Having lived most of my adult life and my entire childhood in ‘snow country,’ I’m always a little surprised when I see signs of spring at the turn of the year here in western Washington. Spring plants are already beginning to poke through mulch, and hellebores, heather, primrose, and snowdrops are blooming. The season is progressing rapidly. It’s time to check off winter chores on your community forest to-do list.
This year’s seminar series is titled ‘Protecting Trees during Development.’ Whether land is converted to residential or commercial property, most communities require that trees be planted as part of the project. In order for trees to grow, flourish, and provide the benefits which are attributed to them, they need to receive long-term care, and that includes structural pruning.
Late winter is a great time to prune. It is easy to see and evaluate branch structure then address any issues accordingly. While this might be viewed as a budgetary burden, structural pruning within the first 7-10 years after planting will prevent most future problems common to urban trees. (Co-dominant stems, bark inclusion, sign and pedestrian interference, etc.) The good thing about pruning young trees, is that just a few cuts can make a big difference. Compared to large cuts on large trees, pruning when trees are young is a much better return on the time and budget invested in tree care.
So here is a quick checklist of pruning tips:
- Sharpen your tools!
- Review best management practices for pruning shade trees.
- Begin to assess a tree’s structure after it is planted, but wait until it has been in the ground for at least one year before pruning.
- Plan your approach. Assess a tree from the top down before making the first cut.
- Plan before making cuts; no more than 25% of a tree’s canopy should be removed per year.
- Most trees should have a single trunk. Identify the strongest “leader” and prune back any co-dominant branches (competing vertical leaders).
- After removing co-dominants, focus on removing dead, diseased, damaged, and crossing or rubbing branches. (dead branches can be removed at any time)
- It is OK to remove lower branches, but no higher than 1/3 of the total tree height.
- Try to encourage side branches that form angles 1/3 off of vertical; the “10:00” or “2:00” position.
- Trees don’t need to be “shaped.” Species have unique shapes, but if you need to shorten a branch growing outside of an expected silhouette, prune back to a bud or another branch at least 1/3 the diameter of the branch being removed. This will help prevent excessive sprouting.
- No need to use wound dressing. Trees grow around pruning wounds.
- With the exception of the period of time when trees are breaking bud or going dormant (dropping leaves), pruning can be done most times of the year
- prune spring flowering trees after they bloom, if you want a full display of flowers.
And here are some pruning resources:
Video series (14) Training Young Trees: Structural Pruning for Home Gardeners, University of California Extension: https://www.youtube.com/user/trainingyoungtrees/videos?sort=da&flow=grid&view=0
Structural Pruning Cue Card: https://hort.ifas.ufl.edu/woody/documents/RPG%20Tree%20Pruning%20Cue%20Card.pdf
Keys to Good Pruning, Arbor Day Foundation: https://www.arborday.org/trees/tips/keys-to-pruning.cfm
Pruning Shade Trees in Landscapes, University of Florida: https://hort.ifas.ufl.edu/woody/pruning.shtml
Developing a preventive pruning program: Young Trees, E. Gilman, A. Bisson: http://edis.ifas.ufl.edu/ep315
If pruning is on your city annual work plan, let us know if we can help increase your knowledge about the art of shade tree pruning. With a class size of at least 10, preferably with participants from several surrounding communities, we’ll hold a pruning workshop where you live. Sound good? Contact us for details, if you’d like to schedule a class.
By Linden J. Lampman, program manager, DNR Urban and Community Forestry Program