Distribution of rain fall in pure Tamarix arceuthoides stand in the riparian forests

Arid and semi-arid ecosystems cover about one-third of the world's dryland and is one of the most vulnerable ecosystems due to periodic droughts and increased use of water resources. This study aimed to evaluate the distribution of rain (stemflow, Interception loss and throughfall) in the Tamarix arceuthoides over a period of rainfall (December 2015 to April 2016) in the riparian forests of Maroon. In order to measure the total rainfall, three plastic collectors were placed in open field and closed to the study stand to collect the gross rain. Tress were divided in three classes based on the tree diameter. Three individual tree were selected in each diameter classes for stemflow measurement. Througfall was calculated using the 50 plastic collectors that were placed 10 m apart in the studied stand. The results showed that the stemflow, throughfall and interception in the fall and growth seasons, are, 3, 62, 35, 2, 53, 45 percent respectively. There was significant positive correlation between gross rain (GR) and interception in growing and non-growing seasons. Furthermore, increasing in the total rainfall values, will result in the stemflow, throughfall and rainfall interception increment. But the interception had reduction trend by increasing the gross rainfall. Our result indicated that increasing in tree diameter can result in stemflow reduction. Our result showed that about 45 percent of precipitation will be out of reach by forest floor and return to the atmosphere by evaporation.