Thesis title: Growth trends and site productivity in boreal forests under management and environmental change: insights from long-term surveys and experiments in Sweden
Forests play a central role in climate change mitigation, since they sequester atmospheric carbon dioxide. However, their carbon sink is very much affected by both management and changes in environmental conditions. Boreal forests are characterised by extended freezing temperatures, shorter growing periods and intensive management, alterations in the growing environment are expected to increase forest productivity. In Sweden, the annual volume growth has increased from about 70 million m3 to 120 million m3 in the period 1950-2020. Important questions are to what extent have management and climate influenced tree growth in the past and how it might respond in the future. To evaluate this, tree growth data from monitoring systems are essential. Today, much more growth data have accumulated from observational plots in long-term experiments and sample-based national forest inventories. Using these datasets and combined methods of empirical statistical correlations, we aim to assess the historical development, present state and future growth trends in Swedish forests. Additionally, models for unbiased estimation of forest site productivity are developed, which will be key to capture current forest growth conditions in the empirical growth models presently used in Sweden. The project seeks to make an important contribution towards the ongoing environmental monitoring programs undertaken by SLU for sustainable management of Swedish forests.
Keywords: Growth trends; Site productivity; Growth models, Boreal forest, Climate change; Sweden