Pattern of resin dripping under Aleppo pines (Pinus halepensis Mill.) of different crown size

Several studies have explored the role of conifer oleoresins in the defense against herbivores and fungal attacks. However, biotic and abiotic injuries on stem and crown also promote resin fall and its accumulation in the forest floor. No study has explored oleoresins accumulation in the litter and soil layers under the crown: the modification of soil properties after fire is unknown. To quantify the magnitude of resin fall in a Mediterranean uneven-aged forest of Aleppo pine (Pinus halepensis Mill.) the amount and pattern of resin dripping was monthly monitored under large, medium and small crowns. During summer (June-September) occurred 58% to 80% of resin fall. Resin amount decreased significantly from the stem towards the crown border; half of the resin was collected along the West direction, which is the dominant wind direction in the study area. The larger amount of resin collected near the stem of trees with large crown could explain the germination pattern found in burnt soil profile bioessays collected in the same position.