Type conversion of a 12 acre plot of chamise chaparral to grassland in the Mud Flat region of the San Bernardino National Forest, San Gorgonio District, California, was completed in 1967.
The conversion was accomplished following standard type conversion techniques for chaparral in California and included retention of a mosaic pattern of islands of the original chaparral for the purpose of improving scenic quality and maximizing edge effect. The islands constituted approximately 9 per cent of the total 12 acres and averaged 3800 square feet per island with an average distance measurement between islands of 96 feet.
Brush removal by a D-7 caterpillar was followed by brush pile burning and discing. The last herbicide treatment of the area was in 1969 and consisted of a mixture of 2 pounds per acre of 2,4-D and 2,4,5-T, applied by hand spray. Replanting was by range land drill seeding a mixture of intermediate wheat grass and pubescent wheat grass, at a rate of 6 pounds per acre.
Density per acre and number of shrubs were reduced by 79.7 per cent and 40 per cent respectively, excluding the chaparral islands in the modified plot. The only shrub which became established in the modified plot which was not present in the natural plot was deerweed with a density of 721 per acre.
The predominant physiognomy of the modified plot six years after conversion, even considering survival of some of the shrubs from the original chaparral community, was decidedly that of a bunch grass community. A basal area of 7 per cent for intermediate and pubescent wheat grass together was recorded, which compares favorably with the 11 per cent reported in the literature for a native bunch grass community in California. Intermediate and pubescent wheat grass considered as an aggregate had a frequency of 87.5 per cent and a density per plot of 2.7 bunches.
Although not native to California, the intermediate and pubescent wheat grass species are thriving and helping to form an established grassland community in the type converted chamise chaparral association within the San Bernardino National Forest.
Earl W. Lathrop
Leonard R. Brand
Robert L. Nutter
Jerome T. Light
Master of Arts (MA)
Year Degree Awarded
Date (Title Page)
Library of Congress/MESH Subject Headings
Chaparral ecology -- California -- San Bernardino National Forest
Loma Linda University Libraries
This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.
Rosario, John A., "A Comparison of Vegetation Structure and Composition in Modified and Natural Chaparral" (1973). Loma Linda University Electronic Theses, Dissertations & Projects. 761.
Loma Linda University Electronic Theses and Dissertations
Loma Linda University. Del E. Webb Memorial Library. University Archives