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ThesisItem Open Access Biomass production and nutrient accumulation in an age series of caesalpinia sappan Linn. plantations(Department of Forest Management and Utilisation, College of Forestry, Vellanikkara, 2006) Imrose, Elias Navas E; KAU; Vidyasagaran, KThe present study was conducted at College of Forestry, Kerala Agricultural University, Vellanikkara on biomass production and nutrient accumulation in an age series (5, 6 and 7) of Caesalpinia sappan plantations in three districts of Kerala. The study reveals that diameter, height, biomass, productivity and volume increased with increasing age. The above ground biomass and biomass components also increased with increasing ages. The above ground biomass produced was 23.81 t ha-1 at 5 year, 37.80 t ha-1 at 6 year and 44.36 t ha-1 at 7 year. The productivity at age 5 year was 4.77 t ha-1yr-1, at age 6 year 6.30 t ha-1 yr-1 and at age 7 year was 6.34 t ha-1 yr-1. The increase of the productivity between 6 and 7 years were very low (0.04 t ha-1yr-1), which indicated that no further increase in the productivity of the trees. It highlights that a levelling off the productivity beyond 6 year. This consideration suggests 6 year as the optimum harvesting period of C. sappan. The percentage contribution of various components to above ground biomass was in the order: bole > branch > twig > fruit > leaves> bark. The biomass components were also showed an increasing trend. The prediction equations were prepared for above ground biomass as well as biomass components with respect to dbh and height. Even though some equations were proved more fit with combination of dbh and height, R2 value and Furnival index were relatively similar to equations with dbh alone could not be selected, it is difficult to measure height of the standing trees with definite accuracy. Hence, equations with dbh alone were selected for predicting the biomass. With respect to the dbh alone as independent variable, the total above ground biomass, the best fit equation was W = b0 +b1 D+ b2 D2. In leaves also this model proves as best fit. The components like bole, bark, branch and fruit, the best fitted equation was ln W =b0 + b1 ln D. But in twig, it was W=b0 + b1 D2. Weight table prepared for bole (UB) and total above ground biomass based on the best fit equation using diameter at breast height The nutrient concentration was increased with increasing age except in bole and branches. Concentration in bole and branches increased from 5 to 6 year and decreased from 6 to 7 year. Leaves had the maximum concentration of the nutrients and bole the lowest. The nutrient accumulation of the above ground biomass as well as biomass components increased with the increasing age of plantation. The maximum nutrients accumulated in bole and minimum in bark. Among the nutrients, N accumulated maximum followed by K and P. Nutrient use efficiency increased with increasing ages. The maximum nutrient use efficiency observed for P followed by K and N. It was found to be maximum in bole and minimum in leaf.ThesisItem Open Access Screening of tree species for growth behaviour, biomass and wood properties(Department of Forest Management and Utilisation, College of Forestry, Vellanikkara, 2006) Arun, Gupta; KAU; Gopikumar, KThe 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.ThesisItem Open Access Performance of multipurpose trees in coconut based agroforestry systems and their influence on soil physico-chemical and biological properties(Department of Tree Physiology and Breeding,College of Forestry, Vellanikkara, 2006) Srinivasan, K; KAU; Ashokan, P KAn experiment was conducted to study the effects of intercropping of three fast growing MPTs viz. Casuarina equisetifolia, Ailanthus triphysa and Leucaena leucocephala in coconut plantations, on soil physico-chemical and biological properties; the field experiment was laid out at the Instructional farm, Kerala Agricultural University, Vellanikkara. The influence of three water harvesting structures viz. simple pits, contour trench and ring trench, which were established in the seedling phase were also compared. The experiment was laid out during 1993 in one year old coconut plantation spaced at 7 x 7m .The MPTs were planted between rows of coconut at a spacing of 2.33 m. The experiment was laid out in Randomised Block Design (RBD), with three replications. The result showed that casuarina recorded maximum height (28.02 m) and girth (GBH of 71.76 cm) and biomass accumulation among different MPTs studied. Ailanthus intercropped systems intercepted about 93 percent available sunlight and control plots (coconut alone) intercepted the least with around 57 percent due to their stand leaf area index of 3.21 and 1.52 respectively. It was observed that MPTs had an adverse effect on the productivity of coconut during later stages of the cropping system. MPTs had tremendously increased the water holding capacity and infiltration rate of the soil. Ailanthus interplanted plots showed better water holding capacity and improved the infiltration capacity of the soil. Resorting to agroforestry practices considerably increased the organic carbon content of the soil. Casuarina interplanted plots showed higher available N, P and K and the surface layer had more concentration of available nutrients. As the soil depth increases the available nutrient concentration was found to decrease. Microbial population viz., bacteria, fungi and actinomycetes were also found to increase due to the influence of MPTs intercropped in coconut plantations. The microbial population viz. bacteria, fungi and actinomycetes was found more in coconut intercropped with casuarina plots. Fungi and bacterial population were found more in the 30-45 cm soil layer but actinomycetes was found more in the surface layers. The percentage of VAM infection on the roots was also seen more in casuarina intercropped in coconut garden.