Vulnerability of Commercial Tree Species to Water Stress in Logged Forests of the Guiana Shield

Abstract

Abstract:The future of tropical managed forests is threatened by climate change. In anticipation of the increase in the frequency of drought episodes predicted by climatic models for intertropical regions, it is essential to study commercial trees' resilience and vulnerability to water stress by identifying potential interaction effects between selective logging and stress due to a lack of water. Focusing on 14 species representing a potential or acknowledged commercial interest for wood production in the Guiana Shield, a joint model coupling growth and mortality for each species was parametrized, including a climatic variable related to water stress and the quantity of aboveground biomass lost after logging. For the vast majority of the species, water stress had a negative impact on growth rate, while the impact of logging was positive. The opposite results were observed for the mortality. Combining results from growth and mortality models, we generate vulnerability profiles and ranking from species apparently quite resistant to water stress (Chrysophyllum spp., Goupia glabra Aubl., Qualea rosea Aubl.), even under logging pressure, to highly vulnerable species (Sterculia spp.). In light of our results, forest managers in the Guiana Shield may want to conduct (i) a conservation strategy of the most vulnerable species and (ii) a diversification of the logged species. Conservation of the already-adapted species may also be considered as the most certain way to protect the tropical forests under future climates.

An individual‐based forest model to jointly simulate carbon and tree diversity in Amazonia: description and applications

“…TROLL could thus help assess forest vulnerability to timber exploitation (e.g., Fargeon et al. ) by modeling logging scenarios, selecting focal species at a reference diameter.…”

“…In French Guiana, only two species, Dicorynia guianensis and Qualea rosea, account for up to 60% of the total timber production. TROLL could thus help assess forest vulnerability to timber exploitation (e.g., Fargeon et al 2016) by modeling logging scenarios, selecting focal species at a reference diameter.…”

Long‐term influence of early human occupations on current forests of the Guiana Shield

“…Species of large diameter (>50‐cm diameter at breast height) used now as timber in the Guiana Shield (Fargeon et al. , Piponiot et al. , ) and requiring the use of a chainsaw, were removed.…”

Can timber provision from Amazonian production forests be sustainable?

“…Typically, the minimum cutting cycles over which timber stocks are assumed to recover to preharvesting levels are 20-35 years despite substantial evidence that without strong limits on logging intensities, these cycles are too short to sustain yields [3,6]. Moreover, shortfalls in timber are likely to be exacerbated further in Amazonia by ongoing climate changes [7], including increased frequency and severity of droughts and wildfire events due to drier and hotter conditions [8]. A consequence of these changes is increased tree mortality, especially of large trees (loggers' main target) that are particularly sensitive to intense droughts [9].…”