CPC Plant Profile: Florida Torreya
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Plant Profile

Florida Torreya (Torreya taxifolia)

This towering tree is one of the last of its kind?no large trees are left in their native habitats. All, like this one, are found only in cultivation. Photo Credit: Tom Ward
Description
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Taxaceae
  • State: FL, GA, NC
  • Nature Serve ID: 137133
  • Date Inducted in National Collection: 03/08/1989

Torreya taxifolia, known as the Florida Torreya, is one of the rarest conifers in the world. Once found as a canopy tree, Torreya is an evergreen dioecious tree endemic to a narrow range of bluffs and ravines adjacent to the Apalachicola River in northwest Florida and extreme southwest Georgia. In the mid-Twentieth Century this species suffered a catastrophic decline as all reproductive age trees died. In the decades that followed, this species did not recover. What remains is a population approximately 0.3% of its original size, which is subjected to changes in hydrology, forest structure, heavy browsing by deer, loss of reproduction capability, as well as dieback from fungal disease. Atlanta Botanical Garden’s dedication and efforts to protect Torreya furthers understanding of its ecology and life cycle as well as the decline of this once majestic species. We present the ongoing research to meet recovery objectives for this species, as well as how they relate to other rare species conservation and evolution under predicted climate change. In 1984 this species was listed Endangered under the U.S. Endangered Species Act. It is currently listed as Critically Endangered on the IUCN Red List.  

Participating Institutions
Updates
  • 10/16/2020
  • Genetic Research

A genetic study found that T. taxifolia has an overall low genetic variation: seven of the 20 loci were variable and each polymorphic focus had no more than two alleles (Schwartz 1993). Schwartz, M. W. and S. Herman (1991) present evidence that fire suppression may have contributed to the fungal decline of Torreya (Torreya taxifolia).

  • 10/16/2020
  • Genetic Research

Allozyme analysis was used to evaluate multiple populations within the 5 ravines in which Torreya taxifolia occurs in 1994. Genetic diversity detected using allozyme markers in the ex-situ population of Torreya maintained at Atlanta Botanical Garden was found to be higher than that in wild populations. Differences are likely due to the bottleneck effect and decline in genetic variation in the wild. Diversity of cultivated collections was close to the average level found in gymnosperms and typical of long-lived species with mixed-mating systems.

  • 10/16/2020
  • Propagation Research

Torreya is shade-loving and intolerant of much light. The soil has to be light, reach, and with lime. The seeds require a long period of (4-5 months) moist and warm conditions followed by an equally long period of mild cold stratification. Propagation from hardwood cuttings are successful in 50/50 sand-perlite mix under poly cover, treated with 5,000-10,000 ppm K-IBA yields 80%+ rooting in 4 months. The most promising technique for Torreya involved application of cytokinins (4 weekly sprays with 100-200 mg/l BA or 2-i-P) to seedlings before culture. Newly stimulated axillary shoots developed additional shoots and multiple "bud-masses" when cultured on WPM with BA (1 mg/l) and NAA (0.01 mg/l). These were slow to develop but could be subcultured with additional growth of multiple shoots. No rooted plantlets were obtained.

  • 10/16/2020
  • Seed Collection

Atlanta Botanical Garden and the University of Georgia have also established a Torreya seed orchard, where nearly 5,000 cones were harvested in 2016.

  • 10/16/2020
  • Seed Collection

Atlanta Botanical Garden and the University of Georgia have also established a Torreya seed orchard, where nearly 5,000 cones were harvested in 2016.

  • 10/16/2020
  • Cryo

ABG in collaboration with Georgia Institute of Technology, developed a somatic embryogenesis tissue culture system to initiate cultures, produce somatic seedlings, and cryogenically store cultures of T. taxifolia.

  • 10/16/2020
  • Tissue Culture

ABG in collaboration with Georgia Institute of Technology, developed a somatic embryogenesis tissue culture system to initiate cultures, produce somatic seedlings, and cryogenically store cultures of T. taxifolia. Large numbers of somatic embryos and resulting seedlings can be developed in culture from a single seed which can be used for disease research, restoration or establishment of seed nurseries for conservation.

  • 10/16/2020
  • Propagation Research

In 1990, Atlanta Botanical Garden (ABG) received 155 clones of T. taxifolia propagated from the remaining natural population. Since then propagation efforts have increased ABG’s collection to include almost 1,000 individuals, including nearly 500 accessions from the wild

  • 10/16/2020
  • Living Collection

The ABG Gainsville ex-situ collection consists of 428 accessioned trees (45% increase from the 2008 collection) that can actually be traced back to a specific tree they were collected from in the wild spanning over the past 30 years.

Elvia Ryan
  • 08/14/2018

The current estimate of Torreya taxifolia is approximately 730 plants down to 0.22% of the original population size primarily due to the Fusarium outbreak that occurred back in the mid-20th century.  The ABG Gainsville ex-situ collection consists of 428 accessioned trees (45% increase from the 2008 collection) that can actually be traced back to a specific tree they were collected from in the wild spanning over the past 30 years.  The main focus of ABG's recovery action plan is to genetically safeguard via seedlings and cuttings every known wild individual from both public and private properties. There are 323 wild individuals safeguarded at ABG and throughout the 21 partnering institutions with approximately 407 left to safeguard which should occur this fall.  In 2017, the main focus was the cage installation of over half of the population on both public and private lands.  A total of 4000 seeds and 2000 seedlings were distributed to the 21 institutions across 8 states including Royal Botanic Garden Edinburgh, Scotland.  This year, ABG also performed in-situ experimental trials:  7 trials in Torreya State Park in Florida, 4 trials on private land, 3 sets of 7 maternal lines (21 seeds per cage to protect from squirrels and hogs).  The Torreya Tree of Life Event was held this year at the Torreya State Park with the University of Florida for the purpose of strategizing the next steps for in-situ conservation and ex-situ research.  (Coffey 2018)

Elvia Ryan
  • 07/31/2018

The main threat to Torreya taxifolia is fungal disease - Pathogens: Fusarium, FSP-1; Phyllosticta, Physalospora, and Macrophoma. Identified back in 2011, Fusarium has actually taken out all the mature trees leaving only a few sexually reproductive trees in the wild.  To this day, Atlanta Botanical Gardens has found seed on two trees in the last five years.  The only seed ABG is currently getting is from their own orchard.  Other threat contributors are deer rub, habitat loss, and climate change.  In addition, squirrels and hogs also pose a challenge.  (Coffey 2018)

Elvia Ryan
  • 07/26/2018

The main focus of ABG's recovery action plan is to genetically safeguard via seedlings and cuttings every known wild individual from both public and private properties. There are 323 wild individuals safeguarded at ABG and throughout the 21 partnering institutions with approximately 407 left to safeguard which should occur this fall.  (Coffey 2018)

Carrie Radcliffe
  • 01/04/2018

Over the past ten years significant progress has been made in developing a variety of techniques for conservation of this critically imperiled species. These collaborative projects have resulted in scientific publications, presentations and educational materials for the public. Future research will determine the host range of the disease and offer insights on its origins. Current efforts include evaluation of the current status of the species, estimation of remaining genetic variability in the wild, and efforts to reintroduce the species into areas where it has been lost.  Seed production in ex situ collections has increased dramatically, increasing diversity of this species in cultivation and availability of plant material for safeguarding and research.

Carrie Radcliffe
  • 01/04/2018

Allozyme analysis was used to evaluate multiple populations within the 5 ravines in which Torreya taxifolia occurs in 1994. Genetic diversity detected using allozyme markers in the ex-situ population of Torreya maintained at Atlanta Botanical Garden was found to be higher than that in wild populations. Differences are likely due to the bottleneck effect and decline in genetic variation in the wild. Diversity of cultivated collections was close to the average level found in gymnosperms and typical of long-lived species with mixed-mating systems.

Carrie Radcliffe
  • 01/04/2018

Garden staff began collaborating with biologists and researchers at the Florida Park Service and the University of Florida in 2008. Efforts have included evaluation and mapping of wild trees. Research has been conducted identifying the disease causing agent as a new species of Fusarium (Fusarium torrayae). Field surveys have found that stem damage from deer antler rubbing is a significant source of stress in addition to disease, and is causing severe impacts to more than 50% of trees. Efforts at understanding ecological requirements of this species for reintroduction include caging the trees to protect them from deer damage. To date 21.6% of surveyed wild trees have been caged for protection. Although the majority of habitat for T. taxifolia is protected in state parks or by The Nature Conservancy, until damage from deer and stem canker can be controlled, recovery of the species is dependent on ex situ conservation efforts.

Carrie Radcliffe
  • 12/13/2017

In 1990, Atlanta Botanical Garden (ABG) received 155 clones of T. taxifolia propagated from the remaining natural population. Since then propagation efforts have increased ABG’s collection to include almost 1,000 individuals, including nearly 500 accessions from the wild. ABG has increased representation of wild individuals through extensive field surveys, which have located additional trees, along with continuous collection and propagation efforts.

Allozyme analysis was used to evaluate multiple populations within the five ravines in which T. taxifolia occured in 1994. Genetic diversity detected using allozyme markers in the ex-situ population of Torreya maintained at ABG was found to be higher than that in wild populations. Differences are likely due to the bottleneck effect and decline in genetic variation in the wild.

One of the limiting factors to ex situ conservation of this species is that T. taxifolia produces recalcitrant wet seeds that cannot be dried for storage in freezers. Therefore, until recently the only way to maintain ex situ germplasm was through living collections.

ABG in collaboration with Georgia Institute of Technology, developed a somatic embryogenesis tissue culture system to initiate cultures, produce somatic seedlings, and cryogenically store cultures of T. taxifolia. Large numbers of somatic embryos and resulting seedlings can be developed in culture from a single seed which can be used for disease research, restoration or establishment of seed nurseries for conservation.
 
Atlanta Botanical Garden and the University of Georgia have also established a Torreya seed orchard, where nearly 5,000 cones were harvested in 2016. Seed has been shared, and seedlings are being distributed to other botanic gardens to use in developing additional ex situ collections and another seed orchard. ABG is currently sharing seeds and seedlings with conservation institutions as part of an agreement with the U.S. Fish & Wildlife Service to distribute material for ex situ conservation. The next step for the conservation program is to reintroduce the species into areas where it has been lost and to continue protecting trees from deer pressure.

 

Clarice Mendoza
  • 11/09/2017

Assisted migration has been implemented for T. taxifolia. The effort was led by a group dubbed the Torreya Guardians. This coalition of botanists and environmentalists established a seed-planting campaign to help this conifer move northwards (Marris 2008). Although it may be considered controversial, assisted migration requires the strict following of best-practice guidelines and adequate research and preparation for maximum success (Hällfors 2017).

NatureServe Biotics
  • 05/02/2017

Endemic to about a dozen ravine complexes along the Apalachicola River in Florida and adjacent Georgia, this species was once common. However, since the late 1950s, a fungal pathogen of uncertain origin and no known control has decimated the populations. There are currently no reproducing individuals known in the wild and the species is persisting only as stump shoots and occasional root sprouts. Most of the Georgia habitat was eliminated by flooding from a major dam.

Irina Kadis
  • 01/01/2010

The decline of T. taxifolia is due to environmental factors such as harvesting (for fence posts, shingles, firewood and Christmas trees) and habitat changes in water flow patterns.

A fungal disease is the primary cause of this species plight and remains the largest threat to its survival (USFWS 1986).

Irina Kadis
  • 01/01/2010

There are less than 1500 trees in the wild (Schwartz 1993) but the population continues to decline (Schwartz and Hermann 1993a).

Irina Kadis
  • 01/01/2010

During the 1950s, Torreya suffered a catastrophic die-back. The Torreya die-back was probably caused by needle pathogens induced through environmental stress. Several environmental stresses were concurrent with the decline of the Torreya. One of these stresses may have been fire suppression. Torreya grows within ravines, where fires usually do not occur. However, smoke from the frequent natural upland fires settled into ravines. [The authors] present data showing that several needle pathogens isolated from Torreya have reduced germination and growth rates on substrates treated with smoke. Succession, as a result of fire suppression, also reduced light incidence within ravines. [The authors] show that Torreya growth is correlated with light incidence. [The authors] discuss the fire hypothesis in the context of other hypotheses for the Torreya decline. Schwartz and Hermann (1993b) conclude that foliar pathogens are the most likely symptom of disease and are associated with a significant decline in photosynthetic capacity brought on by canopy shading. Low light has also been found to be the primary limiting factor to T. taxifolia (Schwartz and Hermann 2000).

Foliar pathogens appear to be sensitive to smoke treatments suggesting that the use fire may play an important role in health maintenance for T. taxifolia (Schwartz and Hermann 1993b). An examination of endophytic fungal communities found associated with T. taxifolia found that a filamentous fungus, Pestalotiopsis microspora was correlated with diseased and non-diseased trees (Lee et al. 1995). It is generally believed that T. taxifolia is intolerant to high levels of light, however, Koehn and Doudrick (1999) found that their study plants recovered from periods of high light and temperature indicating that this species may be more tolerant to light than originally thought.

A genetic study found that T. taxifolia has an overall low genetic variation: seven of the 20 loci were variable and each polymorphic focus had no more than two alleles (Schwartz 1993). Schwartz, M. W. and S. Herman (1991) present evidence that fire suppression may have contributed to the fungal decline of Torreya (Torreya taxifolia).

Irina Kadis
  • 01/01/2010

Considerable effort has been made to propagate and establish the species away from its original area (Dirr 1994). Its survival will likely depend upon cultivation in the gardens (Foote & Jones 1994). There are a few large specimens growing undamaged in botanical gardens and nurseries. At several locations in the Southeast, the plantings ave escaped the fungal disease and produce viable seed. The plant considered as a national champion is in Norlina, NC at 45 feet tall and 40 feet wide. A 30-feet high specimen is in Lee, FL. T. taxifolia has been often planted on the public grounds in Tallahassee, FL as an ornamental.

Karl Kern, Wyoming Nurseries in Cincinnati, OH supplied the Arnold Arboretum with plants of T. taxifolia. In 1962, Karl Kern said that they had a large specimen in the area that had survived perfectly. R. Allen, Calloway Gardens, Pine Mountain, GA 31822, collected seeds in Florida in 1981 for the Arnold Arboretum. Barry Yinger, York Haven, PA (Curator of Asiatic Plants, National Arboretum) in 1983 mailed cuttings from his plant, which, as he stated, had survived -17F in York Co., PA.  The plant had originated from Semmes, Alabama. Rob Nicholson and Ida Hay in 1985 collected cuttings for the Arnold Arboretum north of Chattahoochee and in five places in Torreya State Park, Florida.
 

Irina Kadis
  • 01/01/2010

The primary objective set forth in the U.S. Fish and Wildlife Service's recovery Plan (1986) is to produce genetically diverse collection of trees from which offspring could be reproduced and reintroduced into the wild . Additional management needs include protecting populations from further decline through individual and habitat protection, conduct studies concerning disease management and study propagation methods (USFWS 1986). Published research on fire adaptations of Torreya taxifolia (Florida torreya) is lacking. A related species, T. californica (California torreya), sprouts from roots, root crowns, and boles after fire. Torreya taxifolia may respond to fire in a similar manner. Until recently, ground fires were a constant influence on the neighboring long-leaf pine (Pinus palustris) forest community. The smoke from these fires may have operated as a natural fungicide by suppressing a fungus that now infects T. taxifolia. Torreya taxifolia is known from northern Florida and southern Georgia.

Irina Kadis
  • 01/01/2010

Torreya is shade-loving and intolerant of much light. The soil has to be light, reach, and with lime. The seeds require a long period of (4-5 months) moist and warm conditions followed by an equally long period of mild cold stratification. Propagation from hardwood cuttings are successful in 50/50 sand-perlite mix under poly cover, treated with 5,000-10,000 ppm K-IBA yields 80%+ rooting in 4 months.

The most promising technique for Torreya involved application of cytokinins (4 weekly sprays with 100-200 mg/l BA or 2-i-P) to seedlings before culture. Newly stimulated axillary shoots developed additional shoots and multiple "bud-masses" when cultured on WPM with BA (1 mg/l) and NAA (0.01 mg/l). These were slow to develop but could be subcultured with additional growth of multiple shoots. No rooted plantlets were obtained.

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Nomenclature
Taxon Torreya taxifolia
Authority Arn.
Family Taxaceae
CPC Number 4295
ITIS 194890
USDA TOTA
Common Names Florida Torreya | Savin | Stinking Cedar | Florida Nutmeg | Gopher Wood | Stinking Yew
Associated Scientific Names Tumion taxifolium | Torreya taxifolia
Distribution T. taxifolia ranges primarily along the east side of the Apalachicola River in Liberty County Florida northward to the southern most portion of Decatur County, Georgia (USFWS 1986).
State Rank
State State Rank
Florida S1
Georgia S1
North Carolina SNA
Habitat

The taxon is an extremely rare conifer that once towered fifty feet above the forested ravines of the Apalachicola drainage system in northern Florida (Godfrey 1968, Foote and Jones 1994). An ancient genus of at least 160 million years old in age, species in the genus Torreya were widely distributed across the northern hemisphere during the Jurassic and Pliocene periods. Named for John Torrey, one of America's most distinguished botanists (1796-1783), this is one of the rarest native trees in the USA. Within its very limited range, it has become nearly extinct. There are no large trees left in its native habitats. What survives are a few scattered young saplings or suckers from root systems and bases of destroyed plants.


T. taxifolia is found in the understory of the rich hardwood hammock beech-magnolia and mixed hardwood forest (USFWS 1983, 1984, 1985). Canopy trees in these forests are mostly deciduous, but evergreen hardwoods and conifers are also common (USFWS 1986). This species can also grow on bluffs and woods along the Apalachicola, steep slopes of ravines (mid-slope) with nearly permanent seeps, and rises in calcareous bottoms. In Florida, Torreya species also occur in lower parts of ravine slopes and adjacent floodplains and prefers shady habitats with dark, moist sandy loam of limestone origin.
 

Ecological Relationships

Seed are favored by rodents, although their dispersal capability is unknown. Root system is susceptible to fungi. Prescribed fires may play an important role in maintaining population health (Schwartz and Hermann 1993b), but further research is needed.

Pollinators
Common Name Name in Text Association Type Source InteractionID
Other
Wind Confirmed Pollinator Link

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