Laboratoire de Biodiversité, de Gestion des Ecosystèmes et de l'Environnement, Faculté des Sciences et Techniques, Université Marien Ngouabi, Brazzaville, République du Congo.
Institut Supérieur des Sciences Géographiques, Environnementales et de l'Aménagement (ISSGEA), Université Denis SASSOU-N'GUESSO, Kintélé, République du Congo.
PLoS One. 2023 Apr 14;18(4):e0273591. doi: 10.1371/journal.pone.0273591. eCollection 2023.
The world's largest tropical peatland lies in the central Congo Basin. Raphia laurentii De Wild, the most abundant palm in these peatlands, forms dominant to mono-dominant stands across approximately 45% of the peatland area. R. laurentii is a trunkless palm with fronds up to 20 m long. Owing to its morphology, there is currently no allometric equation which can be applied to R. laurentii. Therefore it is currently excluded from aboveground biomass (AGB) estimates for the Congo Basin peatlands. Here we develop allometric equations for R. laurentii, by destructively sampling 90 individuals in a peat swamp forest, in the Republic of the Congo. Prior to destructive sampling, stem base diameter, petiole mean diameter, the sum of petiole diameters, total palm height, and number of palm fronds were measured. After destructive sampling, each individual was separated into stem, sheath, petiole, rachis, and leaflet categories, then dried and weighed. We found that palm fronds represented at least 77% of the total AGB in R. laurentii and that the sum of petiole diameters was the best single predictor variable of AGB. The best overall allometric equation, however, combined the sum of petiole diameters (SDp), total palm height (H), and tissue density (TD): AGB = Exp(-2.691 + 1.425 × ln(SDp) + 0.695 × ln(H) + 0.395 × ln(TD)). We applied one of our allometric equations to data from two nearby 1-hectare forest plots, one dominated by R. laurentii, where R. laurentii accounted for 41% of the total forest AGB (with hardwood tree AGB estimated using the Chave et al. 2014 allometric equation), and one dominated by hardwood species, where R. laurentii accounted for 8% of total AGB. Across the entire region we estimate that R. laurentii stores around 2 million tonnes of carbon aboveground. The inclusion of R. laurentii in AGB estimates, will drastically improve overall AGB, and therefore carbon stock estimates for the Congo Basin peatlands.
世界上最大的热带泥炭地位于刚果盆地中部。在这些泥炭地中，最丰富的棕榈是 Raphia laurentii De Wild，它形成了大约 45%的泥炭地面积的主导或单优势种。R. laurentii 是一种无干的棕榈树，其叶片长达 20 米。由于其形态，目前尚无适用于 R. laurentii 的异速生长方程。因此，它目前被排除在刚果盆地泥炭地的地上生物量（AGB）估计之外。在这里，我们通过在刚果共和国的一个泥炭沼泽森林中对 90 个个体进行破坏性采样，为 R. laurentii 开发了异速生长方程。在破坏性采样之前，我们测量了茎基直径、叶柄平均直径、叶柄直径总和、总棕榈高度和棕榈叶数量。破坏性采样后，将每个个体分为茎、鞘、叶柄、叶轴和小叶类别，然后干燥和称重。我们发现，棕榈叶至少占 R. laurentii 总 AGB 的 77%，叶柄直径总和是 AGB 的最佳单一预测变量。然而，最佳的总体异速生长方程结合了叶柄直径总和（SDp）、总棕榈高度（H）和组织密度（TD）：AGB = Exp(-2.691 + 1.425 × ln(SDp) + 0.695 × ln(H) + 0.395 × ln(TD))。我们将我们的一个异速生长方程应用于附近两个 1 公顷森林样地的数据，一个由 R. laurentii 主导，其中 R. laurentii 占总森林 AGB 的 41%（硬木树木 AGB 使用 Chave 等人的 2014 年异速生长方程估计），另一个由硬木物种主导，其中 R. laurentii 占总 AGB 的 8%。在整个地区，我们估计 R. laurentii 在地上储存了约 200 万吨碳。将 R. laurentii 纳入 AGB 估计，将大大提高总体 AGB，从而提高刚果盆地泥炭地的碳储量估计。
