International Journal of Research and Scientific Innovation (IJRSI) |Volume IX, Issue XI, November 2022|ISSN 2321-2705
P. G. Dikwaththa1*, D. T. Jayawardana1, and D. Pindeniya2
1Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Sri Lanka
2Wetland Management Division, Sri Lanka Land Reclamation and Development Corporation, Sri Lanka
*Corresponding Authors
Abstract: Annona glabra is a widely spreading invasive species which reduces biodiversity in ecosystems. The volume prediction of the tree is imortant for better preventive measures. The objectives of the study were to construct a volume prediction model, determination of the root and shoot ratio and field measures of A. glabra. Random sampling was used in Thalangama tank to collect the data from two age classes of 7 years and 12 years. Total biomass was estimated using fresh weight and dry weight of destructive tree samples. Mean total tree biomass estimated for 7 years and 12 years are 6.98 kg per tree (±0.42) and 7.59 kg per tree (±0.40) respectively. Root: shoot ratio for 7 years and 12 years are 1: 2.6 and 1: 2.4 respectively. Model for predicting tree age and tree volume estimated by regression analysis and the best fit models were selected based on R2 value. The models were construted of Age = (-2.527) + (1.525 Ht) for prediction of age of tree and V = (-0.014) + 5.494 BA + 0.002 Ht for prediction of individual height of tree of A. glabra. The introduced models of A. glabra would provide better calculation of volume stock and helps in better management practises of wetland ecosystems.
Keywords: Annona glabra, invasive species, tree modelling, biomass, DBH
I. INTRODUCTION
Wetlands are the most diversified, dynamic, productive, and environmentally delicate regions on Earth. These wetlands play a significant role in maintaining ecosystem services including preserving the hydrological cycle, agricultural production, fisheries, water filtration, biodiversity and habitat for many flora and fauna species, and regulation of the climate and socio-economic support systems for the city inhabitants [8], [34]. Though, Stakeholders, the government, and the general public continue to disregard or undervalue the value of wetland ecosystems since the majority of the services they provide are not been traded in the economic market [34].
Colombo can be considered as a city built on and around wetlands. Wetlands within the Colombo metropolitan region (CMR) have been progressively degraded with time, infilled and lost. Human activities are progressively degrading the wetlands within the CMR which alter the hydrological dynamics represents a significant threat to native biodiversity across the wetlands. According to Amarasinghe, 2019 [3] unplanned and poorly regulated developments, failure to manage solid waste disposal, a range of point and diffuse