TWIG CHARACTERISTICS WITH THE SCALE LEAF AND ITS LEAF AREA ESTIMATE MODEL IN JUNIPERUS CHINENSIS L.

Leaf area measurement is particularly challenging for the scale leaf due to its tiny incomplete leaves overlapping in a decussate phyllotaxy. This study developed a non-destructive, rapid, and accurate method to measure the leaf area of a scale leaf twig. To achieve this, we used a vernier calliper to measure the length (L) and the diameter in the middle in 3 different directions of 202 twigs in Juniperus chinensis L. and calculated the equivalent diameter (D). Then, utilizing ImageJ and 12,612 photos of the scaly leaves on these twigs, we calculated the total leaf area (LA) and finally weighed the twig dry mass (DM) after drying. The study analyzed an estimating model for the leaf area of the twigs and the relationship between twig traits and LA using SPSS. The coefficient of variation (CV) of LA was 0.611, with a range of 67.068 similar to 79.490 mm(2) (95% CI). Furthermore, LA showed a significant positive correlation with both length and dry mass (r=0.949, 0.920). The optimal multivariate linear regression model for LA was: Y= -47.841 + 2.409 L + 19.151 D+ 1.059 DM (R-2= 0.931, RMSE = 11.808, AIC = 1265.624). The model exhibited a prediction accuracy of 90.03%. This study provides a suitable model for estimating the leaf area in Juniperus chinensis L.