April 2009

The DNR communications team works with agency experts to develop the weekly questions and provide the answers. This feature addresses current DNR issues, interesting topics, or the most frequently asked questions from around Minnesota.





As the snow melts in the spring, and during lengthy periods without rainfall, the Department of Natural Resources (DNR) issues fire restrictions. Is there a difference between a restriction and burning ban?

Burning restrictions involve the issuing of burning permits. Burning permits are required for running fires, such as a grassy ditch or field, or piled vegetative debris. When restrictions are in place, permits are only issued for management or prescribed burns, or special burns such as construction companies burning trees and brush cleared from roads. Burning bans, which are issued by the DNR commissioner, prohibit other types of fires. For example, bans may disallow campfires completely or restrict them certain hours of the day. They may also restrict any fire outdoors, including smoking and barbeque grills. Bans are only imposed when extreme fire conditions have existed for a long period of time.

- Jean Bergerson, Minnesota Interagency Fire Center information officer


It’s not uncommon for lakeshore property owners to return to their cabins in the spring to find damage to their shoreline, docks, boatlifts, retaining walls and sometimes to the cabins themselves. What causes this?

This type of property damage is caused by a phenomenon called “ice heaving” or “ice jacking.” As ice freezes and thaws, cracks form because of the different contraction rates at the top and bottom of the ice sheet. This is especially true in years when there’s a lack of insulating snow cover.  When water rises in cracks and freezes, the ice sheet expands slightly. Rising air temperatures warms the ice, which causes the additional expansion to exert a tremendous thrust against the shore. This powerful natural force forms a feature along the shoreline known as an ice ridge. These ridges can sometimes reach as high as five feet or more. Additional warming and cooling of an ice sheet can cause additional pushing and exert enough pressure to nudge bridge masonry piers out of plumb and push houses off their foundations.

For more information, including specifics about when a repair permit is needed, contact your local DNR area hydrologist.

- John Fax, DNR hydrologist, Water Permits Program


National Volunteer Week is April 19 - 25. Each year thousands of people volunteer their time to help the Department of Natural Resources (DNR), and other organizations, with a variety of projects. What sort of volunteer opportunities does the DNR have to offer?

Volunteer opportunities vary across the state from assisting with wildlife research to cleaning rivers to playing Smokey Bear at the State Fair - just to name a few. Right now the DNR is looking for volunteers to help count loons, catch and identify dragonflies, conduct nighttime listening surveys of frogs and toads, monitor bluebird trails and plant trees at selected State Parks, clear trails, do historical research, and use their woodworking skills to build portable field desks for students doing outdoor studies. Volunteer positions are listed on the DNR Web site at www.mndnr.gov or by calling toll free 1-888-MINNDNR (646-6367). Opportunities are changed on a seasonal basis.

- Renée Vail, administrator, DNR Volunteer Programs


Minnesota derives great benefit from having healthy, productive forests. What role does logging play in maintaining or improving forest health?

Minnesota’s forests are a renewable resource. And the timber industry plays a key role in maintaining and improving forest health. Generally, loggers harvest mature or over-mature trees, which often with age become increasingly susceptible to a host of insect and disease problems. Loggers also harvest areas that suffer catastrophic affects from wind, fire, or outbreaks of deadly diseases or insects thereby protecting adjacent forests from the spread of insects and diseases.

By harvesting older and damaged stands, the carbon tied up in the trees will be locked up for long periods of time in wood products we use everyday. Without logging, decaying dead trees contribute to atmospheric carbon. Logged areas are regenerated and the young, more vigorously growing trees also help reduce atmospheric carbon, provide habitat for animals that depend on early successional forests, and provide forests for future generations to use and enjoy.

-Alan Jones, DNR Division of Forestry


DNR Question of the Week Archive