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Fraser fi r (Abies fraseri (Pursh) Poir.) Christmas trees were sheared once an- nually over a 4-year period using fi xed schedules ranging from July to March. Shearng in July reduced potential growth of the upper crown by 38%; when done in October or March, the reduction was about 50%. Length, dry weight, and one-sided area of indi- vidual needles were smallest on nonsheared trees, and increased to maximum values on trees sheared in March. In the upper crown (top three internodes), trees sheared in July were 16% to 33% heavier than those sheared in August or later. Dry matter in the upper crown was 30% foliage and 70% woody material. Sixty-one percent of the biomass in the upper crown was branches for trees sheared in July, compared to 55% for October. In the upper crown, foliage comprised about 50% of the branch dry weight (all treatments); in 3-year-old branches, it was 54% to 58%. Among treatments, shearing in July caused the smallest reduction of potential growth and yielded the largest and heaviest branches with signifi cantly more foliage and lateral shoots, all of which would be expected to improve crown density and commercial value. October was the least favorable time to shear. Fraser fi r (Abies fraseri) is a valuable Christmas tree species indigenous to isolated mountain tops in western North Carolina, eastern Tennessee, and southwestern Virginia. Christmas trees acquire their dense, conical shape as a result of annual pruning or shear- ing. True fi rs (Abies Mill.) are sheared once annually (Douglass, 1983; Whitfi eld, 1977), whereas faster growing species, e.g., virginia pine (Pinus virginiana L.), in warmer climates are sheared two or three times (Brown, 1979; Davis, 1972). An important issue is when to shear for best growth and quality. The shearing season varies by species. Eastern white pine (Pinus strobus L.) has a narrow window of time for successful shear- ing (Whitfi eld, 1977). Virginia pine can form adequate numbers of buds on the current-year shoots when pruned throughout the summer (Brown, 1979; Davis, 1972). Abies can be sheared almost year-round, but middle to late summer shearing normally yields the best quality trees (Brown and Heiligmann, 2002; Douglass, 1983; Hinesley and Derby, 2004; Powell, 1982). Beyond that general observa- tion, few specifi c growth effects resulting from pruning at different times have been documented, e.g., quantity and distribution of foliage; number, size, and distribution of branches; and allocation of growth to stems, branches, and foliage. Our objective was to examine the growth and distribution of dry matter in Fraser fi r Christmas trees in response to annual shearing on different dates. One current-year needle and one 2-year-old needle were taken from a dominant 2-year- old branch on each tree. Foliage is typically in a decussate (2-ranked) confi guration with the largest needles attached to the abaxial (lower) side of the branch, mid-way between the proximal (inner) and distal (outer) ends of the internode (Brewer et al., 1992). One large needle was collected at that position in each internode. Needles were taped to labeled sheets of white paper, and stored in sealed freezer bags on ice. The next day, sheets were photocopied to preserve the images. Sheets, with needles attached, were dried at 65 °C, and needles weighed to the nearest 0.1 mg. Length and projected area were determined for each image using a Monochrome Agvision System area meter (Decagon Devices, Pullman, Wash. with DIAS II software (version 1.0, about 1989). Projected areas were multiplied by 1.145 to correct for the elliptical upper surface of needles (Brewer et al., 1992) . During winter (2000-01) two large branches (fi rst-order laterals, 3 years old, opposite sides of the trunk) were selected at the top of the 1998 internode (25 trees/treatment), cut fl ush with the trunk, tagged, and placed in a nylon or burlap bag. The trunk was cut at the base of the 1999 internode, and all biomass above the cut was bagged with the two large side-branches. Material was transported to Raleigh, and stored at -1 °C. Processing large branches. After measuring basal diameter (two directions), each of the two large branches from each tree was subdivided into shoot segments, by age (1, 2, and 3 years), and the number of segments counted. Segments were combined, by age, for each branch. After drying to constant weight at 65 °C, foliage and woody material were separated and weighed for each sample. Averages were computed for the two branches from each tree. Stem segments were processed similarly. Processing the upper crown. For each tree, branches were removed, counted, and segregated for each of the three internodes. Leaders were counted and combined into one sample. Samples were dried at 65 °C, parti- tioned into wood and foliage, and weighed. Total dry weight was the sum of woody and foliar components. Statistical analysis. Data were analyzed with general linear model (GLM) procedures (SAS Institute, Inc., 1990). Linear contrasts (1 df) were used to make certain treatment comparisons.

Growth of Fraser Fir Christmas Trees In Response to Annual Shearing