November 2004

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.






Many anglers are anxiously waiting for the moment the lakes freeze over so they can resume their favorite pastime. Are we getting closer to that moment?

First of all, it is important to know that ice is never 100 percent safe. It is also important to realize the calendar does not dictate when lakes and ponds freeze over, so just because they were frozen over Dec. 1 one year, doesn't mean they'll be that way the next. Here are a few basic rules anglers and others who venture out onto the ice should follow. For foot traffic, a minimum of four inches of new clear ice is recommended; five inches for ATVs and snowmobiles; and a minimum of eight to 12 inches for cars or small trucks. Again, these thicknesses are merely guidelines. Many factors, other than thickness can cause ice to be unsafe. Before heading out onto a lake or pond, ask a local resort or bait shop for ice thickness and point out areas to stay away from. Also, use an ice chisel to check ice thickness as you go, bring ice picks along and wear your life jacket just in case you fall in.

Tim Smalley, DNR Boat & Water Safety Specialist


Not every bird species migrates from Minnesota to warmer climates down south before winter sets in - some stay behind. Is there anything that can be done to help these brave birds survive winter?

An easy plan for winter bird feeding is to provide three main choices of food - large seeds, small seeds, and suet. Black-oil sunflower seeds and cardinal mixes have the greatest appeal to the broadest variety of winter birds and contain a high-energy content. Water is a critical ingredient of a winter-feeding program. There are excellent birdbaths with heating elements and thermostats available from bird feeding supply stores. The heated water is primarily for drinking. Don't worry about birds freezing if they bathe on a cold winter day because native song birds seem smart enough not to bathe when the wind chill is 40 below. For more information on winter bird feeding, check out the DNR Web site .


I think I might have buckthorn in my yard. Why is it such a problem, and what should I do about it?

It is very easy to identify buckthorn this time of year because it is one of the only trees with dark green leaves still on it. There are two types of buckthorn found in Minnesota. One species, common buckthorn, is known to cause problems in wooded natural areas, while the other, glossy buckthorn, primarily invades wetlands. Buckthorn is a threat to native species throughout Minnesota, especially the forested areas, because it out-competes native plants for important nutrients, light and water. As a result, this invasive species degrades wildlife habitat, serves as a host for other pest species and crowds out beneficial forest-floor plants that help control erosion. In North America, buckthorn lacks its natural enemies, such as insects or disease, to control its spread, which is why it has become so abundant in Minnesota. Now is the best time to remove any buckthorn from your property. The best tactic is to pull the small plants by hand or with a "Weed Wrench." If the plants are too large to pull, it's best to cut them and treat the stump with an over-the-counter, ready-to-use herbicide containing Triclopyr. For more information about buckthorn identification and control, visit the DNR's Web site.

Luke Skinner, DNR Invasive Species Program


Winter heating bills have been relatively high the past couple winters. How can planting trees help lower energy bills in the winter and summer?

Shade trees can reduce air conditioning bills by nearly 25 percent and reduce annual fuel bills by up to 20 percent. Also, trees throughout the community help keep us cool in summer and shelter us from harsh winter winds. In order to achieve these savings and benefits, trees should be strategically located on your property and throughout your neighborhood. For example, avoid planting shade trees near south-facing windows. If a tree already blocks a south-facing window, remove the lower branches. The angle of the sun is much lower in the winter so not blocking these windows will allow you to take full advantage of the free solar energy when it's cold outside. On a regional scale, trees could significantly reduce energy use during peak load periods and reduce air pollution. More information on how trees can lower your energy bills can be found on the DNR's Web site at Energy conservation through trees.

Ken Holman, DNR Community Forestry Program Coordinator


In terms of the ongoing concerns about chronic wasting disease (CWD), what do hunters need to know about transporting elk, deer or moose into Minnesota from other states? Are there any restrictions?

Restrictions for importing carcasses into Minnesota are in place for counties in eight states where CWD has been identified in wild deer and/or elk. These states include Colorado, Illinois, Nebraska, New Mexico, South Dakota, Utah, Wisconsin and Wyoming. Hunters bringing animals back from those areas must comply with import regulations. They include meat that is cut and wrapped, quartered animals with no part of the spinal column or head attached, properly cleaned skull plates that are attached to antlers, and finished taxidermy mounts. As the restrictions only apply to certain areas of the affected states, hunters are urged to contact officials in the state they're hunting prior to making the trip. For individuals hunting in areas without CWD, hunters may bring back the whole carcass. Information regarding import restrictions can be found on page 53 of the 2004 Minnesota Trapping and Hunting Handbook. A map of the restricted counties in the eight states can be found on the DNR's Web site at www. dnr. state. mn. us.

Lou Cornicelli, DNR Big Game Coordinator


DNR Question of the Week Archive