scholarly journals Tree species richness increases ecosystem carbon storage in subtropical forests

2018 ◽  
Vol 285 (1885) ◽  
pp. 20181240 ◽  
Author(s):  
Xiaojuan Liu ◽  
Stefan Trogisch ◽  
Jin-Sheng He ◽  
Pascal A. Niklaus ◽  
Helge Bruelheide ◽  
...  

Forest ecosystems are an integral component of the global carbon cycle as they take up and release large amounts of C over short time periods (C flux) or accumulate it over longer time periods (C stock). However, there remains uncertainty about whether and in which direction C fluxes and in particular C stocks may differ between forests of high versus low species richness. Based on a comprehensive dataset derived from field-based measurements, we tested the effect of species richness (3–20 tree species) and stand age (22–116 years) on six compartments of above- and below-ground C stocks and four components of C fluxes in subtropical forests in southeast China. Across forest stands, total C stock was 149 ± 12 Mg ha −1 with richness explaining 28.5% and age explaining 29.4% of variation in this measure. Species-rich stands had higher C stocks and fluxes than stands with low richness; and, in addition, old stands had higher C stocks than young ones. Overall, for each additional tree species, the total C stock increased by 6.4%. Our results provide comprehensive evidence for diversity-mediated above- and below-ground C sequestration in species-rich subtropical forests in southeast China. Therefore, afforestation policies in this region and elsewhere should consider a change from the current focus on monocultures to multi-species plantations to increase C fixation and thus slow increasing atmospheric CO 2 concentrations and global warming.

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Tarit Kumar Baul ◽  
Avinanda Chakraborty ◽  
Rajasree Nandi ◽  
Mohammed Mohiuddin ◽  
Antti Kilpeläinen ◽  
...  

Abstract Background The homestead forests of Bangladesh occupy 0.27 million hectares (10% of the total forested area) and have potential to store carbon (C) and conserve biodiversity. Small scale forestry practices, however, are lacking reliable estimation of C stocks and tree species diversity. This may hinder successful implementation of REDD + and similar mechanisms as they concentrate on large-scale forests. This study aimed to estimate the above- and below-ground carbon stocks in homestead forests of Maheshkhali Island in Bangladesh and how tree species diversity and stand structural variation affect these C stocks. We randomly surveyed a total of 239 homestead forests in the hillside, beachside, and inland in 2019. Results Tree biomass C stocks were 48–67% greater in the inland and hillside forests than in the beachside due to significantly greater stand density, basal area, tree diameter. In total we found 52 tree species, but most abundant species in the inland and hillside forests, Mangifera indica, Samanea saman, and Artocarpus heterophyllus stored the most C in tree biomass. Greater tree species richness and diversity index in the inland and hillside forests indicated greater above- and below-ground tree biomass C stocks. An increase in tree species richness and diversity index by one unit was found to increase the tree biomass C stock by 22 and 30 Mg C ha−1, respectively. The total soil C stock was also affected by tree species diversity, stand density, and their interaction with soil properties. Total soil C stocks were greatest (51 Mg ha−1) in the inland forests, having also the greatest stand density and tree species richness. C stock in soil surface was greatest in the hillside forests due to the greatest litterfall, but the average share of litterfall from the total biomass C was only 0.1%. Conclusions Homestead forest ecosystems could store 96 Mg C ha−1 in total, which can contribute to climate change mitigation by generating C credits for small-scale homestead forests owners. Above- and below-ground tree biomass C stocks were found to correlate with tree species diversity, which may also contribute to biodiversity conservation in the REDD + in Bangladesh and countries alike.


2020 ◽  
Author(s):  
Tarit Kumar Baul ◽  
Avinanda Chakraborty ◽  
Rajasree Nandi ◽  
Mohammed Mohiuddin ◽  
Antti Kilpeläinen ◽  
...  

Abstract BackgroundThis study aimed to estimate the carbon (C) stocks in homestead forest ecosystems (trees, litterfall, and soil) of Maheshkhali Island in Bangladesh and how tree species diversity and stand structural variation affected these C stocks. We randomly surveyed a total of 239 homestead forests proportionately allocating in hillside (67), beachside (69), and inland (103) in 2019 for measuring woody plants and sampling litterfall and C in soil at 0-30 cm depth. Tree (above- and below-ground) biomass was estimated by using pan-tropical allometric equations, and carbon of litterfall and soil were analyzed in a laboratory. ResultsWe found a total of 52 tree species, of which, 41, 42, and 48 species were in the hillside, beachside, and inland, respectively, corresponding to the individuals of 840, 540, and 1504 sampled. According to the results, species diversity, richness, stand density, basal area (BA), and tree diameter at breast height (DBH) and height were significantly (p ≤ 0.05) greater in the hillside and inland homestead forests, compared to the beachside. Most abundant species, for example, Mangifera indica, Samanea saman, and Artocarpus heterophyllus in the inland and hillside homestead forests stored most C in biomass, compared to the beachside forest. Tree biomass C stocks were 48-67% greater in the inland and hillside than on beachside forests due to significantly (p ≤ 0.05) greater stand density, BA, and DBH. The overall C stock of litterfall was 0.1% of the total biomass carbon. C stock in soil surface was greatest in the hillside homestead forests due to the greatest litterfall. The total soil C stock was also affected by tree species, stand density and species richness, and their interaction with soil properties. Total soil C stocks across the depths were greatest (51 Mg ha-1) in the inland homestead forests, with the greatest stand density and species richness. ConclusionsHomestead forest ecosystems across the area stored total 96 Mg C ha-1, which thus can contribute to climate change mitigation while generating C credit for small-scale homestead forests owners as well as conserving biodiversity in Bangladesh and countries alike.


Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1810
Author(s):  
Reimo Lutter ◽  
Gustav Stål ◽  
Lina Arnesson Ceder ◽  
Hyungwoo Lim ◽  
Allar Padari ◽  
...  

The new European Union Forest Strategy for 2030 aims to plant an additional 3 billion trees on non-forest land to mitigate climate change. However, the choice of tree species for afforestation to achieve the maximum climate benefit is unclear. We compared the climate benefit of six different species in terms of carbon (C) sequestration in biomass and the harvested wood substitution in products to avoid carbon dioxide (CO2) emissions from fossil-based materials over the 100-year period by afforesting about ¼ of the available area in northern Europe. The highest climate benefit was observed for larch, both at a stand scale (1626 Mg CO2 eqv. ha−1) and at the landscape level for the studied scenario (579 million Mg CO2 eqv.). Larch was followed by Norway spruce, poplar, hybrid aspen and birch, showing a climate benefit about 40–50% lower than that for larch. The climate benefit of willow was about 70% lower than larch. Willow showed 6–14-fold lower C stocks at the landscape level after 100 years than other tree species. The major climate benefit over the 100-year period comes from wood substitution and avoided emissions, but C stock buildup at the landscape level also removes significant amounts of CO2 already present in the atmosphere. The choice of tree species is important to maximize climate change mitigation.


2020 ◽  
Author(s):  
David Lefebvre ◽  
Jeroen Meersmans ◽  
Guy Kirk ◽  
Adrian Williams

<p>Harvesting sugarcane (Saccharum officinarum) produces large quantities of biomass residues. We investigated the potential for converting these residues into biochar (recalcitrant carbon rich material) for soil carbon (C) sequestration. We modified a version of the RothC soil carbon model to follow changes in soil C stocks considering different amounts of fresh sugarcane residues and biochar (including recalcitrant and labile biochar fractions). We used Sao Paulo State (Brazil) as a case study due to its large sugarcane production and associated soil C sequestration potential.</p><p>Mechanical harvesting of sugarcane fields leaves behind > 10 t dry matter of trash (leaves) ha<sup>-1</sup> year<sup>-1</sup>. Although trash blanketing increases soil fertility, an excessive amount is detrimental and reduces the subsequent crop yield. After the optimal trash blanketing amount, sugarcane cultivation still produces 5.9 t C ha<sup>-1</sup> year<sup>-1</sup> of excess trash and bagasse (processing residues) which are available for subsequent use.</p><p>The available residues could produce 2.5 t of slow-pyrolysis (550°C) biochar C ha<sup>-1</sup> year<sup>-1</sup>. The model predicts this could increase sugarcane field soil C stock on average by 2.4 ± 0.4 t C ha<sup>‑1</sup> year<sup>‑1</sup>, after accounting for the climate and soil type variability across the State. Comparing different scenarios, we found that applying fresh residues into the field results in a smaller increase in soil C stock compared to the biochar because the soil C approaches a new equilibrium. For instance, adding 1.2 t of biochar C ha<sup>‑1</sup> year<sup>‑1</sup> along with 3.2 t of fresh residue C ha<sup>‑1</sup> year<sup>‑1 </sup>increased the soil C stock by 1.8 t C ha<sup>‑1</sup> year<sup>‑1 </sup>after 10 years of repeated applications. In contrast, adding 0.62 t of biochar C ha<sup>‑1</sup> year<sup>‑1</sup> with 4.5 t of fresh sugarcane residues C ha<sup>‑1</sup> year<sup>‑1 </sup>increased the soil carbon soil stock by 1.4 t C ha<sup>‑1</sup> year<sup>‑1</sup> after 10 years of application. These are reductions 25% and 40% of the potential soil C accumulation rates compared with applying available residues as biochar.   </p><p>We also tested the sensitivity of the model to biochar-induced positive priming (i.e. increased mineralization of soil organic C) using published values. This showed that the C sequestration balance remains positive over the long term, even considering an extremely high positive-priming factor. Upscaling our results to the total 5 Mha of sugarcane in Sao Paulo State, biochar application could sequester up to 50 Mt of CO<sub>2</sub> equivalent per year, representing 31% of the emissions attributed to the State in 2016.</p><p>This study provides first insights into the sequestration potential of biochar application on sugarcane fields. Measurements of changes in soil C stocks in sugarcane field experiments are needed to further validate the model, and the emissions to implement the practice at large scale need to be taken into account. As the climate crisis grows, the need for greenhouse gas removal technologies becomes crucial. Assessing the net effectiveness of readily available technologies is essential to guide policy makers.  </p>


2018 ◽  
Vol 285 (1888) ◽  
pp. 20182090 ◽  
Author(s):  
Xiaojuan Liu ◽  
Stefan Trogisch ◽  
Jin-Sheng He ◽  
Pascal A. Niklaus ◽  
Helge Bruelheide ◽  
...  

2019 ◽  
Vol 15 (4) ◽  
pp. 20180866 ◽  
Author(s):  
Anne Ola ◽  
Arnault R. G. Gauthier ◽  
Yanmei Xiong ◽  
Catherine E. Lovelock

Mangroves harbour large soil organic carbon (C) pools. These C stocks are attributed to the production and slow decomposition of the below-ground biomass. Novel in-growth containers were used to assess the effect of soil bulk density (BD: 0.4, 0.8 and 1.2 g cm −3 ) on morphological, anatomical and chemical traits of the below-ground fraction of aerial roots of the mangrove Rhizophora stylosa . Dense soils increased total root biomass and primary root diameter, while the primary root length decreased. Furthermore, high soil BD reduced aerenchyma lacunae and led to the formation of structural features such as fibrous strands. These morphological and anatomical changes were not reflected in tissue chemistry, with lignin levels averaging 17.0 ± 0.6%, although roots grown in high BD had higher nitrogen levels. This likely affects decomposition rates. Thus, variation in soil BD has major implications for C sequestration in Rhizophora- dominated mangroves.


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