Our directory of things of interest

University Directory

Beetlemania as invasive species spreads north

A southern pine beetle, yesterday A southern pine beetle, yesterday KC Film
07 Sep
2017
After an ‘unprecedented’ surge northwards into New Jersey, New York and Connecticut, the southern pine beetle is expected to continue expanding its range into large portions of northern US and southern Canadian forests

Nova Scotia by 2020. Southern New England and Wisconsin by 2060. Canada by 2080. These are the years that researchers believe regions could make the ultra-destructive southern pine beetle ‘southern’ no longer.

At just half the length of a grain of rice, the bugs don’t look threatening. However, they burrow themselves within the inner bark of pine trees, where they feed on its vital tissue – or phloem. Enough beetles prevent the transportation of essential nutrients within the tree, damaging it beyond repair. Infestations were responsible for a loss of 14 million cubic metres of timber across the southeastern states of Pennsylvania, Ohio and Maryland between 1990 and 2004.

A southern pine beetleThe southern pine beetle (Image: US Department of Agriculture)

‘Our projections indicate that the southern pine beetle will continue to spread into forests that have never seen it before,’ says Corey Lesk, graduate student at the University of Columbia and lead author of the research published in Nature Climate Change. According to his findings, the beetles’ range depends on winter temperatures, specifically those of the phloem. The team found that once the inner bark stays above -10ºC for a decade, the beetles begin to appear. So far, infestations have followed warmer winters in New Jersey since 2001, while populations were found in New York in 2014 and Connecticut in 2015. The study predicts that forests further up the east coast to Nova Scotia could be hospitable to beetles by 2020, southern New England and Wisconsin between 2040 and 2060 and much of southern Ontario and Quebec in Canada before 2080. Overall, ‘there is huge vulnerability across a vast ecosystem,’ states Lesk.

Pine tree covered in resinA pine tree covered in tell-tale blobs of resin, or ‘pitch tubes’ (Image: Bugwood.org)

The predictions combined 27 different global climate models and two greenhouse gas emission models. Because these models don’t unanimously or perfectly predict the climate, they show different years when the beetles could emerge. Overall, they found a 43-year range between the earliest and latest year a suitable climate for the beetles would become established. ‘There are also ecological uncertainties that the study doesn’t cover, such as whether beetles will be successful in northern pine species that they have never seen before, or whether increased droughts could make trees more vulnerable to the beetle,’ explains Lesk. ‘Although we haven’t yet fully answered these questions, we think our results suggest that we should consider how we will prepare for these new threats to our forests.’

Infestations are difficult to control once they are underway. ‘The main strategy to prevent damage is to cut and remove infested trees so that the beetles can’t reproduce,’ says Lesk. ‘That’s effective for keeping down the intensity of an outbreak.’ Sometimes, removing strips of forest can also hinder the spread of pests. ‘But,’ warns Lesk, ‘there is some evidence that these beetles can travel very large distances, so that will likely not work in this case.’

Related items

Geographical Week

Get the best of Geographical delivered straight to your inbox every Friday.

LATEST HEADLINES

Subscribe to Geographical!

Adventure Canada

EDUCATION PARTNERS

Aberystwyth University University of Greenwich The University of Winchester

TRAVEL PARTNERS

Ponant

Silversea

Travel the Unknown

DOSSIERS

Like longer reads? Try our in-depth dossiers that provide a comprehensive view of each topic

  • National Clean Air Day
    For National Clean Air Day, Geographical brings together stories about air pollution and the kind of solutions needed to tackle it ...
    The Air That We Breathe
    Cities the world over are struggling to improve air quality as scandals surrounding diesel car emissions come to light and the huge health costs of po...
    Hung out to dry
    Wetlands are vital storehouses of biodiversity and important bulwarks against the effects of climate change, while also providing livelihoods for mill...
    The Nuclear Power Struggle
    The UK appears to be embracing nuclear, a huge U-turn on government policy from just two years ago. Yet this seems to be going against the grain globa...
    Mexico City: boom town
    Twenty years ago, Mexico City was considered the ultimate urban disaster. But, recent political and economic reforms have transformed it into a hub of...

MORE DOSSIERS

NEVER MISS A STORY - Follow Geographical on Social

Want to stay up to date with breaking Geographical stories? Join the thousands following us on Twitter, Facebook and Instagram and stay informed about the world.

More articles in PLACES...

Mountains

In this extract from his new book, Tides, mountain climber…

Cities

New data from the World Health Organization reveals that nine…

Water

In the wake of the water crisis in Flint, Michigan,…

Mapping

Benjamin Hennig maps out the global production and distribution levels…

Water

Millions of Americans are living in areas at high-risk of…

Mapping

New interactive maps combine precipitation and temperature to show climate…

Cities

Public transport in India could be on the verge of…

Water

To retrace the route of the fur voyageurs on the waterways…

Cities

IPCC Cities and Climate Change Conference: Alberta host dresses non-renewable…

Water

Increased carbon dioxide is affecting freshwater ecosystems

Forests

The latest laser scanning technology reveals new insights into the…

Forests

Deforestation is having an unexpected effect in the Amazon: fewer…

Forests

The iconic Douglas fir tree, familiar to fans of the…

Forests

Rocky Mountain forests are not regenerating after wildfires

Cities

Cape Town is edging closer to ‘Day Zero’, the long-feared…

Water

Ongoing restoration projects are breathing new life into Florida’s Everglades

Cities

Despite protests, an experimental pedestrianisation system is proving to be…

Mapping

National Archives map historian, Rose Mitchell, highlights some of the…

Water

An expedition into the Jordanian desert is helping teachers and…

Mountains

Trivia fans take note, Mount Hope in the British Antarctic…