Study on Canopy Interception of Fraxinus mandshurica

The relationships between canopy interception of Fraxinus mandshurica Rupr.and rainfall were studied from May to September in 2003 by surveying and statistic methods.The result showed that the canopy interception of Fraxinus mandshurica for rainfall was 68.77 mm,which accounted for 17.41% of total rainfall in the same periods.The rainfall was redistributed by the proportion of penetration 72.50%,interception 17.41% and the stem flow 10.08%;the redistribution of rainfall by canopy could be simulated precisely by the improved Horton model,the canopy rainfall adsorption capacity of Fraxinus mandshurica was 0.84 mm.The parameter which means coefficient of evaporation of canopy regionally was 0.118 3.It was indicated that the curve of forest interception with rainfall marked 3 phase such as descent quickly phase(interception rate more than 19% while rainfall less than 10 mm),descent gradually phase(interception rate is in 19.0%—12.8% while rainfall 10—30 mm)and stable phase(interception rate less than 12.8% while rainfall more than 30 mm),which could explain the relationships of interception with canopy geometry shape characteristics of Fraxinus mandshurica.The stable interception rate was 12.8%.