Classification of Vegetation Associations from the Marin County Open Space District in Marin County, California By Jennifer Buck and Julie Evens California Native Plant Society Vegetation Program 2707 K Street, Suite 1 Sacramento, CA 95816 In cooperation with Mischon Martin Marin County Department of Parks and Open Space 3501 Civic Center Drive, Rm. 260 San Rafael, CA 94903 March 2010 Photos on Cover: Top Left: Serpentinite outcrop at Cascade Canyon Preserve with Adenostoma fasciculatum– Arctostaphylos glandulosa–Ceanothus jepsonii/Calamagrostis ophitidis Association in the foreground Top Right: Chaparral at Lucas Valley Preserve with Adenostoma fasciculatum–Arctostaphylos glandulosa Association in the foreground and mixed oak and bay woodland on following slopes Bottom Right: Oak woodland at Lucas Valley Preserve with Quercus lobata–Quercus agrifolia– Umbellularia californica Association Bottom Left: Serpentine grassland at Ring Mountain Preserve with Nassella pulchra–Lolium multiflorum–Trifolium spp. Association intermixed with other grassland types b TABLE OF CONTENTS Introduction ............................................................................................................................. 1 Background and Standards .................................................................................................... 1 Methods .................................................................................................................................. 1 Study Area .......................................................................................................................... 1 Figure 1. Area map of Marin County Open Space District preserves. ................................2 Field Sampling .................................................................................................................... 3 Vegetation Classification..................................................................................................... 3 Description Writing.............................................................................................................. 5 Results .................................................................................................................................... 7 Species and Vegetation Data.............................................................................................. 7 Table 1. Vegetation samples conducted in 2008 at Marin County Open Space preserves. ........................................................................................................................................................8 Table 2. Vegetation classification of alliances and associations from 19 preserves of the Marin County Open Space District, California ........................................................................9 Tree Overstory Vegetation Descriptions ............................................................................... 18 Aesculus californica Alliance............................................................................................. 18 Aesculus californica–Umbellularia californica/Mimulus aurantiacus Association............18 Arbutus menziesii Alliance ................................................................................................ 20 Arbutus menziesii Association.................................................................................................20 Arbutus menziesii–Quercus agrifolia Association ................................................................22 Arbutus menziesii–Umbellularia californica(–Lithocarpus densiflorus) Association........24 Arbutus menziesii–Umbellularia californica–Quercus kelloggii Association.....................26 Arbutus menziesii Alliance (no association defined for sample) ........................................28 Chrysolepis chrysophylla Alliance..................................................................................... 30 Chrysolepis chrysophylla/Vaccinium ovatum Association ..................................................30 Cupressus sargentii Alliance............................................................................................. 32 Cupressus sargentii/Arctostaphylos montana Association .................................................32 Lithocarpus densiflorus Alliance........................................................................................ 34 Lithocarpus densiflorus–Arbutus menziesii Association......................................................34 Pseudotsuga menziesii Alliance........................................................................................ 36 Pseudotsuga menziesii Association .......................................................................................36 Pseudotsuga menziesii-Chrysolepis chrysophylla-Lithocarpus densiflorus Association38 Pseudotsuga menziesii–Quercus agrifolia Association.......................................................40 Pseudotsuga menziesii–Umbellularia californica/Polystichum munitum Association.....42 Pseudotsuga menziesii–Umbellularia californica/Toxicodendron diversilobum Association .................................................................................................................................44 Pseudotsuga menziesii Alliance (no association defined for sample)...............................46 Quercus agrifolia Alliance ................................................................................................. 48 Quercus agrifolia/Adenostoma fasciculatum Association ...................................................48 Quercus agrifolia/Grass Association ......................................................................................50 Quercus agrifolia/Toxicodendron diversilobum/Grass Association ...................................52 Quercus agrifolia–Arbutus menziesii–Umbellularia californica Association .....................54 Quercus agrifolia–Quercus kelloggii Association .................................................................56 Quercus agrifolia Alliance (no association defined for sample) .........................................58 i Quercus douglasii Alliance................................................................................................ 60 Quercus ×eplingii Association .................................................................................................60 Quercus douglasii Alliance (no association defined for sample)........................................62 Quercus garryana var. garryana Alliance or Habitat......................................................... 64 Quercus garryana var. garryana Alliance (no association defined for sample) ...............64 Quercus kelloggii Alliance................................................................................................. 66 Quercus ×moreha Association ................................................................................................66 Quercus kelloggii–Arbutus menziesii–Quercus agrifolia Association................................68 Quercus lobata Alliance .................................................................................................... 70 Quercus lobata–Quercus agrifolia/Grass Association .........................................................70 Quercus lobata–Quercus agrifolia/Toxicodendron diversilobum Association..................72 Quercus lobata–Quercus agrifolia–Umbellularia californica Association .........................74 Quercus lobata Alliance (no association defined for sample).............................................76 Quercus spp. Alliance ....................................................................................................... 78 Mixed oak/Grass Association ..................................................................................................78 Quercus wislizeni Alliance ................................................................................................ 80 Quercus wislizeni/Arctostaphylos glandulosa Association..................................................80 Quercus wislizeni/Heteromeles arbutifolia Association .......................................................82 Quercus wislizeni–Arbutus menziesii/Toxicodendron diversilobum Association.............84 Sequoia sempervirens Alliance......................................................................................... 86 Sequoia sempervirens/Polystichum munitum Association..................................................86 Sequoia sempervirens–Acer macrophyllum–Umbellularia californica Association.........88 Sequoia sempervirens–Arbutus menziesii/Vaccinium ovatum Association .....................90 Sequoia sempervirens–Chrysolepis chrysophylla/Arctostaphylos glandulosa Association .................................................................................................................................92 Sequoia sempervirens–Lithocarpus densiflorus/Vaccinium ovatum Association............94 Sequoia sempervirens–Pseudotsuga menziesii–Umbellularia californica Association..96 Sequoia sempervirens–Umbellularia californica Association .............................................98 Umbellularia californica Alliance ..................................................................................... 100 Umbellularia californica (Pure - Coastal) Association........................................................100 Umbellularia californica/Polystichum munitum Association ..............................................102 Umbellularia californica–Acer macrophyllum