资源环境科技发展态势分析平台

The National Forests and Grasslands in Texas (NFGT) adopted a standardized methodology to collect vegetation data in regards to both short-term and long-term effects of their prescribed fire regimes in Texas National Forests. Using this methodology, 24 research plots were installed in six unique forest cover/monitoring types in East Texas on the Sam Houston, Davy Crockett, and Angelina/Sabine National Forests. Each forest has defined objectives and target goals based on forest composition and cover type. The effectiveness of existing burn regimes and prescriptions was analyzed using data collected between 2015 and 2018 and comparing outcomes to the ecosystem-specific objectives outlined by NFGT. Ecosystem-specific objectives include parameters regarding fuel loads, litter depth, percent herbaceous cover, and understory woody stem density. Under current burn practices, the majority (85%) of objectives are not being met. Our findings suggest there is need to review or modify existing definitions and verify if current objectives are realistically achievable. Linear curve predictive models display a strong correlation between overstory density and litter weight. The models illustrate deleterious effects on herbaceous species composition from the encroachment of woody stems, as well as the benefits of frequent prescribed burns for improving herbaceous composition while reducing understory woody stem intrusion. Recommendations include altering current burn seasons and ignition patterns to be more analogous to historical standards, as well as reducing overstory tree basal area to more effectively obtain desired stand conditions and meet the defined ecosystem-specific objectives.