Foliar Temperature-Respiration Response Functions for Broad-Leaved Tree Species in the Southern Appalachians
We measured leaf respiration in 18 eastern deciduous forest tree species to determine if there were differences in temperature-respiration response functions among species or among canopy positions. Leaf respiration rates were measured in situ an4 on detached branches for Acer pensylvanicum L., A. rubrum L., Betula spp. (B. alleghaniensis Britt. and B. renta L.), Carya glabra (Mill.) Sweet, Cornus florida L., Fraxinus spp. (primarily F. americana L.), Liriodendmn tulipifra L., Magnolia fraseri Walt., Nyssa sylvatica Marsh., Oxydendrum arboreum L., Platanus occidentalis L., Quercus alba L., Q. coccinea Muenchh., Q. prinus L., Q. rubra L., Rhododendron maximum L., Robinia psuedoacacia L., and Tilia americana L. in the southern Appalachian Mountains, USA. Dark respiration was measured on fully expanded leaves at 10, 15, 20, 25, and 30 °C with an infrared gas analyzer equipped with a temperature-controlled cuvette. Temperature-respiration respons functions were fit for each leaf. There were significant differeuces in response functions among species and by canopy position within species. These differences were observed when respiration was expressed on a mass, nitrogen, or area basis. Cumulative nighttime leaf respiration was calculated and averaged.lover ten randomly selected nights for each leaf. Differences I mean cumulative nighttime respiration P were statistically significant among canopy positions and species. We conclude that effects of canopy position and species on temperature-respiration response functions may need to be considered when making estimates of whole-tree or canopy respiration .