El estrés hídrico es una reacción fisiológica de las plantas ante la disponibilidad limitada de agua. Este estudio valoró el efecto del estrés en plántulas de Gliricidia sepium cultivadas en condiciones de invernadero, utilizando plantas testigo y dos tipos de estrés (lineal y cíclico). El estrés generó reducciones en el crecimiento en altura del 30 % y de la lámina foliar del 40 %. Las plantas con estrés lineal mostraron a los 98 días un estrés severo con valores fisiológicos mínimos (fotosíntesis 4.51 µmol m^-2.s^-1, transpiración 6.56 µmol m^-2.s^-1, conductancia 48.6 µmol m^-2.s^-1); en cambio, las plantas con estrés cíclico si bien se expusieron a un estrés moderado, mostraron recuperación con valores fisiológicos finales estables (fotosíntesis 12.96 µmol m^-2.s^-1, transpiración 6.22 µmol m^-2.s^-1, conductancia 196.05 µmol m^-.²s^-1), con un retardo del crecimiento del 30 % con respecto a las plantas testigo, encontrando que en 42 días de estrés la condición es grave. Water stress is a physiological reaction of plants to the limited availability of water. The study assessed the effect of stress on seedlings of Gliricidia sepium grown in greenhouse conditions, using control plants and two types of stress (linear and cyclic). Stress generated reductions in height growth of 30 % and foliar leaf 40 %. Plants with linear stress showed severe stress with minimal physiological values at 98 days (photosynthesis 4.51 µmol m^-2.s^-1, transpiration 6.56 µmol m^-2.s^-1, conductance 48.6 µmol m^-2.s^-1), on the other hand, plants with cyclic stress, although they were exposed to moderate stress, showed recovery with stable final physiological values (photosynthesis 12.96 µmo m^-2.^.s^-1, perspiration 6.22 µmol m^-2.s^-1, conductance 196.05 µmol m^-2s^-1), with a 30 % growth delay with respect to the control plants, finding that 42 days of stress the condition is severe.

Climate change has impacted the environmental conditions in which forest plantations grow worldwide. Droughts and extreme temperatures have compromised the survival and productivity of plantations, and the effects on carbon and water balance have increased risks to sustained productivity and sustainability. Interestingly, opportunities for improvement rely on a better understanding of the ecophysiological response of species or genotypes, their tolerance or resistance to thermal and water stress, and genetic–environmental interactions. Our manuscript summarizes tree and stand-level major reported ecophysiological responses that could challenge the establishment and development of forest plantations under future climate change scenarios. The manuscript discusses potential climate change effects on plantation forest productivity, carbon balance, water use, and water use efficiency, and suggests some potential silvicultural strategies to avoid or reduce risks under uncertain climate scenarios. An integrated approach to understanding the linkages between water resource availability and plant-stand carbon balance is proposed to provide sustainable management that may alleviate the social and environmental concerns associated with challenges relating to climate change for managed forests and the forest industry.

The first attempts to establish energy crops in the tropical regi­on using short rotation species are premised on the utilization of clones for wood production. Therefore, the present study is aimed at examining the growth aspects (survival, diameter and tree height), leaf architecture (leaf area index [LAI], number and angle of the branches and sylleptic branches), biomass production, as well as biomass flow at the age of 24 months of two clones of Gmelina arborea in short rotation crops within three spacings (1.0x1.0 m, 0.75x0.75 m and 1.0x0.5 m). The results showed an increment with age, as the diameter increa­sed from 3.00 cm at six months to 8.0 cm at 24 months, where­as the total height increased from 2.00 m at six months to 10.00 m at 24 months. Clone survival varied from 20 to 60 %, whereas the LAI, branch angle and sylleptic branches increased with age. The differences between clones appeared after 12 months. Biomass production was similar between clones, from 6 ton/ha at six months to 67 ton/ha at 24 months, with clone 2 showing greater biomass flow than clone 1. On the basis of biomass pro­duction results and the development of diameter as well as height, clone 1 is recommended for spacing 1.0x1.0 m and clo­ne 2 for spacings 0.75x0.75 m and 1.0x0.5 m.