以黑龙江帽儿山森林生态定位研究站42年生红松人工林为研究对象,选择有代表性的优势木、中等木和被压木各3株,2004年5月29日—10月30日应用热扩散技术对不同径级红松树干液流进行测定,并同步测定相关的主要环境因子。通过生长锥获得不同径级红松边材宽度,建立边材面积与胸径的关系方程A=8.032DBH-46.95(R2=0.82,P<0.001)。结果表明:晴天红松树干液流呈明显的单峰曲线,最大值一般出现在12:00—14:00,且优势木>中等木>被压木;而在阴雨天呈不规则曲线,最大值的出现没有规律,夜间也不同程度地出现液流,且优势木、中等木和被压木之间液流密度的差异缩小。日液流通量随着生长季节的进程基本呈现减小的趋势,且优势木>中等木>被压木。相关分析和逐步回归表明,影响生长季红松树干液流的主要环境因子为蒸汽压亏缺和光合有效辐射。由液流通量和边材面积的推算获得,被测红松人工林边材面积为89436.94cm2·hm-2,生长季蒸腾耗水量为678.95t·hm-2;其中优势木、中等木和被压木分别占整个林分耗水量的54.83%、35.68%和9.48%。优势木、中等木和被压木在生长季的日总蒸腾量分别为0.06～1.42、0.014～0.83和0.017～0.25t。
In a 42-year-old Pinus koraiensis plantation in Maoershan Forest Ecosystem Research Station,3 representative trees each of dominant,intermediate and suppressed trees were selected and sap flux density was measured using thermal dissipation probe (TDP) method from May 29 to October 30,2004. Meanwhile,the related environmental factors,including air temperature,air relative humidity,soil relative humidity,photosynthetic active radiation (PAR) and global radiation were simultaneously measured with various sensors attached to Campbell Scientific dataloggers (CR23X). The sapwood thickness of another 40 trees selected based on diameter distribution in the stand was measured with tree coring method for developing the relationship between sapwood area and diameter at breast height (DBH) A=8.032DBH-46.95(R2=0.82,P<0.001). The result showed that the sapflow density in a sunny day exhibited a mono-peak diurnal pattern with its maximum occurring between 12:00 and 14:00,while that in cloudy and rainy days had no clear diurnal pattern with irregular peak values and even had night-time sapflow signals. In sunny days,the daily maximum sapflow density was in an order of dominant > intermediate > suppressed trees. However,the difference among the tree crown classes decreased in cloudy or rainy days. There was an obvious growing seasonal pattern in daily sapflow flux,in which the daily sapflow flux showed a magnitude order of dominant > intermediate > suppressed trees and declined with the growing season processing. Correlation and stepwise regression analyses indicated that the main environmental factors influencing sapflow density in the growing season were vapor pressure deficit and photosynthetic active radiation. Scaled up from sapflow measurements and sapwood area (89 436.94 cm2·hm-2 in total) in the stand,the total transpiration from the Korean pine stand during the growing season was 678.95 t·hm-2 ,of which the dominant,intermediate and suppressed trees accounted for 54.83%,35.68% and 9.48%,respectively. The mean daily transpiration of the dominant,intermediate and suppressed trees was 0.06～1.42 t,0.014～0.83 t and 0.017～0.25 t,respectively.
全 文 ：