321,566 research outputs found

    Occurrence and management of oak in southern Swedish forests

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    This article describes the current proportions of forest types with oak (Quercus robur and Q. petraea) in southern Sweden, provides an overview of oak distribution over time and reviews literature about oak regeneration relevant for the region. Further we discuss silvicultural possibilities to maintain and promote oak in Scandinavia. In Götaland pure oak forest covers 1% of the forest area and mixed forest types with > 10% oak proportion cover approximately 10% of the area. Common types of mixture are spruce-oak and pine-oak forest. Both mixtures are frequent in mature forest, especially pine-oak. Additionally, about one third of spruce-oak mixtures can be found in medium-aged forest. Intensive management would be necessary to promote single oak trees in old pine stands or spruce plantations, but the proportion of oak in coniferous forest provides some potential to maintain additional oak trees. The distribution of acorns by Jays, enhanced measures against browsing, and the release of single oak trees from competing tree species could help to maintain more oak trees for nature conservation. However, regarding management of oak for timber production, conventional methods are recommended. Planting after clear cutting of coniferous forest, or short shelter periods after mast years in oak stands, are established methods to regenerate pure oak stands. Another possibility to develop mature oak forest are mixed oak-spruce plantations, as traditionally practised in a small region in southern Sweden. The different approaches of oak management in Sweden were presented in April 2012 on the annual meeting of the section silviculture of DVFFA (German Union of Forest Research Organizations) in Wermsdorf near Leipzig to give an overview and access to recent forest research in Sweden

    The role of informal protected areas in maintaining biodiversity in the Western Ghats of India

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    Although it is widely believed that an important function of protected areas is to conserve species that are unable to survive elsewhere, there are very few empirical studies in which a comparison is made between biodiversity of protected areas and that of the cultivated landscape surrounding them. We examined the diversity of trees, birds, and macrofungi at 58 sites in three land-use types in a tree-covered landscape in Kodagu district in the Western Ghats of India. Ten forest reserve sites in the formal protected area, and 25 sacred groves and 23 coffee plantations in the neighboring cultivated landscape were sampled. A total of 215 tree, 86 bird, and 163 macrofungus species were recorded. The forest reserve had a large number of trees that were restricted in their distribution, and the sacred groves had a large number of macrofungi. We observed that deciduous trees and non-forest-dwelling birds increased, and evergreen trees and forest-dwelling birds decreased with increasing intensity of land management. We found that trees having non-timber uses and macrofungi useful to the local people, as well as those with medicinal properties, were abundant in sacred groves. We found no significant differences in the distribution of endemic and threatened birds across the three land-use types. Although endemic trees were more abundant in the forest reserve than in sacred groves, threatened trees were more abundant in sacred groves than in the forest reserve. We attribute the high diversity in sacred groves to the native tree cover in shade coffee plantations. We conclude that informal protected areas are as important as formal ones for biodiversity conservation in Kodagu. We recommend that a conservation strategy that recognizes informal protection traditions is essential for successful biodiversity conservation in regions where formal reserves are surrounded by a matrix of cultivated land

    Forest cover estimation in Ireland using radar remote sensing: a comparative analysis of forest cover assessment methodologies

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    Quantification of spatial and temporal changes in forest cover is an essential component of forest monitoring programs. Due to its cloud free capability, Synthetic Aperture Radar (SAR) is an ideal source of information on forest dynamics in countries with near-constant cloud-cover. However, few studies have investigated the use of SAR for forest cover estimation in landscapes with highly sparse and fragmented forest cover. In this study, the potential use of L-band SAR for forest cover estimation in two regions (Longford and Sligo) in Ireland is investigated and compared to forest cover estimates derived from three national (Forestry2010, Prime2, National Forest Inventory), one pan-European (Forest Map 2006) and one global forest cover (Global Forest Change) product. Two machine-learning approaches (Random Forests and Extremely Randomised Trees) are evaluated. Both Random Forests and Extremely Randomised Trees classification accuracies were high (98.1–98.5%), with differences between the two classifiers being minimal (<0.5%). Increasing levels of post classification filtering led to a decrease in estimated forest area and an increase in overall accuracy of SAR-derived forest cover maps. All forest cover products were evaluated using an independent validation dataset. For the Longford region, the highest overall accuracy was recorded with the Forestry2010 dataset (97.42%) whereas in Sligo, highest overall accuracy was obtained for the Prime2 dataset (97.43%), although accuracies of SAR-derived forest maps were comparable. Our findings indicate that spaceborne radar could aid inventories in regions with low levels of forest cover in fragmented landscapes. The reduced accuracies observed for the global and pan-continental forest cover maps in comparison to national and SAR-derived forest maps indicate that caution should be exercised when applying these datasets for national reporting
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