Characteristics of exposed cavities of urban trees in a landscape of Southtern Jakarta and their filling using polyurethane foam

A study was conducted to determine the characteristics of exposed cavities on the trunk of urban trees in a Central Business District (CBD) landscape, South Jakarta. The position and number of exposed cavities, as well as the dimensions, were recorded. Each exposed cavity was then filled using a polyurethane foam, followed by wound dressing using colored resin. One month after the filling process, the reliability of the filled cavities was measured using a micro-drilling resistance technique. The results showed that most of the exposed cavities were found in the main trunk (48.84%) followed by primary branches (41.86%), stem base (6.98%), and secondary branches (2.32%). Almost 69% of the exposed cavities revealed symptoms of decay, including discoloration. The exposed cavity volumes ranged from 0.04 dm3 to 63.61 dm3 with an average of 9.79 dm3. Most of the exposed cavity were 10 cm to 30 cm deep (41.86%), followed by those 5 cm to 10 cm deep (25. 58%), 3 cm to 5 cm deep (18.60%), 30 cm – 50 cm deep (9.30%), and more than 50 cm deep (4.65%). The filling of exposed cavities using polyurethane foam indicated good reliability. There was no checking and/or cracking on the surface of the filled cavity, either on the Trembesi trees, Flamboyan trees, or palm trees.