Comparative Analysis of Runo and Sediment Yield with a Rainfall Simulator After Experimental Fire

Changes produced in runoff and sediment levels before and after fire and during the revegetation process were examined using a rainfall simulator. The area was burned in an experimental fire, reaching temperatures from 35° to 563° C. Then it was revegetated using different species combinations. Fifteen permanent plots were established in the burnt area (4 treatments and a control replicated three times). Simulated rainfall of 15 mm per 5 min was applied in each treatment. No significant differences were found in sediment yield and runoff between treatments, but greatest runoff was observed to occur immediately after the fire. A significant relationship was found between runoff and woody cover, and a decrease in runoff can be observed as cover increases. The relationship between sediment yields and runoff rates was also positive. The low rates observed during rainfall simulation are due to the effect of natural vegetation rather than revegetation treatments. The high organic matter content also had an influence on the low rates of runoff and sediment.     

The influence of heat and mechanical scarification on the germination capacity of Quercus pyrenaica seeds

The germination capacity of Quercus pyrenaica seeds subjected to different temperatures (60°C, 100°C and 150°C for 1 and 5 minutes) and mechanical scarification was studied. Germination increased after mechanical scarification and heat treatment at 60°C for 1 minute. Germination percentages for the rest of the treatments were lower than those for the control, but statistically significant differences (p < 0.05) were only observed between 150°C for 5 minutes and the other treatments (except for 150°C for 1 minute). These results show that seed germination of Quercus pyrenaica would not be affected by soil temperatures reached during a low intensity fire or by the action of agents which can mechanically damage the external coat.