PRODUCTION OF FINE ROOTS AND THE SEASONALITY OF THEIR GROWTH IN A MEXICAN DECIDUOUS DRY FOREST

Very limited information regarding fine-root growth and production of tropical dry forests is available. Fine roots and small roots are defined as rootlets with diameters < 1 mm and 1.1 to 5 mm, respectively. Live and dead fine-and small-root mass fluctuations were studied over one year by means of soil core analyses in the deciduous dry forest of Chamela, Mexico, at 19° 30′, 2 km inland from the Pacific Ocean. By means of systematically varying the distance of soil core extraction points from tree stems, it was shown that random core collection is justified. A difference between fine-root biomass on south and north facing slopes was documented, although this difference was significant only during the rainy season. The live/dead ratio of fine roots was highest during the rainy period. The annual fine-root production for 1989 was estimated at 4.23 Mg ha-1 by summing significant fine-root biomass changes between sampling dates. This value is higher than most of the comparable data from other ecosystems. © 1990 Kluwer Academic Publishers.