冠层分析仪在板栗冠层光辐射特征研究中的应用

Study on canopy radiation characteristics of Castanea mollissima Bl. by using WinsCanopy 2006a

采用WinsCanopy 2006a冠层分析仪测定燕山地区迁西县23个典型的板栗园115棵板栗树的冠层光辐射参数,通过计算获得光合有效辐射(PAR)透过率与消光系数K,并对各参数进行相关性分析。同时采用LI-3000C叶面积仪测定叶面积指数(LAIdi),与冠层分析仪提供的方法测定的叶面积指数(LAIin)进行相关性比较。结果表明:(1)板栗冠层光辐射参数中,林隙分数、开度和叶面积指数与冠下总辐射和定点因子显著相关,并且不同树体间差异较大,表明林隙分数、开度、叶面积指数对板栗冠层光截获能力影响较大,而平均叶倾角与冠层光辐射其他参数无显著相关性。(2)叶面积指数LAI(Ellips)-Lin与LAIdi呈显著相关,相关系数为0.893(P<0.05),表明采用冠层分析仪提供的LAI(Ellips)-Lin方法测定板栗叶面积指数具有较高的可靠性。(3)PAR透过率和消光系数K的最小值分别达到0.666和0.037,说明板栗冠层光截获能力较强。因此,修剪对板栗冠层结构的调控非常必要,冠层分析仪在板栗冠层光辐射特征研究中的应用前景广阔。

With WinsCanopy 2006a,the canopy light radiation parameters of 115 Chinese chestnut trees were measured in 23 typical orchards in Qianxi county of Yanshan area.Through the calculation,the transmission rate of photosynthetic effective radiation（RPART） and extinction coefficient K were obtained,then the parameters correlations were analized.The leaf area indexes of the tested trees were measured by using LI-3000C leaf area meter.The correlation comparisons between the measured values（ILAC） by LI-3000C and those（ILAIW） by WinsCanopy 2006a were conducted.The results show that（1）the gap fraction,openness and ILA had significant correlation with the total under canopy radiation（TUCR） and fixed site factor,and there were large differences among different trees,which indicate that the gap fraction,openness and ILA had significant influences on the light interception ability,the AML had no significant correlation with other canopy optical radiation parameters;（2）The ILAW had significant relationship with ILAC and the coefficient was 0.893（P 0.05）,it means that the ILAIW had higher reliability;（3）The minimum of extinction coefficient K and RPART were 0.666 and 0.037,respectively,this shows that the light interception ability of Chinese chestnut canopy was strong.Therefore,it is necessary to regulate the Chinese chestnut canopy structure by pruning,and there is a wide application prospect of canopy analyzer in chestnut canopy radiation features study.