Potential Solar Radiation as a Driver for Bark Beetle Infestation on a Landscape Scale

Pavel Mezei,Mária Potterf,Jaroslav Škvarenina,Jakob Gulddahl Rasmussen,Rastislav Jakuš

doi:10.3390/f10070604

Abstract

In recent decades, Norway spruce (Picea abies L. Karst.) forests of the High Tatra Mountains have suffered unprecedented tree mortality caused by European spruce bark beetle (Ips typographus L.). Analysis of the spatiotemporal pattern of bark beetle outbreaks across the landscape in consecutive years can provide new insights into the population dynamics of tree-killing insects. A bark beetle outbreak occurred in the High Tatra Mountains after a storm damaged more than 10,000 ha of forests in 2004. We combined yearly Landsat-derived bark beetle infestation spots from 2006 to 2014 and meteorological data to identify the susceptibility of forest stands to beetle infestation. We found that digital elevation model (DEM)-derived potential radiation loads predicted beetle infestation, especially in the peak phase of beetle epidemic. Moreover, spots attacked at the beginning of our study period had higher values of received solar radiation than spots at the end of the study period, indicating that bark beetles prefer sites with higher insolation during outbreak. We conclude that solar radiation, easily determined from the DEM, better identified beetle infestations than commonly used meteorological variables. We recommend including potential solar radiation in beetle infestation prediction models.

Highlights

Massive forest mortality events affecting many tree species in the last two decades have prompted concerns that drought, insects, and wildfire may devastate more forests in the coming decades [1].Mountain spruce forests
Our results show that bark beetle spots occurred in sites with higher potential solar radiation loads, especially during peak and decline outbreak phases
We found that initiation of beetle infestation spots strongly depends on solar radiation loads, especially during peak and decline phases of beetle outbreak

Summary

Introduction

Massive forest mortality events affecting many tree species in the last two decades have prompted concerns that drought, insects, and wildfire may devastate more forests in the coming decades [1].Mountain spruce forests Massive forest mortality events affecting many tree species in the last two decades have prompted concerns that drought, insects, and wildfire may devastate more forests in the coming decades [1]. The main drivers of such disturbances in the Carpathians are wind and bark beetle outbreaks [2,3], the latter usually initiated by extreme weather events [4,5] and affected by forest management [6,7,8]. In Europe, the European spruce bark beetle (Ips typographus L.) is an insect species that often reaches epidemic levels [9,10]. The heat- and drought-induced physiological stress on trees likely triggers the development of forest insects, such as bark beetles [12,16]

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Conclusion