High aboveground carbon stock of African tropical montane forests

Abstract

Tropical forests store 40-50% of terrestrial vegetation carbon 1 . Spatial variations in aboveground live tree biomass carbon (AGC) stocks remain poorly understood, in particular in tropical montane forests 2 . Owing to climatic and soil changes with increasing elevation 3 , AGC stocks are lower in tropical montane compared to lowland forests 2 . Here we assemble and analyse a dataset of structurally intact old-growth forests (AfriMont) spanning 44 montane sites in 12 African countries. We find that montane sites in the AfriMont plot network have a mean AGC-stock of 149.4 Mg C ha -1 (95% CI 137.1-164.2), comparable to lowland forests in the African Tropical Rainforest Observation Network 4 and about 70 per cent and 32 per cent higher than averages from plot networks in montane 2,5,6 and lowland 7 forests in the Neotropics, respectively. Notably, our results are two-thirds higher than the IPCC default values for these forests in Africa 8 . We find that the low stem density and high abundance of large trees of African lowland forests 4 is mirrored in the montane forests sampled. This carbon store is endangered: we estimate that 0.8 million ha of old-growth African montane forest have been lost since 2000. We provide country-specific montane forest AGC stock estimates modelled from our plot network to help guide forest conservation and reforestation interventions. Our findings highlight the need for conserving these biodiverse 9,10 and carbon-rich ecosystems.

Local Perceptions of Climate Change and Adaptation Responses from Two Mountain Regions in Tanzania

“…(H: Highlands). 1 [63]; 2 [48]; 3 [27]; 4 [59]; 5 [45]; 6 [60]; 7 [61]; 8 [62]; 9 [42]; 10 [60]; 11 [60]; 12 [4]; 13 [76]; 14 [77]; 15 [65]; 16 [32]; 17 [66].…”

“…Notably, even poor Chagga households are relatively wealthier than poor Hehe households in terms of assets-for example, owning a radio. [63]; 2 [48]; 3 [27]; 4 [59]; 5 [45]; 6 [60]; 7 [61]; 8 [84]; 9 [42]; 10 [60]; 11 [60]; 12 [35]; 13 [76]; 14 [78]; 15 [28]; 16 [85]; 17 [66]. Interestingly, gender did not influence perceptions of climatic changes, impacts, or adaptive strategies.…”

“…African mountains are centres of biodiversity and endemism due to their topographical variation and ruggedness [5]. Tropical forests in African mountains are also vitally important carbon stores [9]. Most African mountains are characterised by intensive land use, averaging between 33 and 500 persons/km 2 , compared to 15 persons/km 2 in the lowlands [10].…”

Warming Responses of Leaf Morphology Are Highly Variable among Tropical Tree Species

“…Afromontane tropical forests are highly productive and store large amounts of carbon compared to tropical montane forests (TMF) worldwide and to central-east Amazonian tropical lowland forests [64][65][66]. However, they are severely understudied and very little is known on how leaf morphological traits are influenced by climate and how they vary among species and successional strategies.…”

A Review of Global Policy Mechanisms Designed for Tropical Forests Conservation and Climate Risks Management

“…Tropical forests play a crucial role in climate risks management. They form the most diverse and productive ecosystem on earth (Cuni-Sanchez et al, 2021), which stores 40-50% of terrestrial vegetation carbon (Blundo et al, 2021). They also provide climate such as carbon sequestration and sinking, which have contributed to reducing carbon from the atmosphere, consequently mitigating the effects of climate change, enhancing community adaptation and ecosystems resilience.…”