk (in Swedish with English summary).
Forestry casts and revenues 2011 -major increase in costs
  • T Brunberg
Brunberg, T., 2012. Forestry casts and revenues 2011 -major increase in costs. Resultat 6/2012, Skogforsk (in Swedish with English summary).
Skogsskötselns ekonomi. Skogsskötselserien nr 18
  • H Ekvall
  • G Bostedt
Ekvall, H., Bostedt, G., 2009. Skogsskötselns ekonomi. Skogsskötselserien nr 18. Skogsstyrelsen.
Retaining trees for conservation at clearcutting has increased structural diversity in young Swedish production forests
  • N Kruys
  • J Fridman
  • F Götmark
  • P Simonsson
  • L Gustafsson
Kruys, N., Fridman, J., Götmark, F., Simonsson, P., Gustafsson, L., 2013. Retaining trees for conservation at clearcutting has increased structural diversity in young Swedish production forests. For. Ecol. Manage. 304, 312-321.