Is leaning trees of Vatica pauciflora (Korth.) Blume related to their crown architecture?

Abstract

Vatica pauciflora (Korth.) Blume (Dipterocarpaceae) or locally known as resak rawa is an important tree. It is categorized as vulnerable regarding the IUCN (International Union for Conservation of Nature) Red List of Threatened Species. We can find the resak rawa tree collection in the Bogor Botanic Gardens, which serves as a place for research and tourism. Due to the diversity in individual tree anatomy within species, understanding correlation among individual tree traits, particularly crown architecture and tree leaning, is of great interest. That will be important because the leaning trees and crown architecture will affect the risk level to the safety of visitors. We can also use the architecture of the tree crown to understand the factors that influence tree growth. This study aims to investigate the correlation between the leaning trees and the crown architecture of V. pauciflora. Eight heritage trees of the species in the Bogor Botanic Gardens at the age of 54–105 years old were purposely, sampled in this study. The variables observed were height, trunk and crown diameter, leaning tree, live crown ratio, and direction of the main branches. The results show that crown shapes will follow the leaning trees with a correlation of 0.97. The main branches will be longer in the direction of the leaning trees (y=0.9956x+11.312; R²=0.9431). Suggestions to the management of V. pauciflora are to provide information boards to visitors and pruning the crown in the direction of the leaning trees is needed. The findings could be used to formulate mitigation measures as to the risk and safety of visitors.