Fine-root mass, growth and nitrogen content for six tropical tree species Article

Valverde-Barrantes, OJ, Raich, JW, Russell, AE. (2007). Fine-root mass, growth and nitrogen content for six tropical tree species . PLANT AND SOIL, 290(1-2), 357-370. 10.1007/s11104-006-9168-2

cited authors

  • Valverde-Barrantes, OJ; Raich, JW; Russell, AE

authors

abstract

  • Although fine roots might account for 50% of the annual net primary productivity in moist tropical forests, there are relatively few studies of fine-root dynamics in this biome. We examined fine-root distributions, mass, growth and tissue N and C concentrations for six tree species established in 16-year-old plantations in the Caribbean lowlands of Costa Rica in a randomized-block design (n = 4). The study included five native species (Hyeronima alchorneoides, Pentaclethra macroloba, Virola koschnyi, Vochysia ferruginea and Vochysia guatemalensis) and one exotic (Pinus patula). Under all species >60% of the total fine-root mass to 1 m deep was located in the uppermost 15 cm of the soil. Fine-root live biomass and necromass (i.e., the mass of dead fine-roots) varied significantly among species but only within the uppermost 15 cm, with biomass values ranging from 182 g m-2 in Pinus to 433 g m-2 in Hyeronima plots, and necromass ranging from 48 g m-2 in Pinus to 183 g m-2 in Virola plots. Root growth, measured using ingrowth cores, differed significantly among species, ranging from 304 g m-2 year-1 in Pinus to 1,308 g m-2 year-1 in Hyeronima. These growth rates were one to five times those reported for moist temperate areas. Turnover rates of fine-root biomass ranged from 1.6 to 3.0 year-1 in Virola and Hyeronima plots, respectively. Fine-root biomass was significantly and positively correlated with fine-root growth (r = 0.79, P < 0.0001), but did not correlate with fine-root turnover (r = 0.10, P = 0.20), suggesting that fine-root accumulation is a function of growth rate rather than mortality. Fine-root longevity was not correlated (r = 0.20, P = 0.34) and growth was negatively correlated with root N concentration across species (r = -0.78, P < 0.0001), contrary to reported trends for leaves, perhaps because N was relatively abundant at this site. © 2006 Springer Science+Business Media B.V.

publication date

  • January 1, 2007

published in

Digital Object Identifier (DOI)

start page

  • 357

end page

  • 370

volume

  • 290

issue

  • 1-2