Grzegorz Mikusiński

Densities of large living and dead trees in old-growth temperate and boreal forests

We recorded and reviewed densities and basal areas of large living and dead trees in old-growth forest in Europe. Recorded densities were similar to those reported from old-growth forests in eastern North America, but lower than in northwestem North America. Based on our results we suggest that, 10-20 living trees per ha with dbh > 70 cm may have been typical values for many central European and south Scandinavian virgin forests. In boreal forests, it was probably common with at least 20 living trees per ha with dbh > 40 cm. Basal areas of living trees in mixed old-growth forests in central Europe and southern Sweden were 34-40 m 2 per ha on dry ground and about 60 m(2) per ha in wet alder-ash-spruce forests. Densities of large trees (dbh > 40 cm) were twice as high in the latter forest type than on dry ground in Bialowieza forest, Poland. Based on our results, we propose the following generalizations to be further tested in other old-growth temperate and boreal forests: 1. Among all standing trunks (including high stumps) about 10% are dead. but this proportion increases for the largest trees. The proportion of standing trees that are dead seem to be independent of total basal areas. Based on this, we suggest that the volume of dead wood is directly proportional to the productivity of old-growth forests. 2. Standing dead trees (snags) are on average larger than downed dead trees. Trees with dbh >40 cm often dominate the basal area and volume of standing dead trees and living trees. 3. About 30% (20-40%) of the basal area and volume of dead trees is standing in old-growth forests. This proportion seems to be independent of total volume of dead wood. Large disturbances by fire, strong winds and insects may temporarily change these proportions considerably in individual stands

Assessing Village Authenticity with Satellite Images: A Method to Identify Intact Cultural Landscapes in Europe

Abstract The village with its characteristic zones of different land use from the center to the periphery is a basic unit of Europes cultural landscapes. However, loss of the authentic pre-industrial village structure characterized by a fine-grained structure of arable land and wooded grasslands is a threat to both cultural heritage and biodiversity in many rural landscapes. Therefore, it is important that the extent and rate of change of such authentic villages in a landscape can be monitored. We studied to what extent loss of authenticity with increasing time after abandonment can be assessed by quantitative analysis and visual interpretation of satellite images. The study was carried out in the Bieszczady Mountains, SE Poland in 1999. Using Landsat Thematic Mapper data from 1998, both the grain size of landscape elements (size of fields) and land-cover composition (encroachment of shrub and forest) were quantitatively described 6 type villages representing different stages of deterioration of the authentic village structure. Historical maps were used to delineate the border of the villages and the former extension of forest and open land was measured. The present land use and the degree of abandonment expressed as grain size and forest encroachment were mapped using satellite data. Deterioration occurred along 2 transformation paths: abandonment and ultimately becoming forest, or intensified agriculture, respectively. To validate these results we classified 22 other villages in a 1000 km2 area by visual interpretation of the original satellite images into 1 of 4 types. We then collected historical data on human population changes over the past six decades. The classification of village authenticity was clearly related to the rate of human population decline. We address the importance of validating and applying this approach for rapid assessment of the authenticity of cultural landscapes in European regions being subject to ongoing as well as expected future change, related to expansion of the European Union. Finally, we argue that the village represents a scale at which integration of natural and social sciences is possible.

Utility of habitat suitability models as biodiversity assessment tools in forest management

Abstract This study addresses questions pertaining to the effective use of habitat suitability models as tools for biodiversity assessment in forest management. Specifically, it discusses, in relation to recent literature, how habitat suitability models could be made more accountable for the multidimensionality of the biodiversity concept, means to generalizing single-species models and addressing population viability, and how to integrate habitat suitability models and forest management planning. Single-species models dominate in the literature, but working with many species, e.g. the focal species concept, provides a feasible option to broaden the conceptual scope of habitat suitability models as tools for biodiversity assessment. The advent of spatially explicit models scaled to the ecologies of species has made habitat suitability models better able to deal with habitat quality and to identify and quantify functional habitat at different spatial scales. The output of habitat suitability models as spatial templates for the simulation of population dynamics is increasingly used to address population viability. Linking species’ habitat requirements with landscape projection models and scenario analysis is the important next step to take in order to make habitat suitability models more efficient as planning tools in forest management.

Distribution of Deciduous Stands in Villages Located in Coniferous Forest Landscapes in Sweden

Abstract Termination of fire along with active removal of deciduous trees in favor of conifers together with anthropogenic transformation of productive forest into agricultural land, have transformed northern European coniferous forests and reduced their deciduous component. Locally, however, in the villages, deciduous trees and stands were maintained, and have more recently regenerated on abandoned agricultural land. We hypothesize that the present distribution of the deciduous component is related to the village in-field/out-field zonation in different regions, which emerges from physical conditions and recent economic development expressed as land-use change. We analyzed the spatial distribution of deciduous stands in in-field and out-field zones of villages in 6 boreal/hemiboreal Swedish regions (Norrbotten, Ångermanland, Jämtland, Dalarna, Bergslagen, Småland). In each region 6 individual quadrates 5 × 5 km centered on village areas were selected. We found significant regional differences in the deciduous component (DEC) in different village zones. At the scale of villages Ångermanland had the highest mean proportion of DEC (17%) and Jämtland the lowest (2%). However, the amounts of the DEC varied systematically in in-field and out-field zones. DEC was highest in the in-field in the south (Småland), but generally low further north. By contrast, the amount of DEC in the out-field was highest in the north. The relative amount of DEC in the forest edge peaked in landscapes with the strongest decline in active agriculture (Ångermanland, Dalarna, Bergslagen). Because former and present local villages are vital for biodiversity linked to the deciduous component, our results indicate a need for integrated management of deciduous forest within entire landscapes. This study shows that simplified satellite data are useful for estimating the spatial distribution of deciduous trees and stands at the landscape scale. However, for detailed studies better thematic resolution is needed to determine biologically relevant differences in quality of deciduous stands.

Conservation planning in forest landscapes of Fennoscandia and an approach to the challenge of Countdown 2010

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.

Optimizing spatial habitat suitability and timber revenue in long-term forest planning

Effective tools must be developed that include consideration of biodiversity in the traditional forest planning process. The objective of this study is to present a spatial habitat suitability model that could be included in the optimization of long-term forest planning where the problem can be solved with an exact solution method. This could be an advantage, since, e.g., many forest planning systems available today are designed for problems that could be solved with an exact solution method. The habitat model consists of two parts: suitability assessment of stand-wise conditions and spatial conditions. To investigate whether the model works in a realistic setting, we used a case study and applied the model to the habitat demands for Hazel Grouse (Bonasa bonasia L.). The results from the case study indicate that the model is effective for including spatial habitat consideration and that the model could be used for creating different degrees of the clustering of habitats. Further, the loss in net present value as a result of the spatial habitat demands was limited in the case study. We suggest that this modeling approach could be extended to other species with large area requirements and add to the existing tools for forest biodiversity assessment in forest management planning.

Difficulties in detecting habitat selection by animals in generally suitable areas.

Species/habitat relationships and their responses at different scales are important aspects of ecological and conservational research. We studied the occurrence of hazel grouse Bonasa bonasia males in a forest reserve over a 10-year period at varying scales and population densities, using two sets of habitat descriptions. Avoidance of pine Pinus sylvestris was the only habitat effect in the hazel grouse/habitat analyses that was significant through all scales, seasons and densities. Thus, in spite of long-term data on a well-known species and detailed vegetation descriptions, only a few clear patterns relating to hazel grouse habitat selection were found at the relatively small scales analysed. We conclude that the non-significant relationships were due to the generally suitable composition and small variation of habitats within the study area, and that significant results may not be expected within the scales analysed and with the methods used. Thus, to find associations between animal species and habitats, a suitable study area must include a certain degree of habitat variation and the relationships should probably be examined at a scale equal to or larger than the home-range of the species in question, or considerably larger if population data are available. The results are discussed in relation to other studies and the applicability of the habitat descriptions and census techniques for conservation of hazel grouse populations in managed forests are discussed.

Incorporating Social and Cultural Significance of Large Old Trees in Conservation Policy

In addition to providing key ecological functions, large old trees are a part of a social realm and as such provide numerous social-cultural benefits to people. However, their social and cultural values are often neglected when designing conservation policies and management guidelines. We believe that awareness of large old trees as a part of human identity and cultural heritage is essential when addressing the issue of their decline worldwide. Large old trees provide humans with aesthetic, symbolic, religious, and historic values, as well as concrete tangible benefits, such as leaves, branches, or nuts. In many cultures particularly large trees are treated with reverence. Also, contemporary popular culture utilizes the image of trees as sentient beings and builds on the ancient myths that attribute great powers to large trees. Although the social and cultural role of large old trees is usually not taken into account in conservation, accounting for human-related values of these trees is an important part of conservation policy because it may strengthen conservation by highlighting the potential synergies in protecting ecological and social values.

Assessment of spatial functionality of old forest in Sweden as habitat for virtual species

Abstract Old forest stands comprise a very small proportion of the managed forested landscapes of Scandinavia today compared with the preindustrial era. Therefore, it is important to develop conservation measures for old forest remnants and temporarily available old stands in managed forests in the most optimal way. This study examines the spatial functionality of old spruce-dominated forest in several regions of Sweden through the perspective of organisms with different ecologies, in terms of their area requirements and mobility. Instead of real species, virtual species were used representing a gradient of these two ecological traits. The main tool was habitat suitability modelling. Countrywide estimates of forest variables derived from the satellite data and field data from the National Forest Inventory using the k-nearest neighbour method were used as sources of habitat distribution data. There was large regional variation in old spruce forest functionality depending on natural conditions and forest history. The relationship between functionality and amount was largely curvilinear. Areas with > 10% of old spruce forest generally had high levels of spatial functionality, whereas high variation in functionality was observed in areas with little old spruce forest cover. This method for multiple-scale assessment of old forest functionality, using virtual species, may be helpful in regional forest biodiversity planning.

Moose (Alces alces) browsing in young forest stands in central Sweden: A multiscale perspective

Abstract Moose browsing on tree saplings in young forests was examined in relation to the surrounding landscape at three spatial scales: stand (mean±SE 8.6±0.8 ha), winter home range of moose (10 km2) and annual home range of moose (25 km2). Landscape patterns at winter and annual home range scales were similar, but annual home range scale was the most important in relation to browsing on birch, aspen and rowan. Browsing on birch was positively related to pine volume and mean patch size of young forest, whereas browsing on aspen was negatively related to the same variables. Browsing on rowan was highest where the volume of deciduous food and overall young forest area were low. In contrast to other studies, no difference in browsing intensity on Scots pine was found among study plots. The results from this study imply that landscape patterns at broad spatial scales can be informative for predicting browsing at smaller scales, and emphasize the need to incorporate landscape characteristics into studies of moose habitat use and in moose and forest management.