A. Raizada , M. S. Rama Mohan Rao , K. T. N. Nambiar , M. Padmaiah

Abstract

Biomass prediction models were prepared for 17 year old Acacia nilotica trees raised on salt affected vertisols of the semi arid tropics in Karnataka. A. nilotica was raised at 8×8 m spacing with an under storey of three grass species - Cenchrus ciliaris, Dicanthium annulatum and Chloris bourneii for the production of fodder. Wide variations occurred in the trees sampled by random selection in the plantation, with respect to diameter (3.1 to 16 cm) and tree height (3.5 to 5.1 m). Leaf biomass varied from 0.5 to 3.1 kg/tree, contribution by big branches (> 2 cm dia.) varied from 3.81 to 24.13 kg/tree. Total above ground biomass ranged from 26.5 to 100.74 kg/tree. Prediction models with the best fit were in the linear form with r² values of 0.8261, 0.9162 and 0.8665 for predicting bole, utilizable and total above ground biomass.

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A. Raizada , S. K. Dhyani , V. N. Sharda

Abstract

Continued degradation of natural forests in India and increased anthropogenic pressures on scarce natural resources are issues of concern. The resilience and potential of degraded forests to recover, under protection, on their own towards more complex communities are described in this review paper. The need to involve 'local' forest dependant communities in forest protection through suitable mechanisms is also highlighted. The appearance of shade loving and shade tolerant species after twenty years of forest fallow cycle and increased species diversity in North-East India, indicates the need for a long fallow cycle after slash and burn agriculture. In the Shiwaliks community protection of forests in watersheds led to significant improvements in species stocking rate. In the ravines of Central India, continued protection led to the appearance of a large number of annual and perennial grasses, herbs and shrub species besides an assortment of tree species. Vegetation development however showed variations with regard to topographical situations. In landslide affected areas in the Himalayas, a period offive to six years was required for pioneer species to be replaced by perennial species. Soil nutrient build up however took several decades to occur, after which stable plant communities established themselves. In areas affected by mining, interventions in the form of suitable soil and water conservation techniques were a prerequisite for vegetation establishment and development. The appearance of early and late colonizers were observed to be directly related to improvements in edaphic conditions. Forest dependant rural communities are often cited to be the culprits with regard to forest exploitation. This paper, on the other hand cites some examples where rural communities have been able to protect, conserve and regenerate large areas of natural forest on their own initiative and by local institutional mechanisms. Participatory planning and inlegrated watershed development, specially in ecologically fragile zones like the Himalayas are essential for ensuring environmental security.

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A. Raizada , A. K. Parandiyal , B. N. Ghosh

Abstract

The paper deals with the estimation of C flux through litterfall (total and leaf litterfall alone) in forest plantations of India, occurring in four major forest groups of India. Using published studies covering 82 stands and 24 species raised as plantations, the annual C flux rates were computed. The C flux rates (M t C/yr) from total litter were 2.17, 1.18, 1.60 and 2.30 in tropical moist deciduous forests, tropical dry deciduous forests, montane sub-tropical forests and montane temperate forests, respectively. The C flux rates from leaf litter alone were highest (3.03 M t C/year) in montane sub-tropical forests. Results indicate that plantations of short rotation tree species with regular leaf shedding patterns have more C sequestering capacity than species with unimodal or bimodal leaf shedding patterns. Such species could be raised in wastelands for twin purposes - biomass production and carbon sequestering.

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A. Raizada , J. S. Samra

Abstract

Rehabilitation of mine spoiled areas through suitable bioengineering measures and allowing natural succession of vegetation to progress is an essential step towards ecosystem recovery. In this paper, the effect of such measures accompanied with protection of an abandoned limestone mine have been described. Development of vegetation and its phytosociological characteristics were compared with an adjoining but slightly disturbed natural forest situated in the lower sub-humid Himalayan region. In the rehabilitated area, an introduced species Leucaena leucocephala, had the highest Importance Value Index (IVI) of 66.05, followed by a sedge species Eriophorum cosmosum (lVI 58.85) and Acacia catechu (IVI 51.85). The area also supported a significant growth of Thysaloena maxima and Saccharum spontaneum. In the adjoining non-mined forest, the highest IVI value was recorded for Corcorus laurifolius (55.98), followed by Mallotus phillipensis (47.55), Murraya koenigii (38.71) and Bauhinia retusa (37.02). These species, which are associates of Shorea robusta forests, are valuable fodder species in the region specially during the winters, and were, therefore, not harvested while timber yielding species like Shorea robusta and Toona ciliata are now totally absent from the area. Cluster analysis and ordination by Principal Component Analysis (PCA) revealed distinct loading of plots along different axis due to an underlying edaphic gradient, external seeding and soil moisture availability. Diversity (H') of tree species in the natural forest was higher than the rehabilitated area, which otherwise had higher diversity values for shrubs and grasses. It is suggested that existing levels of biotic disturbances be restricted for some more time to provide an opportunity for late colonizers to establish themselves in the area.

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J. Jayaprakash , A. C. Rathore , A. Raizada , Charan Singh , M. G. Dasthagir

Abstract

To improve the growth and yield of Acacia nilotica Linn. (Babul) a study was conducted using genetically superior elite trees. The study revealed that the selected traits viz. plant height, basal diameter, number of branches and volume were highly significant which indicate higher variability among half-sibs. Further, regression analysis revealed that the half-sibs of TNPKM1 and KRKL2 are best and may be utilized for future breeding programmes. Overall study implies that the traits like plant height, basal diameter and number of branches have maximum influence on volume, hence the traits will be useful in selecting Acacia nilotica trees for agroforestry development programmes.

Keywords

Genetic Advance, Phenotypic Variation, Genotypic Variation

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A. Raizada , M. Padmaiah

Abstract

The effect of tree stump spacing on sprouting and growth of sprouts was studied in four tree species (Azadirachta indica, Acacia nilotica, Leuctuma leucocephala and Eucalyptus hybrid), in a 6 and 5 year old energy plantation, growing in the semi-arid vertisols in Karnataka State. Bark thickness did not appear to be a hindrance in permitting sprouting of coppice shoots, although stump diameters were greater under wider spacing (3 × 1 m). Sprouting took place in all four species, and the optimum spacing for obtaining tall coppice shoots was 3 × 1 m for A. nilotica and L. leucocephala, and 2 × 2 m for A. indica and Eucalyptus hybrid.

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