Effect of Improved Planting Stock on Tree Growth, Wood Properties, and Soil Fertility of Teak Plantations 10 Years After Planting
Аннотация
Teak (Tectona grandis Linn. f.) is one of the most economically valuable types of tropical forest because teak wood has high durability, resilience and good aesthetic qualities. Teak tree improvement in Indonesia was initiated in 1983 producing planting stock for reforestation, i.e. clonal seed orchards (CSO) to produce seedling as sexual reproduction (referred to seedling), and hedge orchards to produce shoot cuttings as asexual (vegetative) reproductive (referred to shoot cuttings). Teak plantations established using seedling and shoot cuttings should improve forest productivity. The objectives of this study were to compare the growth rate, wood properties, and soil fertility of teak plantations propagated using seedling and shoot cuttings. Three square plots of 100 trees (10 10 trees; 1,000 m 2 ) were established on both types of plantation and tree growth characteristics, wood properties, and soil fertility were monitored. The tree growth characteristics were diameter at breast height (DBH), tree height (H), clear bole height (CB), and volume of standing stock (Vss), and the wood properties included pilodyn penetration (PP) and stress wave velocity (SWV). Soil fertility was assessed from soil samples collected from three soil depths, with three replicates in each plot: 0-5 cm (top layer), 6-30 cm (middle layer), and 31-60 cm (bottom layer). Soil samples were analysed for total nitrogen, total phosphorus, total potassium, total calcium, and total magnesium. The results showed that the mean DBH, H, CB, and Vss differed significantly between the type of planting stock. The DBH, H, CB, and Vss values were 28.4%, 46.8%, 49.1%, and 130.1% higher, respectively, in teak plantations from shoot cuttings than from seedling. Moreover, the SWV of shoot cuttings planting stock plantation was 3.6% higher than from seedling. The mean PP did not differ significantly between teak plantations from shoot cuttings (22.00 mm) and seedling (21.80 mm). Furthermore, the planting stock did not affect soil fertility, which was highest in the top layer in all treatments. Our results suggest that teak plantations from shoot cuttings would increase growth, forest productivity, maintaining wood quality and soil fertility. Thus, it can maintain sustainable teak forest plantations.