With Christmas just weeks away, many families will be making the annual trip to their favorite tree farm or retail lot to choose the “perfect tree” for their holiday enjoyment. Once the tree has been cut, consumers want to know how to keep it fresh and green throughout the holiday season.
According to Washington State University Christmas tree research scientist Dr. Gary Chastagner, water is the key. Chastagner’s research indicates that daily water consumption by a fresh cut Christmas tree, ranging from 5 to 8 feet high, averages slightly less than a quart of water per inch diameter of the trunk. In other words, a three inch diameter tree needs a minimum of three quarts of water per day. When a Christmas tree is cut, over half of its weight is water. With proper care, you can maintain the quality of your displayed tree throughout the entire holiday season.
Once you get the tree home, make a fresh cut to remove a quarter- to half-inch thick disk of wood from the butt end of the trunk before putting the tree in the stand. Make the cut perpendicular to the stem axis. Don’t cut the trunk at an angle or into a “V” shape. The most efficient water transporting cells are just below the bark. Once the water level falls below the exposed surface on a tapered trunk, drying will begin. An angle or “V” cut will require more water depth to cover the cut surface. It also makes the tree more difficult to hold upright in a stand and less stable. Drilling a hole in the base of the trunk does not improve water uptake. Put your tree in water just as soon as possible after re-cutting the trunk.
Choosing a large capacity stand is one of the most important steps to maintaining tree freshness. Avoid small “coffee cup” stands and check the water level frequently to make sure it does not drop below the base of the tree. With many stands, there can still be water in the stand even though the base of the tree is no longer submerged in water.
Chastagner’s research has shown that plain tap water is by far the best. Some commercial additives, including floral preservatives, commercial tree preservatives, molasses, sugar, bleach, soft drinks, aspirin, honey or other home concoctions, can actually be detrimental to a tree’s moisture retention and will increase needle loss. Water holding stands that are kept filled with plain water will extend the freshness of the tree for weeks. The temperature of the water used to fill the stand is not important and does not affect water uptake.
Keep displayed trees away from sources of heat (fireplaces, heaters, heat vents, direct sunlight). Lowering the room temperature will slow the drying process, resulting in less water consumption each day. On a final note, Dr. Chastagner found that water use changes during the display period and also varies among species. Species such as Noble and Fraser fir tend to use large quantities of water over extended display periods. A typical 6-foot-tall Noble or Fraser fir can easily use a gallon of water per day during the first week, and two to three quarts per day thereafter for the next three to four weeks. In contrast, water use by a Douglas fir may decrease noticeably after a week.
In general, if a tree continues to use a relatively constant amount of water, it indicates that the tree is maintaining a fairly high moisture level. If there is a marked reduction in water consumption, it probably indicates the tree is beginning to dry.
Using tree preservatives
What about tree preservatives which you add to the water — do they help?
Do not use additives in the water, including floral preservatives, commercial tree preservatives, molasses, sugar, bleach, soft drinks, aspirin, honey and other concoctions. Some additives can damage trees and or increase the rate of water uptake from the stand. Clean water is all that is needed to maintain freshness. By the same token, applying film forming anti-transpirants to the tree does not have a significant effect on the rate of moisture loss from the tree. These products supposedly block the evaporation of water from the surface of the foliage, but in reality they have little effect.
What about spraying an anti- transpirant on the tree foliage? Will that extend tree life?
Applying film-forming, anti–transpirants to the tree does not have a significant effect on the rate of moisture loss from the tree. These products supposedly block the evaporation of water from the surface of the foliage, but in reality they have little effect. Monitor the tree for dryness. If the tree becomes dry, remove it from the house.
This column is printed as a service of the Washington State University Extension Office at Elma. Donald D. Tapio is the gardening and farming specialist for the Twin Harbors.