PARENT SESSION
Poster Session #9: Success Criteria and Monitoring Restoration.
Monday, August 5. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC
97
When is understory herbaceous biomass and diversity restored?: A seven-year case study from southwestern ponderosa pine.
MOORE, MARGARET*,1, CASEY, CHERYL1, SPRINGER, JUDY2, FULE', PETER1,2, COVINGTON, WILLIAM1,2, 1 SCHOOL OF FORESTRY; NORTHERN ARIZONA UNIVERSITY, FLAGSTAFF, AZ2 ECOLOGICAL RESTORATION INSTITUTE; NORTHERN ARIZONA UNIVERSITY, FLAGSTAFF, AZ
ABSTRACT- Success criteria are necessary to determine if expectations are being met for any restoration activity. We measured aboveground biomass and species richness on 55 herbaceous understory plots for seven years following a replicated field application of control (untreated), partial restoration (small-diameter tree thinning), and complete restoration (thinning, prescribed burning) treatments in a ponderosa pine-bunchgrass community in northern Arizona. We further stratified treatments into four "canopy types". The remnant grass patches were used as the baseline and assumed to be more representative of the original understory plant community. Results show that both partial and full restoration treatments have significantly increased overall herbaceous biomass for all years compared to control, with an average post-treatment increase of 450% for partial (312 kg/ha), and 369% (254 kg/ha) for complete treatment. In 1999, species richness had also increased significantly. Results for canopy types show that both biomass and species richness of grass patches were significantly greater than the other types. Using the complete restoration canopy type in 1999 as an example, biomass and diversity within the grass patch was 1906 kg/ha and 35 native species, respectively, compared to 39 to 730 kg/ha, and 16 to 28 species for the other types. These results indicate that restorative treatments are necessary to increase understory production and diversity; and that it will take longer than seven years to reach understory restoration goals in these southwestern ponderosa pine systems.
KEY WORDS: restoration, understory, pinus ponderosa, southwestern