Effects of fire on the canopy cover of grasses (Case study: Semi Steppe Rangelands of Kordan)

Many natural fires occur in arid and semi arid rangelands and may result in destruction of desirable forage as well as soil erosion, which eventually will lead to great environmental and financial losses. To study the effects of fire on annual and perennial grasses, a research project was carried out in semi steppe rangelands of Kordan, located in southern Alborz Mountain. A completely randomized block design was used with two treatments (control and burned rangelands) and 20 replications (quadrates) for three years (2008-2010). Vegetation of the studied area (control and burned rangelands) was examined using transects and quadrates in the first spring season after fire with one year intervals for three years of research. In each quadrate, the percentage of canopy cover was measured. Statistical analysis was performed through a factorial experimental design and means comparisons were done by Duncan's test. The results showed that in the first and second year of the study, the presence of perennial grasses was more in control area with no significant difference while in the third year, their presence was equal in both studied area. On the other hand, our results indicated that fire had a positive effect on the presence of annual grasses (p<0.99) and the differences between years and also between the studied areas were significant.