Management trade‐off between aboveground carbon storage and understory plant species richness in temperate forests

Abstract

Abstract. Because forest ecosystems have the capacity to store large quantities of carbon (C), there is interest in managing forests to mitigate elevated CO 2 concentrations and associated effects on the global climate. However, some mitigation techniques may contrast with management strategies for other goals, such as maintaining and restoring biodiversity. Forest thinning reduces C storage in the overstory and recruitment of detrital C. These C stores can affect environmental conditions and resource availability in the understory, driving patterns in the distribution of early and late-seral species. We examined the effects of replicated (N ¼ 7) thinning experiments on aboveground C and understory vascular plant species richness, and we contrasted relationships between aboveground C and early-vs. lateseral species richness. Finally, we used structural equation modeling (SEM) to examine relationships among early-and late-seral species richness and live and detrital aboveground C stores.Six years following thinning, aboveground C was greater in the high-density treatment and untreated control than in moderate-(MD) and variable-density (VD) treatments as a result of reductions in live overstory C. In contrast, all thinning treatments increased species richness relative to controls. Between the growing seasons of years 6 and 11 following treatments, the live overstory C increment tended to increase with residual density, while richness decreased in MD and VD treatments. The richness of early-seral species was negatively related to aboveground C in MD and VD, while late-seral species richness was positively (albeit weakly) related to aboveground C. Structural equation modeling analysis revealed strong negative effects of live overstory C on early-seral species richness balanced against weaker positive effects on late-seral species richness, as well as positive effects of detrital C stocks. A trade-off between carbon and plant species richness thus emerges as a net result of these relationships among species traits, thinning treatments, and live and detrital C storage. Integrating C storage with traditional conservation objectives may require managing this trade-off within stands and landscapes (e.g., maintain early-seral habitat and species within dense, C-rich forests and, conversely, live and detrital C stores in early-seral habitats) or separating these goals across scales and species groupings.

Forest Restoration Using Variable Density Thinning: Lessons from Douglas-Fir Stands in Western Oregon

“…Such an approach would have to include setting priorities about which features and processes are more important in the short versus long term. Treatments prescription and expectations could then be managed to account for different response patterns, trade-offs, and synergies (as highlighted in Figure 4, see also [64]). As an alternative to compromising when achieving multiple structural and compositional goals simultaneously, foresters may explore options to spatially separate specific restoration goals within stands and across the landscape.…”

Assessing patterns of oak regeneration and C storage in relation to restoration-focused management, historical land use, and potential trade-offs

“…As such, there were no strong trade-off between the two potentially conflicting management objectives of maintaining positive biomass increment and promoting oak regeneration. Previous studies have shown some degree of trade-offs between C storage and features that might increase adaptive capacity such as structural and compositional complexity (D'Amato et al, 2011;Bradford and D'Amato, 2012;Burton et al, 2013;Seidl and Lexer, 2013), but did not specifically address regeneration as an adaptive factor. The lack of trade-offs in this study may be somewhat related to the low-intensity of management and lack of disturbance-caused mortality of overstory trees in the system.…”

Carbon distribution and its correlation with floristic diversity in subtropical broad-leaved forests during natural succession

“…Forest managers have expanded their objectives from traditional timber production to include broader goals of providing ecosystem goods and services (Burton et al 2013). However, the primary aims of common international and national forest protection measures regarding afforestation and reforestation are to enhance productivity and mitigate CO 2 accumulation by sequestering C. Climate change and biodiversity loss are two interrelated global crises but are independent of forest protection programme objectives launched by most national governments.…”