USDA Forest Service Rhizotron

A view from one of the windows of what's going on underneath an actively growing forest. As soil temperature increases and snow melts, biological activity in the soil increases. During spring Nightcrawlers burrow deep into the soil, pulling dead leaves through the upper soil horizons. (Those are their tunnels in the photo above.) As summer approaches, roots begin to grow and soon soil moisture decreases, lightening the soil color. As winter approaches and the snow falls, the earthworms remain active while root growth goes dormant.

A rhizotron is an underground tunnel allowing for the non-invasive study (i.e., no digging) of underground processes involving root systems, decomposition, organisms, and bacteria. Here 24 large windows looking at underground soil structure when stainless steel covers are slid open.

It's an inconspicuous but important addition to the Michigan Tech campus — one of only two U.S. rhizotrons looking at northern forest ecosystems. It's part of the U.S. Department of Agriculture Forest Service research lab here, one of 17 Forest Service labs on university campuses in the north central states.

The role of forests in storing or retaining carbon while producing sustainable supplies of renewable energy is a hot topic today, now that climate change is taken seriously not only by most scientists but by more of the public and their elected representatives. The current rhizotron project leader is Erik Lilleskob.

The rhizotron, finished in 2006, is a big step forward in learning more about how forests store carbon and investigating the uncertainties about how northern forests might respond to future climate change.

Local loamy sand and maple, birch, and aspen are outside the rhizotron's east windows. Mostly white pine seedlings grow in the coarse sand soil from Atlantic Mine outside the west windows. The tunnel temperature is kept at the outdoor soil temperature, which is 35 degrees or so in winter, what with the insulating snow blanket.

As the soils develop (earthworms and brown centipedes were the first to come), they will attain the complexity of mature soils in terms of bacteria, organisms, fungi, and decomposing leaves.

Regular tours for the general public are given year-round on the first Friday of each month from 3-4 p.m. Group tours can be arranged for all levels of interests. Call (906) 482-6303. 906 482 6303 x 10 Ruth


Behind the USDA Forest Service Northern Research Station, 410 MacInnes Dr. (Uphill from the light at the Michigan Tech Campus). Clearly signed. Easy parking behind building. (906) 482-6303. Wheelchair-accessible.

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