© 1998 Heron Publishing—Victoria, Canada
Effects of temperature and tissue nitrogen on dormant season stem and branch maintenance respiration in a young loblolly pine
(Pinus taeda) plantation
C. A. Maier (1), S. J. Zarnoch (2) and P. M. Dougherty (3)
1. Southern Research Station, USDA Forest Service, 3041 Cornwallis Road, Research Triangle Park, NC 27709, USA (cmaier@rtpmail.emapfhm.gov) / 2. Southern Research Station, USDA Forest Service, 200 Weaver Blvd., Ashville, NC 28806, USA / 3. Westvaco, Forestry Research Laboratory, 180 Westvaco Road, Summerville, SC 29484, USA / Received February 28, 1996
Summary
We measured dormant season (November through February) maintenance respiration rates (Rm) in stems and branches of 9-year-old loblolly pine (Pinus taeda L.) growing in plots under conditions of controlled nutrient and water supply in an effort to determine the relationships
between Rm and tissue size (surface area, sapwood volume, sapwood dry weight), tissue nitrogen content and temperature. Dormant season
Rm per unit size (i.e., surface area, μmol m–2 s–1; sapwood volume, μmol m–3 s–1; or sapwood dry weight, nmol g–1 s–1) varied with tissue size, but was constant with respect to tissue nitrogen content (μmol mol–1 N s–1). Cambium temperature accounted for 61 and 77% of the variation in stem and branch respiration, respectively. The basal respiration
rate (respiration at 0 °C) increased with tissue nitrogen content, however, the Q10 did not. Improved nutrition more than doubled stem basal respiration rate and increased branch basal respiration by 38%.
Exponential equations were developed to model stem and branch respiration as a function of cambium temperature and tissue
nitrogen content. We conclude that failure to account for tissue nitrogen effects on respiration rates will result in serious
errors when estimating annual maintenance costs.
Keywords:
carbon balance, productivity, temperature–nitrogen model of maintenance respiration, tissue nutrition, woody tissue.
