Starhill Forest Arboretum is operated under a management plan which provides direction for the growth and development of plant holdings and associated facilities and functions. The plan defines guidelines for the arboretum and describes roles for the participating parties. It outlines the manner in which the living collections will develop and grow, and it charts the content of the arboretum and the general nature of its research and educational programs for the future. This policy is subject to the management plan, and is presented here as an extension and interpretation of the plan. The founders and curator serve as the collections committee to implement the plan and to ensure that the collections, especially the signature collections (currently Quercus), will remain significant worldwide and useful for research programs and study.  


The mission of Starhill Forest is to promote an understanding and appreciation of trees and nature through programs that integrate science and the liberal arts, focusing upon native landscapes and well-documented plant collections arranged aesthetically and ecologically in a naturalistic design for professional and public study and quiet enjoyment. 


The living collections are the primary focus of the arboretum. There are taxonomic (generally genus-specific) collections listed by priority, which are determined using the criteria outlined below. There also are habit-specific, habitat-specific, aesthetic, and other collections. 

The collections include hardy woody plants, herbaceous plants, non-hardy (conservatory) plants, and natural habitat communities. All collections in the arboretum are to be displayed within an aesthetically pleasing informal garden context and/or a natural-appearing, ecologically sound habitat.

The arboretum’s curated collections are divided into several categories which define the level of collection depth, breadth, and documentation as well as priorities for management and preservation. The arboretum provides the greatest resource commitment to the signature collections, which are already or are intended to become nationally or internationally significant.  Primary collections are scientifically significant at a regional (state or county) level and managed accordingly. General collections add to the beauty and diversity of the arboretum and to its genetic reservoir. Other features, including champion and significant trees and aquatic areas, contribute in various ways to the whole.


  1. These collections are already, or are intended to become, comprehensive collections of distinction recognized nationally or internationally.
  2. Curation of these collections is central to the mission of the arboretum and will receive the highest priority.
  3. These are collections for which the arboretum has made or will make a long-term commitment, and they are to be maintained in their depth and diversity indefinitely for multiple generations.
  4. Non-destructive scientific investigations involving these collections will be encouraged and will include research, evaluation, documentation, propagation, cultivar selection, and dissemination of research results.
  5. Signature collections will attempt to include all significant taxa from wild origins that are adapted to local environments or horticultural management, augmented as necessary by accessions ex horto
  6. Divestiture of a signature collection, or components thereof, will proceed only after another institution has agreed to accept responsibility and has made a commitment to preserve the genetic material represented or the accessions involved have been replicated elsewhere on the arboretum grounds.
  7. Signature collections should be submitted for recognition as Plant Collections Network (PCN) National Collections under the auspices of the American Public Gardens Association, and managed accordingly if accepted. (The Quercus collection already is certified under this program.)


The only current signature collection is the Quercus collection, including species accessions, provenance tests, cultivars, hybrids, and non-hardy oaks and related species wintered in greenhouses, as well as associated library documents. This collection already is known worldwide and should continue to be the primary focus of management and budget for the arboretum.



  1. These collections may focus upon or exhibit aesthetic values or diversity within selected families or genera. Usually those taxa adapted well to general conditions in the arboretum will be most strongly represented.
  2. Primary collections represent valuable genetic resources at the regional level but do not include the depth and breadth of the signature collections.
  3. Divestiture of a primary collection, or significant components thereof, should not be considered until the value of the collection or component has been carefully weighed against the reason for removal. Sanitation, hazard or dead tree removal, selective thinning of a portion of an accession, and unavoidable construction impact are examples of such potential reasons.

Current examples of primary collections include Carya, Juglans, Pinus, Rhus, Carpinus, Crataegus, and Ostrya, as well as provenance demonstration plantings such as the Populus tremuloides grove. Some of the genera included under the general collections category may be significant enough, although small in number, to be given the funding and management priority of primary collections.


  1. These collections include more limited numbers of taxa within each genus but a much higher number of genera than the signature and primary collections. They also include exemplar specimens and unusual taxa.
  2. Genetic selections may be less important than aesthetic and educational attributes when choosing plants for these collections, as long as taxonomic accuracy is ensured. Nonetheless, as some of these collections expand or become the focus of future botanical study they may move into the primary collection category; thus, full documentation remains important. 
  3. Even within general collections, documented wild-source material shall be obtained when possible.

Current examples of general collections include Picea, Ulmus, Celtis, Acer, Fagus, Syringa, Castanea, and Aesculus. Many monotypic or restricted genera also fit this category, such as Torreya, Leitneria, Amorpha, Asimina, Liriodendron, Hemiptelea, Cotinus, Fontanesia, Cladrastis, Chionanthus, Zelkova, Forestiera, Maclura, Cudrania, Eucommia, Toona, and Sassafras. Some of these would be important enough to warrant inclusion in a primary or signature collection if their numbers were larger, and their prioritization should reflect this. A variety of subtropical and tropical taxa that are wintered in the greenhouses also are included in this category, such as Firmiana simplex, Eriobotrya japonica, Aesculus californica, Ficus carica, Ungnadia speciosa, Laurus nobilis, and assorted Agaves and other desert plants.

Criteria for Accession

  1. A taxon considered for accession should add meaningfully to the comprehensiveness of the collection or the aesthetic, historic, or scientific attributes of the site.
  2. The taxon should provide the possibility to support research opportunities which the arboretum or its cooperators can undertake.  
  3. Accession and management of the taxon should fit within the arboretum’s staff time, building and land facilities, equipment capacity, and financial resources.
  4. The taxon should be appropriate to the cultural attributes of the site (e.g., drought or flood tolerant as needed and adaptable to local temperature extremes, soils, and levels of insolation and exposure).
  5. The taxon, if non-native, should not carry significant risk of becoming invasive beyond the reasonable capacity of the staff to control recruitment.
  6. Trees, and genera consisting primarily of trees, will be given priority in the development of the arboretum’s collections. Shrubs, vines, and herbaceous plants will be incorporated into the landscape design for visual or wildlife effect and may be included for ex-situ conservation or study purposes. 
  7. Sufficient curatorial support (at least one full-time, qualified staff person and funding) is provided to acquire, develop, maintain, study, and disseminate findings associated with signature and primary plant collections, and to maintain significant trees and the general collections.
  8. A “friends” support organization is established to provide volunteer labor, visitor assistance, and fund-raising. Gifting of plants or other donations to augment collections will be considered through the Friends organization with oversight from the Collections Committee. 
  9. Internships, work-study opportunities, and volunteer activities will be implemented for the dual purpose of enhancing participants’ skills and knowledge as well as benefitting the arboretum. 
  10. Each accession will be managed whenever possible to provide connections to and synergies with other programs (e.g., education, cultivar development, conservation science, and aesthetic benefits).
  11. Collecting will emphasize source-documented wild-collected material and typical exemplars where possible, as opposed to cultivars and ex-horto accessions. All such collecting will be responsive to ethical concerns such as trespass, CITES, and minimization of disturbance to natural habitats.


A critical management component in curating all collections is verification of the authenticity of plant identity and maintenance of suitable data resources. All reasonable attempts will be made to document and record available provenance data for each accession, including but not limited to botanical name, propagation/collection method, year of acquisition, permanent location in the arboretum, and detailed source data. These records will be maintained in a searchable digital format maintained by the arboretum curator. Herbarium and photographic voucher systems are planned for the future.

Collection Management

All accessions will be inspected frequently by the director and/or curator as part of the ongoing maintenance process, and at least annually. Condition, affirmation of phenotypic taxonomy, presence of labeling, need for pruning or release from competition, and general observations will be made at such inspections. Plants and plant records will be protected from loss or physical damage to the greatest extent reasonably possible. Decisions regarding plants which are found to be degraded to the extent that their usefulness is compromised, or which are found to be misidentified, will be made in accordance with the management plan and this collections policy. Actions may include relabeling, restorative work, propagation and replacement, interim retention, or deaccessioning, in accordance with the guidelines of the management plan.  


The highest priority for access will relate to research and educational programs. As one of the world’s most significant Quercus collections, access for oak research will be given top priority. Other compatible uses will be accommodated as much as possible within the constraints of staffing and funding, in accordance with the management plan. Plant propagules may be made available to other public gardens, researchers, and serious collectors to the extent that the arboretum, its collections, and its budget and staff can accommodate such uses. All harvest of such propagules will be made under the direct supervision of the curator or director.