Abstract: Understory vegetation is one of the main components of forest ecosystem. To understand the characteristics of understory biomass and its ecological effects is of significance in studying the structure and function of forest ecosystem. This paper summarized the relationships of the distribution of understory biomass with forest type, forest age class, and stand characteristics, and discussed the main roles of understory vegetation in maintaining nutrients recycling, preventing soil erosion, indicating forest environment change, affecting forest ecophysiological characteristics and succession, protecting animals inhabit, and keeping ecological balance.

Key words: Attractant, Trap, Lure, Monochamus alternatus