Biomass and carbon estimation for scrub mangrove forests and examination of their allometric associated uncertainties

Abstract

Reliable estimates of biomass and carbon storage are essential for the understanding of the environmental drivers and processes that regulate the productivity of scrub forests. The present study estimated total (above-ground, AGB + below-ground, BGB) biomass and carbon storage of a scrub forest dominated by Avicennia germinans (L.) L. based on the existing allometric models for the AGB, while novel models were developed to estimate the BGB. Data collection followed a destructive approach by using the "sampling method", from 45 trees divided into three height classes. Tree height and diameter were used to estimate the BGB of these forests, providing more accurate estimates of their biomass. Our findings indicate the existence of a direct relationship with increasing topography and interstitial salinity, which result in an increase in the percentage contribution of the AGB. By contrast, increasing topography also led to reduction in tree height and contribution of the BGB, although this compartment represents approximately half of the total biomass of these forests. The contribution of BGB estimates increased from 43 to 49.5% from the lowest to the highest height class and the BGB and AGB values reached approximately 87 Mg ha-1 (48.6%) and 91.7 Mg ha-1 (51.4%), respectively. The estimates of the biomass and carbon stocks of scrub mangroves vary considerably worldwide, which reflects the uncertainties derived from the application of distinct sampling methods. Specific models developed for each height class should be considered instead generalist models to reduce the general uncertainties on the production and distribution of biomass and the storage of carbon. Overall, our results overcome a major lacuna in the development of allometric equations to estimate the production of BGB and the storage of carbon by scrub mangrove forests, contributing to the refinement of the total biomass estimates for this type of mangrove forest.

Standing Crop Biomass and Carbon Content of Mangrove Avicennia marina (Forssk.) Vierh. along the Red Sea Coast of Saudi Arabia

“…In accordance with existing research [14,65,66], these results illustrated the critical dependence of natural carbon stocks and plant establishment in A. marina forests on multiple environmental factors. They also served to demonstrate how, even when within the same or very similar habitats, these factors can change dramatically, causing observable alterations to the ecosystems.…”

“…For the northern or central locations, it is the transplanted mangroves in Egypt's Nabq and Ras Mohammed Protected Area (53.1% AGB) [88], Bangladesh's Oligohaline zone of the Sundarbans (64.8% AGB) [89], and Mozambique's Sofala Bay (52% AGB) [87] that show similar values. Biomass overall was purported to differ considerably over climate gradients by Simard et al [90], and a significant number of authors concur that geomorphological settings also have a substantial impact on biomass [25,26,66]. Although the proportion of AGB was still greater than BGB in the central and northern locations, they were both significantly closer to being evenly split than the southern zone; i.e., the BGB-to-AGB ratios were 0.7 in the north, 0.6 in the centre, and 0.4 in the south.…”

Salt marsh vegetation and secured woody debris facilitate the recolonization of Avicennia germinans

“…Instead, the degraded area has been recolonized naturally by A. germinans, Laguncularia racemosa and succulent herbaceous vegetation with Blutaparon portulacoides and S. portulacastrum (Menezes et al, 2008). However, hypersalinity has restricted tree height growth to below 2 m, resulting in a shrub-like and multi-stemmed dwarf tree architecture (Cohen & Lara, 2003;Virgulino-Júnior et al, 2020). The remaining CWD has been distributed throughout the area but was, at the time this study was carried out, fixed under partial sedimentation.…”

Dynamics of Biomass Stocks in Areas of Secondary Forest Located in Western Amazon Between 2016 and 2020

“…Allometric equations are important for their application in forest biomass and carbon assessments both locally and nationally. Generalized pan-tropical models of biomass estimation equations have been developed by several researchers (Kenzo et al 2020;Virgulino-Júnior et al 2020;Romero et al 2020;Zhou et al 2021;Latifah et al 2021;Saha et al 2021). The adjustments to these equations were obtained by measuring multiple tree species and several distinct locations and are intended to be applied to a wide variety of tropical forests.…”