Sunday, September 14, 2014

Time for Trees to Pack Their Trunks?

Some scientists and conservationists warn that mixing species will degrade “ecosystem integrity.” (Credit: B. Gilmour/flickr) Click to enlarge.
During the last two springs, contract planters for The Nature Conservancy (TNC) have spread out through the pine, spruce and aspen forest of northeastern Minnesota.  Wielding steel hoedads, they have planted almost 110,000 tree seedlings on public land.

What’s noteworthy about planting trees in a forest?  Usually foresters plant seedlings grown from seeds harvested nearby, on the assumption that local genotypes are best suited to local conditions.  But these TNC workers were planting red and bur oak (which are uncommon in northern Minnesota) from seed sources more than 200 miles to the southwest, and white pine from as far away as the Lower Peninsula of Michigan, 400 miles to the southeast.

TNC is anticipating a day soon — within the lifespan of a tree — when a changing climate may make the forest unsuitable for some tree species and varieties that now live there.  Projections for northeastern Minnesota predict warmer and possibly drier conditions — bad news for the boreal species such as white spruce, balsam fir and paper birch that have defined the forest here for centuries.  But a warmer, drier climate would likely make the area better suited for species such as oaks.

“Our goal is to maintain a forest going forward,” says Meredith Cornett, TNC director of conservation science for Minnesota and the Dakotas.  “We run the risk of losing forest cover because we don’t have a suite of species that is resilient to climate change — that they won’t be able to hang in there or keep pace with the rate of climate change.”

TNC is jump-starting the future forest to protect not only the forest, but also the goods the forest provides, such as clean water, wildlife habitat, tourism, logs and pulpwood.  “We care about that because our livelihoods up here really depend on that,” says Cornett.

Time for Trees to Pack Their Trunks?

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