Penentuan Titik Transisi Kayu Juvenil ke Kayu Dewasa pada Sengon (Paraserianthes Falcataria (L.) Nielsen) dan Jabon (Anthocephalus Cadamba Miq.)

Abstract

Wood as an important forest resource has been processed in large quantity to fulfill an increasing need of humans. To satisfy the increasing demand for the wood products, the supply of the wood will be come from fast-growing tree species grown on plantation forest and community forest. This fast-growing wood species will tend to be harvested in short age rotations and will contain higher proportions of juvenile wood. The objective of this research is to know characteristics of juvenile and to obtain consistent estimates of transition age from juvenile to mature wood of Sengon and Jabon woods. Segmented modeling approach was used to estimate the age of transition, and the non-linear procedure was employed to identify the juvenile to mature wood transition point. In an attempt to determine the juvenile and mature transition age for Sengon and Jabon, 6 trees were sampled in three age classes (5, 6, and 7 year) from a community forest in Sukabumi. Disks of 5 cm thick were collected at 1.3 meters (diameter breast height) from each tree to determine fiber length, MFA, density, and green-moisture content. Wood density was measured from pith to bark by X-ray densitometry. Fiber length and microfibril angle (MFA) were measured on isolated segmented rings of 1 cm width from pith to bark by visual interpretation on maceration and microtome samples. The segmented regression models and visual interpretation of tangential patterns of variation in fiber length and MFA reveal that juvenility in Sengon and Jabon extends up to 7 years, respectively. Fiber length and microfibril angle appear to be good anatomical indicators of age demarcation between juvenile and mature wood, although maturation age often varies among the properties. The projected figures for proportion of juvenile wood in Sengon and Jabon at age of 7 year are 80–100% and 100%, respectively.