Abstract
On a poor site in northern California, a mature brushfield was treated in various ways that left initial density categories of light, medium, and heavy shrubs. Density, foliar cover, and height of seven shrub species (alone and combined) and ponderosa pine seedlings in these categories were quantified from 1967 through 1978. Heretofore, density and development data for five of the seven shrub species were unavailable. From the beginning to the end of the study, vegetation in the plantation was subjected to damage from insects, disease, snow, wind cupping, winterburn, a parasitic vine (dodder), and application of an herbicide. In general, greenleaf manzanita, which was the most abundant shrub species in the study area, prospered, as did bitter cherry, choke-cherry, and Fremont silk tassel; huckleberry oak endured; and bush chinquapin and mountain whitethorn declined. Among shrub categories at the end of the study in 1978, the density of combined shrubs ranged from 19,800 to 8,300 plants per acre; foliar cover from 14,000 ft2 to 8,900 ft2 per acre, and height from 2.8 to 2.5 feet. Ponderosa pine seedlings began to recover from damage in 1974, and because upturned branches had replaced dead and damaged tops, seedling form improved. Pine seedlings growing with a low amount of competition were significantly taller and had more foliar cover than counterparts with heavy competition in 1974, a finding that continued for foliar cover through 1978
Keywords
competition,
northern California,
plant community development,
ponderosa pine seedlings,
poor site,
silviculture
Citation
McDonald, Philip M. 2003. Development of a Mixed-Shrub-Planted Ponderosa Pine Communicty on a Poor Site After Site Preparation and Release. Res. Paper PSW-RP-248. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; 28 p.
