The Jack Pine Ecosystem
This is the Jack Pine ecosystem that is the center of the Kirtland's Warbler historic range in Michigan's norther Lower Peninsula. More than 90 percent of Kirtland's Warblers' nests are in one small area of northern Michigan, some 70 miles from north to south and 90 miles from east to west.
There's not much here -- Jack Pine trees, of course, along with grasses, sedges, blueberries in the undergrowth and a few shrubs and trees. The soil in this ecosystem is sandy and nutrient poor, which severely limits what can grow.
Fire is historically has been a fundamental part of the ecology of the Kirtland’s Warbler’s ecosystem. The warbler and the other plants and animals in this area have not just adapted to fire, they have come to depend upon it. But no species in this ecosystem requires fire more than the Jack Pine. The Jack Pine's cones usually remain undamaged by the heat from a wildfire because fire moves through the tree so quickly. After the fire, the wind can disperse the winged seeds onto the ash-rich ground as far as 130 feet from the tree.
The Jack Pine is one of the most common trees in northern North America. A Jack Pine belt stretches across Canada from the Rockies to the Atlantic Ocean, and extends south into northern Michigan and as far north as Hudson Bay. The Jack Pine is able to live on the thin, acidic soil of the Canadian Shield, on rocky outcrops on mountainsides and in wet riverbeds. So with all these Jack Pines across North America, why does the Kirtland’s nest where it does? The answer is in the ground.
That’s because much of the soil here is composed of Grayling sand. The combination of low-hanging, overlapping branches of young Jack Pines with this sandy, well-draining soil that rarely floods is perfect for a bird that nests on the ground.
Today, this ecosystem is managed by both the U.S. Forest Service and the Michigan Department of Natural Resources. Through regular harvests and replanting, the agencies are creating new stands of young Jack Pines desirable to the Kirtland's Warblers.