GROWTH AND POST-TRANSPLANTING STRESS OF PINE TREES IN URBAN SALINE SOIL

Abstract

The urban environment and some arboriculture practices cause a reduction of tree growth (physiological stress), that cannot always be perceived visually. Stress has been studied in several arboreal species using diverse methods that require costly high-precision equipment. In Mexico there is little research on this, despite the great amount of species with arboriculture use potential. This investigation has the purpose of identifying stress in Pinus greggii Engelm., transplanted into urban saline soil. We used 25 seven-year-old trees; some were balled and burlaped (B & B) 90 and 180 days before being transplanted, with and without sulfur in the soil. Control trees were not (B & B) nor transplanted. Techniques used to identify stress in the trees were: leaf photosynthetic efficiency, measured as chlorophyll fluorescence; intensity of green in the foliage; and plant-geoelectric current of the soil-plant system; also tree height and trunk diameter growth. According to results obtained, photosynthetic efficiency and plant-geoelectric current identified a growth decrease (stress) in pines, as a result of B & B and trasplanting. According to B & B period, 180-day treatment recovered their levels for the variables considered before those plants bagged for 90 days. Soil salinity did no affect treatments, because trees were watered regularly, avoiding stress due to moisture deficiency and lixiviating excess salts from the soil.