Abstract: Geostatistic method was applied to study the spatial distribution of woody plant fine root biomass in a natural broad-leaved Korean pine (Pinus koraiensis）mixed forest soil in Changbai Mountain. The investigation was carried out in three selected plots, sized 50 m×50 m, in 2008. In the three plots, the living fine root biomass in surface soil (0-20 cm) was 3.195, 1.930, and 2.085 t·hm^-2, and the dead fine root biomass was 0.971, 0.581,and 0.790 t ·hm^-2, respectively. In 0-10 cm soil layer, the living fine root biomass had no correlation with the dead fine root biomass; but in 10-20 cm soil layer, a significant positive correlation was found between them (r=0.352，P<0.05). The variograms of living fine root biomass and dead fine root biomass could be well fitted by spherical model. Spatial variation explained more than 70% of the total variance of fine root biomass across three plots. The regressed ranges were 5.2, 14.6, and 9.8 m for living fine root biomass, and 4.3, 20.4, and 20.1 m for dead fine root biomass in plots 1, 2, and 3, respectively. For comparison, Bayesian method was also used to estimate the ranges for the fine root biomass. The results obtained by geostatistic method and Bayesian method were consistent with each other.

Key words: fine roots, geostatistics, semivariogram, Bayesian statistics, net anthropogenic nitrogen input (NANI), Huaihe River Basin, nitrogen pollution, nitrogen budget.