As described in the Methods section, trees on individual plots were randomly assigned to treatments without regard to growth rate, bud set, or branch angle. These characteristics can markedly affect how a tree responds to shearing and, as noted by Brown (1999), these traits vary widely in West Virginia balsam fir.
Since the inception of this study, experience and observations by the authors and experience by growers have suggested that careful evaluation of individual trees can substantially improve the quality of trees sheared with longer terminals. Specifically, individual West Virginia balsam fir exhibiting good terminal growth and bud set and relatively upswept lateral branaches can produce a quality tree when sheared with longer terminals, while those with poorer terminal growth, bud set, and/or flatter lateral branches require a shearing strategy with relatively shorter terminals (Figure 11).
In fact, premium quality trees 8 to 11 feet in height can be produced in seven to eight years from appropriately selected trees growing on good sites with good weed control and fertility (Figure 12). Depending on the individual tree, terminals in some years may be up to 20 inches or more in length. It is important to note, however, that this strategy does not necessarily produce a marketable tree at shorter heights. Trees sheared with long terminals require sufficient time for the internodal branches to fill and develop the density and uniformity necessary for a marketable tree.
The importance of carefully selecting individual trees if longer terminals are to be left cannot be overemphasized. If West Virginia balsam fir are sheared with longer terminals without selecting individual trees suited to that strategy, the quality of trees produced will probably resemble that achieved in this study with the progressive shearing treatment, or worse, if longer terminals are left.
It is probable that individual Fraser fir could also be selected for production of Christmas trees with shorter rotations using the same general criteria described for West Virginia balsam fir. However, as indicated previously, trees of Fraser fir generally have fewer lateral buds and limbs on terminal shoots, branch angles are somewhat “flatter” than on West Virginia balsam fir, and it would probably take an additional one to three years to produce high-quality 8- to 11-foot trees.