Study On Characteristics Of The Water Consumption For Transpiration Of Pinus Tabulaeformis Carr. Plantation Of Daqing Mountain

The temporal and spatial variation of water consumption for transpiration and the influence factors on it for 30a Pinus tabulaeformis Carr. plantation were researched in Guluban and Kuisu tested areas in Daqing mountain in growth seasons from 2005 to 2006. The main results showed as follows:(1)The sap flow velocity in different radial depths of stem of 30a P. tabulaeformis indicated the position of the greatest velocity located 3cm below cambium (the relative position was 0.45～0.50), and the sap flow velocity hadn't obvious difference between north and south of stem. Using sap flow velocity and the breast diameter could calculate the water consumption of the stand.(2) The daily course curve for leaf transpiration of P. tabulaeformis had two types which showed the one peak and the double peaks and the maxima of leaf transpiration were in 10:00～14:00, while the daily course curve for the sap flow velocity generally presented the single peak that could be in night or in day. The leaf transpiration was effected obviously by the solar radiation intensity, air temperature and saturation vapor deficit, and besides them the sap flow velocity of stem had the effected factors which were the 20cm soil temperature, 20-60cm soil water content and stand density.(3) The water consumption for transpiration in the stand increased as the stand density increased, and the relationship curve between them can be showed as"S". Based on the critical of the curve the best and the maximum density of the P. tabulaeformi plantation in Daqing mountain could be obtained, and they were respectively 1869 stocks/ha and 2958 stocks/ha for Guluban tested area and respectively 1457 stocks/ha and 2449 stocks/ha for KuiSu tested area. The results could be the basis on the cultivation and the management of P. tabulaeformis plantation in the former of Daqing mountain and the indexes which were used to evaluate the stabilization of forest vegetation, and the results had greatly the theoretic and practical value for vegetation construction in this area.