Ecohydrological functions of canopy are significantly influenced by landuse change. This study was conducted across four current landuse types within the Gale-gol watershed (Khorramabad, Lorestan), including semi-natural forest, disturbed forest, forest farming, and orchards established on converted Brant's oak (Quercus brantii Lindl.) stands. Field measurements of precipitation (P) and T were made over a period of 12 months starting from January 2013. Four rain collectors were placed in an

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... area adjacent to each of the landuse types to measure P. In addition, 12 trees were randomly chosen for each of the landuses and four throughfall collectors were installed under the canopy of each tree to measure T. Tree parameters were measured using 15 sample plots of 2500 m2 for each landuse type. I and S were estimated using P and T measured data. The results showed a rate of annual P = 526.3 mm. Furthermore, ANOVA results revealed an outstanding difference between T and I across four investigated landuses including semi-natural forest (T = 353.9, I=172.4 mm), disturbed forest (T = 403.0, I = 123.4 mm), forest farming (T = 429.8, I = 96.5 mm), and orchards (T = 418.3, I = 108.0 mm) at 5 percent significance level. The ecohydrological functions of canopy in semi-natural forest (with 60% canopy and a density of 212 tree/ha) were associated with the minimum negative effects when compared to forest farming (with 26% canopy and a density of 144 tree/ha) and disturbed forest (with 11% canopy and a density of 52 tree/ha). The components of Linear Regression models also proved that the I estimated by P (0.794 < r2 < 0.856) is more accurate than DBH (0.654 < r2 < 0.837). The findings of this study are concluded to improve the existing understanding of ecohydrological canopy function. This function can be implemented as a part of forest resources management to regulate the relationship between canopy and water resources cycle.