Abstract: Based on determinations of the four microelements, including Cu, Zn, Fe,and Mn, whthin Dahurian larch plantation ecosystem in the eastern part of no-rthern China, analyses of nutrient concentrations, distribution, accumulation,removement and cycle through the ecosystem were conducted. The results wereas follows, The total amount of the microelements accumulated in the ecosystemwas 173493.368kg/ha, in which nearly 99% was stored in the soil pool, whileno more than 1% in the vegetation system; The annual absorption of the mic-roelements was 6. 4483kg/ha, in which the annual retention and the annual re-turn were 3.3250kg/ha and 3. 1233kg/ha, respectively, and the return/absorp-tion ratio was 48.440; The input thrfough hydrologic way into the ecosystemand the output through runoff out of the ecosystem were 0.8720kg/ha·a and0.4114kg/ha, respectively, and thus the net gains of the system was 0.4606kg/ha·a and the average net change ratio was 52.8% with the highest value of77.8% for Cu; The circulation diagram of microelemental cycle within the eco-system was described and the dynamic models were established.

Key words: Larch, Plantation ecosystem, Microelemental cycle, Dynamic model