| In this study, we applied the thermal diffusion technique to measure the sap flow of the Chinese fir in the second-generation Chinese Fir Plantation station for a long time. In the experiments, We corrected Granier original formula and analyzed the diurnal variation of Chinese fir sap flow velocity and seasonal variation to study the relationship between Chinese fir sap flow velocity and environmental factors, and establishment the Chinese fir flow and environmental factors in multivariate regression equations, obtained the yearly transpiration of Chinese fir plots. Further analysis of the relationship between the diameter and Chinese fir sapwood area, as well as the relationship between diameter and transpiration of Chinese fir. Lastly, according to the annual volume growth of Chinese fir obtained the trunk wood stage fir volume growth of water consumption units. The main results as follows:(1)The Chinese fir’s Granier correction formula (Fd= 0.0114*K0.8919) is different from other diffuse porous wood and ring porous wood species, the stem sap flow rate from the original formula as high as 41.72% undervalued, and therefore the application of Chinese fir Granier formula for measuring flow, it is necessary to correct Granier formula.(2) Chinese fir’s day sap flow generally beginning approximately 1.5h after radiation started, and saturation deficit began to rise closer to the time, peak time and total radiation correlation coefficient representing the peak point well, different seasons have different delays. Seasonal differences in the flow rate of the larger Chinese fir, in descending order of summer> spring> autumn> winter. Maximum flow velocity in summer can reach 2 times the maximum flow rate of fall, winter, five times the maximum flow rate. The maximum flow rate of the spring is relatively close to the maximum flow rate of the summer, indicating a good spring rain and hot sunny conditions, flow rates up to the level close to the maximum.(3) In trunk wood stage plantations, the DBH and sapwood area’s relationship is:S = 0.755*D1.8777. The differences between Chinese fir flow north-south orientation is extremely small, in the same stand, the larger the diameter of the larger trees plot transpiration contribution. DBH and the total amount of sap flow’s relationship formula is Yi= 1359* D2.7005,DBH and the per unit area of sap flow’s relationship formula is Y2 = 685.74*D+6133.7.(4) Monthly fir sap flow in June, July and August reach a larger value, the maximum appeared in August, the minimum appeared in December. Based on daily flow rate variation of Chinese fir, Chinese fir’s growth cycle will be divided into five stages: dormancy, bud stage, early growth, growing vigorously, growth stage, and this is similar to Yu Xintuo based on phenology and growth morphology to division fir growing, but in generally the growth cycle of Huitong Chinese fir compared to ahead 1-2 weeks. The volume growth of Chinese fir in trunk wood stage have two peak periods, appeared in May and August, the volatility curve and change is consistent to its total photosynthetic active radiation.(5) In the influence of environmental factors and flow rate, play the major role are the saturated and photosynthetically active radiation. The regression equation is:Sv= 0.0005208+0.0007380* E+0.0000059* P. The regression equation calculated by the annual flow of liquid and fluid flow measurement in comparison, a difference of only 0.00727% of the actual amount. DBH considered as a impact on the flow rate, the diameter at breast height as the other relevant factors, derived regression equation:Sv=-0.003383+0.000215*Ddbh+0.0008014*E+0.00000788*P.(6) In 2015,20-year-old Chinese fir forest transpiration is 419.59mm, volume growth transpiration water consumption 207.75t/m3. |
PDF Full Text Request