Abstract: In this paper, ordered plot clustering (OPC), a non-hierarchical agglomerative algorithm based on the algorithm of the "gold-partitioning method" (Fisher's method), is introduced to vertical belt partition of Guandi Mountains, Shanxi.The result of the vertical belt partitioning is as follows:1.deciduous broadleave forest belt (800-1600m above sea level), including 2 subbelts:I.temperate coniferous forest subbelt (800-1400m above sea level), and Ⅱ.deciduous broadleave forest subbelt (1400-1600m above sea level);2.coniferous and broadleave mixed-forest belt (1600-1750m above sea level);3.cold-temperate coniferous forest belt (1750-2600m above sea level);4.subalpine shrub and meadow belt (2600-2831m above sea level).The results obtained by OPC analysis are then compared to TWINSPAN using data on the floristic composition of vertical belts of the Guandi Mountains, Shanxi, North China.The result of analysis by OPC is considered as superior to that by TWINSPAN because some TWINSPAN plot groups cannot be explained according to existing vegetation distribution, contrary to the OPC result.

Key words: Ordered plot clustering, TWINSPAN, Non-hierarchical agglomerative algorithm, Vertical belt of natural vegetation, Gold partitioning method, Guandi Mountains, Shanxi