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Accueil du site → Projets de développement → Projets de recherche pour le Développement → 2002 → ECOLOGY, RESTORATION, AND THE ROLE OF FIRE IN WESTERN JUNIPER WOODLANDS AND SAGEBRUSH STEPPE

United States Department of Agriculture (USDA) 2002

ECOLOGY, RESTORATION, AND THE ROLE OF FIRE IN WESTERN JUNIPER WOODLANDS AND SAGEBRUSH STEPPE

Fire Juniper Woodlands Sagebrush Steppe

United States Department of Agriculture (USDA) Research, Education & Economics Information System (REEIS)

Titre : ECOLOGY, RESTORATION, AND THE ROLE OF FIRE IN WESTERN JUNIPER WOODLANDS AND SAGEBRUSH STEPPE

Identification : ORE00113

Pays : Etats Unis

Durée : Jul 1, 2002 à Sep 30, 2008

Mots clés : juniperus occidentalis artemisia fire history fire old growth stands wildfire woodlands forest ecology restoration grasslands plant ecology fire management range management wildlife ecosystem management structure productivity botanical composition plant communities community structure guidelines classification disturbed areas fuel

Partenaire : OREGON STATE UNIVERSITY CORVALLIS,OR 97331

Objectifs
Objective : Improve our understanding of the functioning of sagebrush and juniper ecosystems and provide applied information that can be used to develop restoration strategies in the northern Intermountain Region. Subobjective 1. Describe and assess the effects of juniper encroachment and juniper control treatments on plant composition, structure, and productivity across different plant associations and sub-associations in upland and riparian plant communities. Subobjective 2. Assess the effects of fire on plant cover, density, and composition over time across a variety of sagebrush communities and conditions. Subobjective 3. Define presettlement fire regimes (fire return intervals and intensity) and their affect on plant community structure and composition for several sagebrush plant associations in the Intermountain Region. Subobjective 4. Develop a classification system and guide for identifying old growth western juniper woodlands

Descriptif
Subobjective 1. Plant succession during woodland expansion and following various disturbance treatments including fire, cutting, and slash treatments will be evaluated in both time and space among different sagebrush plant sub-associations. Parameters measured include : (1) tree cover, density, height, and canopy diameters (2) shrub cover and density, (3) ground cover of different functional groups (bare ground, rock, litter, biological soil crusts and mosses, shrubs, perennial grasses, annual grasses, perennial forbs, and annual forbs), and (4) nested frequency of herbaceous species. The line intercept technique is used to measure tree and shrub cover. Subobjective 2. Plant community response to fire will be evaluated across the big sagebrush and low sagebrush cover types across the study area. Plant succession following various fires will be evaluated in both time and space. Parameters used to evaluate community level response are described in objective 1. Shrub age will be measured to evaluate the chronology of shrub establishment following fire. Twenty to 30 samples will be collected in each macro plot below the crown along the 60 m transects. Samples will be prepared and rings counted in the laboratory. Individual plant response to fire will be measured before and after fire for several key grass and for species. Parameters measured on perennial grasses are crown area and % live crown area, total live shoot density (#/cm2), reproductive shoot density, and aboveground standing crop per unit crown area and mortality. Parameters measured on perennial forbs are volume, weight, mortality, and reproductive effort. Subobjective 3. Presettlement fire regimes will be described using fire scar and charred presettlement wood were available. Sample sites will be selected opportunistically. We reconnaissance large areas for presettlement ponderosa pine trees associated with mountain big sagebrush steppe communities. Fire frequency, fire interval variability, and season will be determined for each cluster of trees across the region. Reconstructing presettlement plant communities - will be determined by integrating mean fire return intervals with rates of shrub and herbaceous establishment and expansion following fire for different plant associations. Subobjective 4. Structure and chronology of old growth woodlands will be described throughout the range of western juniper using an adopted version of West et al. (1998). Categories developed for the classification are : Series - dominant tree, SubSeries - georegion, Association - dominant shrub, SubAssociation - dominant grass, Site Type - soil and topography. Plant species composition, soils, landform, and various site parameters will be measured for different stands across the region where western juniper is found. Macro-plots will be sorted into species groups by developing association tables using PCORD. Multivariate and regression analyses relating physical features with plant composition and structure will also aid in developing plant community types

Présentation : USDA

Page publiée le 8 décembre 2015, mise à jour le 30 octobre 2017