Urban vs. Natural Sugar Maple Growth: II. Water Relations

Abstract

Physiologic measurements of the internal water relations of sugar maple in a natural forest and along an urban street in Michigan were performed as a complement to a companion site characterization study. Investigations were carried out to determine how street trees are affected by the urban habitat, and to confirm through correlation analysis that siterelated water stress adversely influences tree growth and vitality. Significant water relations differences exist between the street site sugar maples and those in natural habitats. Predawn water potential, osmotic potential, and stomatal conductance were significantly lower in the street trees, and were significantly correlated with the low soil moisture levels and high atmospheric demands of the street site. Findings of this study, in conjunction with the site characterization data, can be of value in selecting appropriate remedial treatments for stressed urban trees, as well as to reiterate the need for further screening of drought-tolerant cultivars for urban sites.