This project is studying the effects of fire and harvesting on insects, pathogens, and understory diversity in naturally regenerated red pine, Pinus resinosa in Upper Michigan. The design is modeled after the national Fire and Fire-Surrogate study, and treatments include fire only, mechanical harvesting only and combination of fire and harvesting to achieve silvicultural goals, as well as untreated control areas. In 2004 and 2005, pre-treatment data were collected from twenty 0.04-hectare plots in each of twelve 10+ hectare treatment areas. All trees in these plots were measured and tagged. Spore traps measured the presence of shoot blight fungi in the genera Sirococcus and Diplodia. In addition, forest health and understory vegetation data were collected. Treatments were applied in 2005-2006, with mechanical harvesting occurring in fall 2005 and prescribed fire treatments carried out in spring 2006. Post-treatment data were collected in summer 2006 and again in 2007.
Results/Conclusions
Damage by red turpentine beetle (Dendroctonus valens) was evaluated. Prior to treatment application, signs of red turpentine beetle attack were rare. Following treatment in 2006, the highest attacks in standing trees occurred in the harvest and burn combination treatment areas. Lower attack rates occurred in other non-control treatment areas and control treatments had no beetle attacks. In 2007, the proportion of standing live trees attacked was significantly higher in both the burn only and the burn combined with harvest treatment areas than the harvest only or control. Attack rates in cut stumps did not differ between burned and unburned harvested stands. These data suggest that attacks on live trees are related to fire, while the infestation of stumps can occur independently of fire.
Shoot blight pathogens were assessed before and after the treatments were applied. In 2006, Sirococcus spore counts were significantly lower in burned treatment areas than harvest only and control and also significantly lower in harvest treatments than control. Diplodia spore counts did not differ significantly between treatment and control areas. Evaluation of the impacts of these treatments on forest vegetation, insects and pathogens will continue, as well as similar work on the recent Sleeper Lakes wildfire.