A Method to Measure Radial Increment in Tropical Trees

1989

12 Abb., 2 Tab., 4 Lit. Ang.

Unselbständiges Werk

9869

200040216

Radial increment was studied in natural forest trees in East Kalimantan, Indonesia, and in mangrove trees in Thailand and on Iriomote Island (Japan). Nails were driven into the trunk at breast height. Barrier zones formed in response were located after felling of the tree, and the amount of wood formed subsequent to nailing was measured. Thanks to the distinctness of the cambial response to nailing, this method appears very effective for measuring radial increment in tropical trees. The following results were obtained: 1. In natural forest trees in East Kalimantan: a) In the Dipterocarpaceae studied the barrier zone formed after nailing is characterised by tangential bands of gum/resin canals. In the 2 specie studied from other families the barrier zone is composed of a tangential band of parechyma. b) Annual diameter increment in meranti puteh (Shorea spp.) ranges from 1.6-20 mm. c) Radial growth was stronges in the period from August to October, during the dry seasons as a result of the production of more cells which had moreover a greater radial diameter than the cells formed during the rainy season. 2. In mangrove trees in Thailand and Japan: a) In mangrove trees in Thailand with a diameter of about 10 cm, average annual radial increment was 13.4 mm in Xylocarpus, 11.6 mm in Bruguiera, 8.4 mm in Rhizophora, and 9.6 mm in Ceriops. b) In the smaller trees on Iriomote Island with dbh of 3-6 cm, annual increment ranged from 3.8 mm in Rhizophora to 5.7 mm in Avicennia.