Understanding the love-hate relationship
WORTHINGTON -- I just love trees, and right after that I can say I hate trees. How do you love trees and hate trees at the same time? It has everything to do with what kind of tree it is and where it happens to be growing.
In a prairie landscape, trees play a vital role in providing one of the necessities all wildlife need to survive.
Take pheasants for example. They need undisturbed grasslands to nest and rear their young. They also need suitable food sources and, last but not least, they need suitable thermal cover to protect them from the stiff winters Minnesota is known for.
In many parts of the pheasant range there are still a few remaining large sloughs that have expansive cattails pheasants use to protect themselves from sub-zero temperatures and 50-mile-per-hour blowing snow.
In southwest Minnesota, these winter refuges are almost non-existent. What wildlife managers have done to compensate for the lack of natural winter cover for pheasants is plant trees. These are the trees I love. They normally consist of five to eight rows of a combination of short height shrubs surrounding multiple rows of eastern red cedars. When an eastern red cedar gets to about 12 feet in height, a pheasant can climb up into the branches and roost in a spot that protects it from predators. The cedars also provide a wind break to help the bird conserve its body heat.
These cedars are surrounded by the likes of red twig dogwoods or freedom honeysuckles. These lower shrub-type trees block the snow from entering the interior of the planting and keep the cedar branches from filling up with snow. It is a pheasant's winter dream home. These spots do exist on state lands around the area and, in the middle of winter, almost all of the pheasants in the area will be using these few spots to roost in at night.
These are the trees I love. They are of the right varieties and are planted in a manner and in the proper location to provide quality habitat for a variety of wildlife -- and that's not just pheasants. It is unfortunate that there are far fewer of the trees I love than there is of the trees I hate.
The trees I hate are normally volunteer trees that have seed in from outer lying areas. All of the research that has ever been done over the past 50 years comes to the same conclusion: Tall trees dispersed throughout a grassland prairie reduce the success rate of the wildlife that tries to nest there. This includes pheasants, ducks and other ground-nesting species.
Individual trees, first and foremost, provide the best possible perch for a red-tailed hawk or other avian predator to scout the area for its prey. Secondarily, if there are too many volunteer trees dispersed across a grass land they start to create travel corridors for nest raiders like raccoons, mink and skunks. Pheasant nesting success within 100 feet of a slough ringed with tall cottonwood trees is just about zero.
What this says is the right trees in the right place provide great benefits to wildlife, but the wrong trees in the wrong place have very negative effects on that same wildlife. With this knowledge in hand, it is then the goal and responsibility of all wildlife managers -- both public and private -- to manage the grasslands under their control to a condition that best suits wildlife.
In order to do that, it requires the removal of undesirable trees. Once the decision is made to do so, what are the available options to accomplish the goal?
The cheapest and most commonly used method is burning. By periodically burning your grasslands (one-third per year), you can torch the young tree seedlings before they get too big.
It is not at all exaggerating to say I have seen a 2-acre spot with 10,000 volunteer cottonwood trees springing up two feet tall. All of these trees can be seeded from one tall cottonwood tree a half-mile away. Not only is it necessary to remove the new growth trees regularly, but you also need to remove the seed source as well. This is harder to do if the seed source tree is on someone else's property.
You can bust your tail trying to control undesirable trees in your grasslands, but if you don't cut off the parentage, your efforts will not achieve any long-term results. Once a tree gets a trunk bigger than one-half inch in diameter, burning as a control method has limited success.
You will now need to cut the tree manually or mechanically and apply chemical to the trunk to kill the root. You can easily see where this gets much more labor intensive and the chemical is not cheap.
Areas that have gone unattended for too long can only be managed by the use of heavy equipment. This takes specialized tools and a rig with a tree eater attachment on the front costs more than $75,000. This rig can literally eat a tree and reduce the branches and trunk to wood chips. These chips are dispersed in an area large enough as to not harm the native vegetation that surrounds the tree removal sight. Chemical is applied to the stump and the tree is no more.
Nobles County Pheasants Forever recently received some habitat funds unused by another chapter. We used these funds to hire Tom Baumann of LeSueur River Seeding Company to come to Nobles County and use this high-tech tree removal equipment to rehab a state Wildlife Management Area. This WMA had been burned frequently by area DNR personnel, but too many oversized trees did not get killed by these fires. After two days with the right equipment in the right spot, this public wildlife area is now back in perfect shape.
The contractor was able to do in a few days what would have taken 25 volunteers several weeks. This is a great success story, but if there is one thing I have learned about tree management it is that it is an ongoing effort that is never completed. These areas need constant attention and, between the efforts of the area DNR staff and your local Pheasants Forever chapter, there is a great chance of success in managing these areas.
I appreciate as much as anyone -- and maybe more -- the majesty of a 100-year-old cottonwood tree. I often wonder, if they could talk, what stories they could tell of the changes from the days of the buffalo to today. Each tree is proper in the proper place. With only 3 percent of Nobles County in undisturbed grassland, there is still more than enough places to enjoy these trees and many others. Grasslands are just not that place.
Scott Rall is the Daily Globe's outdoors columnist. His column can also be read weekly at www.dglobe.com.