The group engaged in a complicated birds-eye view of the forest, seeking to understand how four key songbirds the black-throated green warbler, eastern wood-pewee, least flycatcher and rose-breasted grosbeak dealt with neighborhood upheaval. The study area stretches over some 3,000 square miles of public and private land from Crystal Falls to the west, east and south to Escanaba and north of Marquette. For two years, the team examined the harvest gaps left in forests when hardwoods are cut down.
Logging changes a forest's composition creating gaps in the canopy that can take years to fill. Matonis, Millington's colleague, recently reported that the current popular way of encouraging regeneration of hardwoods like sugar maples, called gap harvesting, isn't always successful. Sometimes it appears deer are chowing on the maple seedlings trying to grow in the sunny gaps left by harvest.
The four songbird species the team picked all are fussy about their canopy. For example, the warbler likes its canopy dense with lots of branches about 50 feet high. The flycatcher, however, digs more open expanses.
"If all the birds like the same thing understanding consequences of logging and differences in tree regeneration would be easier," Millington said.
The analysis is ambitious and complicated. The team seeks to create models that show how a forest shapes up at different rates of regeneration, both in timber-centric and bird-centric points of view.
The bottom line: Regeneration in harvest gaps of species that become large canopy dominant trees such as sugar maple is crucial for forest managers to have choices. If trees aren't growing back well, there's no opportunity to even start watching out for the forest's residents.
|Contact: Sue Nichols|
Michigan State University