Degradation of White Birch Shelterbelts by the Attack of White-Spotted Longicorn Beetles in Central Hokkaido, Northern Japan

Kazuhiko Masaka,Yohichi Wakita,Masato Hayamizu,Kenta Iwasaki

doi:10.3390/f13010034

Kazuhiko Masaka, Yohichi Wakita + Show 2 more

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https://doi.org/10.3390/f13010034

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Journal: Forests	Publication Date: Dec 29, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: Iwate University, Hokkaido Research Organization

Abstract

A widespread decline of white birch (Betula platyphylla var. japonica) shelterbelts was observed in central Hokkaido, Japan. Many exit holes bored by white-spotted longicorn beetles (Anoplophora malasiaca) were found at the base of the trunks of trees in these stands. The present study aims to evaluate the effects of infestation on the degradation, and demonstrates whether the number of exit holes (Nholes) can be used as an index of the decline of trees. We selected 35 healthy appearing stands and 16 degraded stands in the study area. A generalized linear mixed model with zero inflation revealed that Nholes of standing dead trees tended to be greater than that of living trees, and the tree vigor decreased with increasing Nholes. These results implied that the degradation of the shelterbelts was caused by the beetle. We also found size-dependent mortality, i.e., only a few larvae can cause the death of smaller trees, but not larger trees. Furthermore, evaluation of the degradation at the stand level (Nholes) using a logistic regression analysis revealed that the degradation at the stand level could be predicted by Nholes. Our findings can be used as a useful index marker for diagnosing white birch shelterbelts.

Highlights

The genus Anoplophora (Coleoptera: Cerambycidae) includes some of the most damaging wood-boring pests in the northern hemisphere [1,2,3,4]
We addressed three questions: (1) To what extent does the number of adult exit holes correlated with the decline of white birch at the individual level? (2) Is there any relationship between the tree size and the minimum number of adult exit holes in the standing dead trees? and (3) To what extent does the severity of attacks correlate with the level of stand degradation?
These results show that the level of attacks by the whitespotted longicorn beetle is a good indicator of the degradation of white birch shelterbelts in central Hokkaido

Summary

Introduction

The genus Anoplophora (Coleoptera: Cerambycidae) includes some of the most damaging wood-boring pests in the northern hemisphere [1,2,3,4]. Anoplophora species have significant preferences for particular host trees [5,6], they have a very wide host plant range that includes more than 100 tree species [7]. Many researchers have focused on the ecology of Anoplophora from the viewpoints of dispersal behavior [9,10,11,12,13], host preference [5,14,15], and invasion process [16,17,18], information on the forest degradation process caused by the beetles is scarce.

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