The responses of four Irish wetland tree species to raised soil water levels

Abstract

The four most common tree species in Irish wetland woods are Alnus glutinosa (L.) Gaertn. (common alder), Betula pubescens Ehrh. (downy birch), Fraxinus excelsior L. (ash) and Salix cinerea ssp. oleifolia Macreight (Salix atrocinerea Brot., common sally). Seedlings of these species were subjected to different soil water levels (half saturated and surface saturated) in their second and third years of growth, and performance was compared to that in a free draining control treatment. All plants survived in the water treatments, except for over 50%, of the B. pubescens. Soil redox potentials indicated a gradient in the degree of hypoxia which seemed to reflect the order of tolerance of the species, as shown by measurements of relative growth and final dry weight. The observed differences in soil redox potentials may have been due to the oxidizing activity of the roots of tolerant species, which showed varying degrees of stem base hypertrophy and associated proliferation of lenticels. Species were affected by the waterlogging treatments in the order B. pubescens (most adversely affected) > A. glutinosa > F. excelsior > S. cinerea ssp. oleifolia. Copyright © 1988, Wiley Blackwell. All rights reserved