Author List: Laurie Blackmore, Lauren Eserman-Campbell, Loy Xingwen, Tanner Biggers, John Evans, Emily E. D. Coffey at the Conservation & Research Department, Southeastern Center for Conservation, Atlanta Botanical Garden
The natural range of Torreya taxifolia is found on ancestral and unceded lands of the Mvskoke (Muscogee / Creek) and Apalachee People. They, along with their ancestors, have been stewards of this unique region throughout generations.
The Florida Torreya (Torreya taxifolia Arn.) is one of North America’s most endangered trees, surviving only in a small remnant of its historic range. Once locally abundant in steephead ravines of the Florida Panhandle and southwest Georgia, the species has experienced a sharp decline since the 1950s from approximately half a million trees to no more than a thousand wild individuals today. Fungal canker diseases, such as those caused by the pathogen Fusarium torreyae, are believed to be the leading cause. Compounding disease pressure, in October 2018, the entire population of Florida Torreya was hit by Hurricane Michael, a Category 5 hurricane. Today, natural reproduction is nearly absent, and the species persists as scattered individuals surviving in deep shade, repeatedly re-sprouting from the base but rarely maturing.
For more than three decades, the Atlanta Botanical Garden (ABG) has worked with the Florida Native Plant Society (FNPS), Torreya State Park, federal partners, and private landowners to safeguard Torreya taxifolia. As this conservation story has unfolded, it has become increasingly clear that the species’ future depends on public–private cooperation—especially the stewardship and access provided by landowners who now host a large proportion of remaining wild trees.
Ashlynn Smith and Emily Coffey monitoring Torreya seedlings.
Uncovering the Critical Role of Public–Private Landscape Co-Stewardship
Between 2018 and 2024, comprehensive surveys on both public and private lands confirmed the presence of 870 living Florida Torreya, with an estimated wild population of 960 individuals. For the first time, consistent survey methods and expanded private-land access enabled a more precise and reliable population estimate, rather than the wide ranges seen previously. Approximately one-third of historically recorded trees died or disappeared in the past decade, likely due to a combination of hurricane impacts, environmental stress, and chronic fungal disease.
Importantly, 55% of all recorded Torreya occur on private lands. Access to privately stewarded ravines and slopes revealed 368 previously undocumented trees, many of which represent unique genetic lineages. This means that understanding population trends, genetic representation, and habitat conditions depends on the participation and cooperation of individual landowners. This work underscores that privately managed forests can sometimes be key to conserving a rare species’ genetic diversity and ecological role, and collective stewardship decisions on these lands have landscape-scale conservation consequences.
Ex Situ Safeguarding: A Critical Repository of Diversity
Because natural regeneration is extremely limited, ex situ conservation has become a cornerstone of recovery planning. ABG maintains an extensive conservation collection of Florida Torreya grown from wild-collected cuttings. This safeguarding collection has grown thanks to support from both public and private landowners. The objective of ex situ conservation is to capture and maintain the full breadth of genetic diversity still present across the wild population.
To date, the ex situ program has produced:
- 1,088 living propagated trees
- Representing 512 genetically unique accessions, many of which are now lost from the wild
To accommodate this growing collection, ABG expanded its Conservation & Safeguarding Nursery in Gainesville, Georgia, from 3 to 7.5 acres, enabling the long-term care of at least two clonal representatives of each genetic lineage. These safeguarded collections function as a living genetic library, essential for:
- preserving irreplaceable diversity
- supplying material for research on disease tolerance
- supporting experimental trials for habitat reintroduction
- maintaining stock for eventual restoration and breeding programs
For conservation horticulturists, this project is far more than simply growing and propagating a rare species. It is the practical backbone of Torreya conservation—where propagation skill, sanitary practice, and provenance documentation come together to build the biological foundation for restoration, disease-resistance breeding, genomic research, and future reintroduction, keeping safeguarding efforts closely aligned with the species’ long-term recovery needs.
Annie, Ashlynn and Heidi in Hurricane gap.
Ecological Monitoring: Effects of Hurricane Michael and Habitat Change
Long-term field monitoring of 40 hurricane-surviving Torreya trees between 2019 and 2023 produced the most detailed ecological dataset for the species to date. We found that increased light from hurricane-induced canopy gaps boosted shoot growth. However, the sudden sun exposure also increased branch mortality and heat stress. In addition, higher ambient temperatures correlated with a greater number of cankers. Finally, we found that forest composition around Torreya shifted toward disturbance-tolerant species, potentially altering long-term habitat suitability. Despite these pressures, 37 of the 40 monitored trees survived for at least five years after the storm, indicating some resilience. However, consistent disease pressure continues to suppress reproductive maturity.
Seed Trials: Evaluating Natural Regeneration Potential
From 2018 to 2023, ABG conducted a seed experiment at Torreya State Park to test germination and survival under natural conditions. Across five sites, 210 seeds were planted with and without protective cages. The results revealed three key insights: herbivore exclusion sharply increased seedling numbers, loose soils promoted germination, and light availability was the strongest predictor of five-year survival. Environmental factors influenced survival but not seedling size, suggesting genetic or maternal effects.
Under ideal conditions, about one in five seeds survived for five years—encouraging, but not enough for large-scale restoration without effective disease management. Still, the study offers practical guidance for seed-based restoration, including where to plant, when protection is needed, and what realistic survival rates look like. If disease can be managed, direct seeding may become a viable tool at carefully selected sites.
Disease Management: A Necessary Next Step
Fungal canker disease remains the primary barrier to recovery. Current evidence indicates that multiple pathogenic fungi are implicated, that these differ between wild and cultivated settings, that disease prevents trees from reaching reproductive size, and that active disease management will be required before any large-scale restoration or augmentation.
ABG has initiated the development of a multi-year fungal treatment plan, including:
- Pathogen identification in wild and ex situ trees
- Controlled fungicide trials at the safeguarding nursery
- Quasi-in situ field trials in cooperation with landowners
- Tissue-culture-based approaches to produce disease-free plant material
- Testing the susceptibility of other tree species from the southern Blue Ridge to this fungus to help inform the safety of translocating Florida Torreya to more northern latitudes; species to be tested include economically and ecologically important tree taxa
For practitioners, this work underscores the importance of pathogen screening, sanitation protocols, and biosecure propagation techniques when working with highly imperiled woody taxa.
The Central Role of Private Landowners
Across every phase of this project, private landowners have been essential partners. Their properties host more than half of all known Torreya, enabling conservationists to locate undocumented trees, collect cuttings, and monitor long-term health. As the work advances into disease management, these same private landscapes will provide near-situ sites to trial fungicide treatments under conditions that mirror the species’ native habitat—an invaluable step that cannot be replicated in greenhouses alone.
Private stewards also help carry the story of this tree into their communities, building awareness and interest that support continued funding. At the same time, effective public–private co-stewardship depends on coordination with researchers and agencies; well-intentioned but unplanned planting in forests or gardens could inadvertently spread disease or undermine recovery goals. What will make the difference is informed, science-based collaboration across all partners.
Monitoring Torreya growth.
Looking Forward
The next phase of Torreya conservation focuses on developing disease treatments, producing clean propagation material, and restoring reproductive capacity. For ecological landscapers, Torreya taxifolia illustrates how applied horticulture and shared stewardship—across both public and private landscapes—can determine the future of a species on the brink.
The authors:
Laurie Blackmore is the Manager of the Conservation & Research Department at the Atlanta Botanical Garden. She is a lifelong conservationist by vocation and avocation, with degrees in forestry (MSc, University of Idaho) and forest management (BSc, University of Washington). At the Atlanta Botanical Garden, she has worked as a grants officer, writer, and manager.
Emily E. D. Coffey is Vice President of Conservation and Research at the Atlanta Botanical Garden, she has grown the conservation program into one of the most recognized in the U.S.—securing over $14.5 million in funding, expanding the team nearly tenfold, and establishing world-class infrastructure, including the Southeastern Center for Conservation.