Abstract: Functional traits of fine roots (≤2 mm in diameter) and their vertical distribution patterns reflect plant resource absorption strategy and determine belowground ecological processes in forests. A stratified excavation method was used to examine fineroot functional traits, vertical distribution and architecture of four cultivated trees (Cercidiphyllum japonicum, Betula platyphylla, Pinus armandii,andP. tabuliformis). The results showed that root length density, fine root biomass, specific root length (SRL) and specific root surface area (SRA) of broadleaf species were higher than those of coniferous species and that average diameter of fine root was smaller in broadleaf species. Root length density and fine root biomass of all the four species decreased significantly with increasing soil depth and concentrated in 0-20 cm soil layer. Moreover, trees grown in high elevation areas had higher root length density and fine root biomass than those in low elevation. There were no significant differences in SRL, SRA and fine root diameter among soil layers or elevations. There were significant differences of fine root architecture among species, with the highest first-order root number, tip density and bifurcation being found in Betula platyphylla, and the highest branching ratio inCercidiphyllum japonicum.However, fine-root architecture did not differ across the elevations. The SRL was positively correlated with the number of firstorder roots and tip density, the branching ratio was positively associated with root length density and fine root biomass, but all functional traits decreased with bifurcations. These results indicated that fine root architecture had significant effects on their vertical distribution and resource acquisition strategy.

Key words: phytoplankton absorption coefficient., estimation models, remote sensing measures, oceanic primary productivity