College of Forestry, Wildlife and Tourism

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Browsing College of Forestry, Wildlife and Tourism by Subject "Acacia mangium"

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    Comparison of volume production, basic density and stem quality between acacia mangium and acacia Aubicuuformis grown in Zanzibar
    (Forest Research Institute Malaysia, 1997) Ali, M.S.; Malimbwi, R. E.; Iddi, S.
    Comparison of volume production, basic density and stem quality between Acacia mangium and Acacia auriculiformis grown in Zanzibar. Volume production, basic density and stem quality of 6-y-old Acacia mangium and A. auriculiformis grown in Zanzibar were compared. Twenty-one plots (11 plots for Acacia mangium and 10 for A. auriculiformis ) were established and used for data collection. From each plot one to two trees free from obvious defects were selected for basic density determination. Cores were then extracted from the selected trees using an increment borer. Basic density of the cores was determined by the water displacement method. Height and diameter data were used for volume estimation. Stem quality was assessed using the scoring method, 4 being the best and 1 the worst. At age 6 y, diameter and height growth did not vary significantly (p = 0.05) between the two species. More than 50 m3 ha"1 volume production was achieved in both species. The average volume weighted basic density values for A. mangium and A. auriculiformis were 570 kgm"3 and 617 kgm"3 respectively. The basic density values for the two species differed significantly (p = 0.05). Stem quality was better in A. mangium than in A. auriculiformis. Based on density, A. auriculiformis can be recommended for fuelwood production whereas A. mangium should be recommended for transmission and building poles due to its good stem form.
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    Rooting pattern of acacia mangium in pure and mixed stands of eucalyptus camaldulensis, Tectona grandis and casuarina montana in the coastal Tanzania
    (Boku University, 2011) Kilawe, Charles Joseph
    This study investigates if Tectona grandis, Casuarina montana and Eucalyptus camaldulensis planted in mixture with Acacia mangium would send their roots toward Acacia in attempt to benefit from its symbiotic nitrogen fixation ability and also to investigate if the roots of mixed tree species would occupy different vertical soil layers for better utilization of site resources. A soil core method was used for root and soil sampling in a 22 months old mixed stand of E. camaldulensis (E), C. montana (C), T. grandis (T) and A. mangium (A) in a 1A:8A; 1A:8E; 1A:8T; 1A:8C; 1E: 8A; 1T:8A and 1C: 8A species combination replicated at three sites. Lateral distribution showed a decreasing root biomass with increasing distance from the tree stem. The highest total root biomass was obtained at 20 cm distance reaching 306.05 g m -2 for Acacia, 229.19 g m -2 for Eucalyptus 156.5 g m -2 for Tectona and 127.0 g m -2 for Casuarina. The lowest total root biomass was observed at 180 cm distance reaching 5.44 g m -2 for Acacia and 0.01 g m -2 for Eucalyptus, Casuarina and Tectona. Lateral spread of other species was higher in the upper layer (0-10 cm) with high density of A. mangium and high in the lower layer (10-20 cm) with low density of A. mangium in the species combination. Vertical distribution revealed a decrease in root biomass with increasing soil depth for all species except T. grandis. Mean root biomass decreased from 162.41 (acacia) to 4.58 g m -2 (teak) in the 0-10 cm layer to 90.26 (acacia) to 5.40 (casuarina) g m -2 in the 10-20 cm layer. Also fine root biomass was high in the upper layer and coarse root biomass was high in the lower layer. It is concluded that, there was not sufficient evidence of other species sending their roots toward A. mangium but there was clear vertical niche separation between A. mangium and other species, particularly with T. grandis