Big Trees Still Needed for Our Landscapes (written in 2001)
Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist
Where have all the big trees gone? In 15 to 20 years that’s a question many people will be asking. For decades, large trees have created a feeling of well-being and comfort in many communities. Area residents who have migrated to this region from other parts of the country can probably recall city streets that were lined with large trees. Where I grew up in Rochester, New York the streets were graced with sugar maples, elms, and Norway maples. Large trees give you a “feeling of place” and help define the character of an area.
We need not look elsewhere for another example. Just drive down the older residential section of Kennewick Avenue, which is lined with large trees. They provide a graceful ambiance to the area even though most of these trees are in poor health due to restricted roots, wood rot, and years of stress. Driving down a street like this, you’re likely to relax a little and envy the people who live there.
This summer I visited the neighborhood where I grew up. There were fewer trees along the street and in front yards. Many of the older trees that had been growing there had been removed and not replaced with similar large species. The neighborhood was stark and much less hospitable. I also visited the area that I later moved to as a teenager. It had been a newer housing development with no large trees, only new plantings. After thirty years, those small trees have grown into big trees. The area was lovely and the homes seemed much more attractive and welcoming. Can you think of a street lined with big trees and how it feels to walk or drive down it?
So why will people in 15 to 20 years be asking where all the big trees have gone? One main reason is our choice of tree species. Campaigns to plant the “right tree in the right place” have sound reasoning behind them. Utility companies have logically recommended using smaller trees when planting near or under utility lines. To decrease the costly pruning required to keep wrongly planted large trees from growing into the lines and to help avoid losses of service from fallen trees and broken branches, planting smaller trees in the right place makes a lot of sense.
You shouldn’t plant a large tree, like a sycamore or a red oak, under utility lines, but there are“right places” for large trees in many of our residential landscapes. Unfortunately, they’re seldom being planted. With the demand for “instant” landscapes and the desire for fast growing trees, species that grow more slowly and become very large over a span of many years aren’t often selected. That’s a shame. Most of the faster growing trees species, such as poplars, don’t survive much past 15 to 20 years. As these newer communities age, many of the faster growing trees will begin to decline and die.
Numerous cities have cut down unhealthy large older trees that posed a hazard to residents and traffic. Large trees have also been removed to allow for growth and expansion. Responsible cities have made commitments to replace removed trees... and to plant trees along new streets in residential and business developments. Considering the maintenance problems that large, older trees caused... uprooting sidewalks, pruning for vehicle clearance, leaf removal, pest management and more, cities have looked for “small” trees with narrower forms to plant along their streets and avenues. While these trees do have merit, they won’t provide big trees for the generations to come. Our children and grandchildren will not be able to enjoy the distinctive beauty of large, old trees and their contribution to our communities.
So what’s the solution? We can’t ignore the definite and sensible need of utility companies and cities to avoid the problems that large trees can create. However, we do need to consider where we can plant large trees and how to plant them correctly to avoid potential problems in later years. Communities should budget adequate money not just for planting trees, but also forpruning and tree health. It’s relatively inexpensive to plant a tree, it costs a lot more to keep it healthy for the years to come.
If you like trees, there are two things you can do to help insure that there will be large trees for future generations. First, encourage your community to plant big trees in suitable situations. Support tree care budgets... trees don’t take care of themselves.
Second, consider your own landscape, and see if a large tree might fit somewhere where it won’t interfere with utility wires. Be sure to consider how tall and how wide the tree you’re planting will become at maturity. If possible, plant the tree where your house will benefit most from the shade in the summer, but be careful not to plant it too close to the structure. Remember the mature size. Select a tree that doesn’t typically have major insect or disease problems. There are no “pest free” trees, but there are more troublesome trees you should avoid.
Here are some of my top picks for big trees to grow in our area.
Big Trees to Consider
Red Oak (Quercus rubra) grows to 75 feet tall. It grows relatively fast compared to many other oaks, but still it’s not a fast growing tree. It has attractive deep red fall color and has relatively few pest or disease problems. It’s also more tolerant of our alkaline soil conditions than pin oak, which should not be planted here. It has attractive furrowed bark. You can see some older red oaks at the Benton County Courthouse in Prosser. These large red oaks have been around for many years and are still beautiful trees.
Red Maple (Acer rubrum) grows to 70 feet tall. This tree has become quite popular because it’s tolerant of a variety of soil conditions including compaction, poor drainage, and excess water. It’s a good durable tree with spectacular orange and red fall color. You can observe young red maples in many area landscapes and parks. They’re one of my favorites and apparently a favorite of many other gardeners too. Don’t plant silver maples that grow very fast. They have weak wood, invasive roots, and no significant fall color.
Japanese Zelkova (Zelkova serrata) grows to 80 feet tall. It’s an attractive tree with a vase-like growth habit and ascending, arching branches, similar to elm trees. It’s in the elm family, but it’s supposedly resistant to Dutch elm disease and elm leaf beetles. It’s tolerant of alkaline soils, and once well established it will also withstand windy and dry conditions. There is one of these on the grounds of the Tri-Cities Country Club. Look for ‘Spring Grove’, ‘Green Vase’, ‘Halka’, or ‘Village Green’. Certain cultivars have moderate fall color. This tree is not extremely common and may be difficult to find locally.
Sweetgum (Liquidambar styraciflua) grows to 75 feet tall. When young, it has a pyramidal shape, but grows into a tree with a more oval or rounded crown. The leaves are thick, glossy and dark green in the summer, turning to brilliant reds and purples in the fall color. The root system will be extensive and needs lots of room to grow, so don’t plant them where there is limited soil or space for roots to grow. The seed “balls” produced by the tree can be quite messy, but there are some cultivars available that produce only limited amounts of the balls. Be aware that there are many different cultivars with varying forms including columnar, shrubby, and shorter forms. Sweetgums are commonly planted in our area. You can see an entire row running along a side walkway next to the main parking lot at the WSU-Tri-Cities campus in Richland.
London Planetree (Plantanus x acerifolia) grows to 100 feet tall and 80 feet wide or more. It is a BIG tree! Often called a “sycamore” it is actually a cross between a sycamore (Plantanus occidentalis) and the Oriental planetree (Plantanus orientalis). It’s advantages are that it’s fast growing, long-lived and has few insect pest problems. It’s tolerant of alkaline, compacted, and droughty soils. It also has attractive flaking bark with a mosaic pattern. It’s disadvantages include abundant very large leaves, the tree’s very large size, its prolific seed balls, and it’s susceptibility to sycamore anthracnose. Two cultivars, ‘Bloodgood’ and ‘Yarwood’ are the best candidates for selection because of their resistance to anthracnose. While I may have disdained this tree in the past, I have to say it’s a very durable tree and tolerant of harsh conditions and poor care, but please plant it only where it has plenty of room to grow and only plant the anthracnose resistant varieties.
Other large trees worthy of consideration include beech (Fagus sylvatica) silver linden (Tilia tomentosa), English oak (Quercus robur), littleleaf linden (Tilia cordata), and river birch (Betula nigra).