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Josefsson, Torbjörn (2004) Using a spatially precise approach to analyse the occurrence of Usnea longissima in relation to present and past stand structure. Other thesis, SLU.

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Abstract

To maintain biodiversity in managed forests, long-term trends in forest structure and ecological processes must be understood since these have a decisive influence on the distribution of many forest species, especially epiphytic lichens. To enhance the understanding of the complex occurrence of Usnea longissima Ash. at the stand level, a spatially precise investigation of present and past stand structure was made in an area in boreal Sweden. Field studies of present occurrence of U. longissima and present forest structure were complemented with dendrochronological analysis and interpretation of different historical sources. Stand structure at present was more or less similar all over the study area. No occurrence of forest fires during the last centuries and absence of forestry operations since the 1930s were most important for the occurrence of U. longissima. However, the distribution of the lichen within the study area could not be explained by present stand structure. Instead, several essential factors affecting the distribution of U. longissima could be related to past stand structure, especially the extent and intensity of previous logging operations and the subsequent stand development. Possibly, pre-industrial forest use and modest selective cuttings may occasionally have contributed to a maintained open forest structure. Evidently, U. longissima appears to be favoured by long-term stability in forest structure, including a somewhat open forest dominated by Picea abies, moderate regrowth of trees and absence of large-scale disturbances. The results indicate that stand history has an important influence on the distribution of epiphytic lichens such as U. longissima and should be considered to achieve a comprehensive management of boreal forests. Furthermore, the use of a spatially precise approach may elucidate many different factors and is practicable for interpreting forest history and long-term changes in habitat conditions.

Item Type: Thesis (Other)
Keywords: Stand history, nature conservation, adaptive forest management
Subject (faculty): Faculty of Forest Sciences
Divisions: SLU > Faculty of Forest Sciences
Depositing User: Kristina Johansson
Date Deposited: 22 Apr 2004
Last Modified: 18 Aug 2015 09:29
URI: http://ex-epsilon.slu.se/id/eprint/116

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