Growth analysys of young trees cultivated in urban conditions under deficit irrigation

CLAUDIA F. MARTINEZ, FIDEL A. ROIG, J. B. CAVAGNARO

Mendoza

Congreso; SECOND JOINT MEETING OF THE BIOLOGY SOCIETIES FROM ARGENTINA; 2011

The urban forests of arid zones have growth patterns related to the availability of water, which is in turn increased by some other variables. The aim of this paper is to evaluate the growth responses of young trees of different species used in the city of Mendoza (Argentina) under differential availability of water. Four tree-species are analyzed: Acacia visco, Platanus hispanica, Fraxinus americana. and Morus alba. The experimental design tests the irrigation responses under controlled conditions in nursery during three growing seasons. Three treatments were applied: T1 Control (reposition of 100% water transpired ); T2 Moderate water deficit (reposition 66%) and T3 Severe water deficit (reposition 33%). The quantified growth?s variables included the height, the stem diameter, the leaf area and the width of tree-rings. Results show that the growth responds to differential volumes of water and that the responses vary between each specie and the treatment. The ANOVA statistical evaluation (α ≤ 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 indicates that a reduction of 33% in irrigation allow a growth comparable to the one achieved under control treatment. F. americana presents difference between T1 and T3. However, M. alba presents significant difference in the height under the three treatments. The accumulated growth in the tree-rings for the test period indicates that under severe 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 is more tolerant and it have a high degree of adaptation to moderate water stress.