8/24/2023 0 Comments Omer michigan forest fireIf, for example, a given stand has a southwest-facing slope and flatter terrain (abiotic factors), and is home to species like big bluestem, a tall prairie grass, or Karner blue butterfly (biotic factors), the fire needs score for that stand is higher. ![]() “We use ‘need’ as a way of saying: ‘Is fire likely to occur given the biotic and abiotic factors that occur in a given place?’” Cohen said. What exactly does it mean for a forest stand today, after 150 years of fire suppression and a lot of landscape changes, to “need” fire? A forest stand is a contiguous group of trees with enough shared characteristics to be a distinguishable unit. The model Cohen helped create integrates a suite of data to produce a “fire needs score” for specific forest stands on state land. Of the 441 vascular plants that MNFI tracks listed as threatened or endangered or of special concern, 100 of those are limited to prairie and savanna ecosystems and are concentrated in Southwest Michigan, Cohen said. Its conclusion: We need more, particularly in the southwest portion of the state, where prairie and savanna systems used to flourish. Prescribed fire-a planned, controlled fire used to meet management objectives-can help restore these lost ecosystems-and maybe hope for the critters that are suffering in their absence.Ĭohen co-authored a recently published assessment of the ecological need for prescribed fire in Michigan. Volunteer prescribed burn crew member wields a rake and a water pump backpack-tools that ensure a burn conducted at The Highlands, a nature preserve in Grand Rapids, stays within its unit. This habitat loss has contributed to a great decline in Michigan’s biodiversity that is only becoming greater. But without regular fire, these species have fewer and fewer places to live. Some of Michigan’s most familiar endangered species prefer the habitat provided by these systems: the Eastern box turtle, the Eastern massasauga rattlesnake and the Karner blue butterfly, to name a few. “With that drop in those fire-dependent systems you have a drop in the species that depend on them.” 02% of their circa-1800 extent,” said Josh Cohen, the lead ecologist with the Michigan Natural Features Inventory (MNFI). “When we look at, for example, our prairies, barrens and savanna systems and compare their current distribution to their historical distribution, they’ve dropped to less than. Now, oak populations are declining swiftly, and fire-dependent ecosystems have been reduced to a fraction of their original foothold in the state. Image: Spencer Highīut after 150 years of fire suppression in Michigan, mesophytic species have had plenty of time to take over. Oak acorn germination prioritizes root growth first, which gives oak seedlings an advantage when fire comes through. By comparison, their mesophytic, or moisture-loving, counterparts, like beech and red maple, don’t stand a chance. Oaks not only persist but thrive when fire happens somewhat frequently. As adults, oaks have especially thick bark that better withstands fire, and when the tree is scarred by fire, it can compartmentalize the wound and prevent decay from spreading. Fire keeps other trees and shrubs from casting shade on baby oaks. They prioritize root growth before stem growth, meaning that once the roots have developed enough, there’s a better chance the seedling could regrow after being topkilled by a fire.įire also supports this kind of growth: To produce wide root systems, oak seedlings need ample sunlight. ![]() Their acorns germinate underground, protecting the delicate bud from the heat of fire on the surface. Oaks, for example, have adaptations at nearly every stage of their life cycle that help them survive when fires pass through. Many plants that do well in xeric conditions have adapted to thrive with periodic fire. When a fire reaches an oak savanna, it slowly crawls through as it feeds on these fuels. Prairie grasses and wildflowers thrive in these soils, and along with the crispy dead leaves that fall from the oaks, they provide great conditions for fire. Oak savannas occur on dry, sandy-or “xeric”-soils. Different plants thrive in different parts of the savanna, creating a biodiverse mosaic of flora that attracts a likewise diverse family of fauna. Thanks to the spaced-out configuration of the trees, the understory of the savanna receives varying levels of sunlight-from pure sun, to dappled partial shade, to cool, full shade. This is the case for the oak savanna, an open field interspersed with wide-growing oaks. ![]() Some of Michigan’s native ecosystems can persist only if they are periodically engulfed in flames.
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