Classification and Mapping of Mendocino Cypress (Hesperocyparis pygmaea) Woodland and Related Vegetation on Oligotrophic Soils, Mendocino and Sonoma Counties, California California Department of Fish and Wildlife Vegetation Classification and Mapping Program Authors: Todd Keeler-Wolf, Diana Hickson, Rosie Yacoub, and Mary Jo Colletti January 2019 ABSTRACT Analysis of field samples of woody vegetation collected on and adjacent to nutrient-poor soils of western Mendocino and northwest Sonoma counties established three new vegetation associations of the Mendocino Cypress (Hesperocyparis pygmaea) Woodland Alliance: Hesperocyparis pygmaea – Pinus contorta var. bolanderi / Rhododendron columbianum, Hesperocyparis pygmaea – Pinus contorta var. bolanderi - Pinus muricata / Rhododendron macrophyllum, and Hesperocyparis pygmaea – Pinus muricata / Arctostaphylos nummularia. Additionally, three other associations were also described: Pinus muricata - Chrysolepis chrysophylla / Arctostaphylos nummularia in the Pinus muricata - Pinus radiata Alliance; Arctostaphylos nummularia in the Arctostaphylos (nummularia, sensitiva) Alliance; and Chrysolepis chrysophylla / Vaccinium ovatum in the Chrysolepis chrysophylla Alliance. Two provisional associations in the Sequoia sempervirens Alliance need additional sampling: Sequoia sempervirens – Pinus muricata and Sequoia sempervirens – Hesperocyparis pygmaea. Mapping the vegetation and land cover types on the extent of the oligotrophic soils in what is likely the historical extent of the Mendocino Cypress (Hesperocyparis pygmaea) Woodland and related vegetation reveals a loss of between 20% and 44% of these sensitive vegetation types due to agricultural and urban development. Cover photos: Todd Keeler-Wolf SUGGESTED CITATION: Keeler-Wolf, T., D. Hickson, R. Yacoub and M.J. Colletti. 2019. Classification and Mapping of Mendocino Cypress (Hesperocyparis pygmaea) Woodland and Related Vegetation on Oligotrophic Soils, Mendocino and Sonoma Counties, California. Vegetation Classification and Mapping Program, California Department of Fish and Wildlife, Sacramento, CA. ii CONTRIBUTORS This project and report represents the hard work of many people and organizations. Special acknowledgments are offered to landowners who provided access to their properties, data contributors, field staff, and data analysts. We thank the following people for their many hours in the field collecting data and for obtaining land access: Tamara Gedik and Melissa Kraemer, California Coastal Commission; Peter Rowland and Tina Fabula, California Department of Forestry and Fire Protection (CalFire); Karen Youngblood, Campbell Global; Terra Fuller and Mona Robison, California Department of Parks and Recreation (State Parks); Mario Abreu, Alison Gardener, John Gurley, Nancy Morin, and Renee Pasquinelli, California Native Plant Society (CNPS); Annie Eicher; Adrienne Long; Asa Spade, Wynn Coastal Planning; Teresa Spade, Spade Environmental; Peter Warner; Nicolet Houtz and Louisa Morris, Mendocino Land Trust; Rixanne Wehren, Mendocino Land Trust and consultant; Haley Ross, Mendocino Redwoods Company; Mike Vasey, San Francisco State University; Linda Perkins, Sierra Club and Audubon; Pam Huntley, The Nature Conservancy; and Brett Hall, University of California Santa Cruz Arboretum. Teresa Sholars, CNPS and Professor Emeritus, College of the Redwoods, shared her vast knowledge and collected data, helped train volunteers, and provided lodging for many of the field staff. Dr. William Russell of San Jose State University, Rhiannon Korhummel of WRA, Inc., Tom Bendure of Mendocino Redwoods Company, and Pat Howard, Lori Hubbart, Mary Hunter, Julia Larke, Bill Maslach, and Dorothy Scherer of the Dorothy King Young CNPS Chapter graciously shared their data. California Native Plant Society Vegetation Program staff, including Anne Klein, Julie Evens, and Jaime Ratchford, helped with CNPS chapter vegetation training and sampling. Julie Evens provided vegetation classification review. California Department of Fish and Wildlife (CDFW) Region 1 staff instrumental in the project included Jennifer Garrison, Linda Miller, Angela Liebenberg, Gordon Leppig, Michael van Hattem, Daniel Harrington, Clare Golec, Cheri Sanville, Rick Macedo, Danielle Castle, and Janelle Deshais. CDFW Vegetation Classification and Mapping Program (VegCAMP) staff included Rachelle Boul, Mary Jo Colletti, Catherine Curley, Diana Hickson, Todd Keeler-Wolf, Anne Klein, Aicha Ougzin, Jaime Ratchford and Rosie Yacoub. We received helpful comments on this report from Jennifer Garrison, Teresa Sholars, and Julie Evens. We gratefully acknowledge landowners who allowed us to sample on their property and thank them for sharing their wisdom. We apologize to anyone we may have left off this list unintentionally. iii CONTENTS Abstract ......................................................................................................................................................... ii Suggested citation: ........................................................................................................................................ ii Contributors ................................................................................................................................................. iii Introduction .................................................................................................................................................. 1 Methods ........................................................................................................................................................ 3 Defining the Study and Mapping Area ...................................................................................................... 3 Sample Allocation Method and Field Sampling ........................................................................................ 4 Data Analysis ............................................................................................................................................. 6 Classification .......................................................................................................................................... 6 Ordination .............................................................................................................................................. 7 Mapping .................................................................................................................................................... 8 Accuracy Assessment ................................................................................................................................ 8 Sample Allocation and Field Sampling ................................................................................................... 8 Scoring ................................................................................................................................................... 9 Results ......................................................................................................................................................... 10 Flora ......................................................................................................................................................... 10 Classification ............................................................................................................................................ 10 Ordination ............................................................................................................................................... 14 Mapping .................................................................................................................................................. 19 Accuracy Assessment .............................................................................................................................. 20 Analysis of the historical loss of Mendocino Cypress and related vegetation ........................................... 21 Restrictive estimate ................................................................................................................................. 21 Soil-inclusive estimate ............................................................................................................................. 23 Literature Cited ........................................................................................................................................... 25 FIGURES FIGURE 1. The Mendocino Cypress Woodland study area ............................................................................. 4 FIGURE 2. An example of a sample allocation map ....................................................................................... 4 FIGURE 3. Field samples collected for the Mendocino Cypress Woodland project ....................................... 5 FIGURE 4. Indicator species analysis ............................................................................................................... 6 FIGURE 5. Example of the accuracy assessment allocation ........................................................................... 8 FIGURE 6. Locations of accuracy assessment samples .................................................................................. 9 FIGURE 7. NMS ordination of 165 samples using presence/absence species data ...................................... 14 FIGURE 8. Ordination of the core plant associations restricted to the oligotrophic soils ...........................