Contents - ä¸­å›½æ£®æž—ç”Ÿç‰©å¤šæ ·æ€§ç›‘æµ‹ç½‘ç»œ

J For ResFig. 1 Representativehemispherical photographbefore (a) and after (b) use ofPhotoshop to remove stems andbranchesa Original photob Photo after masking of stemsand branchesLAI (branches and stems removed)1.510.50.5 1 1.5Effective LAIFig. 2 Comparison of LAI calculated before and after masking ofstems and brancheseffective LAI changed over time. LAI was maximal onJuly 1 and minimal on November 1. LAI decreasedfrom July 1 to mid-September, albeit slowly. From mid-September to early October, LAI decreased rapidly—theaverage ‘‘true’’ LAI decreased from 5.28 to 3.20, indicatingthat the rate of needle/leaf fall was maximal from mid-September to early October. In July, the ‘‘true’’ LAI westudied ranged from 3.90 to 10.52, with an average of6.69. Figure 3h shows the entire falling period ofeffective LAI versus ‘‘true’’ LAI (R 2 = 0.8351). Themaximum ‘‘true’’ LAI for the entire litter-fall season was10.52, the minimum was 1.79, and the average was 4.79.From July to November, effective LAI underestimated‘‘true’’ LAI by 52.61, 53.65, 57.65, 57.68, 44.80, and58.90 %, respectively, and for the entire litter-fall season,by 53.16 %.Figure 4 shows LAI dynamics of ‘‘true’’ LAI, effectiveLAI, corrected LAI for each period, and corrected LAI forthe entire litter-fall season. Data for each LAI type indicatedthat LAI is dynamic over time. The maximum ‘‘true’’LAI was 6.69 ± 1.37 and the minimum was 2.79 ± 0.56,reflecting significant seasonal dynamics.The ‘‘true’’ LAI dropped significantly after mid-September (see Fig. 3c, d). Effective LAI was smallerby comparison, with a maximum of 3.17 ± 0.43 andminimum of 1.15 ± 0.22, and this LAI exhibited lesserseasonal dynamics. We applied Duncan’s multiple comparisontests to these different LAIs for each period. LAIvalues corrected via the correction model for each periodwere consistent with the corresponding ‘‘true’’ LAI values.There were no significant differences between LAI valuescorrected for the entire litter-fall season versus the ‘‘true’’LAI calculated for July and August, whereas the valuescalculated after September were significantly different, andthe LAI was underestimated in September and Novemberand overestimated in October. There were significant differencesbetween effective LAI and ‘‘true’’ LAI in eachperiod.Corrected LAIs for each period were very close to the‘‘true’’ LAIs, but there were so many models (Fig. 3a–g)and the calibration process was so complicated that themodels were not suitable for calibrating seasonaldynamics of LAI. On the other hand, there was a singlecorrection model (Fig. 3h) for the entire season, and thecalibration process was simple; however, there were somedifferences between the corrected LAIs and ‘‘true’’ LAIs.Upon consideration of advantages and disadvantages ofthe correction models for each period and for the entireseason, we combined the two methods. First, we combinedthe data for July and August and carried out apaired-samples t test at the 95 % significance level todetermine whether there were significant differencesbetween ‘‘true’’ LAI and effective LAI. The idea was that,if there were no significant differences, we would combinethe data of July, August, and early September, andcarry out a paired-samples t test again; if there weresignificant differences, we would combine the data of Julyand early September, and make paired-samples t test. By12328