Detection of Retention Trees on Clearcuts,a 50-Year Perspective  

作　　者：Emma Holmstrom Ellen Nordstrom Delphine Lariviére Ida Wallin 

机构地区：[1]Southern Swedish Forest Centre,Swedish University of Agricultural Science,Alnarp,Sweden [2]The Forestry Research Institute of Sweden,Skogforsk,Ekebo,Svalov,Sweden [3]Chair of Forest and Environmental Policy,University of Freiburg,Tennenbacherstr,Freiburg,Germany

出　　处：《Open Journal of Forestry》2020年第1期110-123,共14页林学期刊（英文）

摘　　要：Changes in clearcut management over time were evaluated using aerial photographs taken between 1960 and 2010. Temporal changes were analysed in two different climatic zones in Sweden: a typical boreal forest zone (the coast of V&#228sterbotten County), and the hemi-boreal zone of southern Sweden (represented by Kronoberg County). The study covers the periods before and after the paradigm shift in Swedish forestry caused by the equalization of the production and nature conservation objectives specified in the first paragraph of the Swedish Forestry Act. Photographs were processed to determine clearcut size and shape and to register solitary retention trees and groups of retention trees. Small but significant changes in clearcut size were detected over time. The number of retention trees increased over time, a result that was also found in other studies using different methodologies. The results demonstrate that measurable structural changes have occurred in Swedish forests over the 25 years since the paradigm shift. Results from this study also show that digital detection of green tree retention could be a future complement to field inventory and monitoring.Changes in clearcut management over time were evaluated using aerial photographs taken between 1960 and 2010. Temporal changes were analysed in two different climatic zones in Sweden: a typical boreal forest zone (the coast of V&#228sterbotten County), and the hemi-boreal zone of southern Sweden (represented by Kronoberg County). The study covers the periods before and after the paradigm shift in Swedish forestry caused by the equalization of the production and nature conservation objectives specified in the first paragraph of the Swedish Forestry Act. Photographs were processed to determine clearcut size and shape and to register solitary retention trees and groups of retention trees. Small but significant changes in clearcut size were detected over time. The number of retention trees increased over time, a result that was also found in other studies using different methodologies. The results demonstrate that measurable structural changes have occurred in Swedish forests over the 25 years since the paradigm shift. Results from this study also show that digital detection of green tree retention could be a future complement to field inventory and monitoring.

关 键 词：FORESTRY CLEARCUT Aerial Photographs Swedish Forestry Model Retention Forestry 

分 类 号：S71[农业科学—林学]