Examples of ash tree seeds that are part of the collection effort. (Photo by Lester Graham)
People have been saving seeds for thousands of years. Gardeners save
seeds of their favorite plants. Governments save seeds to protect
their food crops. Now, some people are freezing the seeds from trees.
That’s because the trees are being destroyed by an insect pest.
Rebecca Williams reports they’re hoping a gene bank will protect the
trees’ DNA and some day help bring the trees back:
Transcript
People have been saving seeds for thousands of years. Gardeners save
seeds of their favorite plants. Governments save seeds to protect
their food crops. Now, some people are freezing the seeds from trees.
That’s because the trees are being destroyed by an insect pest.
Rebecca Williams reports they’re hoping a gene bank will protect the
trees’ DNA and some day help bring the trees back:
Seeds are a pretty amazing little package. They might be small, but
they’re tough. They can live through very dry and very cold
conditions.
(Sound of seed being shaken out of a paper bag)
These seeds are from ash trees. In some parts of the Upper Midwest and
Ontario, ash trees have been wiped out. The seeds are all that’s left.
That’s because of the emerald ash borer. It’s a tiny green beetle that
got into the US in cargo shipped from China. So far, the beetles have
killed 20 million ash trees. No one’s been able to stop the beetles
from spreading.
David Burgdorf works for a lab with the US Department of Agriculture.
He says people might not even know they had ash trees until the trees
got attacked:
“If your lawn was filled with the ash tree and you had all this great
shade and your energy bills were low, but now the ash tree’s gone, you
only miss it when it’s gone.”
Burgdorf says a lot of people love ash trees for their gold and purple
fall colors. They grow fast and hold up well under ice storms. Native
American tribes depend on black ash for making baskets and medicine.
David Burgdorf is trying to make sure ash trees won’t disappear completely
if the beetle spreads across the country. He’s gathering ash seeds
sent in by volunteers. He’s hoping to build a collection that
represents the entire ash tree gene pool:
“We want to try not to have to bring something back. We don’t want it
to be extinct. It’s important we at least save the seed so we can maybe cross
it, or do something, breed in resistance to the tree and have it
available to come back.”
Burgdorf says he thinks of the seeds as an investment for the future.
The seeds are definitely being treated like a precious commodity.
They’re sorted and they’re X-rayed to make sure the living embryos in
the seeds haven’t been damaged.
Then, the very best seeds in the bunch are off to a high security
government vault:
“We kind of joke that it’s the Fort Knox for seeds.”
Dave Ellis is the seed curator at the National Center for Genetic
Resources Preservation. It’s a giant seed bank. Ellis says the ash
seeds are dehydrated and frozen at 0 degrees Fahrenheit. These steps
put the seeds into a deep sleep:
“In a dehydrated state, degradation of DNA happens much more slowly,
over a course of tens of years or hundreds of years.”
Ellis says the ash seeds should be viable for at least 25 years, if not
longer. He says researchers might be able to use the stored genetic
material to breed new pest-resistant ash trees in the future. Ellis
sees gene banks as a safeguard against a world that’s changing fast.
Scientists say wild plants and crops we depend on will face many new
threats. Climate change might bring more drought.
Escalating global trade could mean importing more pests.
Deb McCullough studies insect pests at Michigan State University. She
says any time you import cargo, you’re running the risk of also
importing pests that can run up huge bills. She says in North America,
one of the big concerns is imports from China:
“If you look at the latitude where China occurs, if you look at the
northern and southern latitude and you overlay that on top of the US and
Canada, it matches up almost perfectly. So you can figure that pretty
much any kind of climate or habitat you find in China, there’s going to
be something similar in the US.”
McCullough says not everything that gets in will turn out to be a pest,
but she says as China’s huge trade surplus with the US grows, there’s a
greater risk more pests will come in.
She says there are some new regulations in place, but restricting
international shipping is a tricky proposition. McCullough says seed
collecting might be one way to preserve plants we rely on:
“People who are molecular biologists, the gene jockeys, have gotten
very good at enhancing or producing resistant varieties of different
kinds of plants. So, that may be something that becomes an option in the
future, maybe not the too distant future.”
McCullough points out there will be serious debate about introducing a
genetically modified tree into the wild. Some people don’t like the
idea of manipulating the genetic makeup of plants or animals.
There are a lot of questions about what might be done with the frozen
seeds, but the seed collectors say regardless, they need to bank up the
DNA of plants that we’re in danger of losing.
For the Environment Report, I’m Rebecca Williams.
