Stem biomass, C and N partitioning and growth efficiency of mature pedigreed black spruce on both a wet and a dry site

• Published in: Forest ecology and management Vol. 310; pp. 495 - 507
• Main Authors: Major, John E., Johnsen, Kurt H., Barsi, Debby C., Campbell, Moira, Malcolm, John W.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.12.2013; Elsevier
• Subjects: Adaptation; Agronomy. Soil science and plant productions; Animal and plant ecology; Animal, plant and microbial ecology; Belowground mass; Biological and medical sciences; Fitness; Forestry; Fundamental and applied biological sciences. Psychology; Growth efficiency; Physical properties; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Soil moisture; Soil science; Synecology; Terrestrial ecosystems; Water and solute dynamics; Wood density; Belowground mass; Growth efficiency; Wood density; Soil moisture; Adaptation; Fitness; Site; Organic carbon; Organic matter; Biomass; Density; Stem; Efficiency; Softwood forest tree; Gymnospermae; Picea mariana; Wood; Forest ecology; Property of soil; Physical properties; Mass; Carbon nitrogen ratio; Soils; Soil water properties; Vegetative apparatus; Forestry; Coniferales; Spermatophyta; Maturity
• ISSN: 0378-1127; 1872-7042
• DOI: 10.1016/j.foreco.2013.08.019

•Wet site have greater stem wood N and bark N (%) than the dry site, but equal soil N.•Slow trees have greater wood density than fast trees on the wet site, but are equal on the dry site.•Drought-tolerant and wet-site trees have greater partitioning to stem than belowground.•They also have greater growth efficiency through greater photosynthesis (Pn) and partitioning.•Greater Pn and re-allocation likely underlie greater stem growth from tree improvement. Worldwide, efforts to manage atmospheric CO2 are being explored both by reducing emissions and by sequestering more carbon (C). Stem biomass, C, and nitrogen (N) parameters were measured in plots of first-generation (F1), 32-year-old black spruce (Picea mariana (Mill.) B.S.P.) from four full-sib families studied previously for drought tolerance and differential productivity on both a dry and a wet site in central Ontario, Canada. The wet site had greater stem wood N and bark N concentrations than the dry site. Site differences in N were most likely driven by soil moisture stress impairing N uptake, as soil N was equal at both sites. Drought-tolerant (faster growing) families had lower wood density than drought-intolerant families on the wet site but there were no wood density differences between families on the dry site. Allometric analysis showed greater total stem dry mass per unit total belowground dry mass for drought-tolerant than intolerant families and for wet than dry sites, indicating a differential allocation of photosynthate dependent on both genotype and environment. Allometric analysis also showed greater total stem dry mass per unit total needle dry mass (growth efficiency) for drought-tolerant than intolerant families and for the wet than the dry site. This indicates greater productivity is a result of greater growth efficiency caused by greater net photosynthesis (shown previously) and greater partitioning of biomass to stem relative to total roots. The variation in physiological processes documented in our previous investigations and the biomass allocation variation shown here most probably underlie the increase in stem productivity from both black spruce tree improvement programs and increased water availability.