Vulnerability to strong winds for major tree species in a northern Japanese mixed forest: analyses of historical data

Abstract

Abstract This study examined historical census data to evaluate the vulnerability of major tall‐tree species in northern Japan to strong winds. Intensive data, which measured more than 20,000 damaged trees (defined as trees that were killed or lost their major crown) in >500 ha of a natural mixed forest, were collected immediately after a severe typhoon in 1954. More than half of the damaged trees had been uprooted, and the negative size‐dependency was found for the proportion of uprooting throughout species. Simple correlation analyses with respect to the averaged species‐specific characteristics suggested that tree species with a high crown‐depth/height tended to uproot (against to stem breakage) in a size‐class with diameter at breast height 30–50 cm. Although the census data had yielded no information about non‐damaged trees, the estimation of pre‐disturbed stand (based on 63 1‐ha plot data together with aerial photographs and GIS) revealed that the observed damage reached ca. 25% in terms of basal area. The proportion of damaged trees seemed to be doubled among species (15–42% in basal area). A higher proportion of uprooting, which indicates a large supply of tip‐up mounds, and mixture of less vulnerable species, might contribute to recovery process after a wind disturbance in this type of mixed forests.