Stand Structure, Allometric Equations, Biomass and Carbon Sequestration Capacity of Acacia mangium Wild. (Mimosaceae) in C?te d’Ivoire

摘要

In addition to bioenergy production, Acacia magium, a fast growing species, plays a major role in climate change mitigation through carbon sequestration from the atmosphere. The objective of this study was to improve estimates of aboveground biomass of 3, 7 and 11 years old stands of Acacia mangium set up through natural regeneration at Anguédédou in C style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">?te d’Ivoire. Tree measurements were done in circular plots of 615 m2 located at the center of each stand. 24 trees of circumference at breast height (cbh) between 31 and 116 cm were felled, weighed and measured. Multiple linear regressions were used to develop allometric equations linking aboveground biomass of trees to cbh and/or height. The carbon stock and sequestration capacity of each stand was assessed using these predictive models. The average cbh was 39.4 cm, 73.5 cm and 91.4 cm respectively for 3, 7 and 11 years old stands with a density ranging between 845 trees style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·ha-1 and 553 trees style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·ha-1. The allometric equations for biomass estimation were Btotal aboveground = exp(-3.455 + 2.081 × ln(C)), Btrunk = exp (-5.153 + 1.681 × ln(C) + 1.056 × ln(H)), Bbranches = exp(-2.005 + 0.498 × ln(C2 × H)), Bleaves = exp(-2.415 + 1.339 × ln(C)). Total height had no influence on total and leaf biomass but increased precision of trunk and branch biomass. The carbon sequestration capacity of aboveground biomass was highest in Acacia mangium stand of 7 years old with 45.14 teqCO₂ style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·ha-1 style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·year-1 and lowest in the 3-year stand with 33.90 teqCO₂ style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·ha-1 style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·year-1.