Category: Theses and Dissertations
Title: Slash Additions: A Tool For Restoring Herbaceous Communities In Degraded Pinyon-Juniper Woodlands
Author: * Stoddard, M.T.
Subject: Pinyon-Juniper, Slash
Abstract: Trees in pinyon-juniper woodlands are encroaching into adjacent intercanopy spaces, developing a continuous canopy structure with high fuel loads and a decline in herbaceous production and species richness. Increases in tree density can contribute to the depletion of essential soil nutrients and moisture from nearby intercanopy spaces, thereby affecting the establishment of perennial grasses and forbs within these interspaces. We established an experiment within interspaces of two pinyon (Pinus edulis) and juniper (Juniperous osteosperma) woodlands to examine the effects of slash and seed additions on soil stability, soil chemistry, soil biota, and graminoid establishment. The study site was in the Grand Canyon-Parashant National Monument, at Mt. Trumbull, Arizona on both cinder and sedimentary soil types. Our goal was to decrease sediment loss and create favorable microsites for soil biota and graminoid seedling establishment. Slash additions increased residual woody and litter debris, which decreased rates of sediment loss. Changes in soil nutrients were not observed, however available N03 decreased significantly with slash additions, suggesting increased microbial activity. Arbuscular mycorrhizal fungi and microbial carbon biomass increased significantly as a result of slash additions. Graminoid cover increased over 200(percent) across both sites in slash and seed treatments compared to seed only treatments. In the second year, 42(percent) of the slash and seed plots contained at least one reproductively active seeded graminoid species. Nineteen percent of the total cover (14.3 (percent)) was comprised of the seeded graminoid species. These results indicate that slash treatments do create favorable microsites for graminiod emergence and establishment, therefore contributing to increase herbaceous production within pinyon-juniper woodland interspaces.
Source: Masters Thesis
Publisher: NAU School of Forestry, http://www.for.nau.edu