Phenology of Quercus ithaburensis with emphasis on the effect of fire

Observations on the phenology of Quercus ithaburensis were carried out during three consecutive years in Yahudia Nature Reserve, Israel. Bud-break occurred mostly in February with minor bud breaks in March-April, May and September-October. Trees shed leaves in October through January with a peak in December-January, but even during these months at least 10% of the trees remained evergreen. Branch growth took place during February-April. Shedding of 1-year old branches was recorded in half of the observations, accompanied by the formation of abscission tissue. Acorns generally began to ripen in November and shedding extended from December until January. The percentage of acorns attaining full ripeness varied considerably from branch to branch and from year to year, reaching approx. 20% of the number of acorns found in May. Ripe acorns appeared exclusively on 2-year old branches. The degree of fire damage to trees greatly depended on the intensity of the fire, which in turn depended on weather conditions, quantity of drypasture vegetation, and the location of the tree relative to cairns.Most trees were located within cairns. which constituted insulation belts, as no herbaceous vegetation grows on them. The effect of grazing intensity was decisive to the extent that fire damaged trees. Reduction of the bulk of dry pasture vegetation, affected the number of trees harmed, both as to their revival and their re-budding potential.Heavy grazing reduced to nearly half the number of trees suffering damage. After an early summer fire, budding was monitored, but not after a late summer fire. (C) 1999 Elsevier Science B.V. [ABSTRACT FROM AUTHOR]