Seeing the forest through the dead trees

The spread and establishment of invasive forest species such as Emerlad ash borer can alter forest ecology and create far-reaching impacts that go beyond just dead trees.

With most invasive forest insect or disease problems that have become established in Michigan (e.g. gypsy moth, emerald ash borer, beech bark disease and more), it is pretty typical to focus almost entirely on the impact the new pest has on tree health and mortality. For example, emerald ash borer has already killed millions of trees across Michigan – so it is hard to ignore at this point in time. Currently, emerald ash borer is widespread and very apparent as you travel across Michigan’s Lower Peninsula as evidenced by dead or dying trees in yards or woodlots.

As invasive pests continue to build-up and advance across the state, they can begin to create other, less obvious problems in our forest ecosystems. This is because in natural ecosystems where “everything is connected to everything else”, changes start to occur once you start “tinkering” with one element of the ecosystem.

Recent research from northern Ohio and southern Michigan (i.e. where Emerald ash borer populations have been established the longest) has uncovered several disturbing findings. For example, as ash trees die and create large “gaps” in the forest canopy, they open up the forest floor to increased sunlight. This increased light on the ground has changed the environment and is allowing invasive plant species – such as garlic mustard, glossy buckthorn and others to increase their own populations within the forest ecosystem. Thus, the impact of ash borer is causing more havoc besides just dead ash trees and is creating greater ecological impacts.

In some cases, there may also be more positive impacts such as woodpecker populations benefiting from an ample supply of food in the form of emerald ash borer larvae. But that may depend on whether more woodpeckers is a plus in terms of the environment in your particular area!

In addition, the impacts of invasive species can go also beyond the natural environment. For example, there can also be social and economic impacts in addition to ecological concerns. With Emerald ash borer, the demise of ash trees is a major concern for some Native American tribes who particularly value black ash for basket-weaving and as a cultural resource. Native American families are not only concerned about having less ash wood to construct baskets in the future, but worry about the impact on their extended families where nearly every family member has a role in these basket-making enterprises.

Consequently, many invasive forest pests are truly troublesome! They are something that people should be more aware of to help identify new problems and avoid further moving existing problems around Michigan.

Fortunately, there is a way that Michigan residents can help track the possible presence and movement of new invasive forest pests through the Michigan Eyes on the Forest and Sentinel Tree Network. Interested citizens can sign-up to become Sentinel Tree volunteers to help keep an eye on trees in their yard or woodlot.

Funded by the Michigan Invasive Species Grant Program, the MSU “Eyes on the Forest: Invasive Forest Pest Risk Assessment, Communication and Outreach Project,” links research with outreach and communication projects through the MSU Department of Entomology and Michigan State University Extension. For more information, go to the Michigan Eyes on the Forest webpage or the Midwest Invasive Species Information Network webpage.

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