Fine Root Biomass Seasonal Dynamics And Spatial Distribution Pattern In Larix Principis-rupprechtii Plantations

30 year old Larix principis-rupprechtii forest was chosen to examine fine root (≤5mm in diameter ) biomass, seasonal dynamics and spatial distribution in one year (2004-2005) study period. The mean annual fine root (≤5mm)biomass was 305.26 g/m2,the contribution to total root biomass was 33%.2-5mm , 1-2mm and ≤1mm fine root biomass were respectively 149.37 g/m2, 295.36 g/m2 and 116.63 g/m2, the contribution to total root biomass was 16%,4% and 13%.1-2mm necromass was 71.85g/m2, the contribution to total root biomass was 8%; 2-5mm necromass was 1.65 g/m2, the contribution to total root biomass was negelected-Siginificant seasonal changes were found in the fine root(≤1mm, 1-2mm) biomass and necromass ( p<0.05 ),while 2~5mm fine root biomass was detected significantly (P > 0.05 ).An flush of root biomass (July or August)was found in the forest,and the minimum value mainly occurred on May or October.The mean SRL (≤1mm, l-2mm )was 36.63m/g,21.29 m/g,and significant seasonal changes were found. The mean SRL(2-5mm) was 11.37 m/g, and the SRL was detected significantly. 52.24% of fine root biomass and 49.2% necromass were found in the top soil of 0-10cm, the fine root biomass and necromass were respectively 159.49 g/m2 and 35.58g/m2. Significant seasonal changes were found in the 0-10cm (P<0.05 ) . Maximum and minimum value was found on August and May , respectively.The fine root biomass and necromass in the 10~20cm and 20~30cm soil were detected significantly (P > 0.05) and the orderliness was not found. Fine root biomass and necromass were detected significantly at different level distances (P > 0.05) . This article aimed to find out the potential underground ecological process and soil productivity of Larix principis-rupprechtii plantation. It would provide fundamental data for evaluating biomass and productivity of forestry ecosystem accurately.