Conservation Assessment for Yellowwood (Cladrastis kentukea (Dum.-Cours.) Rudd) Steven R. Hill, Ph.D. Division of Biodiversity and Ecological Entomology Biotic Surveys and Monitoring Section 1816 South Oak Street Champaign, Illinois 61820 Prepared for the U.S.D.A. Forest Service, Eastern Region (Region 9), Shawnee and Hoosier National Forests INHS Technical Report 2007 (28) Date of Issue: 7 May 2007 Cover photo: Cladrastis kentukea (Dum.-Cours.) Rudd, from the Nyugat-Magyarországi Egyetem Botanikus Kertje page, Botanic Garden of the University of Sciences, Budapest, Hungary http://columbia.nyme.hu/~novenytan/botkert/kepek/Cladlute/Cladlute.htm This Conservation Assessment was prepared to compile the published and unpublished information on the subject taxon or community; or this document was prepared by another organization and provides information to serve as a Conservation Assessment for the Eastern Region of the Forest Service. It does not represent a management decision by the U.S. Forest Service. Though the best scientific information available was used and subject experts were consulted in preparation of this document, it is expected that new information will arise. In the spirit of continuous learning and adaptive management, if you have information that will assist in conserving the subject taxon, please contact the Eastern Region of the Forest Service - Threatened and Endangered Species Program at 310 Wisconsin Avenue, Suite 580 Milwaukee, Wisconsin 53203. 2 Conservation Assessment for Yellowwood (Cladrastis kentukea (Dum.-Cours.) Rudd) Table of Contents Acknowledgments............................................................................................................................4 Executive Summary.........................................................................................................................5 Nomenclature and Taxonomy..........................................................................................................6 Description of the Species..…...........................................................………..................................7 Habitat and Ecology.........................................................................................................................8 Distribution and Abundance..........................................................................................................11 Protection Status............................................................................................................................13 Life History....................................................................................................................................14 Population Biology and Viability..................................................................................................15 Potential Threats............................................................................................................................17 Research and Monitoring...............................................................................................................19 Restoration.....................................................................................................................................20 Summary........................................................................................................................................21 References......................................................................................................................................22 Websites Consulted........................................................................................................................25 Contacts..........................................................................................................................................26 Appendix 1. Representative specimens of Cladrastis kentukea examined or cited in the literature...............................................................................….....………………….........28 Appendix 2. The distribution of Cladrastis kentukea in the United States. Information from herbarium specimens and the literature.....………………………....................................30 Appendix 3. Natural Diversity Database Element Ranking System..............................................31 3 Conservation Assessment for Yellowwood (Cladrastis kentukea (Dum.-Cours.) Rudd) ACKNOWLEDGMENTS I would like to thank the staffs of the United States Forest Service, Shawnee and Hoosier National Forests, for the opportunity to compile these conservation assessments and for their invaluable assistance with data and field opportunities. Beth Shimp and Steve Widowski have been particularly helpful in facilitating these cost share agreements. I would also like to thank the grants and contracts staff of the Illinois Natural History Survey and the University of Illinois, Champaign, for their assistance with logistics necessary to complete these reports. Curators of several herbaria, cited in the appendices to this report, were very helpful in allowing access to the collections to obtain data on this plant. Several people also assisted by contributing information on this locally rare plant, especially Mike Homoya in Indiana, and Mike Vincent in Ohio. This material is based upon work supported by the U.S.D.A. Forest Service, Eastern Region, under Cost Share Award No. AG03-CS-11090804-024. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the author and do not necessarily reflect the views of the U.S.D.A. Forest Service, Eastern Region. 4 Conservation Assessment for Yellowwood (Cladrastis kentukea (Dum.-Cours.) Rudd) EXECUTIVE SUMMARY This Conservation Assessment is a review of the taxonomy, distribution, habitat, ecology, and status of Yellowwood, Cladrastis kentukea (Dum.-Cours.) Rudd, throughout the United States and Canada, and in the U.S.D.A. Forest Service lands, Eastern Region (Region 9), in particular. This document also serves to update knowledge about the potential threats, and conservation efforts regarding Yellowwood to date. Yellowwood is a small tree in the bean family that grows to 15 (-20) m tall, with yellow heartwood, thin smooth bark, alternate, pinnately-compound leaves, and showy, fragrant clusters of white flowers that appear in the spring. The species is found in portions of the eastern United States and in adjacent Ontario, Canada, in nutrient-rich upland forests and calcareous bluffs often located on or at the base of north-facing slopes. While it has been recorded historically from twenty states and one Canadian province, its distribution is irregular and discontinuous. It is thought to have been historically (and currently) native to just thirteen states, and the other occurrences are a result of the establishment of widely cultivated individuals. Yellowwood is listed as Endangered in Illinois, and as Threatened in Indiana. It is included on the Watch List for species of conservation concern in Georgia, Mississippi, Missouri, and North Carolina, it is a species of Special Concern in Alabama, and it is of Regional Concern in South Carolina. Currently, Yellowwood has no formal federal protection status. Yellowwood is included on the Regional Forester Sensitive Species list (RFSS) for the Shawnee National Forest but not the Hoosier National Forest, where it has not been found. Globally, this species has been ranked as apparently secure, but it is a North American endemic, an ancient relict with a limited overall range, and it appears to be declining overall in the wild. It could face extirpation in the wild in several states if it is not properly protected. In addition to species listed as endangered or threatened under the Endangered Species Act (ESA), or species of Concern by U.S. Fish and Wildlife Service, the Forest Service lists species that are Sensitive within each region (RFSS). The National Forest Management Act and U.S. Forest Service policy require that National Forest System land be managed to maintain viable populations of all native plant and animal species. A viable population is one that has the estimated numbers and distribution of reproductive individuals to ensure the continued existence of the entity throughout its range within a given planning area. The objectives of this document are to: -Provide an overview of the current scientific knowledge on the species. -Provide a summary of the distribution and status on the species range-wide and within the Eastern Region of the Forest Service, in particular. -Provide the available background information needed to prepare a subsequent Conservation Approach. 5 Conservation Assessment for Yellowwood (Cladrastis kentukea (Dum.-Cours.) Rudd) NOMENCLATURE AND TAXONOMY Scientific Name: Cladrastis kentukea (Dum.-Cours.) Rudd [1972] Common Names: Yellowwood; Yellow-wood; Yellow Wood; Kentucky Yellowwood; American Yellowwood; Virgilia Synonymy: Sophora kentukea Dum.-Cours. [basionym – 1811] Virgilia lutea Michx.f. [1813] Cladrastis fragrans Raf. [1824] Cladrastis tinctoria Raf. [1825] Virgilia kentukensis Dum.-Cours. ex Raf. [1825, as Virgilia kentuckensis] Cladrastis albiflora Raf. [1836] Cladrastis lutea (Michx.f.) K.Koch [1869] Class: Magnoliopsida (Flowering Plants - Dicotyledons) Family: Fabaceae (= Leguminosae; The Bean Family) Plants Code: CLKE (USDA NRCS plant database, W-1) http://plants.usda.gov/ The legume genus Cladrastis Raf. contains a single species in North America north of Mexico. The genus is a small one, and six other similar species