A. San Miguel

Subterranean biomass of Quercus coccifera L. shrublands in Eastern Spain

Se ha estimado la biomasa subterranea de los matorrales de Quercus coccifera en la provincia de Valencia (Espana). El muestreo se realizo en ocho matorrales de coscoja con estructuras aereas de diferente edad y supuso la excavacion de una superficie de 24 m2. La biomasa subterranea total oscilo entre 34 y 81 t/ha (M.S.), con una media de 53 t/ha, lo que confirma el importante papel edafogenesico, protector y estabilizador de estas comunidades. La biomasa subterranea se concentra en los 45 cm superficiales del suelo, y la extension superficial de las raices supera en todos los casos a la de los brotes aereos. La relacion biomasa subterranea - biomasa aerea, muy alta, oscila entre 2,61 y 4,73, y es superior a la de otros ecosistemas forestales mediterraneos.

Diagnosis of genuinity and suitability for Quercus coccifera in Spain

This paper presents the analysis of phytoclimatic genuinity and suitability for Quercus coccifera L., according to the methodology developed by Allue Andrade. 67 thermopluviometric stations where Quercus coccifera shrubland is the climax vegetation were used for that purpose. The predominant climate of the species belong to the phytoclimatic subtype IV1. The coincidence between hierarchies deriving from geographical distribution and ecological conditions is emphasized. Phytoclimatic preferences of Mediterranean Quercus (Q. ilex, Q. suber and Q. coccifera ) show a high degree of complementarity. The aptitude of each climatic station is established regarding the phytoclimatic ambit of kermes oak, and a taxonomic key is presented with the aim of determining the suitability of the species for a concrete locality (climatic station).

Structure, evolution and yield of Quercus pyrenaica Willd. coppices in Central Spain

Quercus pyrenaica Willd. is a submediterranean broadleaved semi-deciduous oak whose main world area is located in the Iberan peninsula. In Spain, its current area is about 600,000 ha. The traditional use of Q. pyrenaica woodlands has been firewood growing and grazing due to its great ability to resprout from stumps and roots after cutting. Therefore, most stands are currently coppices, with or without standards. In Central Spain, where this preliminary study has been carried out, it occurs mostly on hillsides and foothills.

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

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.