Estimation of Aboveground Oil Palm Biomass in a Mature Plantation in the Congo Basin

Forests

卷:11

Pierre Migolet¹  Kalifa Goïta¹  Alfred Ngomanda²  AndréanaPaola Mekui Biyogo³ 

[1] Centre D’Applications et de Recherches en Télédétection (CARTEL), Département de Géomatique Appliquée, Université de Sherbrooke, 2500 Boulevard de l’Université, Sherbrooke, QC J1K 2R1, Canada;

[2] Commissariat Général du Centre National de la Recherche Scientifique et Technologique (CENAREST), Libreville, B.P 842 Libreville, Gabon;

[3] Independent Geomatics Consultant, Former Employee of Olam Palm Gabon, 79 rue du Radoux, 1430 Rebecq, Belgique;

关键词: agro-industrial plantations;    oil palms;    aboveground biomass;    allometric equations;    Congo Basin;    Gabon;   

DOI  :  10.3390/f11050544

来源: DOAJ

【 摘 要 】

Agro-industrial oil palm plantations are becoming increasingly established in the Congo Basin (West Equatorial Africa) for mainly economic reasons. Knowledge of oil palm capacity to sequester carbon requires biomass estimates. This study implemented local and regional methods for estimating palm biomass in a mature plantation, using destructive sampling. Eighteen 35-year-old oil palms with breast height diameters (DBH) between 48 and 58 cm were felled and sectioned in a plantation located in Makouké, central Gabon. Field and laboratory measurements determined the biomasses of different tree compartments (fruits, leaflets, petioles, rachises, stems). Fruits and leaflets contributed an average of 6% to total aboveground palm biomass, which petioles accounted for 8%, rachises for 13% and the stem, 73%. The best allometric equation for estimating stem biomass was obtained with a composite variable, formulated as DBH² × stem height, weighted by tissue infra-density. For leaf biomass (fruits + leaflets + petioles + rachises), the equation was of a similar form, but included the leaf number instead of infra-density. The allometric model combining the stem and leaf biomass yielded the best estimates of the total aboveground oil palm biomass (coefficient of determination (r²) = 0.972, p < 0.0001, relative root mean square error (RMSE) = 5%). Yet, the model was difficult to implement in practice, given the limited availability of variables such as the leaf number. The total aboveground biomass could be estimated with comparable results using DBH² × stem height, weighted by the infra-density (r² = 0.961, p < 0.0001, relative RMSE (%RMSE) = 5.7%). A simpler model excluding infra-density did not severely compromise results (R² = 0.939, p < 0.0003, %RMSE = 8.2%). We also examined existing allometric models, established elsewhere in the world, for estimating aboveground oil palm biomass in our study area. These models exhibited performances inferior to the best local allometric equations that were developed.

【 授权许可】

Unknown