Structure and yield of cork oak (Quercus suber L.) stands in southern Spain

Abstract

On a sample of 12 (1256 m2) square plots and 427 cork oak trees from southern Spanish cork oak stands, variables affecting cork yield and quality have been studied. Results presented in Table 1 show the variation of N (number of trees per ha.), HD (Bark Stripping Height), SD (Bark Stripping Area), PC (Cork Yield), PCM2 (Cork Weight per m2), CB (Cork Thickness), ID (Bark Stripping Intensity) and SPC (Crown Projection Area) with CBC (Circumference at Breast Height Under Cork). Results presented in Table 2 show average figures of the most important variables affecting cork yield and quality for each CBC class and for an average hectare. Cork yield can be precisely estimated through the expression: PC = BA x IDM x PCM2 where BA = Basal Area, IDM = Stand Average Stripping Intensity. PCM2 depends upon site quality and Bark Stripping Rotation Length, but BA and IDM can be modified with silvicultural treatments, thus affecting cork yield. On even-aged stands, PC can be estimated from BA through the expression: PC =124.25 + 433.53 BA for BA ranging frin 4,6 ti 25,37 m2/ha.