Effect of fire on density and vegetation composition in wooded rangelands of Vanon Khalkhal region

Fire is one of the dynamic and effective factors on forest and rangeland ecosystems so that the evaluation and monitoring of its effects has an important role in planning and management of natural ecosystems. To determine the short-term effect of fire on vegetation changes, a burned area and a homogeneous area without fire (control) in Vanon Khalkhal region were selected. Four transects with length of 200 m were established using systematically random method and 10 plots of the 1 m2 were installed on each transect at a distance of 20 m. Vegetation sampling was done for 3 years in 2018, 2019, and 2020. The results showed that there was a significant difference in density, forage production and canopy cover percentage during the studied years. The average plant density in burned area in 2018, 2019 and 2020 years were 25.05, 31.65 and 33.91 N/m2, respectively and in the control area at the same time were 17.74, 18.17 and 22.84 N/m2, respectively. Forbs decreased from 40.1% of canopy in the control area to 23.4% in the burned area, while grasses increased from 28.2% in the control area to 59.4% in the burned area. Therefore, the fire has been effective in increasing grasses and reducing forbs. In general, Bromus tomentellus, Festuca ovina, Agropyron repensis and Agropyrun trichophorum due to their fire resistant and presence in the burned area are recommended for the rehabilitation of burned areas.