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Stand density manipulation and fertilization studies on teak
(College of Forestry,Vellanikkara, 1991) Gawande, S R; Mohankumar, B
With the object of standardizing the density manipulation and fertilization strategies for teak, a study was carried out at Vellanikkara during 1990-91. The experimental variables consisted of high, medium and low site quality classes (classified on basis of tree heights), three thinning intensities (control, 30 per cent density reduction and 50 per cent density reduction) and three fertilizer levels (control, 50:25:25 kg of N, P2 O5 and K2O ha -1 yr-1, 100: 50:50 kg of N, P2 O5 and K2O ha-1 yr-1). The results indicate that mean height of trees was strongly influenced by density manipulation. The combination of high site quality with medium and heavy fertilizer doses also significantly increased the mean height of trees. However quadratic mean diameter, stand basal area, basal area increment and height increment were not substantially different among the thinning site quality and fertilization regimes. Tree biomass, foliage area and leaf weight allometry were examined for the first time in teak. The results suggest that leaf area and the biomass yield are strongly dependent on the allometry of trees. High sites consistently recorded higher values for estimates of leaf area, leaf biomass and tree biomass. Combinations of high site quality with medium and heavy thinning as well as medium and heavy fertilization recorded high tree biomass yield, foliage area and leaf area followed by medium and low site quality classes. Foliar analyses showed a general increase in leaf nitrogen during summer (May) and a gradual decline of the same during the fall season (August). High site quality with medium and heavy fertilization recorded highest nitrogen content. Thinning on higher sites significantly increased foliage phosphorus and potassium levels. In general the trend concerning nutrient contents of different tree organs followed the order leaves> stemwood> branchwood. Branch wood and stem wood N levels were relatively higher on high sites. Potassium content was, however, greatest in the low sites. Soil nutrient analysis did not indicate any substantial changes in the soil physico-chemical properties consequent to thinning and fertilization which incidentally substantiates Miller’s hypothesis on forest fertilization that fertilizers benefits only the trees and not the sites.
Open Access
Comparative performance of three exotic tree species in social forestry strip plantation in Trichur Social Forestry Division
(College of Forestry,Vellanikkara, 1990) Nandakumar, G; KAU; KrishnanNair, V R
A study was conducted in 1987-88 on the social forestry strip plantation on the premises of the Sitaram Textile mills Ltd. In the Trichur Social Forestry Division of Kerala State; to compare the performance of three exotic fast growing tree species, Casuarina equisetifolia, Acacia auriculiformis and Eucalyptus tereticornis in social forestry strip plantation. Comparisons were made on the three year old plantation in respect of growth, biomass production and impact on the soil and undergrowth. General observations were also made on the tree form, occurance of pests and diseases and wild life habitat improvement. The site of experiment was being used for dumping coal cinders and other wastes from the textile mill and was barren before planting. The experiment was laid out in RBD with five replications. The results obtained in the study have been summarised below : At the end of the third year Acacia auriculiformis had a DBH of 4.56 cm followed by Eucalyptus tereticornis with 3.82 cm and Casuarina equisetifolia with 1.62 cm. The mean annual diameter increments were 1.44 cm/year in Acacia, 1.20 cm/year in Eucalyptus and 0.51 cm/year in Casuarina. Acacia had more primary branches (27/tree) followed by Eucalyptus (23/tree) and Casuarina (17/tree). The first primary branch was 3.18 m above the ground in Eucalyptus, 2.22 m in Acacia and in 2.16 m in Casuarina. Acacia had 100% survival at the third year while Eucalyptus had 88%. But Casuarina had only 72% survival rates. In growth as well as survival, Acacia auriculiformis was found to be the best among the three. Eucalyptus tereticornis was found superior to Casusrina equisetifolia while the latter was the least impressive of the three. The total biomass yield at the third year was 98.438 mt (drymatter)/ha in Acacia auriculiformis, 48.424 mt/ha in Eucalyptus tereticornis and 12.506 mt/ha in Casuarina equisetifolia. Acacia had a mean annual biomass increment of 32.813 mt/ha. MAI of Eucalyptus was 16.141 mt/ha while that of Casuarina was only 4.169 mt/ha. In biomass production too, Acacia auriculiformis was found superior to Eucalyptus tereticornis and Casuarina equisetifolia. Of the three species Casuarina equisetifolia with a light intensity on the floor of 49.5% was the least shading one, followed by Eucalyptus tereticornis with 43.6% and Acacia auriculiformis with 30.6%. Eucalyptus was found to permit luxuriant undergrowth, so also casuarina. The above ground phytomass was 1.431 kg drymatter/m2 in Eucalyptus and 1,176 kg/m2 in Casuarina. But Acacia was found to inhibit undergrowth (0.183 kg/m2 ). Even the little undergrowth that was permitted by it comprised mostly of its own seedlings. The undergrowth in Eucalyptus comprised mostly of woody species (65.5%) while that of casuarina comprised mostly of grasses (68.5%). The presence of coal cinders had caused a rise in the soil pH, organic matter content, available Nitrogen content and available phosphorus content of the soil. The lowest pH value in the top soil was found in Acacia soil 4.31. Eucalyptus soil had 4.69 and Casuarina soil had 4.94 compared to the barren laterite (5.16) and the barren laterite with coal cinders (5.32). At the depth of 30-45 cm, the pH values were 4.85 in Acasia soil, 5.17 in Casuarina soil and 5.32 in Eucalptus soil. The barren laterite had a pH of 5.24 and in the barren laterite with coal cinders it was 5.42. The pH at 60-70 cm depth was 4.88 in Acacia soil 5.24 in Casuarina soil, 5.33 in Eucalyptus soil, 5.36 in barren laterite and 5.52 in barren laterite with coal cinders. All the three species reduced the pH of the soil. But Acacia auriculiformis was found to lower the pH of the soil more than the other two. pH increased with the depth in all the treatments. The organic carbon contents in the top soils were 0.57% in Acacia, 0.41% in Eucalyptus, 0.49% in Casuarina, 0.39% in barren laterite and 0.43% in barren laterite with coal cinders. The organic matter content was found to decrease as depth increased in all the treatments. There was a general rise in the organic carbon content of the soils due to the impact of the three species with the maximum in Acacia soils and the minimum in Casuarina soils. The available Nitrogen content in the top soil was 1277 kg/ha in Acacia, 1165 kg/ha in Eucalyptus, 1098 kg/ha in Casuarina, 874 kg/ha in barren laterite and 963 kg/ha in barren laterite with coal cinders. There was a reduction in the available Nitrogen content as the soil depth increased in all the treatments. All the three species caused an increase in the available Nitrogen content of the soil, the highest being observed in Acacia auriculiformis followed by Eucalyptus tereticornis. The available Potash content of the soils did not record any change under the different species. The available phosphorus contents of the top soils were 92.7 kg/ha in Casuarina, 90 kg/ha in Eucalyptus, 81.5 kg/ha in Acacia. 79.3 kg/ha in barren lateric and 87.4 kg/ha in the barren laterite with coal cinders. There was reduction in the content of the nutrient as depth increased in all the treatments. In Acacia soils the content of the available Phosphorus had decreased. Regarding the general observations, Acacia auriculiformis showed pronounced branching habits while Eucalyptus and Casuarina had more or less clean boles. Pests and diseases were not observed excepting the pink disease (c.o. Corticium salmonicolor) in Eucalyptus. Crows and rodents were the principal representatives of wild life in the plantion. Honey bees commonly foraged the inflorescence of Acacia. Acacia auriculiformis proved itself to be a highly promising tree for energy plantations and for afforesting sites dumped with coal cinders and for sites offering little protection from anthropogenic influences and grazing. It also improved the organic matter content and available nitrogen content of the soil and was free from graziers. But at the same time there were also unwelcome effects due to Acacia such as increasing the acidity of the soil and supressing undergrowth. It also tended to be highly branching. Eucalyptus tereticornis also was found to be good in growth and biomass production and could be recommended for similar sites. The species also enriched the soil by increasing the contents of organic carbon and available Nitrogen. Though it too reduced the pH of the soil, the species was found to support luxuriant undergrowth and was spared by graziers. Casuarina equisetifolia was a less suitable species for such a site as seen from the performance of the species. It suffered heavily from browsing and showed lesser survival growth and yield. But the species increased the organic carbon content and available Nitrogen content of the soil and permitted luxuriant undergrowth especially grasses.
Open Access
Social behaviour, dominance hierarchy and reproductive behaviour of sambar deer (cervus unicolor)
(College of Forestry,Vellanikkara, 1991) Krishnakumar, Kumar; R, KAU; Jacob Cheeran, V
A study was undertaken to investigate the social behaviour, dominance hierarchy and reproductive behaviour of sambar deer in captivity, mainly with the intention of evaluating the adaptability of the species to captive breeding. This study was conducted on the population of sambar deer in captivity at Trichur and Trivandrum zoos. Behavioural observations were made during a period spanning five months totally – from November – December 1988 to April – May 1989, on days at random. There were 21 deer in the herd at Trichur and 20 at Trivandrum. It was observed that the living conditions of the deer in these zoos are far from comparison to that of their natural habitats. Food, herd size, competition, nearest neighbour relationship etc: are strikingly different from nature. But, in spite of all adversities, the sambar deer have learned to adapt amazingly to changing conditions, and survive fairly well. The physiological processes of their lives, such as antler casting, rut, mating, gestation and delivery remain as scheduled, except for observations that births occur at any time of the year in captivity sometimes, which is in effect to the advantage of the captive -breeder ! Maintenance of ideal herd composition at any given time would help better the living conditions as well as curtail traumatic injuries and casualties. Paucity of adequate space is a serious constraint faced by these zoos. It is time that voluntary organisations and individuals came forward with earnest interest in the upkeep of zoos as in foreign countries ; rather than leaving the whole show in the sole hands of the government as the present practice. General awareness and overall change in the attitude of the public towards our vanishing wildlife is the need of the hour.
Open Access
Anatomy and utilization of two cane species of Kerala
(College of Forestry, Vellanikkara, 1988) Mohan, Varghese; KAU; Bhat, K M
Variation in certain anatomical and physical properties has been investigated and compared in two rattan species, viz. Calamus thwaitesii and C. travancoricus, the former representing the larger diameter and the latter possessing small-diameter canes of kerala. Five stems possing more or less similar number of internodes have been sampled in each of two species. There were significant differences between the two species in certain physical properties such as length and diameter of internode, stem “wood” density and initial moisture content although volumetric shrinkage did not differ appreciably. Similarly, quantitative data for anatomical properties such as corted percentage, number of vascular bundles per unit area, vascular bundle diameter, xylem and phloem percentage, metaxylem vessel element and fibre dimensions were markedly different between the two species while the fibre percentage had almost similar values. With the exceptions of internode size and fibre width, the mean physical and anatomical properties in each species showed definite patterns of longitudinal variation, which could be best explained using quadratic regression models. However, patterns of longitudinal variation were different between the species in volumetric shrinkage, number of vascular bundles per mm2, vascular bundle diameter, phloem percentage, metaxylem vessel element and fibre length. The most important useful features in distinguishing between the two species are internode length, stem diameter, epidermal cell and its lumen shape, diameter and frequency of vascular bundles as well as the diameter of wide metaxylem vessels. The most important determining factors of “wood” density are fibre percentage, fibre wall thickness and lumen width as well as the diameter of metaxylem vessels although features like the size and number of vascular bundles per unit area also influences this property. Volumetric shrinkage and moisture content are inversely related to the density of “wood”. With higher density owing to more thick walled fibres and narrower wide metaxylem vessels, basal portion of the stem is harder and heavier than top portion.
Open Access
Ecological studies of a sacred grove
(College of Forestry, Vellanikkara, 1988) Induchoodan, N C; KAU; Balasubramanian K
Sacred groves serve as unique examples of in situ genetic resource conservation through involvement of local people in the most economic and efficient manner. Ecological studies in Sacred Groves are practically nil and the present investigation, in such a fascinating field has brought out many interesting data for the first time. The forests of Iringole Sacred grove, lying at 100 10’N Latitude and 760 30’ E longitude, within Perumbavoor Municipality can be considered as Southern tropical West coast Evergreen Forest (Low lying). The area is hot and humid with an annual precipitation exceeding 3000 mm. The dry season lasts from January to March.
Open Access
Stand density regulation in even aged teak plantations
(Faculty of Agriculture, College of Forestry, Vellanikkara, 1990) Prasoon, Kumar; KAU; Mohankumar, B
A teak density management diagram was constructed using the stand inventory data on teak collected from Parambikulam, Thrissur and Chalakudy areas. Density management diagram is a graphical representation of the stand growth through time, in terms of density and quadratic diameter, volume, height and Reineke’s stand density index. A size –density based index such as Reineke’s stand density index incidentally provides a good biological basis for the translation of management objective into levels of growing stock. Stand density index (SDI) incidentally is also independent of site quality and age. The data – set also revealed that Parambikulam is a better site for teak followed by Thrissur and Chalakudy. The maximum SDI for teak was found to be 600 which probably covers all possible combinations of size and density included in the data – set. The use of diagram for designing two alternate density management regimes for a hypothetical stand is illustrated. Designing a density management regime requires the translation of management objectives into appropriate levels of growing stock. Maximization of volume production and maximization of individual tree growth are the two alternate but contrasting silvicultural strategies in this context. For maximization of volume per unit area the level of the growing stock should fall in the zone 11 of the Langsaeter’s curve. On the other hand, if the land management objective is to maximize individual tree growth, then trees should not experience much competition (preferably in zone 1 of the Langsaeter’s curve). So, in the former case the levels of growing stock will be naturally higher than that of latter. After fixing the appropriate upper and lower levels of size – density relations the stand is allowed to grow till it reaches upper limit and then thinned down to the lower limit. This process is repeated as many times as necessary. The diagram has diverse utility from designing alternate density management regimes to comparing the results of optimization analyses. However, it suffers from some shortcomings such as lack of memory, prediction of same rotation age irrespective to the path taken by stand, rotation ending before culmination of periodic annual increment, the assumption of single maximum size – density relationship and slight bias of the model with respect to the independent variables outside the range of the data base. However, with more work many of these defects could be over come.
Open Access
Investigation on the production of healthy seedling of teak (Tectona grandis Linn.f.) in the nursery
(College of Forestry, Vellanikkara, 1988) Syam, V; KAU; Chacko, K C
Teak seeds have dormancy which may vary from a few weeks to a year or even years. Selection of a suitable pretreatment to overcome this dormancy has been on age old problem. Several complex and inter – related factors like the physiological condition of the fruit, the special fruit characteristics and the after ripening phenomena complicate the problem. A study was conducted using fruits from seven middle aged teak plantations in Trichur Forest Division. A germination trial was carried out in Factorial Randomized Block Design. The fruits were size graded and four presowing treatments were tested in vermiculite and sand media and the germination characters recorded during a 30 day observation period. A cutting test was also performed before hand to estimate the average emptiness, viability percentage and other fruit characters of the size graded teak fruits. Thereafter the seedlings were transplanted from the germination trays to polybags filled previously with potting mixture and kept in the open. After completion of three months the seedlings were taken out from the polybags and the biometric observations recorded. The tap root, lateral roots, leaves and stem were separately dried to constant weight and the dry weight recorded. The dry matter production of the entire seedling was also computed. From this data the effect of fruit grading, pretreatments and germination media was analysed statistically. It was found that larger sized fruits (above 15 mm diameter) were superior to the other grades with respect to germination characters, seedling growth and dry matter production. The pretreatment of the fruits using GA3 at 100 ppm was significant with respect to germination characters, biometric and biomass observations of the teak seedlings. Vermiculite was a better germination medium for teak seed germination then sand and the seedlings grown in that medium recorded better tap root growth and dry matter production. The potted seedlings thus produced can be used for planting in areas where seedling planting is resorted to for raising new plantations and for replacement of casualities during June – July in areas where stump planting is adopted as the method of artificial regeneration during premonsoon showers in the month of April – May.
Open Access
Regeneration status of some important moist deciduous forest trees in the Trichur Forest Division
(College of Forestry, Vellanikkara, 1988) Narayanan, Illath Valappil; KAU; Mohankumar, B
Sustained management of forests depends on their ability to regenerate. The pace at which the older trees are replaced by younger ones, is very important in this respect. The details of sylvigenesis is little known, especially of the moist deciduous forests. To get a general idea of the regeneration behaviour of the moist deciduous forests eight localities of varying levels of disturbance were sampled in the Trichur Forest Division. Enumeration of trees and their regeneration were done and data were analysed at three levels of organization, viz. ecosystem level, stratum level and species level. Physiognomically the moist deciduous forests comprise three vertical strata namely, upper, middle and the lower. The middle stratum is richest in species. Most of the species represented in the upper stratum are commercially important. Five species, Dillenia pentagyna, Grewia tiliifolia, Lagerstroemia microcarpa, Terminalia paniculata and xylia xylocarpa, occupying the upper stratum, possess higher values of basal area, relative basal area, density per hectare, relative density and importance value index, and are the dominant ones. The average growing stock of desirable commercially important species > = 20 cm DBH per hectare is 149.79. This is slightly lower than the average of 167 trees/ha cited by Seth and Kaul. The growing stock of trees > = 1 cm DBH, of the middle and lower strata decrease exponentially with increasing cover gaps. The upper stratum on the other hand is not much affected by disturbance. In fact, with slight disturbance it increases a little. Relative importance value index of the middle stratum increases where that of the lower straum decreases and vice versa. Frequency distribution statistic for stands and strata conform to the negatively exponential model. Mortality rates are maximum in the lower size classes. Comparison of observed frequencies of unestablished seedlings to the expected frequencies of the commercially important stratum indicates that the reproductive potential of stands is not poor. On the other hand, the growing stock of established seedlings (saplings + poles) is very low. Owing to very low survival probability in the sapling stage acute paucity of poles of the upper stratum is observed. The five dominant species show the same pattern of population structure and distribution of survival probability as the stratum. Regeneration of important species in the moist deciduous forests is under various stresses of which that of human origin is the most hazardous. Grazing, browsing, fire, and illicit cutting are the greatest constraints. Some species like Lagerstroemia microcarpa also show some intrinsic constraints.
Open Access
Spatial arrangement and harvesting schedule in a Silvipastoral system
(Department of Forestry, College of Forestry, Vellanikkara, 1988) Sunil, P L; KAU; Krishnan Nair, V R
An experiment was conducted in the Social Forestry Plantation located at Viyoor, near Trichur from August 1987 to June 1988 to evaluate different spatical arrangements and harvesting schedules in a silvipastoral system. The crop components were subabul and guinea grass. The experiment, replicated thrice, was laid out in a factorial RBD with twenty treatments, involving five spatial arrangements and four harvesting schedules. The results revealed that subabul – guinea grass intercrop gave higher green fodder yields during the summer season compared to a sole crop of either species. Dry matter yields of 1.83 T and 9.36 T/ha/year were obtained from subabul and guinea grass, respectively. The spatical arrangement in which subabul was planted at 1.5 x 1.5 m spacing with five rows of guinea grass between two adjacent rows of subabul and the harvesting schedules in which subabul was harvested every second month and guinea grass 15 days earlier or later recorded higher green fodder yields. Percentage rate of increase in height of grass decreased with increasing light intensity, while tillering rate increased. Light intensity received during the experimental period steadily increased and the maximum lux readings were obtained between 12.20 and 14.20 MST. Soil chemical analysis conducted before and after the experimental period indicated that the organic carbon, available N and soil pH of the intercropped treatments increased significantly. This proved the soil ameliorating properties of subabul.

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