Mixed-species effect on tree aboveground carbon pools in the east-central boreal forests

Abstract

This study investigates the potential of mixed forest stands as better aboveground carbon sinks than pure stands. According to the facilitation and niche complementarity hypotheses, we predict higher carbon sequestration in mature boreal mixedwoods. Aboveground carbon contents of black spruce ( Picea mariana (Mill.) Britton, Sterns, Poggenb.) and trembling aspen ( Populus tremuloides Michx.) mixtures were investigated in the eastern boreal forest, whereas jack pine ( Pinus banksiana Lamb.) and trembling aspen were used in the central boreal forest. No carbon gain was found in species mixtures; nearly pure trembling aspen stands contained the greatest amount of aboveground carbon, black spruce stands had the least, and mixtures were intermediate with amounts that could generally be predicted by linear interpolation with stem proportions. These results suggest that for aspen, the potentially detrimental effect of spruce on soils observed in other studies may be offset by greater light availability in mixtures. On the other hand, for black spruce, the potentially beneficial effects of aspen on soils could be offset by greater competition by aspen for nutrients and light. The mixture of jack pine and trembling aspen did not benefit any of these species while inducing a loss in trembling aspen carbon at the stand level.

Forest management and carbon sequestration in the Mediterranean region: A review

“…González-González et al (2012) found that mixtures with Q. ilex (Holm oak) in Spain showed lower soil carbon stocks than pure stands, although the differences were not statistically significant. Cavard et al (2010) found that the mixture effect can be unfavorable when two species are mixed in a highly competitive environment (competing at the same level for the light, water and nutrient resources) in the absence of complementarity. Forrester et al (2013) found that soil organic carbon in mixed plantations of Eucalyptus and N-fixing Acacia in Australia was higher than in pure plantations due to the increase in productivity resulting from the inclusion of the latter species.…”

Species-site matching in mixed species plantations of native trees in tropical Australia

“…However, in many situations mixed species systems offer no change, or a reduced productivity compared to monocultures (Cavard et al 2010;Chen et al 2003;Erickson et al 2009;Forrester et al 2005;Hunt et al 2006) and it is acknowledged that a mechanistic understanding of the underlying processes is required to enable better predictive ability for situations where mixtures can be successful (Forrester et al 2005;Manson et al 2006).…”

“…The positive effects from species interactions can however be limited to specific ecological contexts, developmental stages and planting densities (Amoroso and Turnblom 2006). Reduced productivity in mixtures has often been associated with asymmetric competition between species as plantations develop (Cavard et al 2010;Hunt et al 2006;Chen et al 2003). Whilst studies investigating neighbourhood effects have identified the inter-specific competitive effects in mixtures (Canham et al 2004;Bristow et al 2006), others have found the size of neighbours, rather than species identity, as the largest source of variation in individual tree diameter and height (Erickson et al 2009;Potvin and Dutilleul 2009).…”

Climate, soil organic layer, and nitrogen jointly drive forest development after fire in the North American boreal zone

“…Such a change in NA boreal forest successional dynamics has the potential to decrease ecosystem carbon storage through increasing litter decay rates and decreasing moss accumulation [Laganière et al, 2010;L egar e et al, 2005]; the effect this shift would have on ecosystem carbon storage is dependent on the age of the forest. In warmer temperatures in younger forests (<100 years), we simulated that deciduous tree growth increased ecosystem carbon relative to black spruce growth due to increased aboveground productivity [Cavard et al, 2010]. In contrast, we simulated older forests that transition from black spruce-dominated to deciduous stands lost approximately 40% of their carbon storage potential (Figures 7e, 7f, 9e, and 9f).…”