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2001 - 20025
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Subject: Silviculture and Agroforestry × End date: 2002 × Start date: 2001 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Conservation strategy for Hopea parviflora Bedd. species through storage of seeds usinhg cryopreservation techniques
    (Department of Silviculture and Agroforestry, College of Forestry,Vellanikkara, 2001) Ani, J R; KAU; Sudhakara, K
    A detailed study was conducted at College of Forestry, Kerala Agricultural University, Vellanikkara, Thrissur, Kerala during 1998-2000 to standardize the conservation strategy for Hopea parviflora Bedd. species through storage of seeds using cryopreservation. Diameter of seeds collected at seven weeks after anthesis was found to be higher than that at sixth week. Physiological maturity of the propagules is attained between five and six weeks after anthesis. The propagules were subjected to different relative humidities, vacuum and dry air for different durations as a pretreatment for cryopreservation studies. In 100 to 46.6 per cent relative humidities, the moisture content and the leachate conductivity of the propagules were found to increase with duration compared to the initial value. Equilibrium moisture content of Hopea parviflora propagules was found to lie between 75.6 to 30 per cent relative humidities. Germination parameters of seed and seed without seed coat were not decreased significantly due to desiccation by relative humidities, vacuum or dry air, but that of embryonic axes was considerably reduced as rapid drying might have been effected due to 30 and 20 per cent relative humidities and also due to vacuum and dry air with duration. High culture contamination was observed in vacuum and dry air treatments. After cryopreservation techniques, the propagules invariably failed to regenerate but could retain green colour for two to three days.
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    ThesisItemOpen Access
    Development of storage techniques for thampakam (Hopea parviflora Bedd.) seeds
    (Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 2002) Shaji, M; KAU; Sudhakara, K
    A detailed study was conducted at College of Forestry, Kerala Agricultural University, Vellanikkara, Thrissur, Kerala during 1999-2001 to develop a suitable storage technique for the seeds of Hopea parviflora Bedd. species through synthetic seed and cryopreservation technology. Moisture content of intact seeds/ seeds without seed coat/: excised embryonic axes decreased with increase in intensity and duration of desiccation levels and only the seeds without seed coat showed significant difference in moisture content due to maturity levels. Leachate conductivity was not significantly affected due to maturity levels of intact seeds and excised embryonic axes. But seeds without seed coat showed significant difference in leachate conductivity due to maturity levels and it was higher at seven weeks after anthesis. Increasing the duration of desiccation significantly increased the leachate conductivity of intact seeds/ seeds without seed coat! embryonic axes. Germination parameters of intact seeds and seeds without seed coat were not affected significantly by increased desiccation. However, excised embryonic axes showed significant difference in germination parameters when the intensity and duration of desiccation was increased. The synthetic seeds developed from these desiccated axes also showed significant difference in their germination parameters. Synthetic seeds stored at 4°C retained maximum viability after four weeks, compared to those stored at 200 C and 27 0 C. When stored at 27 0 C, the synthetic seeds developed from six weeks mature embryos retained viability up to three weeks whereas those at seven weeks after anthesis retained viability up to two weeks only. After cryopreservation, the propagules invariably failed to regenerate but could retain green colour for two to three days.
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    ThesisItemOpen Access
    Root competition between coconut palms and interplanted multipurpose trees under varying nutrients management regimes
    (Department of Silriculture and Agronomy, College of Forestry, Vellanikkara, 2002) Sanjeev Gowda, H B; Mohanakumar, B
    Coconut based production systems in the tropics often aim at improved resource capture through incorporating several trees and field crops. However, competition between the system components are probable when multipurpose trees are systematically interplanted in the coconut plantations. Soil fertility regimes are presumably important in determining the magnitude of below ground competitive interactions. Hence a study was conducted to evaluate the influence of interplanted multipurpose trees on coconut productivity along a soil fertility gradient, to assess the performance of multipurpose trees and to determine the nature of below ground interactions between coconut palms and multipurpose trees, at Vellanikkara since 1992. Treatments included combinations of cocounut with anyone of the three multipurpose trees namely, Vateria indica, Ailanthus triphysa and Grevillea robusta, following two planting geometries(randomised block design, replicated thrice). A soil fertility gradient, was super-imposed with high, medium and low fertility levels in 2000. 32p soil injection technique was employed to characterize . root interaction and logarithmic spiral trenching technique for evaluating root distribution pattern. Results show that coconut yield was not adversely affected by multipurpose trees interplanting until the trees reached eight years of age. Vateria, ailanthus and grevillea showed marked variations in their growth rates. Initially vateria recorded higher height and radial growth albeit ailanthus registered higher growth rates subsequently. Isotopic studies reveal that 32p absorption by coconut palms was similar in both sole and mixed cropping situations along the fertility gradient; probably implying the non-interfering nature of multipurpose trees. 32p absorption by vateria and ailanthus suggests that the absorption of radioactive phosphorus declined linearly with increasing distance ie. 32p absorption by multipurpose trees also did not affect the 32p uptake by coconut, suggesting that integrated land use systems involving multipurpose trees and coconut are ideally suited for improved resource capture and increased system productivity. Excavation of multipurpose tree root systems showed that proximal locations recorded higher rooting intensities and that the rooting intensities decreased with increasing distance. Size of the trees showed discernible differences in respect of spatial root distribution pattern. Large sized trees showed higher root distribution compared to small and medium. The first 10cm soil layer recorded the highest rooting intensities. Ailanthus roots were distributed upto a maximum distance of 469 cm, vateria upto 163 cm and grevillea upto 227 cm. Implicit in this is the species-dependent'variations in lateral root spread. In general, vateria and ailanthus have a well developed and ramified root systems. Grevillea, however, had a less spreading root systems. Selection of tree species with low root competitiveness and/or trees with complementary root interactions is of strategic importance in agroforestry.
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    ThesisItemOpen Access
    Evaluation of fuelwood characteristics, physical and mechanical properties of selected agroforestry tree species
    (Department of Silviculture and Agroforestry, College of forestry, Vellanikkara, 2001) Shanavas, A; KAU; Mohankumar, B
    An experiment to evaluate the fuelwood value, and physical and mechanical properties of selected agroforestry tree species was conducted at the College of Forestry, Vellanikkara. The study involved determination of the fuelwood value of 48 species/materials and assessment of the physical and mechanical properties of three promising multipurpose trees having local importance, viz., Acacia auriculiformis, Acacia mangium and Grevillea robusta. Variations abound in the calorific values of agroforestry species and their tissue-types. Ash content, specific gravity, chemical composition and moisture content of tissues are primary factors affecting calorific value; while species and tissue-types, may exert a secondary control. Ash content and moisture content had a negative correlation with calorific value, whereas specific gravity exerted a positive influence. Based on the range in calorific values and fuelwood value indices obtained, different species and tissue-types could be broadly divided into three categories: high, medium and low. Calorific value of different tissue fractions decreased in the order: heartwood> sapwood > bark. Mean ash percentage of tissue-types followed the order: bark> sapwood > heartwood. Variations of ash content along bole height followed the order: branchwood > top > bottom > middle. Mean specific gravity of tissue-types followed the order: heartwood> sapwood > bark. For sample positions it followed the sequence: bottom> middle> top> branchwood. Wood moisture content increased from bottom to top along tree height and for tissue-types, it followed the order: bark < heartwood < sapwood. Coconut shell recorded the highest fuel value index (FVI) which was approximately 25 times greater than the highest value for tree species (Casuarina equisetifolia). Physical and mechanical properties of Acacia auriculiformis was significantly supenor to that of Acacia mangium and Grevillea robusta. The physical and mechanical properties were affected by both species and sample positions. Wood specific gravity increased from inner to outer sample positions along radial direction except for Grevillea robusta, which followed the order: outer < inner < middle. Moisture content decreased from inner to outer sample positions in Acacia mangium; while Grevillea robusta exhibited a divergent trend. Variations in shrinkage along radial direction followed the same trend as that of moisture content but was inconsistent with that of specific gravity. Most of the strength properties followed a trend similar to that of specific gravity. On a final note, specific gravity, work to limit of proportionality in static bending, work to maximum load in static bending, compressive stress at limit of proportionality in parallel to grain, compressive stress at limit of proportionality in perpendicular to grain and end-hardness of Acacia auriculiformis were greater than the values reported for teak. The physical and mechanical properties of Acacia mangium and Grevillea robusta except for shrinkage were less than that of teak.
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    ThesisItemOpen Access
    Productivity of ailanthus (Ailanthus triphysa) under different fertilizer regimes and population densities
    (Department of Sivilculture and Agroforestry, College of Forestry, Vellanikkara, 2001) Naveed, Shujauddin; KAU; Mohankumar, B
    A split plot experiment involving ailanthus (Ailanthus triphysa (Dennst.) Alston) at four population densities (3333,2500, 1600 an 1111 tpha) and four fertiliser regimes (0:0:0, 50:25:25, 100:50:50 and 150:75:75 kg N:P205:K20 ha" yr") was initiated in June 1991. The objectives included evaluating the biomass production potential of ailanthus grown under different spacing and fertiliser regimes and estimating nutrient export through whole tree harvesting. Height, diameter and stand leaf area of ailanthus trees at 8.7 years of age was greater in the 2500 trees per hectare (tpha) stand than other density levels. Lower densities recorded higher biomass on a per tree basis whereas on a stand .basis, the high density stand (3333 tpha) showed greater biomass yield. Fertilisers applied at 1.2, 2.25 and 5.25 years had no significant effect on biomass accumulation. Regarding the partitioning of tree biomass, stemwood was the most important component in all density and fertiliser treatments while foliage contributed the least. Nonetheless, foliage registered the highest N, P and K concentration (%). NPK concentration of other fractions decreased in the order: branchwood > roots> stemwood. Nutrient accumulation (N, P and K) on a per tree basis was higher in the lower densities while on a stand basis, greater accumulation was noted in the higher density stands (3333 and 2500 tpha). Bole fraction accounted for only 56 per cent of total nutrients removed during harvest. Thus leaving other biomass components (foliage and branches) at the site will greatly reduced the nutrient export associated with tree harvesting. Stands with 1600 and 1111 tpha showed higher N and K use efficiencies whereas for P, the tree population density of 2500 tpha 'showed the highest efficiency. Regarding fertiliser effect, trees in the control plot (no fertiliser) exhibited highest efficiencies for N, P and K. Available soil P, K and organic carbon concentrations declined with increasing tree population density. However, there was an overall increase in total N and available K levels compared to the previous. observation at 3 years of age. Increasing levels of fertilisers in general resulted in higher soil organic carbon, N, available P and K levels.