Forest Management with Reduced-Impact Logging in Amazonia: Estimated Aboveground Volume and Carbon in Commercial Tree Species in Managed Forest in Brazil’s State of Acre

Abstract

Tropical forest management has both positive and negative effects on climate change, and quantifying these effects is important both to avoid or minimize negative impacts and to reward net positive effects. This study contributes to this effort by estimating the aboveground volume and carbon present in commercial tree species in a managed forest in the forest harvest stage in Brazil’s state of Acre. A total of 12,794 trees of commercial species were measured. Trees were categorized and quantified as: “harvested trees” (“harvest or cut”), which were felled in the harvest stage, and “remaining trees” (“future cutting,” “trees in permanent protection areas or APPs,” “seed trees,” “rare trees” and “trees protected by law”) that remained standing in the forest post-harvest. Aboveground volume and carbon stocks of the 81 commercial species (diameter at breast height [DBH] ≥ 10 cm) totaled 79.19 m³ ha−1 and 21.54 MgC ha−1, respectively. The category “harvested trees” represents 44.48% and “remaining trees” 55.49% of the aboveground volume stocks. In the managed area, the category “harvested trees” is felled; this is composed of the commercial bole that is removed (19.25 m³ ha−1 and 5.32 MgC ha−1) and the stump and crown that remain in the forest as decomposing organic material (15.97 m³ ha−1 and 4.41 MgC ha−1). We can infer that the 21.54 MgC ha−1 carbon stock of standing commercial trees (DBH ≥ 10 cm) represents 13.20% of the total aboveground carbon in the managed area. The commercial boles removed directly from the forest represent 3.26% of the total aboveground carbon, and the stumps and crowns of the harvested trees represent the loss of an additional 2.70%. For sustainability of the management system in terms of carbon balance, growth in the 35-year management cycle must be sufficient to replace not only these amounts (0.27 MgC ha−1 year−1) but also losses to collateral damage and to additional logging-related effects from increased vulnerability to forest fires. Financial viability of future management cycles will depend on replenishment of commercial trees of harvestable size (DBH ≥ 50 cm).