Woody invaders in future climate


Minnesota boasts around 17 million acres of forestland – an area larger than the state of West Virginia. The value these lands bring our state in timber, recreation, tourism and environmental health and diversity is enormous. Unfortunately, our forests face increasing pressures from invasive species and changing weather.  

Honeysuckle (Lonicera morrowiiL. tatarica) and buckthorn (Frangula alnusRhamnus cathartica) are two invasive shrubs that have already taken hold across central and southern regions of the state. As temperatures and precipitation levels stand to change over time, these shrubs may be poised to become a bigger problem in Minnesota's northern forests as well.

Researchers engaged in this project will begin by mapping the current distribution of invasive honeysuckle and buckthorn across Minnesota. They will then compare how invasive and native trees fare under both current and potential future weather conditions. Ultimately, this will help managers identify possible future "hotspots" of invasion. The team will also test the success of vegetation barrier zones for slowing the spread of invasive shrubs.

Three researchers are looking down at vegetation, surrounded by instruments and equipment.

Research questions

  • What are the growth responses of woody invasives and native tree species to past and current climate conditions?
  • What is the potential threat for future woody invasive spread, statewide and in northern forests?
  • What are effective methods of creating local barriers to woody invasive spread?

Practical implications

This project will test new approaches to slow the spread of woody invaders across Minnesota, allowing agencies to plan ahead for future “hot-spots” of invasion.


Findings from this project tell the story of how exotic honeysuckle and buckthorn have invaded Minnesota forests, how and why new areas are likely to be invaded in the future, and how we may be able to mitigate invasion using native tree species. 

The project team found invasive and more southern native species to be favored by warming conditions in terms of their growth and survival, whereas more northern native species were often strongly disfavored. They established programs to detect current invasion at fine-scale spatial resolution and predict future invasion based on the findings above, and set up long-term experiments to test the ability of tree plantings to slow invasion into new areas.


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