Title: Woodland restoration by natural regeneration and plantation (assisted regeneration) in Iceland

In a given area different ecological restoration methods can be used depending on the extent and duration of past disturbances, cultural practices that shaped the landscape and present opportunities and constraints. The objective of this study was to evaluate the spreading of birch (Betula pubescens) in areas with natural and assisted regeneration. The study was done at two sites in southern Iceland. Aerial photographs from 1987 and 2008 were used to map birch cover change in Gunnlaugsskogur (natural regeneration) and aerial photographs from 2008 to quantify the existing birch cover in the Bolholt (plantation) using ArcGIS10. Two age classes were used at both sites. Within each age class permanent plots of 10x20 m size with three replications were used to measure the basal diameter and height of the tallest and average tree to see if there were significant differences in the two sites. There was no significant difference in height and basal diameter due to the regeneration methods. However, height and diameter of birch trees at both sites was significantly affected by age. There was an overall increment of birch cover detected in aerial photographs of Gunnlaugsskogur over the 21 years. The areal increment was, however, higher in the higher diameter classes (4.7 ha) and there was a decrease in area coverage of the lower cover class (25-50% canopy cover). The recruitment of birch plants was directional with most recruitment in the north and northwestern part of the site. In Bolholt, since the first plant was planted in 1990, 23 ha of the planted area had more than 75% canopy cover of birch and a total of 60 ha had greater than 25% canopy cover. The cost of birch establishment in Bolholt per hectare was around 122,000 Icelandic kronas (ISK) whereas it was negligible for Gunnlaugsskogur.