© 1993 Heron Publishing—Victoria, Canada
Neutralization and buffering capacity of leaves of sugar maple, largetooth aspen, paper birch and balsam fir
G. E. Liu and Benoît Côté
Department of Renewable Resources, MacDonald Campus of McGill University, 21, 111 Lakeshore, Ste-Anne-de-Bellevue, Québec
H9X 1C0, Canada / Received October 24, 1991
Summary
We compared the acidity, the external acid neutralizing capacity and the buffering capacity of leaves of four commercially
important tree species, largetooth aspen (Populus grandidentata Michx.), sugar maple (Acer saccharum Marsh.), paper birch (Betula papyrifera Marsh.) and balsam fir (Abies balsamea (L.) Mill), at two sites of contrasting soil fertility in southern Quebec. External acid neutralizing capacity (ENC) of leaves
was determined by measuring the change in pH induced by soaking fresh leaves in an
acidic solution (pH 4.0) for two hours. The ENC was highest for largetooth aspen (14.3 µequiv H+ g–1), and lowest for sugar maple and balsam fir (< 5 µequiv H+ g–1). The buffering capacity index (BCI) was determined by measuring the amount of acid necessary to produce a change of 5 µequiv
H+ in the leaf homogenate. The BCI ranged from 883 µequiv H+ g–1 for largetooth aspen to less than 105 µequiv H+ g–1 for sugar maple and balsam fir. Leaves of sugar maple and balsam fir had a lower internal pH and a higher percentage of ENC
over BCI than paper birch and largetooth aspen. Overall, ENC was correlated with the concentration of all leaf nutrients except
Ca, and BCI was correlated with Mg, N and Ca. The site effect was relatively unimportant for all variables.
Keywords:
Abies balsamea, Acer saccharum, acid precipitation, Betula papyrifera, foliar leaching, soil fertility.
