Sapling density in burned areas was low at the start ( 1.8 m tall but 5.0 cm dbh. In burned areas it increased during the first few years, but then remained constant until declining during the study’s last year. In 1996, shrub density was similar between burned and unburned areas. Seedling density in burned areas increased rapidly between 19, at which time it was about the same between burned and unburned areas. High numbers of oak stump sprouts suggest that burned areas will develop into woodlands in the future. However, by study’s end in 2005, burned areas became more similar to unburned ones, except for a lack of Ashe juniper. Oak dominance in burned areas, measured as a percentage of basal area, was significantly lower than in unburned areas across all soil types. Densities of Ashe juniper in burned areas were very low throughout the study period. Researchers observed low relative bundance of woody species and basal reas in the burned areas. In the tudy’s final year, stem density and basal area were calculated by species for Ashe uniper, post oak, shin oak, and Texas red ak. Stem density and basal area were calculated for four categories of woody plants: seedlings, including resprouts (0.3 but 1.8 m tall but 5.0 cm dbh). Data were collected annually from 1996 to 2002, and in 2005. Control transects were placed in unburned mature oak-juniper woodlands on the same soils. Within a few months after the fire, permanent vegetation monitoring transects were established in burned areas of former golden-cheeked warbler habitat, randomly located on all three soil types. Inset: golden-cheeked warbler (Photo: Gil Eckrich). Background: unburned Ashe juniper-oak woodland (Photo: Charlotte Reemts). Crown fires in these oak-juniper woodlands included more than 2,000 ha of golden cheeked warbler habitat, and affected more than 4,000 ha of woodlands overall. In February 1996, following a year-long drought and during a period of high temperatures and strong winds, military exercises at Fort Hood sparked grass fires that spread into adjoining woodlands and burned for more than two weeks. Post oak dominates the deeper Evant soil type shin oak dominates the shallow, flat Eckrant soil type and Texas red oak dominates the sloped Real soil type. Communities vary according to slope, moisture levels, fire frequency, and especially the soil type. Unlike oaks, Ashe juniper does not resprout after being top-killed by fire. In the region’s oak-juniper woodlands, Ashe juniper can co-occur with live oak (Q.
The latter hosts one of the largest known breeding populations of the golden-cheeked warbler. A limestone area with steep-sided mesas and wide valleys, this area historically supported communities ranging from mixed-grass prairies to floodplain forests, including oak shrublands, oak savannas, and oak juniper woodlands. The study occurred on the Fort Hood Military Reservation, located at the intersection of the Cross Timbers Southern Tallgrass Prairie and the Edwards Plateau ecoregions. Of particular interest was determining the length of time needed for reestablishment of Ashe juniper trees, a required habitat component for the federally endangered golden-cheeked warbler (Dendroica chrysoparia), and how it varied across three locally common soil types: Evant silty clay (Evant) Eckrant-rock outcrop complex (Eckrant) and Real-rock outcrop complex (Real). In this study, researchers investigated plant community changes over nearly a decade following a crown fire in mature oak-Ashe juniper woodlands (Quercus spp.-Juniperus ashei) of central Texas.
RESEARCH BRIEF 26 CLICK HERE TO DOWNLOAD AS PDF MANAGEMENT IMPLICATIONSĪshe juniper, a critical component of golden-cheeked warbler habitat, is a slow-growing species that may require decades to recover following a crown fire.ĭue to the paucity of available golden-cheeked warbler habitat, crown fires in mature oak-juniper woodlands should be avoided.