Distribution of snags in temperate forest stands of different land use history

Background/Question/Methods

The survival and persistence of forest species is dependent on the presence, abundance, and distribution of key resources. Dead wood is one of these key resources that is critical for numerous organisms including species of fungi, cavity nesting organisms, wood boring insects and the animals that eat them.  This study investigated how the key resource of standing dead trees is spatially distributed in temperate forest stands of different land use history in SW Ohio. Specifically we examined the relationship between the number and size (diameter) of dead trees to a primary old-growth stand and a secondary post-agricultural stand that originated in the 1960s. I hypothesized, based on known dynamics of age-differing forests, that there would be more standing dead trees (SDT) in the younger, post agricultural forest undergoing self-thinning. I also hypothesized that these trees would be smaller in diameter at breast height (DBH) than trees dying in older forest.

Results/Conclusions

Analysis of the data from the two stands revealed a highly significant difference in both the number of SDT and mean diameter at breast height. In the post-agricultural stand, the density of SDT was significantly higher. However, these trees were also significantly smaller in diameter than STD in the primary forest. There were no statistically significant differences in the decay stage or in the distribution pattern of DBH between the two stands. These results have an effect on the density and type of organisms able to use each stand. High densities of SDT allow high densities of dependent organisms. However, some organisms such as large, cavity-nesting birds may be unable to use these SDT in the post-agricultural stand due to their small size.