How often we have seen a beautiful tree die just because it was planted in the wrong location. Not only do trees die but also untold amounts of damage is done to buildings, streets, and walks. Just walk through an older section of town and see how the walkways are heaved and buckled by the tree roots. In places it is not even safe for children to ride bikes or the elderly to walk.
In defense of our ancestors, most of which grew up in the country, they were only planting trees that they were familiar with, the oaks, elms, and maples of the woodland lots. Many trees available today were unheard of 50 years ago. Most cities are covered with silver maples and why not, fast growing, hardy, and best of all requiring little maintenance. To this day, many cities plant silver maples every Spring to replace those that died, a never ending chain. Maybe someday, someone will question why, but I would not hold my breath.
The mighty oaks and stately beech of our woodland forest belong in the countryside. Small urban lots call for small-sized trees. Thanks to testing by Colorado State University, homeowners have a variety of trees that should do well for city living. Their research show the following trees are better choices for city lots:
Acer tataricum ‘Tatarian Maple’
– Shows less iron cholorsis than the widely planted silver or amur maples.
Pyrus ussuriensis ‘Ussurian Pear’
– This is more cold hardly and shows less winter dieback than Bradford Pear.
Malus hybrids
– Five promising crabapple varieties listed with their flower colors, the varieties are Beverly, Centurion, Indian Magic, Red Baron, and Red Splendor.
Prunus armenica mandshurica ‘Manchurian Apricot’
– A well-adapted urban tree that features a striking appearance with a round-headed shape and lush green foliage.
Syringa reticulata ‘Japanese Tree Lilac’
– A slightly larger tree with a rounded crown is notable for its white, 6-12 inch flowers borne in mid-June, and it’s distinctive, reddish-brown, cherry-like bark.
Acer saccharum var. grandidentatum ‘Wasatch Maple’
– Is one of the best small trees for low water landscapes. This tree grows to a height of 30 feet with a 20-foot spread. The leaves are 3-5 lobed, similar to the eastern sugar maple.
Crataequs ambiqua ‘Russian Hawthorne’
– A moderately slow grower, it peaks at 25 feet high and l5 feet wide. The plant’s best features are the small, pinkish-white May flowers, red fruit in the fall, and glossy, deeply lobed leaves.
Urban trees are also often planted along narrow boulevards or in pits usually round or square, with bricks, concrete or metal grates surrounding the trunk base. Trees die if they are unable to get adequate water and oxygen. Since bricks and concrete effectively keep water from seeping into the ground, metal grates are preferable. Even then metal grates must be cut periodically to prevent the grate from girdling the tree.
In our opinion, the best sidewalk pit is an open hole, with a good bedding of mulch surrounding the tree. These are easy to maintain, healthier for the tree, and attractive.
The City of Chicago Urban Planting Ordinance is a prime example of a city’s efforts to provide sound leadership in city forestry management. The City of Chicago requires:
“a minimum width of 11’6″ from the curb to the property line for planting trees in sidewalk pits. The minimum dimensions for the pit itself are 5′ x 5′, but the bigger the better”
They recognize that continuous soil pits are preferable because they provide more room in which roots can grow. The greater soil mass keeps the soil temperature stable, thus the trees roots are less likely to hurt by the extremes of heat and cold.
The City of Chicago recommends the following trees for sidewalk pits:
Callery Pear
– A highly adaptable tree, noted for its white flowers and leathery, lustrous heart-shaped leaves that turn a glossy purple or scarlet in autumn 20-40 feet.
Chanticleer Pear
– This is an upright, narrow tree that has an abundance of white flowers that are less susceptible to late spring freezes because of late blooming. It grows to 35 feet making it another good choice for small spaces.
Thornless Honeylocust
– Fast-growing and takes well to transplanting, it is tolerant of road salt, drought and soil variations. It can grow anywhere from 30-50 feet and its delicate leaves turn bright golden yellow in autumn.
Ginkgo
– Transplants well and is particularly urban tolerant, withstanding heat, pollution, road salt spray and almost any soil condition. Its fan-shaped leaves turn a brilliant yellow in autumn. The ginkgo is slow-growing, but can eventually reach a height of 50-70 feet.
Green Ash
– Noted for it’s compact and glossy foliage crown, the Green Ash grows to a height of 40-50 feet. It transplants well and once established is highly tolerant of drought. Its fall foliage is yellow.
Japanese Tree Lilac
– This small 15-20 foot tree copes well with limited space. It produces an explosion of creamy white flowers the Spring.
Kentucky Coffeetree
– This native Midwestern tree has a coarse picturesque look. It can reach a height of 40-50 feet.
Little Leaf Linden
– Noted for its shiny, small, heart-shaped leaves, the Little Leaf Linden grows 60-70 feet. It has smooth bark and fragrant flowers that bloom sometime in June and July.
Redmond Linden
– This hybrid tree, which grows 40-50 foot, is noted for its heart-shaped leaves, smooth bark, fragrant June flowers and formal pyramidal shape. It is very urban tolerant.
While the Honeylocust and the Kentucky Coffeetree are extremely urban friendly, they are our least favorites because they can be messy in the Fall. We would recommend the Japanese Tree Lilac and Redmond Linden for sidewalk planting and the Manchurian Apricot or one of the crabapple hybrids for urban lots. For further information you may wish to check out TreeLinks or the Morris Arboretum.
