Category: Ecological Research
Title: Gambel Oak Growth Forms: Management Opportunities for Increasing Ecosystem Diversity
Author: * Abella, S.R.
Subject: Gambel Oak (Quercus gambelii), Ponderosa pine (Pinus ponderosa), Management
Abstract: Gambel oak (Quercus gambelii) clones have several different growth forms in southwestern ponderosa pine (Pinus ponderosa) forests, and these growth forms each provide unique wildlife habitat and resource values. The purposes of this note are to review published growth-form classifications for Gambel oak, provide examples of ecological effects of different growth forms, and summarize management strategies for promoting desired growth forms. Four different growth-form classifications have been published, which generally recognize variants of three basic forms: shrubby thickets of small-diameter stems, pole-sized clumps, and large trees. These growth forms exemplify ecological and management tradeoffs. For example, shrubby forms provide browse and cover yet produce few acorns, while larger oaks supply more acorns but offer little accessible browse or cover near the ground. Large oaks can be encouraged by thinning competing trees and protecting existing large stems from damage by prescribed fire or unauthorized fuelwood harvest. Pole-sized clumps may develop from thickets through time by self-thinning. Mechanically thinning within clumps may accelerate growth of remaining stems, depending on resource allocation within clones. Burning or cutting to stimulate sprouting sustains shrub-thicket forms.
Source: USDA Forest Service Research Notes