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ThesisItem Open Access Pheno-morphological studies of selected tree species in a tropical forest ecosystem(Department of Tree Physiology and Breeding, College of Forestry, Vellanikkara, 1994) Gopakumar, S; KAU; Luckins Babu, CA pheno – morphological study was carried out in pattikad Range of Trichur Forest Division, Kerala. Two groups of ten species each, where each group represented the moist deciduous and the semi – evergreen tract, were used for the present investigations. The study was initiated in March 1993 and was continued for a calendar year upto February 1994. The study was pursued with the objectives of supplementing information on the different phonological cycles of the commonly found species of this forest area. Along with this, the important macromorphological features of these trees were noted. An attempt was also done to understand the tree architectural principles of these species. The pattering of the phonological events like flowering, fruiting, leaf fall and leaf flushing, no doubt, are partly under endogenous control. However, in general, the timing of these life cycle events were noticed to follow a climatic cue. The deciduous habit exhibited by the study species during the dry weather had an ecological significance, because it strongly helped the trees to tide over the moisture limiting summer months. Likewise, dry season flower and fruit production shown by the species might be a part of a much complex adaptive strategy developed by these species through the course of competitive evolution. Apart from these climatic triggers, there exists possibilities of several, other external stimuli, that might have favoured these important seasonal cycles. However, the cardinal factor effecting these events would be the climatic factors, through its direct and indirect influences on the physiological mechanisms of these woody plants. Regarding tree architecture, it was noted that all the species build up through a progressive duplication of their basic architectural units. This architectural metamorphosis continued from seedling stage upto the death of the tree. Branch production and initiation of sexuality were intermediate events. However, the free expression of the architecture was found drastically affected, possibly due to the different stresses that perennial woody species encounters in its long life span.ThesisItem Open Access Incidence of tapping panel dryness in rubber in the small holdings of Meenachil Taluk(Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 1994) Sebastian Michael; KAU; Kesavachandran, RThe study was conducted to find out the extent of incidence of TPD and related parameters in the rubber growing small holdings of Meenachil taluk. Fifty four small holders who sell their produce as latex and representing different parts of the taluk were selected for the study. Holdings with trees tapped either on BO 1 or Bo 2 panel only were included in the study. The study revealed that the small holders have high preference for the clone RRII 105 due to its inherent capacity for faster growth, higher yield and disease resistance. Rainguarded tapping is not being practiced on a large scale, as only 35.19 per cent of the holdings resorted to this practice. Tapping intensity in the surveyed holdings was invariably 1/2S d/2, without any rest on Sundays. Planting density varied from 460 ha-1 to 550 ha-1 and density of trees under tapping varied from 300 ha-1 to 500 ha-1. Planting density upto 550ha-1 was found not to have any effect on bark thickness or incidence of TPD. The mean incidence of TPD, in terms of complete dry cuts, was 7.56 per cent for the clone RRII 105. During the initial four years of tapping, the incidence was below five per cent in the holdings surveyed. In the present study, positive correlation was observed between dry rubber yield per unit area and incidence of TPD. Mean bark thickness showed highly negative correlation with incidence of TPD. Also, bark thickness was found to have highly significant positive correlation with annual mean drc. But no correlation was observed between annual mean drc and TPD incidence. Bark consumption showed highly significant correlation with TPD incidence, and non significant correlation with yield. This indicates induction of TPD by recovery tapping without concomitant increase in yield. Thus comparable incidence of TPD was encountered in rainguarded and nonrainguarded holdings, without realizing comparable yield. Low incidence of TPD was observed in plantations with slower growth. High incidence of TPD was generally observed near house holds and cattle sheds, in low lying areas, banks of rivers and canals etc.ThesisItem Open Access Food and feeding habits of Asian elephants (Elephas maximus Linn.) - A case study of Idukki wildlife sanctuary(Department of Wildlife Science, College of Forestry, Vellanikkara, 1994) Vinod, T R; KAU; Jacob, V CheeranThe present investigation was carried out in Idukki wildlife Sanctuary, Kerala during 1992 – 94 with the objective of identifying the food plants of elephants and to study the feeding habits of the animal in its natural condition. The study also aimed at finding out how elephants acts as a seed dispersal agent and to estimate the elephant population in the study area. Information on food plants of elephants in the study area was obtained by direct observation. Activity time budget was also studied by direct observation. The proportion of time spent in grazing, browsing and debarking, were computed by observing the elephants in different habitats and noting the time spent on each category of feeding. Elephants in Idukki Wildlife Sanctuary were found to feed on 61 species of plants. About 38 per cent of the food plants belong to the family Poaceae. Barks of 24 species of trees were eaten. Fruits of Careya arborea and Dillenia pentagyna were also commonly consumed by elephants. Feeding accounted for 65.45 per cent of elephant activity in dry season whereas it was 80.77 per cent in wet season. Time spent in drinking varied from 2.73 per cent in dry season to 1.96 per cent in wet season. The seasonal difference in time spent in feeding is found to be significant whereas that of drinking is found to be non-significant. Grazing was predominant in both dry (63.89 per cent) and wet (71.43 per cent) seasons. Search for fresh elephant dung were made and undamaged seeds were collected. Trees were located and raw seeds were also collected and the germination rate was compared with raw seeds. Elephant in the area was found to act as a seed dispersal agent. A total of 682 seeds representing 4 species were collected from the elephant dung. Seeds of Dillenia pentagyna and Careya arborea were found to be most frequent and abundant in the dung examined. The germination rate was slightly higher in the ingested seeds as compared to the fresh seeds collected from the trees. A direct simultaneous count was made in the area. A total of 72 elephants were observed. The ecological density was estimated to be 1.6 animal/Km2 and crude density was about 0.9 animal /Km2. Herd size varied from 1 to 19 in wet season to 1 to 10 in dry season. The male-female ratio of adults was found to be 1:15.3. Dung density distribution showed a clear movement of elephants from the sanctuary to the adjoining areas.