Satakunta Forest diversity experiments

Trees are the key species of forest ecosystems which support a broad array of other organisms and provide a wide variety of provisioning, regulating, supporting and cultural ecosystem services. Low tree species richness in boreal forests suggests potentially important functional role for each tree species because of low redundancy and pronounced differences in functional traits. Therefore, any changes in tree species richness, proportional abundance of individual tree species, growth patterns or functional traits of these trees are likely to have significant impact on above- and belowground processes and the resulting ecosystem services in boreal forests.

Within the Satakunta forest diversity experiments, our research focuses on exploring the effects of tree species diversity and intraspecific genetic diversity on:

1. Tree growth
2. Tree survival
3. Leaf traits, including leaf chemistry and morphological/physiological traits
4. Light absorption and light use efficiency
5. Carbon accumulation and water use
6. Fine root production

Our current research explores to what extent tree species richness and genotypic diversity effects on ecosystem processes are mediated by changes in tree growth and plant secondary metabolites. Plant community diversity and neighbour identity may cause changes in plant growth and biochemistry, which in turn may affect ecosystem processes such as herbivory, litter decomposition and microbial processes. Plant secondary metabolites may be particularly important as regulators of above- and belowground processes because of their role in defences against herbivores and in litter decomposition.

Here are some examples of recent studies on the above topics conducted at the Satakunta forest diversity experiment:

• Contrasting effects of tree diversity on young tree growth and resistance to insect herbivores across three biodiversity experiments
• Moose browsing alters tree diversity effects on birch growth and insect herbivory
• Interactions and competition processes among tree species in young experimental mixed forests, assessed with chlorophyll fluorescence and leaf morphology 
• Does species richness affect fine root biomass and production in young forest plantations?
• The influence of tree species mixture on ecosystem-level carbon accumulation and water use in a mixed boreal plantation