Forest Diversity Experiments

Our work at the Siemianice research site in Poland builds on a collaboration begun in 2003 with the Polish Committee for Scientific Research group (funded by the Polish equivalent to NSF), which has developed a focus on subdominant plant species, soil microbial ecology and soil fauna.

In only 30 years, tree species caused major divergence in soil pH, and forest floor and mineral soil Ca that were correlated with changes in soil biota and organic matter dynamics. Our work involves experiments and observations using ecophysiological, ecosystem, geochemical, and isotopic approaches to address questions regarding the biotic and abiotic mechanisms causing the patterns.

Another research project, called 'International Diversity Experiment Network with Trees' or IDENT is a functional diversity experiment with sites located globally. IDENT is a network of Biodiversity - Ecosystem Functioning (BEF) experiments in North America and Europe. IDENT focuses on the early tree development, the role of functional diversity, and BEF relationships over stress gradients. The experiment consists of seven sites. In total, 1640 plots have been planted with native as well as exotic tree species. The objectives of this study are to determine how components of functional diversity affect ecosystem processes in forests to provide ecosystem managers recommendations concerning the benefits of maintaining biodiversity. One of the research sites is located at the Cloquet Forestry Center.


Mueller, K. E., S. E. Hobbie, J. Chorover, P. B. Reich, N. Eisenhauer, M. J. Castellano, O. A. Chadwick, T. Dobies, C. M. Hale, A. M. Jagodziński, et al. 2015. Effects of litter traits, soil biota, and soil chemistry on soil carbon stocks at a common garden with 14 tree species. Biogeochemistry 123(3), DOI: 10.1007/s10533-015-0083-6

Mueller, K.E., .DM. Eissenstat, S.E. Hobbie, J. Oleksyn, A.M. Jagodzinski, P.B. Reich, O.A. Chadwick, J. Chorover. 2012. Tree species effects on coupled cycles of carbon, nitrogen, and acidity in mineral soils at a common garden experiment. Biogeochemistry (6 January 2012), pp. 1-14, doi:10.1007/s10533-011-9695-7.

Wyka, T.P., J. Oleksyn, R. Żytkowiak, P. Karolewski, A.M. Jagodziński, P.B. Reich. 2012. Responses of leaf structure and photosynthetic properties to intra-canopy light gradients: a common garden test with four angiosperm and seven gymnosperm tree species. Oecologia DOI 10.1007/s00442-012-2279-y.

Knight, K., J. Oleksyn, A.M. Jagodzinski, P.B. Reich, M. Kasprowicz. 2008. Overstorey tree species regulate colonization by native and exotic plants: a source of positive relationships between understorey diversity and invasibility. Diversity and Distributions 14:666-675.

Hobbie, S.E., P.B. Reich, J. Oleksyn, M. Ogdahl, R. Zytkowiak, C. Hale, and P. Karolewski. 2006. Tree species effects on decomposition and forest floor dynamics in a common garden. Ecology 87:2288-2297.

Reich, P.B., Oleksyn, J., Modrzynski, J., Mrozinski, P., Hobbie, S. E., Eissenstat, D. M., Chorover, J., Chadwick, O. A., Hale, C. M. and Tjoelker, M. G. 2005. Linking litter calcium, earthworms and soil properties: a common garden test with 14 tree species. Ecology Letters 8:811-818.

Reich, P.B. and J. Oleksyn. 2004. Global patterns of plant leaf N and P in relation to temperature and latitude. Proceedings of the National Academy of Sciences 101:11001-11006. 

Reich, P.B., Wright, I., Cavender-Bares, J., Craine, J., Oleksyn, J., Westoby, M. and Walters, M.B. 2003. The evolution of plant functional variation: traits, spectra, and strategies. International Journal of Plant Sciences 164: S143-S164.