1. Oak growth during periods of extreme precipitation:
understanding the effects of soil clay content
Oak is one of the most deep-rooted forest trees in Sweden and can tolerate a relatively wide range of soil conditions (Rosengren & Stjernquist 2004; Bespalov & Os’kina, V 2006), making this species a good candidate for sites on the soils with increased clay content. Since the soil clay content is inversely related to acidification and litter accumulation, oaks growing on clay rich soils (content by volume above 5%) enjoys generally non-acidified conditions, higher soil water availability during dryer periods, and, possibly, a high level of microbial activity in the soil. However, oak stands on heavy soils may be at risk during periods of excessive soil water content, e.g. during springs and periods of high summer precipitation.
The main aim of this project is to quantify a non-linear relationship between growth response to periods of extreme precipitation and soil clay content in commercial oak stands in Southern Sweden. This knowledge should be important in helping the forest managers assess the risk of stand declines resulting from the extensive precipitation amount halting the functioning of the oak fine root system.
2. Pattern of modern fire activity in Sweden: role of human vs natural factors
Despite efficient fire suppression, forest fires do occur in Sweden and it is of theoretical and practical interest to understand human and environmental controls of this fire activity. The fires caused by humans are often unintentional and small but in combination with climatic factors like low amount of summer precipitation, may quickly increase in size and pose a serious danger to growing stock and infrastructure. It has been proved in several studies that the natural fires usually occur over a large area and pretty seldom than human induced fires. Understanding the correlations between human presence in the landscape and long-term forest fire patterns helps optimize resource allocation for fire fighting activities. In this project we will use country-wide datasets on different properties of Swedish counties (economical, logistic-, and infrastructure-oriented), GIS, and modern fire statistics to understand non-climatic controls of fire activity in Sweden over the recent decades.
3. Development and dendroclimatic analysis of a regional beech chronology of Southern Sweden
The project will endavoir to extract climatic signals from a number of beech site chronologies and to develop a regional beech chronology. Further, the study will attemp to partition climatic, forest management, and masting effects on beech growth, and make sound predictions about dynamics of beech biomass accumulation under future climates.
Please contact igor.drobyshev(at)slu.se for further information on any of these projects.