Abstract: [Objective] The forest pest disasters are increasing year by year, thus the disaster loss assessment is getting more and more attention by the forestry administrative department and the forestry research department, and it has become hot spot to construct a suitable index system of the forest pest damage assessment. [Method] In this paper, a forest pest damage assessment index system is constructed, including 3 first grade indexes, 14 second grade indexes and 30 third grade indexes, according to the scientific, systematic, hierarchical, feasibility and comparability principles, by using technical and economic approach, replacement cost approach, defensive expenditure approach, market value approach, and willing to pay approach.[Result] The 3 first grade indexes are for direct economic loss, ecological service function loss and social benefit loss. The 14 second grade indexes are for forest economic loss, fruit economic loss,prevention and treatment cost, afforestation and management cost, water conservation loss, soil conservation loss, carbon fixation and oxygen release loss, nutrient accumulation loss, atmosphere purification loss, forest protection loss, biodiversity conservation loss, forest recreation loss, forest culture loss, and non-forestry industry loss. The 30 third grade indexes are for forest stock volume loss, forest growth amount loss, timber grade lower loss, fruit production loss, fruit quality loss, prevention cost loss, treatment cost loss, afforestation cost loss, management cost loss, water adjustment loss, water quality purification loss, soil solidification loss, fertilizer retaining loss, carbon fixation loss, oxygen release loss, accumulation loss of N,P,K,OM, oxygen ion provision loss, pollution absorption loss, noise reduction loss, dust retardation loss, farmland protection loss, pasture protection loss, road drainage protection loss, biodiversity protection loss, recreation environment damage loss, forest culture impact loss, and other related industries losses caused by forest pest disaster. The evaluation index system standardized the meaning and quantitative calculation model of direct economic loss and ecological service function losses by forest pests. For forest recreation loss, forest culture loss, and other related industries losses which are difficult to be quantitative calculate, it could be calculated by the method of willing to pay is used, and the economic loss could also be calculated directly by using the survey method.[Conclusion] This assessment index system can be applied to not only forest pest disaster loss assessment in a region, but also the estimation of losses caused by other disasters, such as forest fire, forest meteorological damage, deforestation. Besides, the quantitative calculation methods of ecological service function losses are equally applicable to the assessment of forest ecological service function. The forest pest disaster loss assessment index system is of great significance for the forest pest control and forest resources management.

Key words: forest pest, disaster loss, assessment index, calculation method