The Ex Situ Conservation of Stinking Cedar

  Bibiana Garcia Bailo
Student
Smith College
Northampton, Massachusetts

Ron Determann
Conservatory Superintendent
Atlanta Botanical Garden
Atlanta, Georgia

Rob Nicholson
Conservatory Manager
The Botanic Garden of Smith College
Northampton, Massachusetts

Stephen Sojkowski
Greenhouse Technician
The Botanic Garden of Smith College
Northampton, Massachusetts

The propagation of plants for food, timber, medicines and aesthetics has been a principal activity of man for millennia. However, the systematic propagation of plant material for the purposes of conservation has a recent history, probably dating back only a few decades. The propagation and distribution of Torreya taxifolia from wild collected, documented material is one of the largest projects of its kind ever attempted, and many positives and negatives will be learned from the ultimate review of this project.

Background: Torreya taxifolia
    Torreya is a primitive member of the Taxaceae, the yew family. Seven species are known worldwide: four species in China, one species in Japan and Korea, one species in California, and one species in Florida and Georgia. Torreya taxifolia is a rare and endangered species known only from a restricted area of the Florida panhandle and adjacent Georgia in the unique ecosystem known as the Appalachicola Ravines.
    The cultivation of Torreya taxifolia began not long after its discovery in 1835 by

Hardy Bryant Croom. By 1859, A.J. Downing reported on the success of the plant growing in cultivation: "Our best specimen is about eight feet high, very dense, showing nothing but foliage, like a thrifty arbor vitae, and remarkable, particularly in winter, for the star-like appearance of the extreme tips of its young shoots. We have returns of this tree from Elizabethtown, N.J., Dobbs' Ferry, Yorkville, Flushing and Newport, in all of which places it succeeds well, and is considered hardy, except at the last place where it is reported tender." Sargent in 1905 wrote that Torreya was "now often planted in the public grounds and gardens of Tallahassee, Florida."
    At present, no trees of any size are known in the northeastern United States and the successful long-term cultivation of Torreya taxifolia north of Virginia remains unknown. The number of mature trees in cultivation outside of Florida may number less than two dozen. In contrast, old and large trees of Torreya nucifera are found in Boston, Massachusetts, and Swarthmore, Pennsylvania.
    Beginning in the late 1950s a sharp
decline in the health and reproductive capacity of the native stands was noticed. Since then, all full-sized mature individuals have perished and seed production is extremely rare in the wild (E.O. Wilson, pers. comm.). Where trees of 60 feet were found, few individuals over 10 feet are now known. Research into the cause of the decline is ongoing, but in situ preservation appears problematic and management efforts now include the propagation of rooted cuttings from documented wild stands to be grown in ex situ populations. Because set seed is so rare in the wild, vegetative propagation is the only means left to secure documented wild germplasm for study, possible distribution, and possible reintroduction.

The Study
    For this study, 2,622 cuttings were collected from 166 trees at 14 individual sites from throughout the native range of the species (20 miles north to south, 14 miles

Copyright July 1998
Public Garden
The Journal of the American
Association of Botanical
Gardens and Arboreta
Vol. 13, No. 3
PAGE 2

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