An Evaluation of the Effect of Controlled Firing on Plant

Controlled fire is one of the management practices for improving the composition of plant cover in grasslands. It causes the omit ion of invader shrubs and prevents natural regeneration of unpalatable species. Finally regeneration of palatable plants, due to controlled firing, causes to produce reasonably sufficient forage. The fire accident, that occurred in enclosures of Sardul in Khalkhal in summer of 1998, caused the change of species composition in 3 hectares of the in and out of enclosure lands. In this study change of the species composition and canopy covering were studied following firing operations and while using Quadrate and Transects studied before. The obtained results of the spring 1998 were compared with the previously obtained data. The results indicated shrubs had been reduced from 24.81% to 2%, but perennial grasses increased from 51.97% to 80.63%. By a comparison of percentages, we can conclude that percentage of total plant covering has been decreased. Results also indicated an increase in plant percentage in Class I and a decrease of plant percentage in Class III. As a matter of fact, decrease in quantity of plant covering was temporary while, quality was shown to improve. Regeneration of the fired shrubs and perennial grasses was studied again in 2002. Results indicate that about 30% of shrubs (Astragalus aureus) and 100% of perennial grasses (Bromus tomentelus, Festuca ovina) had been regenerated and total plant covering had been increased to 64.5% Thus it can be concluded that under conditions where soil erosion is not a constraint , eliminating on aggressive spiny plants causes improvement in and development of perennial grasses.