How Science Is Building A Better (And More Resilient) Christmas Tree

It's all about needle retention. Scientists are breeding the Christmas trees of the future, which are resistant to disease and still look nice in your living room.

Mr. Christmas Tree, as Gary Chastagner of Washington State University is known among friends and colleagues, doesn’t have a ton of competition for the moniker. He leads one of the handful of academic research groups around the world devoted to improving the world’s body of knowledge about farming Christmas trees.

Christmas trees seem quaint—the traditional nostalgic image involves an axe, a forested backyard, and some parent-child bonding time. But the vast majority of Christmas trees are farmed, and given that the trees are part of more than a $1 billion a year industry, tree farming is an important business in large tree-producing states like Oregon, North Carolina, Michigan, and Pennsylvania. To keep that business going, scientists are attempting to breed new varieties of trees that can withstand changes brought on by climate change, and also hold up to the new demands of owners, who are keeping trees in their houses for longer than ever.

That business has had a rough year. In Iowa, disease, drought and deer are a problem. Vermont farmers are battling summer flash floods and heat waves. In Florida, record high temperatures have slowed purchases. And in North Carolina, an unusually wet summer has devastated some Fraser fir farms with root rot—a fungus that invades wet, poorly drained soils and causes mature trees to die. No fungicide works against it. (Press attention to this problem has also caused sellers to panic because customers mistakenly think trees for sale are "moldy." The fungus attacks the roots, and these trees never make it to the store).

Is Mr. Christmas Tree going to need to save Christmas? Probably not. The fir trees that make the best Christmas trees aren’t in quite that much trouble, and they are actually doing fine this year in the Northwest. That's where many farmers have started to plant non-native species, such as Turkish and Nordmann firs, which can better resist root rot. But they are under growing environmental duress, and Christmas-loving consumers want only the best trees.

"We’ve had an extremely wet year. They’ve had 30 inches of rain in a month. There are some questions as to whether global warming will make this worse," says Jill Sidebottom, a Christmas tree expert with the North Carolina State cooperative extension service. "When root rot, also called phytophthora, first became a problem in the 1970s, frigid winters would kill the fungus in the soil." But the winters have warmed since then. "If it’s less cold, you don’t have the same die out," she says.

Both at Washington State and North Carolina State, the hunt has been on, especially in the last decade, to build more resilient (but still house-ready) Christmas trees that can withstand these diseases. A plant pathologist for more than 30 years, Chastagner been collecting trees all over the U.S. in the name of discovering the species and individual, genetically gifted specimens that thrive and make great Christmas trees—and understanding why others do not. "It’s about understanding which species of trees or sources of a given species are well-adapted to an area, and what their disease and insect problems are. And then, as important, it’s looking at what’s the post-harvest quality of those trees," he says (i.e. whether needles dry out and shed easily).

That search led to Nordmann and Turkish firs becoming decent, disease-resistant alternatives to the U.S. native Noble and Fraser firs. The latter two, with their high needle retention, lovely fragrance, and strong branches, make perfect Christmas specimens—but they are also highly susceptible to the disease. Farmers in Oregon and Washington are increasingly turning to these European and Asian alternatives in certain soils, Chatagner says. In North Carolina, researchers have tried grafting the Fraser tree onto the more resistant foreign tree rootstock, but that’s proven to be difficult, says Sidebottom.

The search is now getting a big boost. Because Christmas trees are seen as more of a luxury item, the industry has never been a hugely funded research area. But in December, Chastagner, along with collaborators at North Carolina State, as well as in Michigan, California, and Penn State, received a $1.3 million grant from USDA to search for the genetic traits that promote resistance to the disease. The idea is now to find those genes, and develop Fraser fir trees that are the best of both worlds: resilient, practical, and beautiful. Doing this could also help reduce the number of pesticides and fungicides used.

Most recently, Chastagner’s focus has been genetically screening his unique collection of specimens to find the traits that lead to good "needle retention" after harvesting. The goal is to help seed orchards turn out the best possible seeds for trees that will retain their needles.

No one likes a messy Christmas tree, especially these days. "I was born in 1948. When I was a kid, the trees commonly showed up in our house a few days before Christmas and were taken down a few days after. Now, people have them for five or six weeks," he says.

[Image: Pines via Shutterstock]

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  • Karen Sherry Brackett

    When one first brings a tree home from the market, cut its base again unless you witnessed the cut at the farm that day because the cut needs to be fresh. Then before ever giving it any water, feed the tree two liters of Mountain Dew and the needles will stay soft and flexible for the season and even long afterward in the brush pile. LOL Problem solved! LOL :D As for the fungus, I have not studied it but something as small as a fungus can certainly be treated once the right solution is found. They just need to study it some more. I did research on Frazier Fur way back in 1990. They are beautiful trees and I would hate to see them ever be replaced by any other specie. They are susceptible to acid rain if grown in sandy soil, of which the mountains in our area do have some patches of sand. The baby trees die off from a hardening of the arteries. The sulfuric acid in the rain breaks the aluminum silicate of the sandy soil mix down and then the baby trees uptake the aluminum which kills them. The fungus may be prone to thrive in greater acidity and may actually only be a secondary blight that may seem unpleasant but actually be more or less harmless in of itself. If levels of acid rain have increased, the same hardening of the arteries may also occur in older trees with increased levels of several other ions which I also studied in the 90's which affect all soil types. Aluminum was simply the most dramatic in baby trees while other ions were more dramatic but require more time to cause harm to older trees. If this is occurring a lot, then I would suggest a review of sulfuric acid releases in the jet stream and question if those regulations have been loosened or need to be tightened up. If it is the acid rain from pollution it will start to affect other crops and fish too as those ions leach into the water system. Something that can happen without ever even noticing a significant pH change in the water system. We already have hard water in our region. I really hate the thought of it becoming any harder because it will also cause a great increase in human skin irritations and allergies not to mention an increase in the incidence of kidney stones and possibly Alzheimer's and other mental diseases too.

  • Anthony Reardon

    Quite the interesting article Jessica,

    from the most practical of standpoints it all sounds good. I'll challenge it anyway since science only improves the more you test it.

    When you talk about research and development for trees like this, there's got to be a much bigger picture than the Christmas Tree industry. I guess it's kind of good that a social phenomena might push this forward somewhat, but we are talking about resilience and fitness in the face of environmental factors like volatile climate, virulent diseases, and the interrelationships thereof, etc.

    So when you put it down in terms of what's going to work to support an industry, you can actually miss the most important points. Yes, you need to understand why things are happening and what to do about them, but if you've defined the problem as "needle retention" then the solutions probably don't fit.

    For instance, why do some trees retain their needles better or worse? Is it an adaptation that fits in a certain environment. For example, shedding needles might allow a tree to go into hibernate mode which is more efficient for their survival in winter climates, but if they hold their needles might not be able to shut down and exhaust themselves to death. You might get trees that catastrophically fail in cold weather conditions.

    Interestingly, some of the earliest work on genetic selection was done with peas. If you can be meticulous, you can isolate and reinforce specific traits in all kinds of ways. However, in nature, this pretty much takes care of itself. You should get enough genetic variability where not all of a given species fail in different conditions- hot or cold, fungal or insect, etc. While it's good to keep an eye out for when to intervene before a condition set gets out of control, you can do more damage by isolating one particular set of attributes too strongly and mass producing it. You've got to be careful about that.

    You might, for instance, appreciate how a fungus might wipe out most of a species when the weather becomes too generally warm, but also find that is where to identify the few that show resilience more or less. The solution is not necessarily to make sure all future species have those traits, but rather to just make sure those traits remain available within the total genetic diversity.

    Every time you strengthen one attribute, you detract from another. However, the one thing that can be said of even the seemingly useless traits is they generally exist for a reason- perhaps conditions that are not currently prevalent, but have probably worked at some point for a given species in a given environment through the possible ranges of climate and other factors. With that said, sometimes what you see is the result of particular attributes having it too good for too long, and enjoying more success ranging for a given time that might actually not be sustainable as things tend to change. Along that same continuum, you can artificially end up doing the same thing. If you are responsible though, you can actually step in at the right time and in the right ways.

    I just don't think focus on the Christmas tree industry is necessarily going to lead to that kind of responsible outlook. It could be a good thing though.

    On that note, I thought I would mention a family tradition we have of planting a Christmas tree instead of chopping one down. You can start with a small sapling and grow it on your property for a good generation or so, perhaps at some point moving it back out into a more natural habitat before it gets too big to move. It's one of my favorite ideas cause it reduces demand and increases supply, and therein is another way of looking at the challenges facing the Christmas tree industry.

    Best, Anthony

  • Kathy Maguire

    Very interesting. My two favorite trees, hemlock and dogwood, have fallen prey to some of the virulent diseases affecting trees. I don't know much about it, but your thoughtful comments have gotten me thinking about "why now" what has changed so that these trees can't survive now and what are we doing to get at root causes? Is it just the evolutionary process. I am now even more motivated to do some reading about it. Unfortunately I am unable to do much more than that and I hope people like you will.

  • Anthony Reardon

    That is nice of you to say Kathy. I think it's an interesting subject that is pretty accessible to anyone, and just by reading up on it, I bet you can make an impact if you want to.

    My home town is known as "The City of Trees", but there are issues like this that affect our community. For instance, foreign breeds were introduced for aesthetic purposes, and consequently we have some pretty significant problems like new fungus attacking native plants, or the unchecked spread of sticker bushes, etc. A cost-effect decision was behind going with one gender of tree for most of the city's infrastructure, so now my town is also known as one of the worst places for spring allergies. Even a little more attention to science and sustainability go a long way.