This study examined the effects of environmental factors on the abundance of black pine bast scale (BPBS), Matsucoccus thunbergianae Miller and Park, in coastal disaster prevention forest stands composed mostly of Japanese black pine. Geographical factors, soil conditions and forest stand conditions were measured to evaluate the hazard rating for the occurrence of BPBS from 35 plots in the coastal forest stands. To assess the hazard rating, a combination of a self-organizing map (SOM), which classified the samples according to their characteristics, and a random forest model, which predicted the probability of the occurrence of BPBS from SOM results, was used in this study. Our results showed that major factors determining the abundance of BPBS were climate, tree size, and tree health. BPBS was more common in low latitude coastal forests, suggesting that warmer conditions were favorable to BPBS population buildup. Tree size also influenced the abundance of BPBS, which was higher in forests composed of larger trees (greater DBH). Finally, BPBS was also more abundant in areas with high soil salinity and clay-loam soil, and north-facing slopes where tree vigor was lower.

The species diversity of macrolepidoptera (larger species of moths) was surveyed using light traps at forests near the Forest Environmental Research Institute located in 9 provinces (Gyeonggi, Gangwon, Chungbuk, Chungnam, Jeonbuk, Jeonnam, Kyeongbuk, Kyeongnam, Jeju) in 2012. Sampling was conducted weekly or biweekly from April to October. Using light traps in 8 forests, 2,961 individuals belong to 530 species from 20 families were collected. The species richness between study sites ranged from 4 (Kyeongnam) to 258 (Chungbuk). Similarly, abundance was the highest at Gyeonggi (1,235 individuals) and lowest at Kyeongnam (11 individuals). Species diversity (H’) was the highest at Chungbuk (5.14) and lowest at Kyeongnam (1.29). Composition of macrolepidopteran species also changed seasonally, showing regional variations. Dominant species in 9 study sites were Lamoria glaucalis in Gyeonggi, Ivela auripes in Gangwon, Idiotephria amelia in Chungbuk, agrotis tokionis in Chungnam, Acosmeryx naga in Jeonbuk, Glyphodes perspectalis in Jeonnam, Spodoptera depravata in Gyeongbuk, Xestia dilatata in Gyeongnam and Lithosia quadra Jeju. Among the species, Ivela auripes, Lamoria glaucalis, and Glyphodes perspectalis were known to be sporadic forest insect pests. Therefore, continuous monitoring can be needed to prevent the potential outbreaks of such insect pests.