Preliminary field assessment of tree size distribution at upper forest limits in finnmark, northern norway

• Main Author: Umemoto Tohru
• Format: Report
• Language: English
• Published: Department of Geography, Tokyo Metropolitan University 2009
• Subjects: forest limit; Scots pine; mountain birch; grazing; Norway; Finnmark; Northern Norway
• Online Access: https://tokyo-metro-u.repo.nii.ac.jp/?action=repository_uri&item_id=3068; http://hdl.handle.net/10748/3820; https://tokyo-metro-u.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3068&item_no=1&attribute_id=18&file_no=1

The purpose of the study is to obtain a brief outlook on the influence of upper forest limits due to the recent temperature change in Finnmark, northern Norway. The forest of this region is dominated by mountain birch (Betula pubescens) and Scots pine (Pinus sylvestris). In most areas, upper forest limits are formed by trees of mountain birch at the elevation of ca. 300 m a.s.l., and in some areas Scots pine takes the place too. Former studies of the tree age structure show that trees forming forest limits germinated in warmer period of the 1940s. Recent warming can make recruits on and above the forest limits. We set five quadrat plots in July 2007 and counted individuals of tree species and measured the tree size. Many seedling and sapling were counted in the birch forest plots, but there is a clear gap in size distribution. Individuals with the height from 50 to 100 cm were almost missing maybe because of heavy reindeer grazing. Scots pine forest also shows a gap in height but it is not clear. This gap is considered to be formed during the colder period of the 1960s to 1980s.