Postharvest Needle Retention and Moisture Characteristics of Canaan Fir Compared with Four Other Christmas Tree Species

The postharvest needle retention and moisture characteristics of precut and fresh cut Canaan fir were compared with those of Fraser fir, blue spruce, Douglas-fir, and Scotch pine for a five-week display period. At the end of the display period cumulative percent needle drop of precut trees averaged 1.5 percent, with no significant differences among species; xylem potential averaged −1.42 MPa, with Scotch pine being significantly lower than blue spruce and Douglas-fir; and needle moisture content averaged 142 percent, with no significant differences among species. For fresh cut trees, cumulative percent needle drop averaged 1.15 percent, with the only significant difference among species being Scotch pine lower than Douglas-fir; xylem potential averaged −1.06 MPa, with Scotch pine and Fraser fir significantly lower than blue spruce, Canaan fir, and Douglas-fir; and needle moisture content averaged 140 percent, with Scotch pine significantly lower than all other species except Douglas-fir. At no time during the display period was there a significant difference in percent needle drop between precut and fresh cut trees of the same species. Significant differences in xylem potential existed between precut and fresh cut trees of the same species at the beginning of the display period but disappeared by the end of the first week. Occasional significant differences in needle moisture content between precut and fresh cut trees of the same species were encountered during the display period, but none existed at the end of the display period. Throughout the display period the xylem potential and needle moisture content of all species followed similar patterns, and the trees did not appear to approach the damage threshold or critical moisture content. Results suggest that Canaan fir's postharvest needle retention is acceptable for a Christmas tree and comparable to four other major species commonly grown and marketed in the northeastern United States. Grower experience supports this conclusion for fresh cut trees (choose and cut market), but not for precut trees (wholesale market). Some reasons are discussed.North. J. Appl. For. 22(4):268–274.