Soil Moisture Dynamics in Response to Precipitation and Thinning in a Semi-Dry Forest in Northern Mexico

Argelia E Rascón-Ramos,Alfredo Pinedo-Alvarez,Federico Villarreal-Guerrero,Raúl Corrales-Lerma,Gabriel Sosa-Pérez,Eduardo Santellano-Estrada,Martín Martínez-Salvador

doi:10.3390/w13010105

Abstract

Understanding soil moisture behavior in semi-dry forests is essential for evaluating the impact of forest management on water availability. The objective of the study was to analyze soil moisture based in storm observations in three micro-catchments (0.19, 0.20, and 0.27 ha) with similar tree densities, and subject to different thinning intensities in a semi-dry forest in Chihuahua, Mexico. Vegetation, soil characteristics, precipitation, and volumetric water content were measured before thinning (2018), and after 0%, 40%, and 80% thinning for each micro-catchment (2019). Soil moisture was low and relatively similar among the three micro-catchments in 2018 (mean = 8.5%), and only large rainfall events (>30 mm) increased soil moisture significantly (29–52%). After thinning, soil moisture was higher and significantly different among the micro-catchments only during small rainfall events (<10 mm), while a difference was not noted during large events. The difference before–after during small rainfall events was not significant for the control (0% thinning); whereas 40% and 80% thinning increased soil moisture significantly by 40% and 53%, respectively. Knowledge of the response of soil moisture as a result of thinning and rainfall characteristics has important implications, especially for evaluating the impact of forest management on water availability.

Highlights

Semi-dry forests where mean annual rainfall is below 650 mm occupy approximately six percent of the world’s forest area [1]
Knowledge of soil moisture is fundamental for developing an understanding of numerous hydrological processes in soil hydrology, meteorology, and ecology research [7]
23.7 m2 ha−1, and the mean tree density was 2210 trees ha−1, with a similar number of trees between micro-catchment 2 and 3, and approximately 100 more trees ha−1 in microcatchment 1

Summary

Introduction

Semi-dry forests where mean annual rainfall is below 650 mm occupy approximately six percent of the world’s forest area [1]. The area with semi-dry forests in Mexico corresponds to transition zones between semi-arid and temperate ecosystems and occupies approximately 22 million hectares, located from 1400 to 2600 m above sea level [2,3,4]. Semi-dry forests are critical in northern Mexico, as they are the main suppliers of water for agriculture and cities located at the valley bottom of watersheds [5]. Water regulation or retention by semi-dry forests are regarded as typical subjects for hydrological services [6]. There is a lack of knowledge regarding hydrological processes and soil moisture behavior as a result of lumber harvesting and silvicultural practices in these ecosystems. Knowledge of soil moisture is fundamental for developing an understanding of numerous hydrological processes in soil hydrology, meteorology, and ecology research [7]

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Conclusion