Trade‐offs between carbon stocks and timber recovery in tropical forests are mediated by logging intensity

Abstract

Forest degradation accounts for ~70% of total carbon losses from tropical forests. Substantial emissions are from selective logging, a land-use activity that decreases forest carbon density. To maintain carbon values in selectively logged forests, climate change mitigation policies and government agencies promote the adoption of reduced-impact logging (RIL) practices. However, whether RIL will maintain both carbon and timber values in managed tropical forests over time remains uncertain. In this study, we quantify the recovery of timber stocks and aboveground carbon at an experimental site where forests were subjected to different intensities of RIL (4, 8, and 16 trees/ha). Our census data span 20 years postlogging and 17 years after the liberation of future crop trees from competition in a tropical forest on the Guiana Shield, a globally important forest carbon reservoir. We model recovery of timber and carbon with a breakpoint regression that allowed us to capture elevated tree mortality immediately after logging. Recovery rates of timber and carbon were governed by the presence of residual trees (i.e., trees that persisted through the first harvest). The liberation treatment stimulated faster recovery of timber albeit at a carbon cost. Model results suggest a threshold logging intensity beyond which forests managed for timber and carbon derive few benefits from RIL, with recruitment and residual growth not sufficient to offset losses. Inclusion of the breakpoint at which carbon and timber gains outpaced postlogging mortality led to high predictive accuracy, including out-of-sample R values >90%, and enabled inference on demographic changes postlogging. Our modeling framework is broadly applicable to studies that aim to quantify impacts of logging on forest recovery. Overall, we demonstrate that initial mortality drives variation in recovery rates, that the second harvest depends on old growth wood, and that timber intensification lowers carbon stocks.

Visual encounters on line transect surveys under-detect carnivore species: Implications for assessing distribution and conservation status

“…Given the location of some of these villages within or adjacent to a multiple-use protected area (e.g., Iwokrama Forest), encounter-based results pointing to the absence of jaguars could result in restrictions on sustainable resource extraction by communities and other stakeholders; for example, people could be restricted from hunting game animals for their own food in order to provide prey for jaguars. A study with camera trapping conducted in the Iwokrama Forest, which included one village and one control site from our study, validated our results for sign: it found healthy jaguar populations, with densities derived from combined camera trapping in unlogged and reduced-impact-logging locations falling within the density ranges reported in the literature for protected areas [72].…”

Shared functional traits explain synchronous changes in long‐term count trends of migratory raptors

“…We evaluated temporal patterns in the count data of migrating raptors using a hierarchical breakpoint model, also called a piecewise regression model. This approach is used to evaluate nonlinear relationships, including assessments of sudden ecological changes that result from anthropogenic impacts (Roopsind et al., 2018; Toms & Lesperance, 2003). Our breakpoint model is an extension of a generalized linear mixed model (GLMM), with species‐level random effects that enable quantification of assemblage‐wide patterns from multispecies count data (Brilleman et al., 2017; Ovaskainen et al., 2017).…”

Implications of Selective Harvesting of Natural Forests for Forest Product Recovery and Forest Carbon Emissions: Cases from Tarai Nepal and Queensland Australia

“…Specifically, timber volume recovery is one of the key determinants of financial attractiveness in forest management [5,9]. Although the level of such effectiveness is defined according to the needs and socio-economic livelihoods of the local people and the political, environmental and market settings of a specific context [10][11][12][13][14], optimizing societal and environmental benefits from forest products (goods and services) has been increasingly important in the context of mitigation of and adaptation to a changing climate [15][16][17][18][19]. However, the current body of knowledge focuses largely on harvesting impacts on forest growth and tree regeneration dynamics [20] and long-term stocks of timber, biomass and carbon [5,21].…”