Indicator forest and wood

Forest damage caused by beetle infestation

Various insects can colonise weakened trees and cause them to die. Trees that are weakened through age, disease or stress are eradicated through this process, which promotes the health of the forest and its resilience. However, when these insects proliferate during extended periods of heat or drought or in the aftermath of storms, healthy trees may also be adversely affected; in the worst-case scenario, entire forests die.

Assessment of the state
medium medium
Assessment of the trend
negative negative
Beetle-infested wood 2017: 320 Beetle-infested wood 2016: 220 Beetle-infested wood 2015: 230 Beetle-infested wood 2014: 160 Beetle-infested wood 2013: 146 Beetle-infested wood 2012: 72 Beetle-infested wood 2011: 98 Beetle-infested wood 2010: 153 Beetle-infested wood 2009: 107 Beetle-infested wood 2008: 107 Beetle-infested wood 2007: 285 Beetle-infested wood 2006: 727 Beetle-infested wood 2005: 1015 Beetle-infested wood 2004: 1350 Beetle-infested wood 2003: 2067 Beetle-infested wood 2002: 1168 Beetle-infested wood 2001: 1310 Beetle-infested wood 2000: 162 Beetle-infested wood 1999: 86 Beetle-infested wood 1998: 78
Beetle-infested wood as a measurement of forest damage caused by bark beetle infestation (in 1,000 m3).

Data for the graph: Excel
Source: Swiss Federal Institute for Forest, Snow and Landscape Research: Swiss Forest Protection
Comment

Insect infestation increased considerably in the aftermath of cyclone Lothar in the winter of 1999/2000, but fell sharply after 2003, before increasing again starting in 2013.

In 2017, spruce stands were infected, especially in the lower altitudes of the Central Plateau, in parts of Grisons and the Southern Alps.

After the increase in 2013, European spruce bark beetle (Ips typographus) infestation has remained consistently high since 2014. While the situation in northern Switzerland was quiet, the infestation increased significantly in individual mountain regions, such as in Grisons and Valais. In many cases, this increase is explained by the regional storm and snow pressure damage in the last two years.

While it is inappropriate to classify the situation as a new instance of mass bark beetle proliferation, the problem can be expected to worsen in the medium to long term due to more extreme weather events such as drought and storms that come with climate change. Bark beetle activity will likely be benefitted by higher temperatures and the consequences of storms.

International comparison

The indicator can be compared internationally only to a limited extent as different tree and beetle species are recorded (only European spruce bark beetles and spruces are recorded in Switzerland; other/additional tree species and bark beetle species are recorded abroad. Note: The damage caused by insect infestation is recorded internationally in hectares of forest area).

Method

The data are collected through a survey of all forest districts in Switzerland. Only European spruce bark beetles and spruces are recorded for this indicator, which covers 80% to 85% of the damage caused by bark beetles. Infestations of other insect species are also surveyed by Swiss Forest Protection through a survey of forest wardens.

 
Last updated on: 27.11.2018

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