Moisture and needle loss characteristics were similar for noble (Abies procera Red.) and Nordmann fir [Abies nordmanniana (Stev.) Spach.] Christmas trees that were displayed in water. After 42 days, trees still had xylem pressure potentials above -2 MPa. In addition, trees that were displayed in water had very little needle loss. When trees were displayed dry, noble and Nordmann fir had similar rates of moisture loss, drying to about -6 MPa in about 3 weeks. Although there was very little needle loss from any of the noble fir trees that were displayed dry, some Nordmann fir trees began to shed large numbers of green needles within 3 to 5 days, which significantly reduced postharvest quality. Unless sources of Nordmann fir are identified that have good needle retention characteristics, the needle loss problem observed when trees dry to about -3 MPa has the potential to limit the use of this species as a Christmas tree in the United States.
Gary A. Chastagner and Kathleen L. Riley
Gary A Chastagner, Ulrik Bräuner Nielsen, and Kathleen L. Riley
Postharvest moisture and needle retention of boughs was examined for four Danish and five U.S. provenances of noble fir grown in Denmark. Boughs were displayed indoors under controlled conditions, and data were collected relating to rates of moisture loss and needle retention. Small current-year shoots had moisture and needle loss patterns similar to larger bough material. Postharvest quality of the Danish and U.S. provenance boughs was very similar. There was also a high correlation between the moisture level of the boughs and shoots, indicating that it should be possible to use small shoots to assess differences in moisture retention in future tests.