|Ares, A - WEYERHAEUSER COMPANY|
Submitted to: Agroforestry Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 17, 2006
Publication Date: September 19, 2006
Citation: Burner, D.M., Pote, D.H., Ares, A. 2006. Foliar and shoot allometry of pollarded black locust, Robinia pseudoacacia L. Agroforestry Systems. 68(1):37-42. Interpretive Summary: Producers have been slow to adopt black locust for livestock browse because of unfamiliarity with cultural practices associated with shrubs managed for grazing. Our objectives were to develop equations describing the relationship of leaf and stem yield to stem diameter as affected by cultural practice (harvest date, stem clipping, and phosphorus fertilization). Stem diameter was strongly predictive of stem yield independent of cultural practice, while predictions of leaf yield were affected by harvest date. These equations provide producers with a convenient, easy alternative to measuring yield of black locust
Technical Abstract: Climatic constraints in summer can cause forage deficits in west central Arkansas, necessitating expensive, supplemental hay feeding. Black locust (Robinia pseudoacacia L.) produces high quality browse, but the temporal distribution of foliage has not been adequately tested. Our objective was to determine effects of harvest date, pollard height (stems cut at 5 , 50 , and 100 cm above ground), and fertilization (0 and 600 kg P/ha/yr) on foliar and shoot allometry of black locust. The test was conducted on a naturally regenerated 2 yr old black locust stand (4400 stems/ha). Basal shoot diameter and foliar yield were measured monthly from June to October in 2002 and 2003. Yield (Y) of foliar and shoot dry matter was best estimated from basal shoot diameter (D) by the function Y = aD**b, with regression explaining > 95% of variance. Allometry of foliar yield was affected by harvest date, increasing at a greater rate with D in September than in June or July, but not by pollard height or P fertilization. Foliar yield was predicted best by month specific equations in June and July, while equations combined across harvests could be used later in the season. Allometry of shoot dry matter was unaffected by cultural practice (harvest date, pollard height, or P fertilization). These equations could be used as a first approximation of foliar and shoot yield for pollarded black locust.