URBAN FOREST IN ARID ZONES: CRITERIA FOR SELECTING SPECIES OF LOW WATER REQUIREMENT

ROIG F. A.; CANTÓN, M. ALICIA; MARTINEZ, CLAUDIA F.; CAVAGNARO J. BRUNO

Congreso; Urban Forest Boundaries 2017; 2017

The urbanforests located in arid zones have growth patterns related to theavailability of water forirrigation. This resource is scarce but vital for the development of trees andfor the sustainability of the urban ecosystem. The aim of this paper is to evaluate the growth responses ofyoung trees of different species used in the city of Mendoza (Argentina) underdifferential availability of water.It was determined the effect of water stress on four tree species(Acacia visco, Platanus hispanica, Fraxinus americana and Morus alba).Also it was establised the growth responses to different levels ofwater availability through morphoanatomic, physiological and dendrochronologyanalysis. The study focuses on the urban condition of the forests as aframework, and draw on concepts and methods provided by dendrochronology andplant physiology for the analysis of growth in relation to water availability. The experimental design tests the irrigation responses undercontrolled conditions in nursery during three growing seasons. Three treatmentswere applied: T1 Control (reposition of 100% water transpired ); T2 Moderatewater deficit (reposition 66%) and T3 Severe water deficit (reposition 33%).The quantified growth?s variables included the height, the stem diameter, theleaf area and the width of tree-rings. Results show that the growth responds todifferential volumes of water and that the responses vary between each specieand the treatment. The ANOVA statistical evaluation (á ≤ 0.05)supports these results. The four species slow growth under severe water stress (T3).For height and diameter, A. visco and P.hispanica show no significant difference in T1 and T2, which indicatesthat a reduction of 33% in irrigation allow a growth comparable to the oneachieved under control treatment. F. americana presentsdifference between T1 and T3. However, M. alba presentssignificant difference in the height under the three treatments. Theaccumulated growth in the tree-rings for the test period indicates that undersevere water deficit the four species decrease their radial growth. Data indicate that P.hispanica, F. americana and M. alba are sensitive to drought, while A. visco ismore tolerant and it have a high degree of adaptation to moderate water stress.This specie shows the most favorable conditions to achieve proper growth withbounded water inputs allowing a rational use of the resource. These resultshighlight the importance of selecting tree species with low water consumption insustainable urban forests of cities located in dryland environments.