Carbon stocks, partitioning, and wood composition in short-rotation forestry system under reduced planting spacing

Abstract

& Key message The use of reduced planting spacings is an important strategy to increase the carbon storage in the abovebelowground biomass and should be recommended for future exploitation of forest energy plantations when the purpose intended is the production of biomass for energy. & Context Recent concerns about global warming have resulted in more concerted studies on quantifying carbon storage in forest systems. Forest energy plantations play an essential role in the carbon storage. & Aims We proposed to evaluate the carbon storage and partitioning in short-rotation forest plantations and to characterize the elemental composition and energetic properties of the forest species Eucalyptus grandis W. Hill ex Maiden, Mimosa scabrella Benth, and Ateleia glazioviana Baill, grown under four planting spacings in Southern Brazil. & Methods A field study was conducted in order to evaluate forest carbon stock and wood composition using samples collected by direct method. The four spacings evaluated were 2.0 × 1.0, 2.0 × 1.5, 3.0 × 1.0, and 3.0 × 1.5 m. & Results The Eucalyptus grandis stored 327.1 Mg C ha −1 at 2.0 × 1.5-m spacing. When compared with the 3.0 × 1.5-m spacing, we observed a reduction of 29% in carbon stored. All forest species showed higher carbon storage in the following partitioning pattern: trunk>roots>branches>leaves>litter. Forest species energetic properties and elemental composition were not affected by planting spacing. On the other hand, variations according the tree portions were observed. For the carbon stocks in the soil, we observed an average accumulated carbon stock for the forest species studied of 77.4 Mg C ha −1 (0-40 cm). & Conclusion Forest managers can accelerate growth and increase the forest carbon storage and biomass yield by using reduced planting spacing that are smaller than the current pattern used by the majority of the forest producers, which is 3.0 × 1.5 m. For Eucalyptus grandis and Mimosa scabrella, the planting spacings recommended to produce biomass and improve carbon stocks were 2.0 × 1.5 and 2.0 × 1.0 m, respectively.

Produção E Qualidade Da Biomassa De Florestas Energéticas No Norte Do Rio Grande Do Sul, Brasil

“…A tendência crescente da produção de biomassa dos diferentes compartimentos em relação aos três períodos avaliados, que é observada nas equações de regressão na Figura 1, corrobora com os resultados de pesquisas de autores que desenvolveram trabalhos relacionados à influência da densidade e da idade do plantio na produção de povoamentos florestais. Dentre esses, pode-se citar os desenvolvidos por Schwerz et al (2020). Outros autores, como Caron et al (2015) encontraram diferença na distribuição de biomassa entre diferentes espécies e para a mesma espécie, em função de fatores como espaçamento de plantio, idade do povoamento e qualidade de sítio.…”

“…Os tratos silviculturais e o manejo florestal visando à produção de biomassa para energia fundamentamse no uso final da madeira, na escolha de material genético adequado, no controle da densidade de plantio e no período de rotação. Um dos aspectos mais importantes a ser considerado na formação de povoamentos florestais para fins energéticos é o espaçamento em que as plantas são estabelecidas no campo (SCHWERZ et al, 2020).…”