Screening of tree species for growth behaviour, biomass and wood properties

Abstract

The present study was conducted in College of Forestry, Kera1a Agricultural University, Vellanikkara to evaluate the growth performance, biomass production, physical properties of wood and leaf nutrients of selected tree species grown in the arboretum during the period 2004-2006. A total of ten species were included in the study with an objective of screening the promising species for their further multiplication in the college nursery on large scale for distribution to farmers for farm/agro forestry and general afforestation programme.

The results revealed that among the species studied, species like Terminalia tomentosa, Terminalia bellerica, Acacia auriculiformis and Acacia mangium were found fast growing in terms of height and girth. Grevellia robusta, Artocarpus hirsutus etc. showed lowest increment in height and girth. Artocarpus hirsutus produced highest number of branches followed by Grevellia robusta. Number of branches did not differ significantly among other species.

The total biomass production was found to be maximum for Terminalia tomentosa while the lowest total biomass was produced by Swietenia macrophylla in terms of both fresh and dry weight. The least dry weight for trunk was also recorded for Swietenia macrophylla followed by Artocarpus hirsutus. Trunk accounted for maximum biomass production followed by branches. The contribution of trunk was followed by branches in all the tree species except Grevellia robusta and Terminalia bellerica where the dry weight of twigs was more than that of branches. Acacia mangium and Acacia auriculiformis produced more heartwood compared to other species. Acacia mangium, Acacia auriculiformis and Swietenia macrophylla could be used for small timber purpose as they showed higher heartwood - sapwood percentage ratio. Swietenia macrophylla recorded maximum bark percentage closely followed by Terminalia tomentosa. Terminalia bellerica, Artocarpus hirsutus and Acacia auriculiformis, were having high calorific values and hence could be used for fuel wood purpose also. Specific gravity was found to be maximum for Swietenia macrophylla and minimum for Terminalia bellerica.

Leaf tissue nitrogen content was significantly highest in Ailanthus triphysa followed by Acacia mangium and Xylia xylocarpa. The phosphorus content was found to be maximum in Ailanthus while potassium in Tectona grandis. Leaves of Xylia xylocarpa were found to record minimum content of phosphorus and potassium.