Estimation of Rubber Tree Canopy Structure Using a Photographic Method

Abstract

It takes a long period before a rubber tree can be tapped for latex. Following the growth and development of the rubber tree canopy is important. A photographic method may be a suitable indirect way to estimate the canopy structure of individual trees from numbered photographs. This study optimized a photographic method to estimate the canopy structure of two-year-old rubber trees. Two plants of clones RRIM 600 and RRIT251 were photographed from four directions. Plant height, diameter, volume and total leaf area of each tree were estimated using a photographic method and were compared to the measured values. Total leaf area was compared with data measured by a leaf area meter (LI-3100). The estimated crown height and leaf area was 6.4 and 0.17% lower than the measured values, respectively. The estimated tree height, diameter and crown volume was 2.7, 10.6 and 9.1% higher than measured values, respectively. The results indicate that under in-field conditions, a photographic method can be used to estimate the canopy structure of individual rubber trees. A set of tools has been developed for ease and accurate measurements of the required camera parameters. This method could be useful to researchers studying the growth and development of the young rubber tree canopy and for other individual trees.