Response of Young Ponderosa Pines, Shrubs, and Ferns to Three Release Treatments

Abstract

Abstract One-year-old Sierra chinkapin (Castanopsis sempervirens) sprouts, greenleaf manzanita (Arctostaphylos patula var. platyphylla) seedlings, and new fronds of bracken fern (Pteridium aquilinum var. pubescens), present in a 1-yr-old ponderosa pine (Pinus ponderosa var. ponderosa) plantation in northern California, were treated once with one of three herbicides (Velpar L, Escort, and Garlon 4) in fall 1986 and spring 1987 and their density and development compared among treatments and to a control. After 6 growing seasons, chinkapin sprouts in the control averaged more than 16,000 per acre, manzanita seedlings over 19,000, and bracken ferns more than 13,000 per acre. After 6 growing seasons, mean ponderosa pine diameter ranged from 2.03 in. in the Velpar treatment to 1.28 in. in the control. Cover of combined shrubs, also after six seasons, was about 3% with Velpar, 7% with Garlon, 20% with Escort, and 51% in the control. Bracken fern cover was greatest (13%) where foliage-active Garlon reduced competing shrubs, and least in the soil-active Velpar treatment (2%) and the control (3%), where heavy competition from shrubs precluded establishment. West. J. Appl. For. 9(1):24-28.