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HomeMy WebLinkAboutItem 5a. 2025 Engineering Standards Update to the Street Trees Major List TREE COMMITTEE AGENDA REPORT SUBJECT: 2025 ENGINEERING STANDARDS UPDATE, STREET TREES MAJOR LIST (8020) FROM: Walter Gault, Urban Forestry Program Coordinator / City Arborist Phone Number: (805) 781-7578 Email: wgault@slocity.org 1.0 RECOMMENDATION Review proposed updates to the Street Trees Major List (Engineering Standard 8020) and provide recommendations to the City Arborist. 2.0 BACKGROUND Municipal Code Section 12.24.040 states that the Tree Committee, with the assistance of the Public W orks and Community Development departments, has developed and will maintain a Street Tree Master List and a Street Trees Major Streets List which shall be adopted by resolution of the City Council and shall be on file in the Public Works Department, Engineering Standards. These documents shall specify the species of trees suitable and desirable for planting in certain areas in order to establish a diverse urban forest. 3.0 DISCUSSION The City is updating its Engineering Standards in 2025. Updates to the City’s Master Tree List (Attachment A) that were reviewed by the Tree Committee in October 2022 but have yet to be reflected in the Street Trees Major List (Attachment B). Staff is proposing the changes proposed to the Street Trees Major List below (and highlighted in Attachment C) to correct errors on the document, update cultivars to reflect nursery availability , and make some minor revisions based on staff observations. Additionally, some species on the Street Trees Major Lists are either no longer available or are no longer suitable for the City’s climate or urban environment. Below is a list of the recommended changes proposed by staff. Links are provided that give more detailed information about the tree species discussed below. Replace Platanus x hispanica  It’s widely used on the list, but it is no longer in nursery production  Replace with Platanus x acerifolia ‘Columbia’, a more anthracnose resistant cultivar than ‘Bloodgood’  At creek crossings use Platanus racemosa Meeting Date: 2/24/2025 Item Number: 5a Time Estimate: 30 minutes Page 25 of 35 Item 5a Remove Lagerstroemia (Crape Myrtle)  No longer on the Street Tree Master List Update Ginkgo references  Ginkgo is utilized as a specific ‘Fairmont’ cultivar and then broadly  Adjust all to be Ginko biloba ‘Princeton Sentry’, a faster growing cultivar Remove Metrosideros excelsa  Not a performer in SLO’s climate  Remove it from Downtown accent trees list Remove Magnolia grandifolia ‘little gem’ and Magnolia ‘Majestic Beauty’ for all entries  Not a suitable street tree due to root damage  Susceptible to aphids and scale  Consider replacing ‘Little Gem” with Michelia doltsopa, a similar looking species with low root damage potential. Remove Fagus sylvatica (European Beech)  High water use, not suitable for climate Remove Pinus canariensis (Canary Island Pine) and Hesperocyparis macropcarpa (Monterey Cypress)  Not desirable as street trees Adjust Quercus (oak) entries to be broader (e.g. Quercus sp. “evergreen”)  Quercus ilex (Holm Oak) is susceptible to sooty mold on its leaves and has epicormic sprouts along trunk  Quercus rubra (Red Oak) and palustris (Pin Oak) are eastern oak species 4.0 ACTIONS 4.1 Recommend support of the proposed updates to the Street Trees Major Streets List (Engineering Standard 8020) and propose adjustments. This action may include recommendations to modify the proposed updates. 4.2 Continue the review to a hearing date certain, or uncertain. An action continuing review of the updates to the Street Trees Major Streets List (Engineering Standard 8020) should include direction to staff on pertinent issues. 5.0 ATTACHMENTS A - Updated Proposed Master Tree List B - Street Trees Major Streets Engineering Standard 8020 C - Engineering Standard 8020 Highlighted Page 26 of 35 All Trees for San Luis Obispo Botanical Name Existing City Tree New Addition City Tree Private yard ok MULGA Acacia aneura x BAILEY ACACIA Acacia baileyana x BLACKWOOD ACACIA Acacia melanoxylon x WEEPING ACACIA Acacia pendula x SHOESTRING ACACIA Acacia stenophylla x PINEAPPLE GUAVA Acca sellowiana x BIGLEAF MAPLE Acer macrophyllum x (native) BOX ELDER Acer negundo x EVERGREEN MAPLE Acer paxii x CALIFORNIA BUCKEYE Aesculus californica x AFRICAN FERN PINE Afrocarpus falcatus x PEPPERMINT TREE Agonis flexuosa x SILK TREE Albizia julibrissin x SYDNEY RED GUM Angophora costata x MARINA MADRONE Arbutus 'Marina'x KING PALM Archontophoenix cunninghamiana TC ? QUEENSLAND PITTOSPORUM Auranticarpa rhombifolia x HONG KONG ORCHID TREE Bauhinia x blakeana x FLAME BOTTLE TREE Brachychiton acerifolius x QUEENSLAND LACEBARK Brachychiton discolor x KURRAJONG Brachychiton populneus x MEXICAN BLUE PALM Brahea armata TC ? GUADALUPE PALM Brahea edulis TC ? PAPER MULBERRY Broussonetia papyrifera TC ? PINDO PALM Butia odorata TC ? LEMON BOTTLEBRUSH Callistemon citrinus x WEEPING BOTTLEBRUSH Callistemon viminalis x INCENSE CEDAR Calocedrus decurrens x CAPE CHESTNUT Calodendrum capense x GOLD MEDALLION TREE Cassia leptophylla x RIVER SHE-OAK Casuarina cunninghamiana x City of San Luis Obispo — Master Tree List Page 27 of 35 All Trees for San Luis Obispo Botanical Name Existing City Tree New Addition City Tree Private yard ok City of San Luis Obispo — Master Tree List BRAZILIAN CEDARWOOD Cedrela fissilis x ATLAS CEDAR Cedrus atlantica x DEODAR CEDAR Cedrus deodara x FLOSS SILK TREE Ceiba speciosa x EUROPEAN HACKBERRY Celtis australis x NETLEAF HACKBERRY Celtis reticulata x CHINESE HACKBERRY Celtis sinensis x CAROB TREE Ceratonia siliqua x EASTERN REDBUD Cercis canadensis x WESTERN REDBUD Cercis occidentalis x MEDITERRANEAN FAN PALM Chamaerops humilis x DESERT WILLOW Chilopsis linearis x CHINESE FRINGE TREE Chionanthus retusus x CAMPHOR TREE Cinnamomum camphora x GHOST GUM Corymbia aparrerinja x LEMON-SCENTED GUM Corymbia citriodora x RED FLOWERING GUM Corymbia ficifolia x SPOTTED GUM Corymbia maculata x SMOKE TREE Cotinus coggygria x CARROT WOOD Cupaniopsis anacardioides x INDIAN ROSEWOOD Dalbergia sissoo x HOP BUSH OR A'ALI'I Dodonaea viscosa x TRIANGLE PALM Dypsis decaryi TC ? TEXAS EBONY Ebenopsis ebano x JAPANESE BLUEBERRY TREE Elaeocarpus sylvestris x BRONZE LOQUAT Eriobotrya deflexa x JAPANESE LOQUAT Eriobotrya japonica x SOUTH AFRICAN CORAL TREE Erythrina caffra x NAKED CORAL TREE Erythrina coralloides x COCKSPUR CORAL TREE Erythrina crista-galli x SILVER DOLLAR TREE Eucalyptus cinerea x Page 28 of 35 All Trees for San Luis Obispo Botanical Name Existing City Tree New Addition City Tree Private yard ok City of San Luis Obispo — Master Tree List RED-CAP GUM Eucalyptus erythrocorys x WHITE IRONBARK Eucalyptus leucoxylon x NICHOL'S WILLOWLEAFED PEPPERMINT Eucalyptus nicholii x SILVER DOLLAR GUM Eucalyptus polyanthemos x RED IRONBARK Eucalyptus sideroxylon x SWAMP MALLEE Eucalyptus spathulata x CORAL GUM Eucalyptus torquata x EDIBLE FIG Ficus carica x INDIAN LAUREL FIG OR CHINESE BANYAN Ficus microcarpa x RUSTY-LEAF FIG Ficus rubiginosa x AUSTRALIAN WILLOW Geijera parviflora x MAIDENHAIR TREE Ginkgo biloba x SILK OAK TREE Grevillea robusta x GOLDEN TRUMPET TREE Handroanthus chrysotrichus x PINK TRUMPET TREE Handroanthus heptaphyllus x SOUTH AFRICAN WILD PLUM Harpephyllum caffrum TC ? TECATE CYPRESS Hesperocyparis forbesii x MONTEREY CYPRESS Hesperocyparis macrocarpa x TOYON Heteromeles arbutifolia x SWEETSHADE Hymenosporum flavum x JACARANDA Jacaranda mimosifolia x CHINESE FLAME TREE Koelreuteria bipinnata x GOLDENRAIN TREE Koelreuteria paniculata x PRIMROSE TREE Lagunaria patersonia x SWEET BAY Laurus nobilis x AUSTRALIAN TEA TREE Leptospermum laevigatum x BRISBANE BOX Lophostemon confertus x CATALINA IRONWOOD Lyonothamnus floribundus subsp. Aspleniifolius x SOUTHERN MAGNOLIA Magnolia grandiflora x MAYTEN TREE Maytenus boaria x HEATH MELALEUCA Melaleuca ericifolia x Page 29 of 35 All Trees for San Luis Obispo Botanical Name Existing City Tree New Addition City Tree Private yard ok City of San Luis Obispo — Master Tree List FLAXLEAF PAPERBARK Melaleuca linariifolia x PINK MELALEUCA Melaleuca nesophila x PAPERBARK OR CAJEPUT TREE Melaleuca quinquenervia x PRICKLY MELALEUCA Melaleuca styphelioides x CHINABERRY Melia azedarach x DAWN REDWOOD Metasequoia glyptostroboides x NEW ZEALAND CHRISTMAS TREE Metrosideros excelsa x SWEET MICHELIA Michelia doltsopa x OLIVE TREE Olea europaea x DESERT MUSEUM PALO VERDE Parkinsonia x 'Desert Museum'x CANARY ISLAND DATE PALM Phoenix canariensis TC ? PYGMY DATE PALM Phoenix roebelenii TC ? FRASER PHOTINIA Photinia x fraseri x CANARY ISLAND PINE Pinus canariensis x MONDELL PINE Pinus eldarica x ALEPPO PINE Pinus halepensis x ITALIAN STONE PINE Pinus pinea x TORREY PINE Pinus torreyana x CHINESE PISTACHE Pistacia chinensis x MEXICAN SYCAMORE Platanus mexicana x CALIFORNIA SYCAMORE Platanus racemosa x YEW PINE Podocarpus macrophyllus x HOLLYLEAF CHERRY Prunus ilicifolia x EVERGREEN PEAR Pyrus kawakamii x COAST LIVE OAK Quercus agrifolia x ENGELMANN OAK Quercus engelmannii x HUNGARIAN OAK Quercus frainetto x HOLLY OAK Quercus ilex x VALLEY OAK Quercus lobata x BUR OAK Quercus macrocarpa x CORK OAK Quercus suber x Page 30 of 35 All Trees for San Luis Obispo Botanical Name Existing City Tree New Addition City Tree Private yard ok City of San Luis Obispo — Master Tree List ISLAND OAK Quercus tomentella x SOUTHERN LIVE OAK Quercus virginiana x INTERIOR LIVE OAK Quercus wislizeni x SILVERLEAF OAK Quercus hypoleucoides x PEPPER TREE Schinus molle x AFRICAN SUMAC Searsia lancea x FIREWHEEL TREE Stenocarpus sinuatus x QUEEN PALM Syagrus romanzoffiana TC ? BRUSH CHERRY Syzygium australe x TIPU TREE Tipuana tipu x WINDMILL PALM Trachycarpus fortunei TC ? WATER GUM Tristaniopsis laurina x CHINESE ELM Ulmus parvifolia x CALIFORNIA LAUREL Umbellularia californica x CALIFORNIA FAN PALM Washingtonia filifera TC ? MEXICAN FAN PALM Washingtonia robusta TC ? CHITALPA x Chitalpa tashkentensis x SHINY XYLOSMA Xylosma congesta x Page 31 of 35 Page 32 of 35 Revised List  Revised List  New Border              MAY 2018    STREET TREES  MAJOR STREETS  8020 KH  MH  1‐18  BL  BL  11‐06  JDL  WAP  1‐98  Page 1 of 2 Note: Percentages refer to mixture of tree types in project area DOWNTOWN DISTRICT % Ficus microcarpa 10 Quercus ilex 20 Quercus rubra (Q. coccinea) 30 Gingko biloba 'Fairmont' 30 Olea europaea 'Swan Hill'-grafted fruitless 10 Downtown Accent Trees Jacaranda mimosifolia Magnolia grandiflora 'Little Gem' Corymbia ficifolia Cassia leptophylla Metrosideros excelsa Lagerstroemia hybrid* BROAD STREET % Monterey St. to Pacific St. Lophostemon confertus 60 Gingko biloba 'Fairmont' 40 Pacific St. to High St. Platanus x hispanica 40 Pistacia chinensis 40 Ginkgo biloba 'Fairmont' 20 High St. to City Limits Platanus x hispanica 30 Quercus palustris 20 Pistacia chinensis* 20 Quercus rubra (Q. coccinea) 15 Lophostemon confertus 15 *Substitute-south of Orcutt At creek crossings Platanus x hispanica 100 CALIFORNIABLVD. % Cal Poly to Mill St. Koelreutaria bipinnata 25 Quercus rubra (Q. coccinea) 25 Cinnamomum camphora 30 Ulmus parvifolia 20 Mill St. to San Luis Dr. Ulmus parvifolia 30 Metrosideros excelsus 40 Lophostemon confertus 30 San Luis Dr. to Johnson Ave. Quercus agrifolia 60 Ulmus parvifolia 40 At creek crossings Platanus x hispanica 100 FOOTHILL BLVD. % Magnolia "Majestic Beauty" 30 Koelreutaria bipinnata 30 Platanus x hispanica 40 At creek crossings Platanus x hispanica 100 GRAND AVENUE % Magnolia 'Majestic Beauty' 50 Platanus x hispanica 50 HIGUERA STREET (east end) % California Blvd. to Santa Rosa St. Use Downtown Accent Trees HIGUERA STREET (Downtown) % Santa Rosa St. to Nipomo St. Use Downtown District HIGUERA STREET (west end) % Nipomo St. to Madonna Rd. Use Downtown Accent Trees Madonna Rd. to City Limit Pinus canariensis 30 Hesperocyparis macrocarpa 30 Hymenosporum flavum 20 Quercus (Red Oak subgenus)1 20 JOHNSON AVENUE % Hwy. 101 to SPRR underpass Magnolia 'Majestic Beauty' 20 Pistacia chinensis 30 Quercus palustris 30 Hymenosporum flavum 20 UPRR underpass to Laurel Lane Quercus agrifolia 20 Pistacia chinensis 20 Ulmus parvifolia 20 Hymenosporum flavum 20 Quercus rubra (Q. coccinea) 20 Laurel Lane to Orcutt Rd. Koelreutaria bipinnata 20 Quercus rubra (Q. coccinea) 20 Ulmus parvifolia 20 Jacaranda mimosifolia 20 Hymenosporum flavum 20 LAUREL LANE % Platanus x hispanica 50 Quercus suber 20 Jacaranda mimosifolia 15 Gingko biloba 15 LOS OSOS VALLEYROAD % Lophostemon confertus 20 Quercus tomentella 20 Fagus sylvatica 20 Quercus agrifolia 20 Pinus caneriensis 20 MADONNA ROAD % Pinus canariensis 25 Pistacia chinensis 25 Quercus agrifolia 25 Quercus rubra (Q. coccinea) 25 MARSH STREET % Use Downtown District MARGARITA AVENUE % Platanus x hispanica 30 Hymenosporum flavum 30 Quercus palustris 40 MONTEREY STREET % Use Downtown District ORCUTTROAD % Pistachia chinensis 60 Lophostemon confertus 20 Quercus agrifolia 20 At creek crossings Platanus x hispanica 100 PRADO ROAD % Platanus x hispanica 40 Pinus canariensis 30 Quercus palustris 30 SANTA ROSA STREET % Highland St. to Murray St. Quercus agrifolia 80 Pistacia chinensis 20 Murray St. to Marsh St. Pistacia chinensis 30 Koelreutaria bipinnata 20 Ficus microcarpa 10 Lophostemon confertus 30 Jacaranda mimosifolia 10 At Creek intersections Platanus x hispanica 100 SOUTH STREET % Tristaniopsis laurina 20 Jacaranda mimosifolia 20 Ginkgo biloba 'Fairmont' 20 Platanus x hispanica 20 Quercus palustris 20 TANKFARM ROAD % East of Broad St. Platanus x hispanica 50 Lophostemon confertus 20 Eucalyptus torquata 30 West of Broad St. Platanus x hispanica 25 Cinnamomum camphora 25 Quercus agrifolia 25 Quercus rubra (Q. coccinea) 25 Page 33 of 35 Page 34 of 35 Page 35 of 35