In the US, the removal of timber harvest residue during harvesting may be a benefit for wild bees.
There’s always a buzz around bees. They aren’t the only insect pollinators, but they are the standard bearers, because of their numbers and the fact that they’re the only pollinator group in which individuals feed exclusively on nectar and pollen for their entire lives.
Researchers at Oregon State University spent two years studying 28 contiguous one-acre clearcut sites within a managed conifer forest in Oregon. They assessed whether the abundance and diversity of wild bees was affected by the removal of timber harvest residue, also known as ‘slash’, and the soil compaction that goes along with it.
Each plot received one of five unique treatments, ranging from removing only the boles, without compacting the soil at all (with no heavy equipment used on the plot), to removing all the logging slash and compacting the entire plot.
The findings were surprising, according to principal investigator Dr Jim Rivers.
“The combination of the most intense timber residue removal and soil compaction treatment made for the greatest number and diversity of bees,” he said.
“We know there are wild bees in managed forest landscapes in our region, particularly young forests. But it was surprising that there were so many bees in our study, particularly as floral resources were missing from our sites because of herbicide application that occurred as a part of the broader study.”
The findings are a step toward understanding how forest management actions might affect bees.
Rivers, J.W., Mathis, C.L., Moldenke, A.R., & Betts, M.G. (2018).Wild bee diversity is enhanced by experimental removal of timber harvest residue within intensively managed conifer forest. GCB Bioenergy, 10(10), 766–781.
