dogwood - The Environment Report

The National Arbor Day Foundation's revised hardiness zone map. (Photo courtesy of the National Arbor Day Foundation)

If you’ve been thinking about landscaping your yard, you should know things have
changed. The climate is warming so quickly that one organization has changed the
plant hardiness zone map. That’s the little map you sometimes see on the back of
seed packets. Lester Graham reports… you might want to check out the new map
before you spend hundreds of dollars on a tree that might not live long in your
warmer zone:

Transcript

You know, I’ve talked to a lot of gardeners and homeowners who do their own
landscaping about this plant hardiness zone map change, and at first they’re
kind of astounded. The growing zones are changing? Because it’s getting warmer?

But then, they sort of pause and think for a moment… and usually say something like,
“That makes sense.”

The United States Department of Agriculture issues the plant hardiness zone map.
It’s basically a map of the annual average low temperatures that helps folks figure
out what they can plant and expect to survive. But the USDA hasn’t updated its map
since 1990.

The spokesman at the National Arbor Day Foundation, Woody Nelson – I kid you not,
the Arbor Day guy’s name is Woody – Woody says his organization issued a new
map because it really needed to be updated:

“You know, people were asking us to help out, you know, ‘This old USDA map just doesn’t
seem to work for us anymore. I don’t think it’s accurate. What can you do to help?’
So we took it upon ourselves to give tree-planters the most up-to-date information
that we could.”

So the National Arbor Day Foundation looked at the low temperature data gathered
by the National Oceanic and Atmospheric Administration since 1990, and the people
were right: things are warming up:

“And over that 15-year span that we used, much of the country had warmed a full
hardiness zone.”

And there’s a ten degree difference from one zone to the next. It shows a real on-
the-ground trend.

Richard Andres is with Tantre Farm. They grow organic produce for farmers’
markets like this one in Michigan. Andres didn’t know about the new Arbor Day
Hardiness Zone map, but it makes sense to him. He says he’s seeing more
extremes:

“You know, last winter was unusually warm. The winter before, unusually warm.
So, we really didn’t even get a decent freeze. We had a huge amount of bugs the
following spring. So we are noticing more extremes.”

But a farmer or gardener can adjust things for annual plants. Long term, you’re
probably wondering whether you can now plant that dogwood or whether you
should plant that spruce from up north.

(Sound of sprinkler)

Phil Walsh sells a lot of trees at Lodi Farms nursery. He knew about the new Arbor
Day Hardiness Zone map. But, he says there’s a lot more to think about than just
the annual average low temperature when you’re thinking about planting:

“Cold is not the only, or really the most, important factor when determining plant
hardiness. Questions like soil: is it well-drained; is it not; is it wet; is it dry; is it acid
or is it alkaline; do you have wind; do you have shade? Questions like this: is it high
in organic material or low in organic material? These tend to have more impact on
whether or not plants survive than strictly the zone rating.”

Walsh says the trees are pretty tough, and most of them can adapt:

“Yes, things have warmed up over the last 15 years and they may well continue or it may change and it may go down. Pick a good, hardy plant that’s well-suited for your soil
and typically one that’s native here, that’s gone through these temperature changes
in the past and I don’t expect anybody’s going to have any problems with them.”

That’s not to say that every kind of tree is taking this in stride. For example, black
spruce trees adapted to Canadian and upper New England cold might not be such a
good choice as far south as it’s been grown in the past.

Woody Nelson at the National Arbor Day Foundation says trees native to the North
are starting to be affected by the warming climate:

“There’s a whole lot of white pines that have been planted in Georgia, in the South
as a nice landscape tree over the years. And now those white pines are coming
under a little bit of stress. The native lodge pole pines, the native loblolly pines in the
deep South, again native species are something that we want to promote and stick
with.”

So, the basic rule is: if the plant hardiness zone map has shifted one growing zone
warmer in just 15 years, you’ll probably want to stick to trees native to your area, or
from just a little south of you just in case this warming trend sticks around for a while.

For the Environment Report, this is Lester Graham.

Transcript

We’re continuing our look at ‘Ten Threats to the Great Lakes.’
Lester Graham is our guide through the series. He says the
experts who were surveyed to determine the threats say rapid
development is among the problems affecting the lakes:

Greg Reisig is standing at the edge of a 20-acre construction site
just down the street from the shore Lake Michigan.

Below him is a man-made pond a few hundred feet long. It was a
dry summer around here, but the pond is full.

In fact, Reisig says the water level is always the same.

“And that indicates there’s a lot of ground water flowing
here…there’s a lot of water in this pond and you can see what
was a whole big wetland complex…there’s a lot of cedar and red
osier dogwood…all the wetland plants.”

There are no wetlands here now.

The site in northern Michigan was excavated for homes a few
years ago.

But now the Army Corps of Engineers says the wetlands that
were here need to be restored. A few acres likely will be
restored. But Reisig says almost the whole site was wetlands
once. He expects it will soon be a subdivision with not much
more than a drainage ditch connecting it to Lake Michigan.

“What will that do to the amount of flow of water going into the
bay? Because of hard road surfaces, hard driveways, roofs,
buildings and supposedly fertilized lawns. What will happen to
the water and how will that increase the flow to the bay?”

The developer’s attorney says this is nonsense. Matt Vermetten
says this land was heavily farmed and mined for clay.

“There are pockets of quote unquote wetland and those are there
because of excavation for clay. So is this a wetland complex of
the nature we speak of when we typically speak of such a thing? I
think not.”

Disputes like this are becoming more common around the Great
Lakes. John Nelson is the baykeeper with the Grand Traverse
Bay Watershed Center. The bay off Lake Michigan and attracts a
lot of people. But Nelson says development doesn’t have to be a
problem.

He says the problem is people don’t think about the ecology of
the lakes. For example, east of Traverse City, Michigan, resorts
dominate the coastline. Along the beach, thick stands of sedges
and rushes extend out a few hundred feet. But the sections of
dark green marsh alternate with stretches of clean sand and white
lawn chairs.

(birds calling on beach)

Nelson grew up here and says this part of the lake was never a
sugar sand beach.

“They’ve located in a coastal marsh. Instead of celebrating and
dealing with that they’ve chosen to see it as they would like to
have it and then change it.”

The impacts of the changes are cumulative. Fish and wildlife
habitat is fragmented. The natural filtering properties of the
wetlands are gone.

So every time the city gets a rain shower all the dust and grime
and pollution are washed right into the lake.

Census data show people are leaving many of the Great Lakes
coastal cities and spreading out along the coastline. But it’s not
clear how local governments should plan for the growth.

Mike Klepinger studies land use planning for the Michigan Sea
Grant program. He says it’s hard to make direct connections
between a healthy lake and particular land uses.

“We are getting more planning along the shoreline than we had
thirty years ago in the state. The number of counties and number
of townships that have a plan has gone up, for example. But we
don’t know whether those plans are really doing any good.”

And it’s hard to implement good planning on a broad basis. In
any area, dozens of different local governments might have
independent control over development.

Multiply that by the number cities, townships and counties along
the coasts of the Great Lakes… and it’s hard to see how it all can
be managed so that enough coastline habitat is preserved.

For the GLRC, I’m Peter Payette.

Tag: dogwood

Growing Zones Warm Up

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