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ThesisItem Open Access Biomass production and root distribution pattern of selected fast growing multi-purpose tree species(Department of Silviculture and Agroforestry, College of Forestry,Vellanikkara, 1994) Jamaludheen, V; KAU; Mohankumar, BA randomized block design experiment involving nine fast growing multi – purpose trees (Acacia auriculiformis A. Cunn. ex Benth., Casuarina equisetifolia J.R. & G Forst., Leucaena leucocephala (Lamk.) de wit. Var. K 8, Ailanthus triphysa (Dennst.) Alston, Emblica officinalis Gaertn, Artocarpus heterophyllus Lamk., Pterocarpus marsupium Roxb., Paraserianthes falcataria (L.) Neilson and Artocarpus hirsutus Lamk.) Initiated during June, 1985 was used for the present investigations. The objectives of the study included quantifying the biomass production potential of nine selected fast growing multi-purpose tree species grown under short rotation intensive cultural systems; characterising the root distribution pattern of these trees and also elucidating the extent of nutrient loss through harvest, besides characterising litter dynamics. Acacia and paraserianthes recorded the highest growth rates in terms of height, radial growth and biomass yield. Biomass production decreased in the order: Acacia > Paraserianthes > Casuarina > A. heterophullus > Emblica Pterocarpus > A. hisrsutus > Ailanthus > Leucaena. The most important component of total biomass undoubtedly, was the bole while foliage contributed least to biomass yield. Nevertheless foliage, in general registered the highest N, and K contents. Among the species, Leucaena had the highest N concentration followed by Paraserianthes and Pterocarpus. For P and K concentrations, Pterocarpus and A. hirsutus registered the highest concentration. A one – to – one correspondence between nutrient accumulation and biomass yield was however, lacking because of wide variations in elemental concentrations among species and also among tissue types. Bole fractions, in general, did not account for more than 50 % of total nutrient export from site. Altering the rate of nutrient removal in products is one of the most important design criteria in planning for sustainable plantion. N-fixing tree plots generally had a higher soil N status. Casuarina, Emblica and Pterocarpus plots were having higher P levels. Acacia, Paraserianthes and A. hisrsutus plots registered markedly higher K level. The amount of litterfall was maximum for Acacia and the minimum for Pterocarpus. Litterfall also followed a unimodal distribution pattern with a distinct peak during the November – January period and the period of lean fall was during May-August. Litter dynamics accounted for bulk of the nutrient inputs into the system. The retranslocation of mineral nutrients from senescing leaves to younger leaves and /or other tissues prior to abscission was obvious. Leucaena, Paraserianthes, Pterocarpus, Acacia, Alinathus and Emblica formed examples of high (> 1.5%) detrital N content. Generally the wet period (June – August) was characterised by increased concentration of N in litter. Litter P did not follow a consistent pattern with respect to seasons. However, a characteristic decline in litter K concentration was noticed during the rainy season. Mass disappearance of litter samples followed a negative expontential relationship. Leucaena litter, having the highest initial N content, decomposed compeletely in the shortest period (9 months). Root system studies suggest that A. hetrophyllus, Emblica and Paraserianthes are perhaps unsuitable for intensive mixing and close planting in agroforestry as they possess shallow and highly spreading root system. Ailanthus is perhaps a better candidate species for the above purpose as it possess relatively lower lateral root spread and at the same time having a deep tap root system. Root activity paatern of Artocarpus hisrsutus revealed that more than 75% of fine roots responsible for water nutrient absorption is concentrated in the 75 cm radius around the base of the tree. Recovery of 32P declined as depth of application increased. The combination of lowest lateral distance (75 cm) and depth (30 cm) accounted for more than 30% root activity.ThesisItem Open 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, KA 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.ThesisItem Open Access Viability of hopea parviffora seeds with reference to temperature , medium of storage and microencapsulation techniques(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 1996) Sunilkumar, K K; KAU; Sudhakara, KA detailed study was conducted at College of Forestry, Kerala Agricultural university, Vellanikkara, Thrissur, Kerala during 1994 – 95 to study the effect of temperature, storage medium, fungicide and microencapsulation of zygotic embryo (synthetic seed) on the storage behaviour of Hopea parviflora seeds. Storing the dewinged seeds with a moisture content below 30 per cent resulted in rapid decline in seed viability due to dehydration injuries irrespective of storage temperature. Sand and neemcake was inappropriate as a storage medium because sand favoured early germination of the seeds in storage condition itself and neemcake caused severe desiccation injuries. Storing fungicide treated winged seeds collected just before natural seedsheding, at 100 C retained high germination percentage upto 40 days. Sythetic seeds were also successfully stored up to 1 month at 100C without significant reduction in germination percentage. Two ppm and three ppm ABA was observed to be helpful for maintaining higher germination percentage of synthetic seeds during storage.ThesisItem Open Access Nutrient content and decomposition of leaf litter of Acacia mangium Willd as affected by season and field conditions(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 1995) Ramakrishna, Hegde; KAU; Gopikumar, KA detailed experiment was conducted at the College of Forestry, Kerala Agricultural University, Vellanikkara, Thrissur, during the period from 1993 to 1995 to study the nutrient content and pattern of leaf litter decomposition of Acacia mangium Wild. During south west monsoon and north east monsoon seasons. The experiment was conducted both in home garden and open area. The rate of decomposition was faster in all the study situations. The initial nitrogen, lignin, C:N ratio and lignin : nitrogen ratio of leaf litter were found to exert profound influence on the rate of decomposition. The decomposition rate was found to be a function of time, soil moisture and soil temperature. The nutrient release pattern in almost all cases followed a characteristic biphasic model with an initial rapid phase followed by a slower latter phase. Among the different nutrients, potassium showed a faster rate of mineralisation in most of the situations while calcium and nitrogen mineralised slowly. Among the several mathematical models tried to predict the absolute amount of nutrients in the residual mass, the second order hyperbolic function was found to be good fit in most of the cases. Though the PH was not altered significantly by the decomposing litter mass, the content of most of the nutrient elements is found to be drastically influenced.ThesisItem Open Access Functional dynamics of an agrisilvicultural system involving coconut palms, Multipurpose trees and kacholam(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 1997) Sureshkumar, S; KAU; Mohankumar, BA factorial experiment involving coconut (Cocos nucifera L.) and three multipurpose tree species (Ailanthus triphysa (Dennst.) Alston., Grevillea robusta A. Cunn. and Vateria indica L.) in two planting geometries (single and double hedge) was established in an existing coconut plantation (14 years old) at Vellanikkara in June, 1992. Kacholam (Kaempferia L.), a herbaceous medicinal plant was introduced in this trial as a floor crop in May 1995. Monocultures of coconut and kacholam were also maintained. Objectives of the study included evaluating suitability of interplanting multipurpose trees in coconut plantations, assessing the consequential changes in growth of multipurpose trees productivity of coconut and kacholam and inter alia characterise the above and below ground interactions between field and tree crop components. Coconut yield was not adversely affected by interplanting multipurpose trees until the multipurpose trees were about 4 years old. Multipurpose trees exhibited wide variations in their growth and crown characteristics. Consequently the light availability beneath the canopy was highly dependent on the multipurpose tree species. Availability of photosynthetically active radiation (PAR) was inversely proportional to the stand leaf area index. Available PAR ranged from 18-45 % and 22-45% of that in the open at 50 and 150 cm above ground level respectively. Planting geometry did not influence this parameter significantly. Kacholam grown in the open (sole crop) exhibited better growth as compared to kacholam grown in association with coconut and multipurpose trees. Nevertheless, rhizome yield (at final harvest) was comparable in all the situations. Tissue nutrient content of kacholam was also independent of multipurpose trees. The results suggests the moderate shade tolerant nature of kacholam, which can be highly useful in intercropping. However, no strong relationship could be established between light availability and rhizome yield. Multipurpose trees exhibited considerable root activity in the coconut rhizosphere, as evident from the data on 32P recovery. However, competition for nutrients between the two components was not evident, probably due to the juvenile nature (4 years old) of the multipurpose trees. Even at this stage, the three multipurpose trees exhibited discernable difference in foliar 32P activity. Cross-feeding of kacholam by coconut roots scavenging kacholam beds was noticed. Three to four years of tree growth did not alter the soil nutrient status very substantially. An increase in soil pH and available potassium was, however, observed. Nevertheless, kacholam cultivation resulted in a modest decline in soil nutrient status.ThesisItem Open 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, BAn 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.ThesisItem Open 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, BA 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.ThesisItem Open Access Soil-plant nutritional status of Tectona grandis L.f. in relation to age and site quality(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 1999) Vimal, M; KAU; Sudhakara, KA study was conducted at College of Forestry, Vellanikkara, KAU, during the period 1994-1996 to identify and assess the nutritional factors limiting productivity of teak plantations, of different age groups belonging to different site qualities, spread through out the State of Kerala. The study was aimed to find out the influence of nutrient status of soil and leaf on the growth as represented through volume and current annual increment in basal area per tree. Another objective was to find out the influence of soil characteristics like pH, organic carbon and nutrient contents on foliar nutrient concentration of teak. The leaf samples were analysed for N, P, K, Ca, Mg, Fe, Mn and Zn concentrations. The soil samples were analysed for pH, organic carbon, available P, total N and exchangeable K, Ca, Mg, Fe and Zn. The whole set of 300 trees was divided into three age groups as < = 20 years, > 20 and < = 40 years and > 40 years and stepwise regression was carried out by taking volume as dependent variable for each group separately. The resultant equations in stepwise regression were utilized to characterize the nature of response surface and to find the optimum levels of soil attributes and foliar nutrient elements. For analysing the relationship between soil attributes and foliar nutrient concentrations a technique called canonical correlation analysis was used. The relation between leaf nutrient status and tree volume was feeble in all the three age groups. In all the three age groups, the critical nutrient concentrations with respect to tree volume do not seem to be attained by the levels of nutrients available in the present data set, indicating a increase in tree volume by adequate supply of the appropriate nutrient elements. 2 The relation between tree growth and nutrient status of soil was stronger compared to the relation between the tree growth and nutrient status of soil. For the first two age group selected, the models were linear in nature. For the older plantations (Age > 40 years), almost 50 per cent of the variation in tree volume was explained by the soil nutrient levels. For this age group soil phosphorus had a quadratic term in the model and the point of maximal response for phosphorus was predicted at P = 26.66 ppm. The relationship between current annual increment in basal area per tree and nutrient status of leaves and soil was also linear. Age related change in current annual increment is positively modified by the level of soil nitrogen. To find out the relationship between the leaf attributes and soil attributes canonical correlation analysis was used. For the younger age group (age < = 20 years) soil organic carbon had a significant positive influence on leaf nitrogen and leaf potassium concentrations while it had a negative effect on leaf Fe and leaf Mg concentrations. Also significant positive correlation was seen between leaf Ca and soil Ca for all the age groups. The canonical correlation analysis showed that as the age of the plantations increases and the canopy closure occurs, the leaf nutrient contents influence the soil fertility attributes to a greater extend due to the effect of litter fall.ThesisItem Open Access Nutrient content and decomposition of leaf biomass of selected woody tree species(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 1994) Kunhamu, T K; KAU; Gopikumar, KA detailed study was conducted at the College of Forestry, Kerala Agricultural University, Vellanikkara, Thrissur, Kerala during 1992-94 to compare the rate of decomposition and nutrient release pattern of leaf biomass of five forest tree species namely, Schleichera oleosa (Lour.) Oken, Pongamia pinnata (L.) Pierre, Macaranga peltata, (Roxb) M.–A., Terminalisa paniculata Roth and Bridelia retusa (L.) spreng. The experiment was laid out in a typical home Garden. Generally, all the species under study showed a faster rate of leaf biomass decomposition. Among the various species tested, B. retusa and T. paniculata showed faster rates of leaf biomass decomposition while P. pinnata exhibited relatively a slower rate. The initial leaf nitrogen content and C:N ratio could not establish a direct relationship with rate of decomposition. However, in all the species, lignin content was found to exert a profound influence on mass loss patterns. All the species showed a faster mineralisation of nutrients in accordance with the mass loss pattern. Among the nutrients, potassium followed a faster rate of mineralisation. A relatively good trend for N mineralisation also has been reported for M. peltata, T. paniculata and B. retusa during the course of the study. Generally, Ca, Mg and S exhibited lower rates of mineralisation. T. paniculata and B. retusa followed an efficient release pattern for all the nutrients while P. pinnata showed slower rates of mineralisation with regard to most of the nutrients.
