Author: sphillips
Look Out for Invasive Pests
Tree damaging insects such as the emerald ash borer, gypsy moth, Japanese beetle, and Asian longhorned beetle are threatening urban forests in Idaho. City workers and arborists play an important role on the front lines of the battle to keep invasive pest species out of our state. Being able to identify the pests and their patterns of damage associated with them will enable arborists to notify the Animal Plant Health Inspection Service (APHIS) if an outbreak occurs in their area.
At the APHIS website you can do your research by looking at picture galleries of the pests in all their life stages and the damage they do. Information about the biology of the pests, regulations, controls and restoration after the damage, is also available on the website.
Insects aren’t the only organisms that are likely to damage to our urban forests. Diseases such as European larch canker and thousand cankers disease are potential threats. The APHIS website has information on these diseases that you can use for identification.
To report a pest or disease in Idaho you can contact the State Plant Health Director. Prompt notification of the presence of invasive insects and diseases can help stop or contain outbreaks and limit damage to Idaho’s urban and community forests.
Right Tree, Wrong Place
By Gerry Bates
IDL Southern Idaho Community Forestry Assistant
As I travel the state working with Idaho communities, I often see tree planting projects that make me scratch my head and wonder why a particular situation occurred. I realize that every tree is planted with good intentions, but good tree selection doesn’t only have to consider whether or not the tree will be successful, but also the location in which it’s planted.
Recently, I was asked to visit the City of Victor to look at a situation where a subdivision developer had used narrowleaf cottonwoods as street trees. The cottonwoods were planted next to a walking path and roadway, lining the entire subdivision. Once the subdivision had been completed, the city assumed maintenance of the right-of-way and the trees began to grow. In a short time (in tree years), the shallow root system of the cottonwoods began to lift up the asphalt of the walking path and in some cases, even the adjoining street. The walking path had been lifted in irregular 6-inch high ridges, making bicycling or handicapped access almost impossible.
The city asked if there were mitigation measures, so we discussed root barriers, root pruning, etc. But the nature of the roots of the species in question made it evident that any measure short of removal would be a short term fix. Therefore, I recommended that the trees be removed and replaced with an appropriate species.
When the subdivision was being planned, the public works director questioned the use of cottonwoods as street trees. Unfortunately, the project moved forward anyway. After the city took possession, the anticipated conflict became reality. I would like to encourage all Idaho cities to work closely between departments. Planning and Zoning should have a close relationship with Public Works, Parks, Streets and so on. Take the time to see if language in your tree ordinance and land use codes is compatible and be sure to have open lines of communication between departments, developers, public officials, and residents. Most issues can be resolved before implementation of a project – it just takes the time and forethought to make it happen.
A Bit of Wisdom: Preventing a Double Top
A very wise and experienced arborist once said, “Besides planting at the right depth (not too deep), the best thing you can do to avoid tree problems is to prevent double tops on young trees. All it takes is a pair of hand shears and minute of your time.”
The result of this simple process is that a tight fork will be prevented. Whether co-dominant leaders or two side branches, tight forks will likely result in included (ingrown) bark that acts like a wedge and creates a weak spot in the tree. Tending to this issue in the first few years of a tree’s life will save time and money later on – and prevent an accident if a split occurs and half of the offending pair falls to earth.
Trees Reduce Our Stress, so Help Relieve Theirs
Researchers have linked trees to human health benefits ranging from faster recovery from operations to safer pregnancies. The key factor may be that they reduce stress and therefore problems like high blood pressure.
Urban trees are under stress, too, for two primary reasons: (1) They are planted outside the natural environment in which they evolved, and (2) Tough growing conditions make them more vulnerable to insects and diseases. You can help by:
- Watering correctly
- Preventing compaction
- Carefully selecting the right trees to plant
- Planting at the correct depth
- Mulching
- Providing adequate growing space for roots
- And implementing other good arboricultural practices
Invest in Tree Education
Few people who work with trees have an innate knowledge of how to best care for them. Also, science and experience are always adding new findings. Whether college educated in arboriculture or working up in the ranks of field work, everyone needs continuing education to best serve the interests of their community. Here are four good ways to economically invest in the continuing education of tree board members, workers and supervisors:
- Provide funding for attendance at one of the conferences or workshops that are listed on this page.
- Participate individually or as a group in webinars.
- Purchase and share texts on arboriculture or urban forestry.
- Download and share a complete set of Tree City USA Bulletins.
Words Make a Difference: Trimming vs. Pruning
It is more than “political correctness” to adjust words we use as times change. Words convey meaning, so it is important to be as accurate and timely as possible in how they are used. Here are two examples in the field of
urban forestry: Trimming and pruning are not the same.
We trim hedges, like mustaches, but we prune trees – or should! The difference is that trimming, or shearing, is the indiscriminate removal of unwanted parts of the plant so that it conforms to a desired shape. Pruning, on the other hand, is the selection of specific branches to be removed for some specified reason.
Another term that has been changing in recent years involves hazards. What was once called hazard tree evaluation is now better termed risk evaluation. In the former, there seemed to be an assumption that hazards exist.
This may or may not be true. Instead, a different concept is a bit like crossing a street – there is almost always some risk involved, but how much? The purpose of a tree examination is to determine the level of risk compared with the level of tolerance for that risk given the specific circumstances such as size and nature of defects if any, the tree’s location, value of the tree, the presence or absence of so-called “targets” (people, buildings, etc.). As evaluations become more sophisticated and the stakes from damage become higher, it is increasingly important to use qualified personnel to do the work.
There are now training avenues available that lead to what is called TRAQ (Tree Risk Assessment Qualification) credentials. Communities are urged to take advantage of this qualification either in-house or when contracting with arborists.
Volunteers Can Get It Done
Volunteers are already busy people and in all cases they have hearts of gold and a sincere desire to make the world a better place in which to live.
Americans contribute millions of hours each year to helping with good causes. As more of our population ages, many more good people are looking for ways to spend their time after leaving decades of work for retirement.
Many cities in Idaho are tapping this population to help with planting and maintaining their public trees in healthy condition. Young people, too, often seek ways to productively contribute and they not only can help, but at the same time learn about the benefits of trees and the care they need.
Community Forestry offers many opportunities for volunteerism. Lay people can plant trees and shrubs, spread mulch, water, prune young trees, distribute doorknob hangers, staff information booths, help with inventories and provide a number of other valuable services.
Twenty years ago, Boise Parks and Recreation launched their Tree Steward program, and the program is stronger than ever today. For the past two decades dedicated tree enthusiasts have volunteered their time to help maintain trees in Boise’s rights-of-way. The volunteers are trained by professional arborists from Boise Community Forestry to prune and train Boise’s young trees and do other maintenance activities. Stewards with more experience mentor new people in the program. In 2017, Boise’s Tree Stewards worked 697 hours and pruned 1,297 trees. The service they provide is invaluable in helping to grow strong healthy trees that reduce maintenance costs later and contribute to the Treasure Valley’s tree canopy for years to come.
If you are not currently using volunteers in your tree program, please consider initiating a program like Boise’s or one of the other communities that are doing this effectively. Contact one of IDL’s community forestry assistants for contact information or assistance in setting up a new program. If you already use volunteers, don’t forget to thank them! Take time to recognize your volunteers and let them know how much they are appreciated. People working in your community don’t expect much in return, just don’t waste their time and do find ways to provide recognition and thanks. This can be as simple as being mentioned during a city council meeting, or something more elaborate like a BBQ or an annual article in the local newspaper.
Encouraging Tree Planting on Private Property
What about trees on private property? Now that would be a contentious topic, especially in Idaho. But if the cleaner air, storm water retention, and other benefits provided by trees are a public good, and with approximately 80 percent of a community’s trees being in yards or other private parcels, this part of the ‘urban forest’ has to be considered.
Here are four ways cities can encourage tree planting and care without appearing to be the big ogre from government!
- Help subsidize planting shade trees purchased at local nurseries on private property.
- Sponsor traditional tree ‘give-aways’ at fairs and Arbor Day celebrations.
- Encourage planting by highlighting the benefits of trees in local media and/or door hangers.
- Visit Arbor Day Foundation’s website, arborday.org/energy. If your utility is a partner in the energy-saving tree program, you are entitled to a free shade tree for your property.
What About Street Right-of-Way Trees?
About 80% of a community’s trees are in residential yards on private property. The majority of others are on street rights-of-way. Do residents in your community know what they can and cannot do with those trees? Many do not.
- Make sure the rules are clear in the city ordinance. Is a permit needed to plant or remove a tree? Who is responsible for street and sidewalk clearance, or other pruning?
- Publicize the rules at least annually – by newspaper ads or a letter to the editor.
- Print door hangers and use Scouts or other service groups to place them at residences.
- Include occasional slips with utility bills or other mailings.
Communication prevents conflicts!
Go Easy on Tree Treatments
When pestilence arrives at our doorstep, defend we must! But a good guide to prevent unintended consequences and to protect environmental quality is: Use the minimum treatment that still gets results.
- Use good practices to keep trees healthy, and monitor regularly.
- Prune infected or damaged parts instead of using sprays when possible.
- When spraying use well-timed, low-toxicity spot spraying.
- Look into biopesticides, horticultural oils and soaps instead of petrochemicals. For more information, contact the Bio-Integral Resource Center at www.birc.org.