Large-area Mapping of the Mass Mortality and Subsequent Regeneration of <i>Abies mariesii </i>Forests in the Zao Mountains in Northern Japan

Abstract

Mass mortality caused by bark beetles occurred locally in a subalpine fir (Abies mariesii) forest in the Zao mountain area in northern Japan. We examined the distribution of the mass mortality of A. mariesii trees and the corresponding locations to analyze the mortality rate in each section of a 50 m mesh, using satellite images and GIS, in a 528 ha fir forest in Yamagata Prefecture. Our results show that there were three areas where sections with mortality rates of 60％ or more were concentrated in this study area. They were located on western slopes with high altitude. However, since there were still many sections with low mortality rates in these locations, the local occurrence of mass mortality could not be explained by location alone. Sasa bamboo (Sasa kurilensis) dominates the forest floor in many fir forests. Study plots with higher sasa coverage had fewer juvenile A. mariesii trees. Sasa coverage tended to increase as altitude increased, and there were no A. mariesii seedlings and saplings in the plots at high altitudes. This tendency was extremely noticeable on the western slope of Mt. Jizoudake, which was also the area in which sections with high mortality rates were most concentrated in this study area. Therefore, mass mortality forests dominated by sasa at high elevations are predicted to be difficult to regenerate because they have few juvenile trees on the forest floor.

Host preference of the tree‐killing bark beetle Polygraphus proximus across a geographic boundary separating host species

“…More recently, mass attack and mass mortality events of Abies trees due to P . proximus were observed with its native range of Japan (Tokuda et al, 2008; Takagi et al, 2018, 2021; Chiba et al, 2020). Given the biogeographic boundary of the Abies species in Japan, it is speculated that the host preference of P .…”

“…In the past decade, P. proximus has become a striking example of range expansion in Russia (Kerchev, 2014b), as this species invaded European Russia and West Siberia, causing mortality across large areas of both planted and natural fir forests (Baranchikov et al, 2010;Kerchev, 2014b). More recently, mass attack and mass mortality events of Abies trees due to P. proximus were observed with its native range of Japan (Tokuda et al, 2008;Takagi et al, 2018Takagi et al, , 2021Chiba et al, 2020). Given the biogeographic boundary of the Abies species in Japan, it is speculated that the host preference of P. proximus would vary between Hokkaido and Honshu.…”

Long-term changes in vegetation and land use in mountainous areas with heavy snowfalls in northern Japan: an 80-year comparison of vegetation maps

“…Alternatively, insect attacks could be the reason for the decrease in A. mariesii abundance. For example, the mass mortality of subalpine fir by the bark beetle (Polygraphus proximus Blandford) is possible (Chiba et al, 2020). The bark beetle is also distributed in the Hakkoda Mountains and flies when temperatures are above 15 °C (Masuya, 2018;Chiba et al, 2020).…”

Colonization success of a tree‐killing bark beetle: Geographic variation and mismatch with host preference

“…P. proximus has invaded European Russia and West Siberia for the past 10 years, causing mortality across large areas of fir forests (Baranchikov et al, 2010 ; Kerchev, 2014b ). P. proximus also caused mass attacks and mortality events in Abies trees in its native range in Japan (Chiba et al, 2020 ; Takagi et al, 2018 , 2021 ; Tokuda et al, 2008 ). They exhibit a bivoltine cycle in their native distribution (EFSA, 2020 ; EPPO, 2014 ).…”