Thursday, August 9, 2007

PS 67-142: Depth-related variations of fine root biomass in natural and afforested Mediterranean riparian forests

Juan A. Delgado and Teodora Martínez. IMIDRA

Fine roots are the most important plant organs for water and nutrient acquisition. The fine root systems of plants play crucial roles in the fluxes of energy and matter in the biosphere and carry out the essential functions of soil resource acquisition. The production, death and decomposition of roots are major processes in the carbon and nutrient dynamics of forest ecosystems.
Due to the disproportionate role of fine roots on forest ecosystem functioning it could be possible to use the monitoring of fine roots variations as an approach to assess the functional condition of forests. In other words, it will be possible to evaluate different forest restoration stages under a functional perspective.
In this work we report depth related variations of fine-root biomass in natural and afforested Mediterranean riparian forests in Central Spain.
We established 9 25x25 m plots at two different aged afforested areas (1994, 1999) and one natural riparian forest along the same riverside. In each plot we performed root profiles (0-10, 10-20, 20-30, 30-40 y 40-50 cm) in January 2006.
Results showed that depth-related fine root variations were very similar for all areas. Nevertheless, total fine root biomass differed between areas in relation to forest maturity. Natural mature forest presented more fine-root biomass than older afforested areas with the more recent afforested area showing fine root biomass values close to those of deforested areas. These results are discussed in relation to the understanding of restoration as the recovering of forest functioning.