Meteorological parameters and evapotranspiration affecting the Zagros forests decline in Lorestan province

Decline of Zagros forest ecosystems assumes to be a multi-dimensional, complicated, and national problem so that it is rather difficult to find a solution due to multiplicity of affecting parameters. The goal of this research, along with examination of the hypothesis of linking forests decline and meteorological parameters, was to reveal the connection of precipitation, air temperature, humidity, and wind speed as well as reference evapotranspiration with forest decline. Meteorological data recorded by nine synoptic stations scattering in Lorestan province and four stations positioned away in neighboring provinces were employed. Long-term trends of meteorological parameters were liken with changes in meteorological data since 2000, when forests decline in the Zagros region was commenced as stated by Iran's forest, range and watershed organization. Mapping forest decline were grouped in five classes. Apart from Pol-e-Dokhtar, precipitation data proposed a noticeable reduction since 2000 in contradiction of rising air temperature. Reference evapotranspiration, as well, showed an increasing trend in most stations. Precipitation (R2:0.779), air temperature (R2:0.776), relative humidity (R2:0.602), and reference evapotranspiration (R2:0.670) were significantly connected with forests decline classes (P‹0.01). This research confirmed that unexpected changes in meteorological parameters and reference evapotranspiration due to world climate changes was correlated with Zagros forests decline.