DYNAMIC OF ORGANIC-MATTER IN FORESTS SUBJECT TO A MEDITERRANEAN SEMIARID CLIMATE IN THE DUERO BASIN (SPAIN) - LITTER PRODUCTION

The production of litter was determined in three forest ecosystems inthe Duero basin (Spain): a climax oak forest of Quercus rotundifolia andtwo repopulated pine forests of Pinus pinea and P. pinaster.The time-course of the litter fall both from the different organs of thetrees and as a total was followed. The mean total production of litterin the oak forest was 2,320 kg/ha-1/yr-1, slightly lower than thesituation in the P. pinea pine forest, which was 2,400 kg/ha-1/yr-1 andhigher than that of the P. pinaster pine forest 1,728 kg/ha-1/yr-1; theleaves and needles account for most of this total production (78, 89 and96%, respectively).