Southeast Michigan now has more trees than in 1985

Thirty years later, the Southeast Michigan tree canopy has increased. As one might expect, the amount of urban…

Thirty years later, the Southeast Michigan tree canopy has increased.

As one might expect, the amount of urban sprawl in Southeast Michigan has increased over the last thirty years. It may come as more of a surprise that so too has the tree canopy in the region.

A new study from the University of Michigan assessed both the urban sprawl and tree canopy in the region from 1985 to 2015. Researchers considered satellite images and aerial photos, using these to “map individual buildings and small patches of street trees.”

The researchers, funded by the U.S. National Science Foundation (NSF), published their study in the Landscape Ecology journal. It is entitled “The impact of urban sprawl on forest landscapes in Southeast Michigan, 1985–2015.”

Trees are important in the fight against climate change. At NSF’s Directorate for Engineering, Bruce Hamilton said that the results showing “an increase in tree cover is encouraging, especially because of trees’ potential to reduce carbon dioxide levels in the atmosphere.”

The study showed 246 square miles more tree cover in 2015 than in 1985. That is a 1.8% increase over thirty years.

It seems odd that the tree cover increased when the amount of urban sprawl went up by 12%. The new urban sprawl amounted to 130 square miles. About 335,000 buildings and 7,000 miles of road were added to the region in the last three decades.

But the tree cover mostly comes from “the maturing of existing trees in older residential neighborhoods and on public lands” and “from former farmland, not from forested areas.” Some of the increase in tree cover is also due to conservation efforts.

Less positive is the news that the forest cover is now more fragmented. More urban sprawl has “interfered with the ability of plants and animals to disperse across the landscape.”

Our results show that the forested landscapes of Southeast Michigan appear more fragmented and less cohesive in areas experiencing urban sprawl, in accordance with findings worldwide.

Dimitrios Gounaridis, the lead author of the study

But the first step to solving this problem is being aware of it. Hopefully, a focus on bolstering tree cover will mean greater dispersion of animals and plants as conservation efforts continue.

Article source: National Science Foundation

Featured image source: Arnaud Mesureur

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