SITE INDEX OF SIAMESE ROSEWOOD (Dalbergia cochinchinensis Pierre) IN PLANTATIONS OF THAILAND

Currently, decreased productivity of Siamese rosewood (Dalbergia cochinchinensis Pierre) is a problem due to illegal logging and the guidelines to manage this prevention being may be insufficient. Forest plantations should be promoted to achieve sustainable wood production for this species. Site index (SI) is a measure that can be used to predict forest productivity to identify appropriate sites for planting Siamese rosewood. The objective of the current study was to predict the SI for Siamese rosewood in Thailand. A sample of 78 temporary plots at 26 sites in 16 provinces of Thailand was selected to construct a site index curve with a base age of 30 years. The results showed that the mean age of Siamese rosewood was 28 years (between 13 and 55 years), the mean diameter at breast height (DBH) was 20.03 cm (between 7.99 and 33.80 cm), and the mean dominant height was 20.79 m (between 7.32 and 24.82 m). The SI equation was: SI = e(lnHdo-12.476(A-1-Ab-1)) with an R2 value of 0.406 at p < 0.0001 (chosen as 30 years in the present study). The equation indicated that 14, 18, 22, 26, and 30 m trees belonged to site classes Ι, ΙΙ, ΙΙΙ, ΙV, and V, respectively. Although in natural forest, Siamese rosewood is distributed in dry evergreen and mixed deciduous forests, in the present study, several sites in areas under both in situ and ex situ conservation were in the good and very good site categories. Thus, both areas can be used to plant Siamese rosewood and increase its productivity

Insect Pollination of Aquilaria crassna (Thymelaeaceae): Effect of Moths for the Fruit Setting in Thailand

The diversity and abundance of insect visitors to flowers of Aquilaria crassna were investigated in a natural forest in Khao Yai National Park and a plantation in Trat Province, Thailand. The behavior and pollinating effectiveness of the major insect visitors were also examined. Data were collected from 2006 to 2008 during the flowering season from March to May. A total of 103 insect species were found, representing 34 families from 4 orders. The highest number of species belonged to the order Lepidoptera (61 species), followed by Hymenoptera (26), and Coleoptera and Diptera (8). The efficiency of moth visitors was measured by the mean number of pollen grains found on the visitor\u27s proboscis. Endotricha species (Pyralidae, Lepidoptera) were the most abundant and frequent visitors in both areas, and had pollen deposits of $16.29 pm 5.36$ (n=9) grains per proboscis. Fruit setting following different pollination treatments was not significantly different in the natural forest and the plantation, and no significant difference was found between hand pollination and open pollination. However, there was a significant difference in fruit setting between hand pollination and closed pollination, indicating that pollen transfer from anthers to stigma by vectors was required for fruit setting of A. crassna flowers