Abstract
The sub-tropical broadleaved forests in Pakistan are the main constituents of the ecosystem services playing a vital role in the global carbon cycle. Monotheca buxifolia (Falc.) A. DC. is an important constituent of these forests, encompassing a variety of ecological and commercial uses. To our best knowledge, no quantitative studies have been conducted in these forests across the landscape to establish a baseline for future monitoring. We investigated the forest structural attributes, growing stock characteristics and total biomass carbon stock and established relationships among them in the phytocoenosis of Monotheca forests along an altitudinal gradient in Pakistan to expand an eco-systemic model for assessment of the originally-implemented conservation strategies. A floristic survey recorded 4986 individuals of 27 species in overstory and 59 species in the understory stratum. Species richness (ANOVA; F = 3.239; p = 0.045) and Simpson’s diversity (ANOVA; F = 2.802; p = 0.043) differed significantly in three altitudinal zones, with a maximum value for lower elevations, followed by middle and higher elevations. Based on the importance values, Acacia modesta and Olea ferruginea are strong companions of M. buxifolia at lower and higher altitudes, whereas forests at mid elevation represent pure crop of M. buxifolia (IVI = ≥85.85%). A similar pattern in stem density, volume and Basal area were also recorded. The carbon stock in trees stratum (51.81 T ha−1) and understory vegetation (0.148 T ha−1) contributes high values in the lower elevation forests. In contrast, soil carbon had maximum values at higher elevation (36.21 T ha−1) and minimum at lower elevation (16.69 T ha−1) zones. Aboveground biomass carbon stock (AGB BMC) of woody trees, understory vegetation and soil organic carbon (SOC) were estimated higher (77.72 T ha−1) at higher and lower (68.65 T ha−1) elevations. Likewise, the AGB BMC exhibited a significant (p < 0.05) negative correlation with elevation and positive correlation with soil carbon. We concluded that lower elevation forests are more diverse and floristically rich in comparison to higher altitudinal forests. Similarly, the biomass carbon of Monotheca forests were recorded maximum at low altitudes followed by high and middle ranges, respectively.
Highlights
Climatic change is a burning issue across the globe as the earth temperature raises up to 4 ◦ C due to greenhouse gases [1]
The study reported a total of 86 plant species belonging to 70 genera and 52 families in the phytocoenosis Monotheca forests.) Of the recorded flora, 31.4% (27 species) were from tree stratum and contributed 25 genera and 22 families, while the remaining 64.5% were shared by shrubs (38.4%), herbs (25.6%) and grasses (4.6%)
The favorable association between plant species richness and altitudinal gradient has already been proven in various studies [4,58,59]; it revealed that species richness is highly influenced by altitudinal linked factors [60]
Summary
Climatic change is a burning issue across the globe as the earth temperature raises up to 4 ◦ C due to greenhouse gases [1]. Carbon is the major component of greenhouse gases that can be reduced by the terrestrial ecosystem budget [2]. The terrestrial ecosystem is considered one of the best and most vital constituents for the storage of carbon [3]. In comparison with other ecosystems, forest ecosystems have the ability to store and sink a high amount of atmospheric carbon because of their longevity and woody nature [4], which makes them a useful and smart choice in the moderation of global climate alteration [5]. During the last few decades, both natural and man-made hazards resulted in the decrease of forest cover, which significantly reduced its role in mitigating the effect of climate change [9]. Due to the unavailability of basic facilities, the deforestation rate is more visible in underdeveloped and developing countries [10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
