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Andersson, Lars (2008) Utvärdering av flygbildstolkning för uppskattning av beståndsvariabler och åtgärdsförslag i ungskogar. Other thesis, SLU.

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Abstract

In Korsnäs district Dala Väst there were problems with information concerning their younger forests, mainly those in pre-thinning stage. They were divided into large, heterogeneous stands with often poor stand data quality. In 2006 an aerial photo interpretation of the young forests was conducted to fix these problems. Necessary information to get from the interpretation were silvicultural management suggestions, new stand delineation and new stand data. This thesis is supposed to evaluate the quality and usability of the interpreted data. To evaluate the interpretation an objective control inventory was conducted in 60 stands, either through callipering or counting stems. Height, number of stems and tree species composition, and in callipered stands also mean diameter and standing volume, were registered. These control measured values were then compared to the interpreted, or from interpreted values calculated, values of the same variables and differences between them were formed. The mean and variation of the difference, and its correlations with other variables, were then investigated. The height is on average well interpreted, with deviations of the same size as previous studies. The deviations for number of stems are bigger in this study than others, and number of stems is generally underestimated. Other studies are however rarely focused on younger forests. The tree species composition shows, similar to other studies, an overestimation of pine percentage. Standing volume according to the stand register, based on interpreted values, is underestimated in some areas and overestimated in others. Mean diameter, also calculated in the stand register, is averagely underestimated. The evaluation of silvicultural management suggestions were based on the management guidelines of Bergvik Skog. Interpreted management suggestions were compared to management suggestions according to those guidelines. Number of years to thinning was calculated using upper height development functions. Between 60 and 80 % of all silvicultural management suggestions are correct, depending on management action type and method of comparison. Proposed, interpreted number of years to thinning is often some years too late. Faulty management suggestions are often correlated with faulty interpretation of stand data. The results of the aerial photo interpretation are generally what could be expected concerning previous studies.

Item Type: Thesis (Other)
Keywords: beståndsdata, flygbildstolkning, gallring, inventering, röjning, åtgärdsförslag
Subject (faculty): Faculty of Veterinary Medicine and Animal Science > Dept. of Forest Ecology and Management
Divisions: SLU > Faculty of Forest Sciences
Depositing User: Ylva Jonsson
Date Deposited: 04 Apr 2008
Last Modified: 18 Aug 2015 10:01
URI: http://ex-epsilon.slu.se/id/eprint/2354

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