As you read this, Christmas tree growers will be seriously involved in the annual tree-shearing phase of Christmas tree farming. This is undoubtedly the most important operation in producing quality trees because here is the part that makes or breaks the successful Christmas tree farm. I've seen more plantations turned into junk from poor shearing practices than from any other cause.
Scotch, eastern white, red and Austrian pines are the leading species in Missouri and the lower Midwest, with Scotch and white pines making up by far the majority of trees grown. Both of these are determinate growth species, which means they put out their entire annual height growth in a relatively short period, from early April until early June. Buds are then formed at the terminal tips of the new growth, which will initiate the new growth in the following year. Since there are no buds along the stem below the terminal bud clusters, there will never be any side branches formed here, only at the very tips of the branches. It is not uncommon for new growth to approach two feet or more in length, thus if not treated in some way, a very open tree would result, not very pleasing to the average Christmas tree consumer.
How long should the terminal be left? A good average is 12 inches, although this can and should vary. Trees with horizontal branches should be cut shorter - 10 inches, or even eight inches in extreme cases. On the other hand, trees with an upswept branching habit can be left longer - 15 inches or even more. Side branches are then trimmed in a straight line from the top of the terminal shoot to the tips of the bottom branches. The terminal shoot is cut on a 45- degree angle, which encourages a bud to form in a higher position on the branch, thus will have a better chance of being a dominant bud the following spring.
I've seen all kinds of tools used for shearing trees, all the way from sewing scissors (yep, that's what I said!), double handled hedge shears, knives, and in the last few years, mechanical trimmers have come into wide use. There are many different styles on the market ranging from gasoline engine or battery powered back-pack models with either a rotary blade or a reciprocating hedge shearing style blade, a walk-behind self propelled unit with several rotary blades. Mechanical trimmers have a tendency to produce straighter sides on trees (many of them cut away anything that is not straight). They are much faster than hand methods, but they do have some disadvantages. It is almost impossible to do some of the correctional work on tops with mechanical trimmers, thus it is advantageous to do tops by hand, or at least go through in a separate operation and do correctional work (straighten crooked leaders, trim out competing terminals, etc.). Another disadvantage is that with a gasoline engine running it is hard to hear the first buzz of a wasp or bald faced hornet and it is difficult to run at top speed with a trimmer when you are being chased.
Hand methods are still used quite extensively by smaller growers and on small trees. I have seen all shapes of trees turned out by shearing crews using knives or other hand tools. Some trees are trimmed to nearly round balls with a spike sticking out the top like an apple, others have vertical sides with round shoulders, some have an exaggerated triangular shape and some approach a teardrop shape. The point being that trees should look as natural as possible if we are to give customers what they demand.
The method I use involves shearing trees with a knife the first three times starting in the second or third year depending on the growth rate. Then switch to a mechanical trimmer until the year they will be harvested when a knife can be used for a light touch up. This gives trees a more natural look, makes them easier to decorate and customers are really pleased with their appearance.
New growers can learn shearing methods from printed material, demonstrations at meetings and by trial and error. The best way is to offer to help an established grower with a good reputation for a few days in order to learn first hand. There are so many small details in the way trees respond to treatment. It is almost impossible to glean it all except by experience.
- Clell Solomon