Water balance of an Atlantic forest remnant under a prolonged drought period

ABSTRACT Since prolonged droughts have impacted Atlantic forests in Southeastern Brazil, further investigations to understand the effects of such stressful conditions in their hydrological behavior are required. This study aimed to assess the changes in the water balance of a semi-deciduous Atlantic forest remnant and how the forest responds to droughts. The Standardized Precipitation-Evapotranspiration Index was applied to identify droughts (from 1961 to 2019) and their severity in both the hydrological year and summer scales. Drought impacts on actual evapotranspiration, potential percolation, and soil water storage were assessed using Hydrus-1D, having net precipitation and potential evapotranspiration as inputs. Error analyses (< 10%) confirmed Hydrus-1D suitability for simulating soil moisture. Uncertainties regarding the soil saturated hydraulic conductivity are due to preferential flows, which are not accounted for in Richards’ equation. Drought intensification changed forest hydrology and triggered physiological responses to deal with it. Semi-deciduous Atlantic forests are adapted to dry conditions because of the existence of dry-affiliated species and the activation of physiological mechanisms. However, such adaptations responded differently regarding the drought scales. The intensification of summer droughts increased evapotranspiration and decreased the potential percolation. Leaf shedding changed the canopy structure in a two-year time lag as a response to the intensification of hydrological year droughts. Changes in forest hydrology are sudden and trigger physiological responses, such as leaf shedding, in a delayed process after droughts take place.

Los árboles que esconden al bosque: Miguel Ángel de Quevedo y los orígenes de la ciencia forestal en México

This article describes the role of civil engineer Miguel Ángel de Quevedo(1862-1946) in the origins of forestry in Mexico. The guiding issue is to determine whether the critiques of some of his contemporaries regarding his project, which prioritised attention to the tree rather than the forest, were well-founded. Particular emphasis will be placed on the first encounters between the state and forestry, the development of ideas that guided the growth of forestry and the training of forestry workers. The principal sources are the texts published by Quevedo himself. The author concludes that Quevedo’s project favoured the tree over the forest, especially after Mexican revolution. However, despite his conceptual shortcomings, his scant scientific legacy in silvicultural matters, his insistence on forest hydrology and his strong conservationist inclinations, Quevedo was undeniably responsible for introducing forestry science to Mexico and making it a state concern. Given the endemic deforestation and the socio-political weight of agriculture in Mexico, this cannot be considered a minor contribution.