The Christmas tree buying season is upon us. Nationally, approximately 30 million real trees are purchased each year from retail lots and choose and cut farms.
Keeping a tree fresh is fairly simple once you learn to separate proper tree care information from the many popular home recipes. Unfortunately, many well-intended, but poorly informed sources recommend ineffective treatments that have no scientific basis.
If you treat your tree as a cut flower and display it in a water stand, it will last for several weeks in your home.
The following tips will help you choose a fresh real tree and to properly care for it. They address some of the more common myths and are based upon years of tree keepability research – most of which is conducted at the WSU Research and Extension Center in Puyallup.
What species keep the best after harvest?
Certain species such as noble fir, Fraser fir, Scotch pine and Douglas-fir last very well. Grand fir, spruces, concolor or white fir do well when in a water stand, but tend to deteriorate faster than others if the butts dry out.
How do you pick a fresh tree?
While most trees on a lot are fresh, there are a few quick ways to test a tree’s freshness.
First, pass on any tree that looks faded, exterior needles are brittle and easily fall off at a gentle touch or when the tree is bounced on a hard surface, smells musty and the bark of the outer branches is wrinkled. Such a tree is excessively dry.
Second, gently grasp a branch and pull your fingers toward you. Very few needles should come off if the tree is fresh. Then, discretely pick off a few needles and bend them between your fingers. If the tree is fresh, the needles should break or crisply snap – just like a fresh carrot.
If they are pliable and bend but do not snap, the tree may have dried to a point where it will no longer drink water.
Fresh pine needles are different because of their fibrous composition. They will bend, not break if fresh.
This is also a good test for freshness for non-pine species in the home. If needles bend like a limp, dried out carrot and the tree is no longer using water, it is drying out and may need to be removed after a few more days.
Should I make a fresh cut before putting my tree in a water stand?
If a tree lot or farm made a fresh cut and the tree has been stored in a bucket of water before bringing it inside, a fresh cut may not be necessary. However, if the butt has been exposed to air for six hours or so, water absorbing cells may have sealed over.
Cutting as little as 1/4 to 1/2 inch off the trunk is enough to reopen these cells before displaying your tree in a water stand.
True fir species such as nobles and Frasers may not seal over for several hours. But making a new cut on any fresh tree within four to six hours will assure that it will drink water.
To repeat an important point, displaying trees in water is one of the most effective ways to keep them fresh and to minimize needle loss.
Tests have proven that trees will last two to three weeks or longer in a water stand versus being nailed onto a wooden stand.
What about the needle mess?
Many tree lots and choose and cut growers mechanically shake trees to remove loose needles and other debris. If they have not done so, you can physically shake the tree and bounce it on a hard surface to dislodge loose needles. Or, fire up the leaf blower – it will work great.
One good technique to protect floors and carpets is to place the tree on a tarp or blanket outside and drag it to where it will be set up. This process can be repeated when removing the tree so the tarp, not the carpet, will collect any debris.
How large should my water stand be?
Using a large enough water stand and keeping it filled is one of the most important steps to maintain tree freshness and to minimize needle drop. Research has found that a tree can use up to one quart of water a day for every inch of stem diameter.
Therefore, if you display an average 6 to 7 foot tree with a 4-inch diameter trunk, your stand should hold at least one gallon of water after the tree is placed in the stand, not when empty.
Trees tend to use more water during the first week of display. Consequently, water stands should be checked daily. This is especially true when the tree has been drilled and mounted on a spike. The spike may cause the tree’s base to rest one-quarter to one-half inch above the bottom of the water bowl.
Other factors also affect water usage. The warmer the room temperature and the lower the relative humidity, the more water a tree will use. Trees with thick, heavy foliage will lose water faster than those with lighter crowns and less foliage because there is more needle surface for evaporation.
Will cutting the trunk at an angle or tapering the base increase water uptake?
No. The most efficient water transport system occurs just below the bark. Once the water level drops below the exposed wood surface on a tapered trunk, drying will begin.
An angle cut would require more water depth to cover the cut surface than if it was a straight or flat cut. Such a cut may also make the tree more difficult to hold upright and less stable in the stand.
Will using hot water increase a tree’s ability to take up water?
Not necessarily. Research on displaying Douglas-fir trees in water ranging from 33 to 122 degrees Fahrenheit had no significant effect on uptake. It is not known if this is true for other tree species.
Will commercial additives or adding bleach, aspirin, fertilizer or soft drinks to the water help trees last longer?
No! This popular myth has been disproved.
Research studying the use of commercial preservatives and various home recipes consisting of 7-up, bleach and sugar found that they had little or no effect on keeping trees fresh.
The best needle retention occurred when plain old water was used. In fact, some additives caused heavy needle loss or increased daily water consumption.
When new products are introduced, they should be tested under controlled conditions by independent and credible third parties to verify a manufacturer’s claims.
Using the above information will help us to properly care for our real trees. They have been carefully nurtured for seven to ten years by America’s thousands of Christmas tree growers. So taking good care of the trees in our homes will help us to enjoy them throughout the holiday season.
For additional information on Christmas trees, visit the website of the National Christmas Tree Association at www.realchristmastrees.org.
(Dennis Tompkins is a Certified Arborist and a consulting forester from Sumner, WA. He is also a recognized expert on the nation’s Christmas tree industry)