Transpiration of a Tropical Dry Deciduous Forest in Yucatan, Mexico

Evelyn Raquel Salas-Acosta,Eduardo Cejudo,Jorge M Uuh-Sonda,Bernardo Figueroa-Espinoza,Jorge Adrián Perera-Burgos,José Luis Andrade,Roberth Us-Santamaría

doi:10.3390/atmos13020271

Abstract

The study of forest hydrology and its relationships with climate requires accurate estimates of water inputs, outputs, and changes in reservoirs. Evapotranspiration is frequently the least studied component when addressing the water cycle; thus, it is important to obtain direct measurements of evaporation and transpiration. This study measured transpiration in a tropical dry deciduous forest in Yucatán (Mexico) using the thermal dissipation method (Granier-type sensors) in representative species of this vegetation type. We estimated stand transpiration and its relationship with allometry, diameter-at-breast-height categories, and previously published equations. We found that transpiration changes over time, being higher in the rainy season. Estimated daily transpiration ranged from 0.562 to 0.690 kg m–2 d–1 in the late dry season (April–May) and from 0.686 to 1.29 kg m–2 d–1 in the late rainy season (September–October), accounting for up to 51% of total evapotranspiration in the rainy season. These daily estimates are consistent with previous reports for tropical dry forests and other vegetation types. We found that transpiration was not species-specific; diameter at breast height (DBH) was a reliable way of estimating transpiration because water use was directly related to allometry. Direct measurement of transpiration would increase our ability to accurately estimate water availability and assess the responses of vegetation to climate change.

Highlights

A central aspect in the study of the hydrology of an area is the description of the water balance, which requires the identification of inputs, outputs, and changes in water reservoirs [1,2,3,4,5]
Such results correspond to the end of the dry season and the end of the rainy season, when moisture and water availability are assumed to be close to the minimum and maximum, respectively, expected in a tropical dry deciduous forest in this area of the Yucatan Peninsula
The use of the diameter at breast height (DBH) and allometric equations to estimate results correspond to the end of the dry season and the end of the rainy season, when moisture and water availability are assumed to be close to the minimum and maximum, respectively, expected in a tropical dry deciduous forest in this area of the Yucatan Peninsula

Summary

Introduction

A central aspect in the study of the hydrology of an area is the description of the water balance, which requires the identification of inputs, outputs, and changes in water reservoirs [1,2,3,4,5]. Evapotranspiration is frequently the least accurate parameter because it is estimated indirectly through other variables such as rainfall, solar radiation, and sensible and latent heat, among others [6,7,8]. Each of these variables involves a certain degree of uncertainty associated with the measurement method and scale [9,10,11]. It is essential to have direct estimates of water outputs to obtain more precise water balances and budgets These contributions may shed light on the role of vegetation in the water and energy exchange within ecosystems, during periods of extreme conditions such as severe drought, in addition to its significance in forests facing global climate change

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