Canadian Forest Service Publications
Growth, allocation, and physiological relationships in Picea rubens, P. mariana, and their hybrids under ambient and elevated CO2. 2015. Major, J.E., Mosseler, A., Johnsen, K.H., Campbell, M., and Malcolm, J. Canadian Journal of Forest Research 45: 877-887.
Issued by: Atlantic Forestry Centre
Catalog ID: 36398
Availability: PDF (download)
Red spruce (RS; Picea rubens Sarg.) – black spruce (BS; Picea mariana (Mill.) B.S.P.) controlled crosses (100%, 75%, 50%, 25%, and 0% RS, balance BS) showed increasingly greater height with increasing proportion of BS in each successive year. Height growth of 4-year-old ambient CO2 (aCO2) grown trees was highly correlated with height of 22-year-old field-grown trees of the same or similar crosses. Bud flush was earliest in BS and declined linearly with increasing proportion of RS with no significant CO2 effect. Percent stem (stem + branches) mass increased under elevated CO2 (eCO2), a quarter of which was due to ontogeny. Conversely, percent needle mass had a significant negative relationship with increasing tree size, and there was a CO2 × tree size interaction. Shoot-to-root ratio was greatest for BS, whereas RS had among the lowest. Hybrid index (HI) 50 had the greatest root mass allocation, lowest shoot-to-root ratio, and among the greatest total mass under eCO2. Growth efficiency increased with tree size and eCO2 but decreased with HI. Percent total biomass stimulation under eCO2 was lowest for BS at 6.5%, greatest for HI 50 at 20.3%, and RS had 17.5%.
Plain Language Summary
Late-successional red spruce performed relatively better than faster growing black spruce under elevated carbon dioxide and this may be related to species’ shade tolerance. We compared growth, components of growth, and biomass allocation between two largely sympatric spruces, red spruce (Picea rubens Sarg.; RS) and black spruce (Picea mariana (Mill.) B.S.P.; BS) using 12 populations from across eastern Canada grown under ambientCO2 (aCO2) and elevated CO2 (eCO2) to evaluate absolute and relative responses to this increasing greenhouse gas. Over 4 years, BS displayed increasingly greater height growth compared with RS. By the end of the 4th year, BS on average had 127 % greater total mass and50 % greater root-collar diameter than RS. Bud flush was earlier for BS than RS, and BS bud flush occurred in the following order: ON, NB, NS.