So trees are a good thing, right?

Not all of them, say federal and state land managers and wildlife biologists who are working to restore Minnesota's tallgrass prairie and the valuable nesting habitat it provides for ducks, pheasants, prairie chicken and a number of non-game migratory birds. It's a job that requires some trees to be removed, particularly the scattered, non-native trees that have become established in valuable tallgrass prairie stands. ?We?re not anti-trees,? said Jim Leach, area supervisor for National Wildlife Refuges in Minnesota. ?Trees in the right places are desirable, but when trees negatively impact wildlife by encroaching upon, or taking over prairie grasslands we need to remove them.?

For several years, the U.S. Fish and Wildlife Service has been working in concert with the Minnesota Department of Natural Resources, The Nature Conservancy, Brandenburg Foundation and other government and non-government partners to restore and protect the vanishing northern tallgrass prairie in western Minnesota and northern Iowa. Estimates place the original tallgrass prairie in Minnesota and Iowa at 25 million acres. Today, only about 300,000 acres remain in the two states, representing a greater than 99 percent decline. Currently, only a small percentage of northern tallgrass prairie habitats are protected, making it one of the rarest and most fragmented ecosystems in America

Wildlife biologists and land managers with the U.S. Fish and Wildlife Service and Minnesota Department of Natural Resources are aggressively removing scattered trees and woody vegetation that are threatening to overtake tracts of tallgrass prairie habitat in western Minnesota. The scattered non-native trees, mostly Russian olive, Siberian elm and buckthorn, as well as trees native to North America like green ash and cottonwood, combine with other woody species to provide cover for predators that threaten nesting waterfowl, prairie chicken, pheasants and other non-game bird species that depend on large open grasslands to thrive.

?Tree nesters are doing okay, but grass nesters ?including waterfowl-- are not doing as well,? said Steve Delehanty, project leader at the Service's Morris Wetland Management District in Morris, Minn. ?Nesting ducks and other non-game birds need all the help we can provide them, and that includes removing woody cover for predators that feed on them.?

The Morris WMD has been developing habitat and managing waterfowl production areas in western Minnesota since 1964. Delehanty and his staff of 15 manage 246 waterfowl production areas on 51,332 acres in eight counties. They also administer 639 wetland easements protecting nearly 21,000 acres of wetland; 49 habitat easement protecting 3,735 acres of grassland and wetland, 23 conservation easements covering 1,237 acres and four units (243 acres) of the Service's Northern Tallgrass Prairie National Wildlife Refuge.

In addition to restoring this vanishing habitat, wildlife biologists are being confronted by a new challenge: educating the public on why removing trees from a prairie landscape can actually be good for wildlife.

?Over the years we have learned more about waterfowl, more about creating and restoring habitat that is ideal for ducks and other wetland dependent wildlife,? Delehanty said. ?Making an area ideal for ducks means removing things that tend to accumulate on old farmsteads: junk piles, rock piles and trees that provide cover for predators like hawks, raccoons and skunks. And, management practices that are good for ducks also benefit other grass nesting birds, both game and non-game.

Since 1999, the Service has worked with the Minnesota DNR to reintroduce prairie chicken--once the state's number one game bird-- to areas of Lac Qui Parle County in western Minnesota. To help ensure success, wildlife biologists are selecting large, treeless areas for reintroduction sites. ?When I evaluate a potential reintroduction site, I want to see large horizons free of trees and woody cover,? said Dave Trauba, area manager at the State's 31,000-acre Lac Qui Parle Wildlife Management Area. ?The prairie chicken, like many of our non-game birds, evolved with open landscapes and they do better in open, grassy areas.?

Research into the effects of woody vegetation on grassland nesting birds such as ducks, prairie chicken, pheasants and others non game species supports the strategy for removing many, but not all, trees and shrubs from the prairie's grassy landscape. For example, researchers in Missouri have found that prairie chicken nesting success is directly related to the distance the nests are from woody cover. A study in western South Dakota found that trees along pond edges decreased use of the pond by mallard broods. During a typical South Dakota winter, cattail wetlands tall grass and food plots ranked highest in pheasant hen use. Nesting success was also found to be lower in shelterbelts in South Dakota and Colorado.

Despite the scientific evidence supporting removal of trees on prairie grasslands some people oppose removing trees. Federal and state wildlife biologists agree that educating the public on where trees are beneficial and where they are not is an important component of their wildlife and prairie restorations efforts.

?Minnesotans are conservation minded and have long believed that if you have trees, you have wildlife. So it's disturbing to some when they see trees being removed from the landscape,? Trauba said. ?But we know more now that we used to about wildlife. We?ve learned that trees and woody cover in the wrong places harbor skunks, raccoons, hawks and other wildlife that are hostile not only to prairie chicken, but for ducks, pheasants and other grassland nesting birds.?

Years ago, when we first started using prescribed fire to control invasive plants and shrubs on grasslands and wetlands, some people didn?t see the benefits it produced for wildlife,? explained Delehanty. ?Today, people have been able to see how the land and wildlife respond to prescribed fire which, like the practice of removing non-native trees, is just one tool we use to manage public land for wildlife.?

Delehanty and other land managers also point out that trees and woody cover removed as part of the prairie restoration effort are only being removed from lands managed by the Service and Minnesota DNR, and that not all the trees on those lands will be removed. At Big Stone National Wildlife Refuge near Ortonville, Minn., managers plan to remove about 800 acres of non-native trees scattered across the prairie refuge's 6,000 acres of grasslands and 3,800 acres of wetlands. Trees will not be removed from the 1,000 acres of bottomland forest along the Minnesota and Yellowbank Rivers.

?We?re not impacting pheasant populations in this area because they will overwinter in cattails and we have acres and acres of cattails,? said Kim Bousquet, wildlife biologist at Big Stone NWR. ?Likewise, white-tailed deer congregate on the river corridor and we?re not impacting that habitat at all. Our focus is on the historic grasslands and our goal is to help protect and restore our remnant prairie habitats that are being invaded by trees,? he said.

While volunteer trees invading prairie areas need to be removed, properly designed tree plantings have value when other landscape features such as cattail marshes or shrubby cover in riparian corridors are not available. ?It's really a unit by unit call,? said Trauba, adding that the Minnesota DNR will not be removing any trees from a State-managed unit along the Minnesota River. ?We want people to know that the trees we?re removing are non-native, aggressive species that take over grasslands,? he added.

?Many people get focused on the missing trees, but they don?t realize that what we?re doing is important to the long-term survival of ducks and other grassland nesting birds. Delehanty added.