Shearing Recommendations for Christmas Tree Producers - Objectives of shearing
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Shearing North Central
Regional
Extension
Publication
Recommendations
No. 310
for Christmas
Tree Producers
Over the past several years, quality has become a principal has a "two-thirds taper"; that is,
Christmas tree production has concern for both growers and the base of the tree is two-thirds as
become a significant industry in consumers. Increasingly, higher wide as the height. For a tree 6
much of the north central United quality trees are required to feet tall, the width of the base
States. Established growers have maintain sales in a very would not exceed 4 feet. Other
expanded their production and competitive market. degrees of taper are permitted
new growers have entered the Many factors contribute to tree (Fig. 1 ), though market demand
business. Today several thousand quality. One of the most for both narrow and wide trees is
Christmas tree producers manage important during the production lower. Acceptable tapers will vary
plantations in many counties period is proper shearing. This to some degree by species; wider
through the region. Operations bulletin suggests some ways to tapers are more acceptable for
range from a few acres managed improve the quality of shearing pines than for true firs, spruces
for cut-your-own markets to large and thereby contribute to the and Douglas fir.
acreages producing trees production of duality trees.
exclusively for the wholesale
market. Regardless of the size of
Objectives of
the operation, management shearing
practices have become more Shearing is done to regulate and
sophisticated as growers attempt direct the growth of individual
to increase both the quantity and trees. The objectives are to
the quality of production while develop a symmetrical shape,
holding production costs at which is characteristic of quality
acceptable levels. trees, and to increase foliage
As the Christmas tree density, which will result in a
industry has intensified its fuller tree with uniform foliage.
tree management Though some variation in the
practices, the shape of trees is permitted both
marketplace has by USDA grading ~' standards
likewise become more and by consumer preferences, the
demanding. Tree ideal treeTree response
to shearing spacing, furrows, etc./. Choice of
As indicated, the purpose of shearing equipment depends on
shearing is to direct the growth of the species of tree, the age of the
branches and foliage so the shape tree and individual preference.
and the amount of foliage Many growers use one type of
developed will be acceptable. The tool (e.g., hedge clippers) when
shearing technique needed to trees are small but another
reach these objectives varies by (knives) for older trees.
species group. Pines respond Shearing equipment must be kept
differently than spruces, firs or Fig. 2. Some of the common tools and clean. Accumulated pitch on
Douglas fir. equipment used to trim and shape Christmas clippers and knives increases the
When pine branches produced in trees.
difficulty of shearing and can
the current growing season are become a safety hazard. Detergent
cut, new buds develop at the bases be delayed until late summer
when branches have stiffened solutions, mineral spirits and
of needle fascicles near the cut petroleum distillates are effective
ends. Normally five to seven buds and bud formation is complete.
cleaning agents. Steel wool is
develop on an uncut branch, but commonly used with these
10 to 18 buds will form- in
response to cutting. Cutting the Shearing tools solutions to remove accumulated
pitch. Teflonbased or other
branches directs the shape of the and equipment non-toxic lubricants should be
tree, and the additional buds will Several types of tools and/or used on mechanical trimmers
develop into twigs that will equipment are used to shear after cleaning. Other lubricants
increase foliage density. New bud Christmas trees (Fig. 2). These can dry or burn the remaining
formation is best on twigs include hand clippers, hedge foliage on the sheared tree.
produced during the current clippers and shearing knives. A
growing season; however, cuts leg guard should also be
made into older (second-year) considered part of shearing
tissue will also result in buds. equipment. Besides hand Time of- shearing
Shearing into this older tissue is equipment, some mechanically The proper time for shearing
usually not necessary if annual powered trimmers are also depends on the species and the
shearing has occurred. To obtain available (Fig. 3). Power trimmer growing location within the
maximum bud development, use is restricted by tree size, region. Pines - including Scotch,
shearing must occur during the terrain and condition of the white, red and Austrian - should
active growing season. Shearing at plantation (weeds, tree be sheared during the active
other times will result in branch growing season when terminal
dieback and misshapen trees. growth is nearly complete. In the
Douglas fir, the true firs and southern portion of the region,
spruces respond differently to this usually occurs between June 1
shearing. These species are and 10; in the more northerly
characterized by lateral buds states, shearing begins between
along the twigs in addition to> a June 20 and 30. Shearing can
terminal bud cluster. When a continue through mid-July to
branch is cut during shearing, new early August, depending on
buds do not form at the bases of location, but most growers plan
the needles, as with pines. Rather, on being finished by August 1 at
the lateral bud nearest the cut the latest. Late shearing results in
surface assumes dominance and the development of fewer and
the new terminal or lateral branch weaker buds. Likewise, shearing
tissue develops from this point. too early (late May to early June,
Shearing of these species should depending on location/ results in
the production of too many buds,
which can develop into weak and
often spindly branches. A
Fig. 3. Mechanical l Christmas tree shearing summary of suggested shearing
units can increase the number of trees
sheared each day.TABLE I. Suggested shearing schedule.,
DATE TREE AGE RECOMMENDED ACTIONS in the second growing season after
PINES SPRUCES - FIRS
June 1- 2 Remove multiple stems, - planting. Examine each tree and
July 30 cut terminal to 12 remove double or multiple tops.
inches, if necessary. The remaining terminal shoot
June 1 - 3 Trim terminal to 12 - should be cut back to a maximum
July 30 inches, cut back lat length of 12 to 14 inches. Little, if
erals, remove lower any, shearing of side branches
branch whorls to form a
handle. should occur. The basal branches
on each tree should be removed to
Aug. 1 - 3 -- Remove multiple form a handle to accommodate the
May 1 stems,
cut terminal to 12 tree stand. Usually I inch of
inches, remove lower handle should be present for each
branches to form a foot of tree height at maturity. All
handle.
branches up to this height (8 to 10
June 1 - 4 -7 Cut terminal to 12 - inches) or to the first complete
July 30 inches, trim laterals whorl of lateral branches should
to develop a two
thirds taper, com be removed.
plete corrective In the third growing season, shear
pruning as necessary. both the terminal leader and the
lateral branches of the tree. Begin
Aug. 1 - 4 to year -- Cut terminal to 12 by cutting the terminal leader to a
May 1 before inches, trim laterals length of 12 to 14 inches, or less if
harvest to develop a two
thirds taper, remove the lateral whorl immediately
multiple stems that below the terminal is not strong
may develop. and vigorous. The cut on the
June 1 - Year of Cut terminal to 12 - terminal branch should be made at
July 30 harvest to 15 inches, lightly an approximate 45 degree angle so
trim laterals as needle fascicles on one side will
necessary to main
tain shape be higher than those on the other
(Fig. 4). This practice will favor
Aug. 1 - Year of -- Cut terminal to 12 to the development of a new terminal
Sept. 1 harvest 15 inches, lightly
trim laterals as bud in a position where terminal
necessary to maintain dominance can be expressed. This
shape will contribute to the development
of a straight stem. The lateral
branches of the terminal whorl are
then cut so they are approximately
two-thirds as long as the terminal
times and activities is presented in shearing of Douglas fir, the true shoot (Fig. 5). Following cutting,
Table I. firs and spruces begins at the end the line established by the
Within the pines, longer-needled of the active growing season (late relationship between the top of the
species such as red and white July and early August) and terminal shoot and the ends of cut
pines should be sheared early in continues through the dormant lateral branches of the terminal
the shearing period. Buds on these season. Some evidence suggests whorl is extended downward to
species are slower to develop than that bud vigor and twig growth the determine where other lateral
those on Scotch pine. Earlier following growing season will be branches should be cut (Fig. 6).
shearing of these species provides better if shearing is done during Minimal shearing of lateral
more time for bud formation and late summer and early fall rather branches in the first few years is
development, thereby contributing than the following spring before recommended. The aim is to
to fuller branch development the growth begins. remove only excessively long
following spring.
Because of differences in bud
Guidelines for branches. Many growers
location and plant response, shearing pines
The shaping/shearing process
for pine species should beginFig. 4. Cutting the terminal leader at an Fig. 5.
approximate 45 degree angle will favor Lateral branches of the terminal whorl are cut so they are about two-thirds as long as the terminal
development of a new dominant terminal leader.
bud.
will shear trees in the third and
fourth growing seasons to develop of the terminal. Trees so trees before shearing those to be
an 85 to 90 percent taper. This is sheared appear unnatural and harvested. They do this because
done to develop. width in the tree are not as well accepted in the they believe that bud set following
-in later growing seasons, lateral marketplace as are more shearing will be better if trees are
growth of the lower branches will symmetrically shaped trees. sheared earlier rather than later.
be considerably less than on upper In the year of harvest, shearing Obviously, bud set on trees to be
brandies. If shearing of the sides should be minimal. Trees are harvested need not be particularly
is "too tight" early in the life of more natural looking and full or complete. Other growers
the tree, trees with a narrow or marketable if only light trimming will shear trees to be harvested
candlestick taper are likely to is done. The basic shape of the early so that budset, needle
result. This is especially likely if tree will have been determined by elongation and coverage of the cut
the trees are allowed to grow to past shearing activities. Shearing twig ends can occur to the fullest,
heights taller than 7 feet. cuts at this time should be light, thereby making the tree look as
In the fourth and later growing removing only those lateral natural as possible. Unless
seasons, shearing continues in branches that extend beyond the shearing is done late (after Aug. 1
much the same manner as in year general outline of the tree. If /, it is probable that needle
three. The length of the terminal multiple terminal shoots are elongation and bud set will be
shoot should not exceed 12 present, they should be thinned to adequate to provide a natural
inches. Cutting of the laterals one centrally located branch. appearance.
.will follow the taper relationship
established by the terminal and
Usually the terminal branch will
be left a little longer than it had
Guidelines for
top laterals. It is important to been in previous years. It should shearing firs and
maintain straight sides on the tree
and avoid rounded or
not exceed 15 inches in length,
however.
spruces
As indicated earlier, growth
bullet-shaped trees /Fig. 7/. These Growers do not agree whether patterns and twig-bud anatomy
result from failure to cut the trees should be sheared early or are different for these species than
laterals on the upper portion of late during the shearing period in for pines. The branches of spruces
the tree short enough in relation the harvest year. Some growers and firs, including Douglas fir,
to the length will complete the shearing of
non-harvestable are characterized by the presence
of single needlesshearing should concentrate on should also be cut (see Fig. 6).
maintaining a central leader After the tree is about S feet tall
(terminal branch) and symmetrical (usually in the fifth or sixth year
tree shape. Unless excessive after planting, shearing practices
terminal growth has occurred / 15 should change slightly. The length
inches or more), the terminal of the terminal shoot should not
shoot should not be cut as long as be allowed to exceed 12 inches
full lateral branch development is and in some cases should be cut
occurring. This is particularly true shorter. This depends on the
if several lateral buds are located fullness and the number of lateral
along the terminal shoot. branches developing from the
Generally it is desirable to terminal whorl. It is sometimes
maintain growing conditions difficult to obtain full foliage
(effective weed control and development in the tips of spruce
adequate soil fertility) favorable and fir trees. Reducing the length
for the formation of at least one of the terminal will thicken the
lateral bud per inch of terminal tree as lateral branch development
Fig. 6. Correct location of lateral shearing cuts branch. These buds will develop continues throughout the tree and
as determined by the relationship between the into lateral branches and so lateral buds and twigs of the
length of the terminal leader and lateral increase tree density. If fewer terminal whorl increase in length.
branches of the terminal whorl.
and lateral buds located along the buds are present /less than one per Little, if any, shearing of lower
twig. As previously mentioned, inch of terminal shoot length), the branches will be necessary
when branches are cut during terminal shoot should be cut back because these tend to grow less
shearing, new buds do not form at to approximately 12 inches in rapidly than branches near the top
the bases of needles. Rather, the length, with the cut made of the tree.
lateral bud nearest the cut twig approximately 1 /2 inch above a In the harvest year, only
end will assume dominance, and lateral bud. Other lateral branches minimal shearing is required,
growth the following growing that extend beyond the line especially for spruces.
season will begin from this point. established from the cut ends of Removing competing leaders
For this reason, the time of the terminal shoot through the and lightly shearing the top are
shearing is not as critical for these ends of the lateral branches of the usually all that is necessary.
trees as for pines. terminal whorl Douglas fir require more
Shearing for spruces, firs and
Douglas fir usually begins in late
July or early August and may
continue through fall, winter and
early spring. Shearing for newly
established plantations should
begin during the third growing
season after planting. Each tree
should be examined, and double
terminal branches and double
stems removed. Basal pruning to
form a clean handle should also be
completed. If a symmetrical
growth pattern is developing
naturally in the tree, little, if any,
shearing will be necessary at this
time.
In the fourth and later years,
Fig. 7. Correct shearing will result in a tree with straight sides deft) rather than the "bullet-shaped"
tree on the right.shearing because upper branches many shoots develop or from damage begins.
tend to grow rapidly and damage to the bud that would have For pines, if this is done early in 'err
secondary growth flushes can developed into a terminal branch. the summer, new buds will form at this
result in excessively long terminal Recommended treatment is to point from which growth will occur the
shoots. Shearing this growth back select a strong lateral branch and following year. Whether the laterals in
to maintain tree symmetry is allow it to become the terminal the terminal whorl should be sheared
usually all that is required because shoot. This requires cutting back depends on how long the terminal
lower branches grow less. all other laterals and positioning branch is. An alternative is to select a
Some problem the selected lateral in a central
dominant position. Some lateral
vigorous lateral branch and either
splint or tie it to the base of the
situations branches may need to be removed damaged terminal so that it develops
One of the challenges in shearing entirely. Developing a dominant into the terminal position.
Christmas trees is maintaining a branch may require tying it to For species such as firs and
strong central terminal branch. other shorter shoots, using a splint spruces, the bud left for the
This is essential to maintain good Fig. 8) or using commercially terminal branch may not develop
form and to produce a tree of a available terminal branch training or the terminal bud on
saleable height in the shortest time devices. ' non-sheared trees will fail to
possible. Unfortunately, problem Damaged or broken terminal grow. In this case, a lateral branch
situations that require special Occasionally terminal branches farther down the terminal shoot
attention frequently develop in the are damaged. Insects such as the can be trained to assume the
terminal whorl of branches. pine shoot borer, birds (grackles terminal position. To do this,
Competing terminals - This find Christmas trees attractive select a vigorous lateral shoot and
situation arises when two or more nesting sites) and strong winds tie the base of it to the main stem
terminal branches or shoots are commonly cause breakage or so it is placed in a central
present. It usually develops at injury. position. The end bud on this
least once and results from the Two approaches are suggested shoot will develop into the new
failure of any one newly formed for correcting such problems. If terminal for the tree. Another
or existing bud to assume a only the upper portion of the approach is to tie two opposite
dominant position. Failure to cut terminal has been damaged, it laterals together at the base so
the terminal branch at an angle should be cut immediately they are vertical. After tying, cut
during shearing increases the below the point where the the weaker one immediately
likelihood that multiple shoots above the point of tying. This
will develop. To correct this technique works best in
situation, remove all but one of midsummer when newly
the competing terminals. Select developed branches are still
the strongest branch that is most relatively flexible.
centrally located and remove the
others by cutting at the base with Strong lateral competing for
a hand clipper, rather than a terminal position –
shearing knife. After the selection In some species, notably Scotch pine,
of a dominant terminal, the it is not uncommon for a lateral shoot
shearing process proceeds formed the previous year to assume a
normally. strong dominant position and compete
No visible terminal - The with the current year's terminal for the
opposite situation to that terminal position. Usually this shoot
described above is to have a should be removed at its point of
terminal whorl of branches with origin; however, it may sometimes be
no one branch assuming a desirable to leave it and remove the
dominant position. This condition current season's terminal whorl of
may result from shearing too branches. This
early so that too
Fig 8. A small bamboo stake can
be used as a splint to train a lateral branch
to become a terminal leader.recommendation is appropriate
when growth on the original North Central Regional Extension Publications are subject to peer review and prepared as a
terminal is weak or, more part of the Cooperative Extension activities of the thirteen land-grant universities of the 12
commonly, crooked. This situation North Central states, in cooperation with the Extension Service-U.S. Department of Agriculture,
Washington, D.C. The following states cooperated in making this publication available.
and the resulting need to select a
new terminal branch are more University of Illinois Iowa State University *Michigan State University
common on some varieties of Ag. Publication Office 112 Printing & Publ. Bldg. Room 10B Ag Hall
69 Mumford Hall Ames, IA 50011-1050 East Lansing, MI 48824-1039
Scotch pine than others. Urbana, IL 61801 515-294-5247 517-355-0240
217-333-2007
*Publishing state
Conclusion For copies of this and other North Central Regional Extension publications, write to:
Shearing Christmas trees is Publications Office, Cooperative Extension Service, in care of the university listed above for
your state. If they do not have copies or your state is not listed above, contact the
probably the single most important publishing state as specified.
process that affects tree quality.
Correct shearing, together with
excellent cultural practices
-including effective weed control,
maintenance of adequate fertility,
and control of damaging insect
and/or disease problems - will help
assure the production of high
quality trees that will be
competitive in today's marketplace.
M.R. Knelling
Department of Forestry
Michigan State University
Programs and activities of the Cooperative Extension Service are available to all potential
clientele without regard to race, color, sex, national origin, religion, age and handicap.
In cooperation with NCR Educational Materials Project
Issued in furtherance of Cooperative Extension work, Acts of Congress of May 8 and June 30,
1914, in cooperation with the U.S. Department of Agriculture and Cooperative Extension
Services of Illinois and Iowa, Michael J. Tate, Interim Director, Cooperative Extension Service,
Michigan State University, East Lansing, Michigan 48824.
March 1991 New 3:91-7M-LKJ-Mb, Price 550, for sale only, FILE: 24.47 (Forestry)You can also read
