The Use of Silviculture and Prescribed Fire to Manage Stand Structure and Fuel Profiles in a Multi-aged Lodgepole Pine Forest

This paper presents several components of a multi-disciplinary project de- signed to evaluate the ecological and biological effects of two innovative silvicultural treatments coupled with prescribed fi re in an attempt to both manage fuel profi les and create two-aged stand structures in lodgepole pine. Two shelterwood silvicultural treatments were designed to replicate as well as enhance the existing multi-aged stand structure on the Tenderfoot Creek Experimental Forest in central Montana: the fi rst, with reserve trees evenly distributed; the second, with reserves contained within small (1/10-1/4 acre) groups. Retention of reserve trees was targeted at 50%, without regard to diameter or species. Eight even distribution and eight group-retention treatments were applied on 16 units totaling 649 acres. Half of the units were broadcast burned following harvest using a common burn prescription on all units. Allowable overstory mortality specifi ed in the prescribed fi re plan was 50%. Plot-based fuel inventories and fi re effects observations were performed at permanent plot locations prior to and following harvest, and after burning. Fuel moisture samples were acquired immediately prior to ignition. Data from four prescribed-burned treatment units were evaluated for this paper: two even-retention units and two grouped retention units. Harvest activities resulted in signifi cant increases in fi loading (1-, 10-, and 100-hour fuel), which was subsequently reduced by prescribed fi re to near pre-harvest levels. Consumption of large woody fuel was similar for both treatment types. The fi re-induced mortality of overstory trees was greater in the even distribution than in the grouped distribu- tion. Despite careful execution of a relatively conservative burn plan, mortality in the even treatments exceeded the prescription threshold of 50% by an additional 28%. Additional data collected at the plots include trees per acre, residual tree mortality, residual tree growth, regeneration, windthrow, hydrologic responses, soil impacts, and beetle activity. A comprehensive summary of the treatments will follow subsequent monitoring scheduled to occur fi ve and ten years after burning.