Contribution of Tree Size and Species on Aboveground Biomass across Land Cover Types in the Taita Hills, Southern Kenya

Abstract

Tropical landscapes comprise a variety of land cover (LC) types with characteristic canopy structure and tree species. Depending on the LC type, large-diameter trees and certain tree species can contribute disproportionately to aboveground biomass (AGB), and these patterns are not described at landscape-level in LC type specific studies. Therefore, we investigated the impact of large trees and tree species on AGB across a range of LC types in Taita Hills, Kenya. Data included 239 field plots from seven LC types: Montane forest, Plantation forest, Mixed forest, Riverine forest, Bushland, Grassland, and Cropland and homestead. Our results show that the contribution of large trees (DBH > 60 cm) on AGB was greatest in Riverine forest, Montane forest and Mixed forest (34–87%). Large trees were also common in Plantation forests and Cropland and homestead. Small trees (DBH < 20 cm) covered less than 10% of the total AGB in all forest types. In Grassland, and Cropland and homestead, smaller DBH classes made a greater contribution. Bushland differed from other classes as large trees were rare. Furthermore, the results show that each LC type had characteristic species with high AGB. In the Montane and Mixed forest, Albizia gummifera contributed 21.1% and 18.3% to AGB, respectively. Eucalyptus spp., exotic species planted in the area, were important in Mixed and Plantation forests. Newtonia hildebrandtii was the most important species in Riverine forests. In Bushland, Acacia mearnsii, species with invasive character, was abundant among trees with DBH < 30 cm. Vachellia tortillis, a common species in savannahs of East Africa, made the largest contribution in Grassland. Finally, in Cropland and homestead, Grevillea robusta was the most important species (>25% of AGB). Our results highlight the importance of conserving large trees and certain species to retain AGB stocks in the landscape. Furthermore, the results demonstrate that exotic tree species, even though invasive, can have large contribution to AGB.

Green Innovation, Carbon Storage and Perceived environmental quality in Lagos State University, Nigeria

“…In another study, Lutz et al [36] stated that trees with large-diameters store considerable quantities of carbon required to lessen climate change. Also, Stephenson et al [37] cited in Mildrexler et al [31] stated that a single large tree is able to store the similar quantity of carbon to the forest in a year more than in an individual medium-sized tree of the similar type. Canopy projection area (CPA) or canopy cover ranged from 4.6 to 18.6 m2 with a mean value of 12.38 m.…”

Carbon Biomass Estimation Using Vegetation Indices in Agriculture–Pasture Mosaics in the Brazilian Caatinga Dry Tropical Forest

“…Forests and family farming contribute to carbon sequestration, while mechanized agriculture can lead to greenhouse gas emissions [1][2][3]. While the mapping of carbon storage and sequestration has been extensively studied in forest regions [4][5][6], there is a lack of research focusing on semiarid areas [7][8][9] and on estimating carbon in different types of vegetation, including regions with agricultural activities [10].…”