PARENT SESSION
Poster Session #30: Disturbance Ecology II.
Tuesday, August 6. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

Pinyon-juniper woodland restoration studies: a watershed scale, multi-disciplinary approach.

Jacobs, Brian¹, Gatewood, Richard², Hastings, Brian², Julius, Christian³, Kleintjes, Paula⁴, Fettig, Stephen^*,1, Allen, Craig⁵, ¹ Bandelier National Monument, NPS, Los Alamos, NM² Colorado State University, Fort Collins, CO³ Rheinischen Friedrich-Wilhelms University, Bonn, Germany⁴ University of Wisconsin, Eau Claire, WI⁵ Jemez Mountain Field Station, USGS-BRD, Los Alamos, NM

ABSTRACT- Restoration studies in Pinus edulis and Juniperus monosperma woodlands at Bandelier National Monument were conducted in semi-closed stands (~35-40% canopy cover) of high density (>1000 stems/ha), young aged (~75% <150 years) trees. Suppressed understory vegetation (<10% total cover), combined with fire history, age-class, and historical evidence, suggest pinyon-juniper woodland effectively displaced Ponderosa Pine savanna, coincident with historic grazing, loss of fire regime, and drought induced mortality of the pine component. In degraded woodlands, exposed soils predominate (>50% cover between trees) and summer monsoons generate unsustainable sediment loss (>2,000 kg/ha/season), which threatens embedded cultural resources. In 1997, mechanical thinning and slash mulching treatments (reducing tree cover to ~10%) were applied at a functional ecosystem scale of paired, 40 ha watersheds. Response to treatment was quantified using both biotic (i.e. plant cover, diversity, and biomass; richness and abundance of arthropods, birds, and butterflies; and ungulate utilization) and abiotic measures (i.e. exposed soil cover; sediment production; soil moisture; and soil micro-topography). At five years post-treatment, understory plant cover increased to >30%, with associated decreases in sediment production (<100 kg/ha/season) relative to control. Butterfly abundance and richness increased significantly in treated areas, while bird populations remained stable. Prescribed fire treatment is also being evaluated for long-term maintenance of mechanically restored savanna structure and function. While response to mechanical restoration treatments are promising, practical management issues persist including implementation at scale (i.e. thousands of hectares) and on public lands designated as both wilderness and cultural landscape.

KEY WORDS: Pinus edulis , Juniperus monosperma , Watershed Restoration, Woodland Restoration