Arb Notes for Feb 10th – The Rushing Fires of Spring

16 February 2012

 Arb Crew and Fall Burn 

Not everyone thinks of it while walking or jogging through the Arb, but managing 800 acres of restored land takes a lot of dedicated work.  Each Fall and Spring 40 students are employed by the Arb, and the work they do covers just about everything.  They pull clover, rake firebreaks, haul out debris in the floodplains, maintain trails, plant trees, remove buckthorn and honeysuckle, sort seeds… the list goes on and on. 

But because of the cold weather and the (usual) presence of snowpack, winter work is less varied.  Instead of forty workers in the winter, there are four.  Most of their time is spent cutting down and removing pine trees, which aren’t native to southern Minnesota, and if left unattended would takeover the restored oak forests.

Though management projects are limited during the cold winter, plans are already being developed for the work to come in the spring.  The most exciting work will, of course, be the prescribed burns.  According to Arb Manager Matthew Elbert, 5 sections of prairie and 1 section of oak savannah are scheduled to go up in a wall of flame this spring.

Now it might seem counter-intuitive to set fire to the very land you’re trying to preserve, but prescribed burning is a well-respected and indispensible tool to land managers across the U.S.  In our Arboretum fire isn’t just important if we want to maintain the health and balance of our ecosystems, fire is absolutely vital.  For millennia fire coexisted with and helped shape the evolutionary path of ecosystems in the Great Plains, and the absence of prescribed burns in any long-term plan to maintain them would be a grave mistake.

When fire runs through a prairie it removes thatch so new growth can sprout unimpeded.  It recycles nutrients, and stems the incursion of the savannah onto the prairie. 

One of the most important functions of fire is its control of invasive weeds.  This is possible because of the native plants coevolution with fire. If the native prairie grasses go up in flame they will re-sprout. Most prairie weeds on the other hand can’t re-sprout after a fire.  With just a few fire cycles managers can diminish or even exterminate populations of weeds on the prairie, and turn otherwise threatening invasive species into a mere nuisance. 

So if you see smoke in the arboretum this spring, or jog past a blackened field once full of grass, worry not.  The prairie is going through an important part of its natural cycle, and will grow again soon, reinvigorated by the fire. 

-Brandon Valle ’14, for the Cole Student Naturalists

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