PARENT SESSION
Poster Session #42: Restoration of Public Lands.
Wednesday, August 7. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC
111
Influence of alternate forest residual treatments on soil moisture and seedling germination and establishment in a forest/range ecotone in central Montana.
Law, Darin*,1, Kolb, Peter1, 1 University of Montana, Missoula, Montana
ABSTRACT- Forest-range ecotones are an important land base for grazing animals as well as numerous wildlife species. Encroachment of dense stands of conifers across landscapes that were historically open savannas has adversely affected forage growth (Arno 1996; Strang and Parminter 1980; Weaver 1943, 1967) by decreasing available light, water and nutrients (Bedunah et. al. 1988). Two dominant tree species, ponderosa pine (Pinus ponderosa (Dougl.) Lawson) and Douglas-fir (Pseudotsuga menziesii (Beissn.) Franco) can be extremely invasive across the forest-range ecotones of Montana, regenerating in dense swaths of seedlings with over 4,900 stems/ha. To restore these areas to open savannas and to better understand the effects of current restoration treatments on conifer regeneration, conifer/grass competition and water relations, six seedbed treatments were established across 10 hectares of thinned ponderosa pine on a central Montana ranch. Treatments included mulched and burned logging debris, mulched logging debris, piled and burned logging debris, piled logging debris, burned control and control. Treatments were randomly seeded with native or exotic dry pasture grass mixes or left un-seeded. Greenhouse ponderosa pine germination trials were conducted that tested surface characteristics of intact range, logging debris, burned logging debris, forest duff and control. Results indicate significant differences among soil surface characteristics. These results suggest that increased ash and organic debris thickness increase seedbed resistance to water loss via decreased evaporation rates and increased infiltration. Organic debris thickness also influences seedbed temperatures through shading and convective heat exchange.
KEY WORDS: encroachment, conifer, savanna, rangeland