Summary:
Published in Tree Physiology 20: 229-238
We investigated effects of nutrient addition on several physiological characteristics of 60-cm-tall black spruce (Picea mariana Mill. B.S.P.) layers (i.e., rooted branches of overstory trees) and 20-cm-tall planted seedlings on a clear-cut, N-limited boreal site. After two growing seasons, current-year and one-year-old needles of fertilized trees (layers and seedlings combined) had higher net photosynthetic rates (An) and maximum capacity of Rubisco for CO2 fixation (Vmax) than unfertilized trees. One-year-old needles of fertilized trees had higher stomatal conductance (gs), higher water-use efficiency, and lower intercellular to ambient CO2 ratio than unfertilized trees. Additionally, fertilized trees had higher predawn and midday shoot water potentials than unfertilized trees.
Stomatal conductance of 1-year-old needles was 23% higher in seedlings than in layers, but there were no significant differences in gs of current-year needles between the regeneration types. For both needle age-classes, An and Vmax of layers were 25 and 40% higher, respectively, than the corresponding values for seedlings. The higher values of An, Vmax and foliar N concentration of layers compared with seedlings after two growing seasons may be associated with the larger root systems of the layers compared with the transplanted seedlings.
Sector(s):
Forests
Catégorie(s):
Scientific Article
Theme(s):
Forestry Research, Forests, Silviculture
Author(s):
PAQUIN, Raynald, Hank A. MARGOLIS, René DOUCET and Marie R. COYEA
Year of publication:
2000
How to get the publication:
Keyword(s):
silvicultural regime, fertilization, photosynthesis, conifer, Picea mariana, black spruce, Rubisco capacity, stomatal conductance, water stress, water-use efficiency, Chibougamau, shoot water potential, gas exchange, chemical analysis, statistical analysis, foliar analysis, sylviculture des forêts naturelles résineuses, sylviculture des forêts naturelles, silviculture and yield of natural forests - softwood stands