Large Trees to Use in the Urban Landscape. Dr. Laura G. Jull Dept. of Horticulture UW-Madison

Transcription

1 Large Trees to Use in the Urban Landscape Dr. Laura G. Jull Dept. of Horticulture UW-Madison

2 Urban Environment: Created by Humans

3 Problems with Monocultures Monocultures: increased exotic pest problems Chestnut blight Dutch elm disease Emerald ash borer Others: oak wilt, dogwood anthracnose Urban landscape dominated by relatively few species Readily available in trade Easy to grow Desirable ornamental characteristics Tough, urban tolerant trees Propagated vegetatively, less genetic diversity

4 Plant Selection in Urban Areas Low number of urban tolerant trees and shrubs available, few are invasive, undesirable due to structural problems or fruit litter Norway maple Amur maple Black locust Siberian elm Tree-of-heaven White mulberry Silver maple Poplars Northern catalpa Nut bearing trees: walnuts, hickories

5 Urban Tolerance Able to withstand: heat, drought, deicing salts, soil compaction, high ph, poor drainage and aeration, low fertility, air pollution, restricted rooting area

6 Diversity is the Key Broader tree diversity needed Guard against possibility of large-scale devastation by native and exotic pests Don t replace one species with large quantities of another species: Freeman maples over planted! Wisconsin DNR tree planting guidelines Plant no more than 20% of a family: i.e. Betulaceae Plant no more than 10% of a genus within a family: i.e. Betula lenta, Ostrya virginiana, Carpinus caroliniana, Corylus colurna Plant no more than 5% of a species or cultivar within a genus: i.e. Betula lenta, Betula nigra, Betula papyrifera, Betula populifolia

7 Diversity is the Key Scatter throughout city to achieve spatial and biological diversity Species Cultivars Clones Have diverse age class of trees Average life expectancy for urban trees: yrs., downtown: 7 yrs. Short life span often direct result of failure to plant trees properly, vandalism, poor growing conditions

8 Diversity is the Key Plant the right tree in the right place Cold hardy Pest resistant Heat and drought tolerant Urban tolerant: adaptable to poor soils Road salt tolerant (if near streets) Not invasive Available in trade Match design intent Maintain diversity, no monocultures Aesthetically pleasing There is no such thing as a perfect tree!

9 Plant the right tree in the right place Enough space for growth of roots/branches Minimum tree terrace of 8 for large trees, 6-8 for medium sized trees and 4-6 for small sized trees Lack of space for both roots and shoots leads to maintenance problems and structural damage Diversity is the Key

10 Examples of Large Trees for Urban Areas

11 Acer miyabei Morton : State Street Miyabe maple (zone 4a) Another one is JFS-KW3AMI : Rugged Ridge

12 Acer Warrenred: Pacific Sunset maple (zone 4b) Other cultivars JFS-KW202 : Crimson Sunset Keithsform : Norwegian Sunset

13 Celtis occidentalis: common hackberry (zone 3b) Common Cultivars Chicagoland JFS-KSU1 : Prairie Sentinel (columnar) Windy City

14 Corylus colurna: Turkish filbert, Turkish hazelnut (zone 4b)

15 Ginkgo biloba: ginkgo, maidenhair tree (zone 4b) Plant only male cultivars! Autumn Gold JFS-UGA2 : Golden Colonnade Magyar The President : Presidential Gold Princeton Sentry

16 Gleditsia triacanthos var. inermis: thornless honeylocust (zone 4a) Common Fruitless Cultivars/Trademarks Draves : Street Keeper (narrower, nearly seedless) Harve : Northern Acclaim Impcole : Imperial PNI 2835 : Shademaster Skycole : Skyline

17 Gymnocladus dioica: Kentucky coffeetree (zone 4a) Common Male Cultivars/Trademarks Espresso J.C. McDaniel : Prairie Titan Kentucky Colonel Stately Manor

18 Phellodendron amurense Longenecker : Eyestopper corktree (male, zone 4a)

19 Platanus x acerifolia Morton Circle : Exclamation! London planetree (zone 5a)

20 Quercus bicolor: swamp white oak (zone 4a)

21 Quercus bicolor JFS-KW12 : American Dream swamp white oak Also, Bonnie and Mike : Beacon is columnar

22 Quercus bimundorum Crimschmidt : Crimson Spire oak (zone 4a)

23 Quercus bimundorum JFS-KW2QX : Skinny Genes oak (zone 4a) Other cultivars Midwest : Prairie Stature Tabor : Forest Knight JFS-KW1QX : Streetspire

24 Quercus schuettei: swamp bur oak (zone 4a)

25 Quercus macrocarpa: bur oak (zone 3b)

26 Quercus macrocarpa JFS-KW14 : Cobblestone bur oak

27 Quercus macrocarpa JFS-KW3 : Urban Pinnacle bur oak

28 Quercus macdenielli Clemons : Heritage oak (zone 4a)

29 Quercus muehlenbergii: chinkapin oak (zone 4b)

30 Quercus warei Long : Regal Prince oak Also: Quercus warei Nadler : Kindred Spirit, both zone 4b

31 Taxodium distichum: baldcypress (zones 4-6 varies) Common Cultivars/Trademarks Mickelson : Shawnee Brave (zone 4b)

32 Tilia Redmond : Redmond linden (zone 4a, but NO road salt)

33 Ulmus americana: American elm (zone 3a) DED American elm resistant cultivars Jefferson Lewis and Clark : Prairie Expedition New Harmony Princeton Valley Forge

34 Ulmus parvifolia: lacebark elm, Chinese elm (zone 5a)

35 Ulmus hybrids: hybrid elms (zone 4b) Morton : Accolade Morton Glossy : Triumph

36 Ulmus Frontier : Frontier elm (zone 5a)

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38 Dr. Laura G. Jull Dept. of Horticulture 1575 Linden Dr. University of Wisconsin-Madison Madison, WI Phone: (608) Fax: (608) (best way to reach me)