Responses of leaf respiration to temperature and leaf characteristics in three deciduous tree species vary with site water availability

Abstract

We measured responses of leaf respiration to temperature and leaf characteristics in three deciduous tree species (Quercus rubra L., Quercus prinus L. and Acer rubrum L.) at two sites differing in water availability within a single catchment in the Black Rock Forest, New York. The response of respiration to temperature differed significantly among the species. Acer rubrum displayed the smallest increase in respiration with increasing temperature. Corresponding Q10 values ranged from 1.5 in A. rubrum to 2.1 in Q. prinus. Dark respiration at ambient air temperatures, expressed on a leaf area basis (Rarea), did not differ significantly between species, but it was significantly lower (P < 0.01) in trees at the wetter (lower) site than at the drier (upper) site (Q. rubra: 0.8 versus 1.1 μmol m-2 s-1; Q. prinus: 0.95 versus 1.2 μmol m-2 s-1). In contrast, when expressed on a leaf mass basis (Rmass), respiration rates were significantly higher (P < 0.01) in A. rubrum (12.5-14.6 μmol CO2 kg-1 s-1) than in Q. rubra (8.6-9.9 μmol CO2 kg-1 S-1) and Q. prinus (9.2-10.6 μmol CO2 kg-1 s-1) at both the lower and upper sites. Respiration on a nitrogen basis (RN) displayed a similar response to Rmass. The consistency in Rmass and RN between sites indicates a strong coupling between factors influencing respiration and those affecting leaf characteristics. Finally, the relationships between dark respiration and Amax differed between sites. Trees at the upper site had higher rates of leaf respiration and lower Amax than trees at the lower site. This shift in the balance of carbon gain and loss clearly limits carbon acquisition by trees at sites of low water availability, particularly in the case of A. rubrum.