Insect and disease response to prescribed burning, harvesting and wildfire in pine forests in the Upper Peninsula of Michigan

The effects of wildfire and combinations of prescribed fire and harvesting on insects and diseases in naturally regenerated red pine (Pinus resinosa) stands are being studied in Upper Michigan. Treatments applied in 2005-2006 included prescribed fire only, mechanical harvesting only and combination of prescribed fire and harvesting, as well as control areas. Damage by red turpentine beetle (Dendroctonus valens) was evaluated pre- and post-treatment. Prior to treatment application, signs of red turpentine beetle attack were rare. After treatments (2007), the proportion of live trees attacked by red turpentine beetle was significantly higher in the burned treatment areas than harvest only or control. Spore traps were used to monitor fungal shoot blight pathogens. In 2006, Sirococcus spore counts were significantly lower in burned treatment areas than harvest only and control and significantly lower in harvest treatments than control. In the summers of 2008-2009 similar data were collected at the Sleeper Lake Wildfire, a lightning-ignited fire that burned 7,365 hectares (18,200 acres) in August of 2007. Flight intercept traps measured insect response in burned and unburned red and jack pine (Pinus banksiana) stands. Sticky traps were used to assess landing behavior of insects on individual scorched red pines. Overstory conditions, understory vegetation and fire severity were also measured. Red turpentine beetle and pine engraver beetle (Ips pini) activity were monitored following the fire. These two research sites represent a rare opportunity to investigate the effects of prescribed fire and wildfire in close proximity to one another in pine-dominated stands in Upper Michigan.