Climate Change and Afforestation Potential in Þingvellir National Park, Iceland

Abstract

Geospatial data was analyzed to determine the optimal strategy to afforest Thingvellir National Park to maximize forest productivity and adaptive capacity. A Geographic Information System (GIS) can map the distribution of soil properties, plants, climate, and land-use and land cover (LULC), By overlaying these maps, habitat suitability can be determined. Birch tree line ecotones were mapped based on data for the present and future climates of the area. A suitability map of birch was created showing that presently 7,615.83 hectares have high suitability for birch afforestation. A one-way ANOVA supported the hypothesis that larches are sensitive to winter warming in Iceland. Maps were created to visualize suitable areas for larches in Thingvellir based on winter average temperature, soil, and land cover presently and for the RCP 4.5 2040-2059 scenario. Mixing tree species has the potential to increase production and reduce abiotic and biotic risks in Iceland. The average tree height in monoculture Sitka spruce forests were compared to mixtures of Sitka spruce and lodgepole pine of the same age class. A one-tailed two sampled t-test indicated a significant difference for mixtures versus monocultures. The average tree height of monoculture Sitka spruce forests were then compared to mixtures of Sitka spruce and black cottonwood of the same age class. Again, a one-tailed two sampled t-test resulted in a significant difference favoring mixtures versus monocultures. These findings suggest that these mixtures should be planted to maximize carbon sequestration in the immediate future.