© 2001 Heron Publishing—Victoria, Canada
Interception loss, throughfall and stemflow chemistry in pine and oak forests in northeastern Mexico
Israel Cantú Silva (1) and Humberto González Rodríguez (1)
1. Facultad de Ciencias Forestales, Universidad Autónoma de Nuevo León, Apartado Postal 41, Linares, NL 67700, México / Received August 18, 2000
Summary
Interception loss, gross precipitation, throughfall and stemflow solution chemistry beneath pine (Pinus pseudostrobus Lindl.), oak (Quercus sp.) and pine–oak natural forest canopies in northeastern Mexico were measured. Coefficients of variation for throughfall
were 12% in pine and oak canopies and 17% in the mixed pine–oak canopy. The variability of stemflow averaged 66, 126 and 73%
for pine, oak and the mixed pine–oak canopies, respectively. Linear regression analysis of net versus gross precipitation
for the three canopies showed highly significant correlations (r = 0.974–0.984). Total precipitation during the experimental period was 974 mm and estimated interception loss was 19.2,
13.6 and 23% for the pine, oak and pine–oak canopies, respectively. Stemflow did not occur following rainfall events of less
than 4 mm and, in all canopies, stemflow represented a minimal proportion of gross precipitation (0.60, 0.50 and 0.03% for
pine, oak and pine–oak, respectively). Throughfall pH in pine (6.2), oak (6.3) and pine–oak (6.3) canopies was significantly
more acidic than gross precipitation (6.6). Stemflow pH ranged from 3.7 (pine) to 6.0 (oak). The pine–oak canopy registered
the highest throughfall and stemflow electrical conductivities, 104 and 188 μS cm–1, respectively. Net nutrient leaching of K, Mg, Na, Fe, Mn and Zn was significantly higher from the pine–oak canopy than from
the pure pine and oak canopies. Mean depositions of Ca and Cu in throughfall behaved similarly among the three types of canopies.
A greater proportion of Zn in gross precipitation was absorbed by the oak canopy than by the pine and pine–oak canopies. Enrichment
factors beneath the pine–oak canopy relative to gross precipitation varied from 1.2 to 3.2 for macro-nutrients (Ca, K, Mg
and Na) and from 1.4 to 3.1 for micro-nutrients (Cu, Fe, Mn and Zn). Stemflow depositions of Ca, K, Mg and Cu were higher
in the pine–oak canopy, whereas stemflow depositions of Na, Fe, Mn and Zn were higher in the pine canopy.
Keywords:
canopy, hydrology, nutrient deposition, Pinus pseudostrobus, Quercus.
