Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut

• Published in: Forest ecology and management Vol. 83; no. 1; pp. 47 - 60
• Main Authors: Fleming, R.L., Black, T.A., Adams, R.S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.1996; Elsevier
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; BRITISH COLUMBIA; COLOMBIE BRITANNIQUE; COLUMBIA BRITANICA; Douglas-fir; Economic plant physiology; ESTOMA; Fundamental and applied biological sciences. Psychology; Lodgepole pine; PINUS CONTORTA; Pinus contorta latifolia; Plant physiology and development; PLANT WATER RELATIONS; Planting; PREPARACION DEL SITIO; PREPARATION DU SITE; PSEUDOTSUGA MENZIESII; Pseudotsuga menziesii glauca; RELACIONES PLANTA AGUA; RELATION PLANTE EAU; SITE PREPARATION; STOMATA; Stomatal conductance; STOMATE; TRANSCRIPCION; TRANSCRIPTION; Water and solutes. Absorption, translocation and permeability; Water relations; Water relations, transpiration, stomata; Canada; British Columbia; North America; America; Canada, British Columbia; Site preparation; Douglas-fir; Water relations; Planting; Stomatal conductance; Lodgepole pine; Pinus contorta; Environmental factor; Herbicide; Pseudotsuga menziesii; Transpiration; Clearcutting; Water regime; Softwood forest tree; Gymnospermae; Coniferales; Spermatophyta
• ISSN: 0378-1127; 1872-7042
• DOI: 10.1016/0378-1127(95)03701-2

Plantation establishment on drier sites is often hindered by harsh microclimatic conditions and inappropriate species selection. This study examined first-growing-season water relations of outplanted Douglas-fir ( Pseudotsuga menziesii var. glauca [Beissn.] Franco) and lodgepole pine ( Pinus contorta var. latifolia Engelm.) on a pinegrass-dominated clearcut in southern British Columbia. Seedlings were spring-planted in two consecutive years in an untreated control and in scalped, ripped, and herbicide site preparation treatments. After mid June, mid-morning stomatal conductance ( g sm) and transpiration ( E m) of both species, and mid-morning twig xylem pressure potential ( Ψ txm) of lodgepole pine, were consistently greater in the site preparation treatments than in the control. In contrast, there was relatively little difference in g sm, E m or Ψ txm of either species in the different site preparation treatments. Stomatal response of both species was largely a function of root zone extractable water ( θ e), seedling-height saturation deficit, and solar irradiance. Site preparation effects on g m were largely manifested through increased θ e. Lodgepole pine g sm and Ψ txm were often higher and soil-plant liquid path resistances lower than those of Douglas-fir, despite similar E m levels for the two species. Lodgepole pine showed greater response in g sm and E m than Douglas-fir to improved environmental conditions resulting from site preparation. Lodgepole pine water relations responses were consistent with a strategy of dehydration postponement, while Douglas-fir responses were consistent with a strategy of dehydration tolerance.