Plant Health Week – day 4

Back in 2009 I was with my family in Poland and we were doing some hill walking in Beskidy, a beautiful mountain range in South Poland. Hills in that range are usually well covered by forests, both mixed and single species – mostly spruce. This is what I was used to at least.

Spruce forest in Beskidy, Poland, 2009.

However, in places, the mature spruce forest was giving way to patches of a rather sad looking dead trees. When the landscape opened even more, we were walking through miles and miles of a apocalyptic-looking dead tree forests; the result of a combined drought and bark beetle onslaught.

Spruce forest in Beskidy, Poland, 2009

Ips typographus, known as an eight-toothed spruce bark beetle or the European spruce bark beetle, is a serious and destructive pest of trees. It usually attacks weakened trees, so its outbreaks often follows dry periods when spruce – with its rather shallow roots – becomes particularly stressed. But, if summers are long and warm, the beetle can fit several generations (from eggs through larvae to adults) into the year. As each generation represents an exponential increase compared to the previous one, a huge outbreak can follow. The resulting density of beetles can overcome the resistance even of healthy trees, resulting in a massive outbreak which devastated forest in southern Poland and nearby Czech Republic and Slovakia.

Map of South Poland showing the extend of deforestration – colours denote year of forest loss, with purple to light blue corresponding to 2001-2009 and green to red corresponding to 2010-2018. http://earthenginepartners.appspot.com/science-2013-global-forest

This pattern is now being repeated again and again in different locations and with different trees and pests. As the climate becomes warmer, with less snow and higher temperature in winters forest insects like Ips typographus are finding it easier to survive. Less snow in winter and hotter summers also means drought which stresses trees. This combination is likely to lead to more and more disappearing forests – at least forests as we know them.

Don’s risk it! https://www.gov.uk/government/news/public-urged-not-to-bring-plant-pests-and-disease-into-the-uk

What can we do? Ips typographus is a native in continental Europe, but not present in the UK. We can try to make sure it is not brought into the UK by accident, and if it arrives – as it happened in Kent in 2018 – to eradicate it as quickly as possible.

Beskidy forest, 2009

We can also replant the forests with other trees, recognising that perhaps the forests we are used to might need to look differently in 20, 50 or hundred years. This requires a lot of planning of how to adapt the forests to the climate change and make them useful as well as beautiful.

Me in Białowieża Forest in northern Poland, 2019. Białowieża is a unique old forest which has recently been devastated by Ips typographus.