Forestry field report from north central Michigan

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

The freeze that hit northern Michigan on the morning of Wednesday, May 28, resulted in some freeze damage to plants in scattered locations. temperatures fell to as low as 25-26°F in some inland areas of the north. Freeze damage to red oaks, still in the tender “mouse-eared” stage of growth, was evident in parts of Roscommon, Crawford and possibly other areas. Some minor damage to low-growing plants, such as bracken fern and young forest trees, was also observed in some areas.

It’s been a banner year in many areas of north central Michigan for the Eastern tent caterpillar. Populations exploded this spring with many scrub cherries supporting several tents of Eastern tent caterpillar. Complete defoliation is now evident on some trees, and the larva are abandoning their tents in search of places to pupate.

Of significant interest are the scattered reports and observations that are starting to emerge from across the north about building populations of forest tent caterpillar. Northern lower Michigan has not experienced a significant outbreak of forest tent caterpillar since 1988-1990. At the height of the last outbreak, wide scale defoliation of northern hardwood stands was very evident across many areas of the lower peninsula. This insect is known to experience high populations that lead to major defoliating events about every 15 years or so.

Here in the Roscommon and Crawford County area, forest tent caterpillars have been observed spinning down on silken threads from red oaks as well as masses of caterpillars forming on the base of scattered trees. No real defoliation was observed, however, at this point. Some calls and reports also were received from Manistee and Otsego counties. So, a major outbreak of forest tent caterpillars may be in the making across the north!

Many of tree species that produce seed in the springtime are experiencing extremely large seed crops this year. In many areas of north central Michigan, the heavy seed crop is very evident on red maples. Looking ahead, once this seed drops to the ground, many of these trees are likely to look bare in spots as the seed crop appears to be displacing a lot of the foliage, therefore expect calls from clients as to “Why is my maple tree looking so bare and ragged?”.

Other species, such as aspen and oaks, also appear to be producing bumper crops of both male pollen and female flowers. Over the last week, oak male flower chains are falling everywhere in mass and there is a lot of cotton flying through the air from aspen and other poplar species. The long summer drought of 2008 is likely the cause of this excess seed production.

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