The historical vegetative aspect of Fort Davis National Historic Site, Texas

Nelson, James

As a basis for formulating a vegetative management program at Fort Davis National Historic Site, Texas, a study was undertaken in the summer of 1981 to determine the historic vegetation scene of the mid to late 19th century period. The vegetative scene in 19 existing historic photographs was compared to that in modern photographs taken in the same locations. In addition to photographic analysis, use was made of botanical information in the historic literature, and data from on-site vegetation sampling was used to compare the present species composition with that of potential climax as described by the Soil Conservation Service range condition guidelines. Present species composition indicates a moderate departure from climax due to an increase of blude grama (Bouteloua gracilis) and several brush species - mostly catclaw mimosa (Mimosa biunicifera). 60-70% of the species reported in the historical literature are listed today on the present species lists for Fort Davis National Historic Site and the Davis Mountains State Park. Photographic analysis indicates that the basic distribution of major vegetation types today is very similar to that of 100 years ago, with some notable exceptions. Grassland areas have decreased by about 7% while brush areas have increased. Brush (catclaw) density has increased from ligh to heavy concentrations. Mesquite, not mentioned in the historic literature or noticeable in historic photos, is prominent today. In some areas tree density (oak and juniper) has increased (on cliffs) while in others it has decreased (flat-lands). Several historic trees were identified. Management recommendations were made to preserve historic trees and to selectively reduce brush by physical and/or chemical means.