In the period between July and September, a substantial field effort was carried out in the 1,500 km transect from south to north in Norway. Each of the 36 field sites was visited.

Inger Elisabeth Hilstad using a 1 sq meter frame to sample vegetation cover. Photo: Ida Marielle Mienna

In the period between July and September 2018, a substantial field effort was carried out. Each of the 36 field sites was visited, and the trees registred in both 2008 and 2012 were remeasured (status (dead/alive), height, diameter at rot collar). Recruited trees were also registered (position, tree species, height, diameter at rot collar). Samples of the surrounding vegetation at the sites were also taken, to enable analyses of the interaction between the establlishment, growth and mortality of trees and the vegetation. A drone was used to collect aerial images for each site. Both a RGB camera and a near infrared camera were used, collecting overlapping images over the sites. The images are processed so that both three dimensional point clouds and spectral information can be spatially related to both trees and vegetation.

The field crew on the move one of the field sites. Photo: Ida Marielle Mienna

A field crew of four carried out the work. Vegard Lien (Mjøsen Skog SA) was in charge, and with him was Ida Marielle Mienna (PhD-student), and master students Kenneth Langlie Simensen and Inger Elisabeth Hilstad. Ingegjerd Meyer replaced Inger Elisabeth in September.

A boulder is facilitating establishment and growth of a birch in the tree line ecotone. Kenneth and Vegard are registering position and tree data. Photo: Ida Marielle Mienna