Application of regression model for estimating gum tracaganth production in Astragalus gossypinus

Unsuitable utilization of Astragalus gosypinus in addition to wrong gum tracaganth extraction are the main reasons of mentioned plants habitat destruction due to remarkable medicinal and industrial values of gum tracaganth as the main minor product of Iranian rangelands. For this، it is of high importance to find and introduce correct methods of gum tracaganth extractiorrent research has been conducted to find the relations between height، basal area، canopy cover and gum tracaganth extraction amount in Astragalus gosypinus. To do this، regression relationships were used to determine above mentioned interrelations and find an acceptable model for gum tracaganth extraction. Results show that there is a good correlation between basal area and canopy cover percentage of Astragalus gosypinus، in different times. despite this high correlation، only changes of canopy cover percentage in different times is detrimental for gum tracaganth amount extraction، that is، more cover percentage leads to higher amounts of gum tracaganth. If the aim is to estimate gum tracaganth extraction rate during a year، yearly analysis model will be of benefit but when gum tracaganth extraction in a short given time is objected using suggested model for the same period will be better. In yearly analysis basal area shows the highest correlation with gum tracaganth extraction rate، while in first time (July)، second time (August)، third time (August) and fourth time (September) analysis models، canopy cover diameter، basal area، canopy cover diameter. Percentage show the highest relationship with gum tracaganth extraction amount، respectively in other word، based on each extraction time model and regarding the obtained relationship it will be possible to have an acceptable estimation of gum tracaganth extraction rate with no damage to this valuable plant.