U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska
Date of this Version
10-1-2005
Abstract
The Post Oak Savannah Ecological Region in Texas was once an open grassland savannah maintained by periodic fires. The Post Oak Savannah can support mid- and tall grasses, such as little bluestem, indiangrass, Texas wintergrass, and purpletop. Today, the savannahs have been replaced by oak woodlands with dense yaupon (Ilex vomitoria) understories that limit grass and forb production and species diversity (Fig. 1). Restriction of fires in conjunction with poor grazing management and periodic droughts are often credited for the dense thickets that occur in the Post Oak Savannah.
Yaupon is a native component of the Post Oak Savannah and is a slow-growing and erect evergreen shrub found in both open areas and in the forest understory. It can form dense thickets from its multistemmed base and reach 26 feet in height. Yaupon growth begins in March and continues through October if soil water is sufficient and grows best on sites with sandy soils and permeable subsoils. Yaupon growing in open areas tends to produce high fruit yields during alternate years. It also reproduces asexually by root or basal crown sprouting.
Yaupon is easily top-killed by burning, but the plant sprouts from the base, resulting in low mortality. Most burning in the region occurs during winter, which provides the safest conditions for burning. However, winter burning favors forbs and reduces grass, which may be desirable for wildlife habitat but detrimental for livestock grazing. A management plan that incorporates only winter burning usually results in fine-fuel loads dominated by forbs, promoting patchy, lower temperature burns in the future. Yaupon thrives under these conditions.
Comments
Published in Rangelands.