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Searching for the perfect Christmas tree


East Carolina researchers study Christmas tree specimens

 
 

 


 


On a plot of land near Falkland, just west of Greenville, wannabe Christmas trees — Nordmann firs and other species — offer themselves up for science. These trees, property of East Carolina University’s biology department, were planted to see how well they tolerate the hot, dry summers typical in eastern North Carolina.

Christmas trees are a $92 million-a-year business in North Carolina; the state is second in the country, behind Oregon, in the number of trees harvested, and first in dollars earned per tree according to the N.C. Department of Agriculture and Consumer Services.

But currently only one percent of the state’s trees are grown in the Coastal Plains. Fraser firs, by far the most popular species with consumers, are not well suited to the local climate. So East Carolina biologists face a challenge: if they want Christmas trees to be the East’s next cash crop, they must find a commercially viable species that will thrive in the region.

Or they’ll have to make one.

Looking for a Contender
In the eastern part of the state, where pine trees are pervasive, varieties like the Scotch, Virginia and white pines often stand in for the favored Fraser at Christmas time. For 30 years, Bobby Brock, president of the Eastern North Carolina Christmas Tree Growers Association, has raised Scotch pines on a 3-acre former tobacco field in what he calls “a very one-horse operation.” He’s become quite familiar with the limitations of the species.

“Some trees, like the Virginia pine, really don’t want to be a Christmas tree,” he said. “They have ‘bad’ genes. They grow crooked and have bare spots. It takes a lot of work to get a good tree.”

Dr. Ronald Newton, a plant physiologist and chair of ECU’s biology department, hopes to provide eastern North Carolina growers with another option. For nearly 25 years he has studied trees and their ability to cope with environmental stresses such as heat, disease and drought. When he came to East Carolina five years ago, the department was just starting to look at Christmas trees as a potential replacement crop for tobacco farmers.

“We’re interested in bringing in Christmas tree species that are adaptable to this area,” Newton said. “The tree that is revered by consumers is the Fraser fir, but it doesn’t do well here, which is understandable when you think about where Fraser firs come from.”

Frasers, which account for 96 percent of the Christmas trees raised in North Carolina, grow almost exclusively in the mountains. So scientists must either create a tougher Fraser through genetic engineering or find an alternative. They are working on both.

“Our goal is to have a Christmas tree species that has all the attributes consumers like and that can be produced in this part of the state,” Newton said. “We’re using two different approaches to accomplish the same thing. With Fraser fir, we are interested in providing resistance to drought and phytophthora, a root-rot disease, and we’re interested in bringing in some new species that might tolerate the environment and increase North Carolina’s share of the national market.”

Those species so far have included the Nordmann fir, Turkish fir, Momi fir, Canaan fir and balsam fir.

“We’re excited because there are some possibilities with those species, particularly the Nordmann, because the Nordmann has characteristics similar to the Fraser fir,” Newton said. Those characteristics include soft needles, a pleasing A shape, strong branches and good needle and moisture retention. “Nordmann is one of the primary Christmas tree species in Europe, particularly in Denmark and the Netherlands,” Newton said.

So far, the Nordmann has proven most resistant to heat and dry conditions. Tests are under way to figure out just what it would need to prosper in this region. Considerations such as the amount of water and fertilizer required are important in determining if the trees can be grown profitably.

Developing a Winner
While researchers look for alternative trees, they have not given up on the Fraser. Genetic engineering might be the key to developing a fir that can take the heat and fight disease.

“If you’re very selective, you can bring in genes to provide resistance to environmental stress or disease,” Newton said. “We have isolated genes from other trees that are induced by drought. We can tell that these genes are very effective when the tree is experiencing drought stress.”

The Aleppo pine of Israel, for example, is a drought-tolerant species that could provide a gene to boost the Fraser’s resistance to hot, dry weather. The Fraser has other enemies, such as fungi and insects, that could also be fought with genetic engineering. That would be a great help to the industry, according to Linda Gragg, executive director of the N. C. Christmas Tree Association, which is based in the western part of the state, where large areas of native trees have been devastated by the phythophtora fungus.

“Just a deer walking across where phythophtora is will spread it from one field to another,” Gragg said. “It is that easy to transfer.”

Genetically modifying plants is not new. Researchers at Cornell University created a variety of papaya tree that resists a virus that threatened to destroy the industry in Hawaii. A type of corn,  Bt , produces its own pesticide, thanks to a gene from a bacterium. Cotton and other crops are made to resist a herbicide that kills off the weeds around them. Newton hopes to accomplish similar transformations with the Fraser fir, but the research still has a way to go.

“There are genes out there that would be effective against insects and drought,” Newton said. “We’ve isolated the genes so we actually have the DNA, but we’re not sure exactly how those genes work. Pine trees can have thousands of genes. We don’t really know all their functions.”

So researchers test the genes by inserting them into a plant using an engineered bacterium. Tobacco is commonly used because it grows quickly, allowing researchers to see the results of their work sooner.

The Clone Wars
Getting the right tree is only half the battle. Scientists must also consider effective propagation techniques to produce enough baby trees for research and to start an industry.

“It takes trees a long time to produce cones and seed, three to five years in most cases. That’s a long time to wait,” said Newton, who points to cloning as a much faster way of creating a supply of plants for the lab or the field. Once a technique for clonal propagation is developed for each species, commercial labs can create thousands of trees from the genetic material of one.

Breeders have spent years in small seed orchards carefully transferring pollen from one tree to the cone of another to produce better trees. This laborious process of selective breeding has been around for millennia. East Carolina collaborates with N.C. State University, which provides top-quality Fraser fir seeds for ECU’s cloning experiments.

“A tree out in the forest can clone itself. Even in your yard, you can see shoots coming up off a tree’s root system. That’s cloning. That shoot that comes up is identical to the mother plant,” Newton said. “We’re doing the same thing Mother Nature does. We’re just accelerating it.”

But it hasn’t been easy; fir trees have proven terribly difficult to clone.

“We’ve been working on it for four summers,” Newton said. “We’re tenacious — and perhaps stupid — but we’re going to continue to do it. Fraser fir in particular has been very tough to work with, but we feel like we’ve cracked the problem with Fraser. But with Nordmann, contamination still seems to be a problem for us.”

The contamination comes from microbes on the seeds scientists are working with. They are cloning the trees by embryogenesis, a process by which a callus (a mass of undifferentiated cells) is formed from the embryonic tissues in the seeds. Tiny but complete plants form on the surface of the callus where they can be harvested and nurtured into what most people would recognize as seedlings but are called plantlets because they don’t come from seeds. During this process, the microbes gain access to plant tissue they normally wouldn’t in the wild, and they usually kill the plant. Faculty and students are trying dozens of techniques to sterilize the seeds.

“It’s been very frustrating, almost embarrassing,” Newton said. “We thought we could make some real progress, but we’ve spent a lot of time trying to get rid of microorganisms.”
Frankentrees?

Newton is well aware that cloning and genetic engineering are technologies that can make people nervous.

“Consumers are going to accept a tree that is based on traditional genetics, where you take the pollen of one tree and place it on another. But some consumers may not like the idea of your taking a gene from bacteria and putting it into a Christmas tree,” he said.

Environmental organizations, including Greenpeace and the World Wildlife Fund, worry that such technologies are moving too fast and that modified species of plants are being introduced before their interaction with their environment is fully understood. They are concerned about plans to create trees that grow faster or produce their own pesticide, often referring to them as “frankentrees” after Mary Shelley’s slapped-together monster. And as Frankenstein’s monster did, critics are concerned that these new life forms will behave unpredictably.

Newton is just as concerned, but more optimistic about the promise of genetically engineered trees.

“Is it going to happen? Yeah, it’s going to happen,” he said. “It’s the kind of research that we have to do. We have a gene now that we could use to make trees more efficient users of nitrogen. If we can do that, we can perhaps enhance growth. It can take 10, 11, 12 years to produce a 6-foot Fraser fir. If we can cut off a couple of years, that’s money in the pocket of the grower.

“But we are very concerned about the environment, and we’ll have all kinds of safeguards in place.”

The most important consideration when creating an engineered tree, he said, is to make sure it can’t reproduce or spread its genetic material to wild trees.

“Once you get these things genetically modified, you want to be careful what you place out there,” Newton said. “You make sure the trees you put out there are sterile, so they don’t produce any cones. There are many people in large labs throughout the country looking at producing sterile trees.”

Benefiting the State
Would more Christmas trees grown in the East hurt the growers in the mountains? Gragg, from the Christmas tree association in Boone, doesn’t think so.

“We don’t want to flood the market, but at the same time, we want to keep our market share,” she said, pointing out that West Coast producers have dramatically increased the number of trees they plant each year.

“Our main competition is the artificial tree; it should not be each other,” Gragg said. “We should work together getting the research done, getting the best tree that will grow on both sides of the state and get that tree out as a North Carolina tree.”

Ultimately, whatever tree East Carolina settles on will be patented so that it can be grown only in North Carolina.

“We’re trying to benefit the people of North Carolina so we’re careful to protect the rights of the citizens of North Carolina,” Newton said. As he sees it, the taxpayers have a large stake in this project, and they are the ones who ultimately should reap the rewards.





This story was originally published in East, the magazine of East Carolina University, and was written by David Etchison.