The elms' dominance ended in the sixties when Dutch elm disease decimated that population--and forty years later the emerald ash borer killed thousands of white and green ashes.And last year's dry winter, an early spring followed by a late freeze, and summer drought were tough on all trees.The dry winter failed to replenish the ground water, an unseasonably warm March forced premature growth that was then killed by the freeze, and the drought stressed them into shedding bark and leaves.
Beyond natural causes like drought and disease, the town's trees have been affected by the reduction of the city forestry department's staff from twenty-five to eight over the last thirty years and the cuts in its budget from $2 million to $1.5 million over the last five.
This sapped the department's resources and left jobs like pruning, planting, and regular maintenance undone or underdone, though a separate $2 million budget paid for removing dead ash and planting replacements. No one knows how many trees the city had before the epidemic of Dutch elm disease, but a recent survey estimated there are 1.45 million on public, private, and U-M property now.
They create an overall leafy canopy that covers 33 percent of the city's land: 46 percent of residential areas, 24 percent in public rights-of-way, and 22 percent in recreational areas.
by James Leonard and Jeff Mortimer From the April, 2013 issue As long as humans have walked Michigan's landscape, they've messed with the trees around them. After the glaciers receded and before European settlers arrived, what would one day be called Tree Town was part of an oak savanna, a vast grassland dotted with widely scattered trees.
Though it looked natural, that landscape was actually a human creation.
Native Americans set fire to the savanna every few years to encourage fresh growth that attracted the deer and buffalo they hunted.
The burns cleared out most shrubs and saplings, leaving only the fire-adapted oaks.
When the settlers arrived, their first surveys showed bur oaks in the center of town, with black oak in the barrens to the west and both oak and hickory in the hills to the north.
But, except for a few scattered survivors, the native oaks virtually disappeared by the mid-nineteenth century, as the land was cleared for farming.