Brad Withrow-Robinson, Forestry & Natural Resources Extension Agent, Benton, Linn and Polk Counties.

For those so inclined, pruning season is now open.

There are many reasons people pick up a saw or loppers to prune up their trees in young stands.   The most common motivations I hear are accessibility, aesthetics and fire resistance/prevention.  Even pruning up just a single- eight foot “lift” can serve any or all of those objectives. 

People want to be able to walk freely around the place without fighting through dense brush the whole way. So many prune to open trails or corridors. This allows them to get to favorite spots more easily, or just get around and see how things are doing. It lets them enjoy the property more (daily walks or bird watching) and also to more easily take care of tasks like spot spraying invasive weeds. Pruning a whole block of trees improves not just access but opens up the line of sight. It quickly changes the look and feel of a young stand and gives the stand an open aesthetic that many people like.

Some people prune up a young stand to increase its fire resistance by getting flammable branches up off the ground. This may be a particularly strong motivation if their property borders a public road, in which case it might make sense to also pull back the pruning slash a few rows in to help keep the ground bare.

There are also some people who are inspired by the thought of their trees producing clear, knot-free wood in the years to come. That objective requires a series of lifts to a short log length (20ft) on selected trees, but deserves a separate article.

Pruning does take some time and exertion, but is pretty straight forward if you follow a few simple rules:

• If pruning into the live crown, you should get it done from the late fall to late winter, rather than summer, as I cautioned last summer. The bark is now tight and insect pests such as the sequoia pitch moth are less likely to be attracted to wounds made in the winter. Pruning dead branches is ok any time.
• Prune close, but not flush with the trunk. [See photos below]. This prevents injury to both the bole of the tree and the branch collar. The collar is the raised area at the base of the branch. Leaving the collar allows the tree to heal over the pruning wound more quickly. It is better to leave a stub than cause injury to collar or bole. Something to keep inmind if using power tools.
• When pruning young trees, be careful not to be too enthusiastic. The rule of thumb is to leave at least half the tree’s total height in live crown.
• Be mindful of potential sun scald. Factors increasing damage risk include: edge trees with SW exposure, drought conditions, pruning in late summer before the rains, leaving the minimum live crown ratio.

So you pruning enthusiasts, get out there and get some exercise while feeling good about the gym membership fee you are not paying.

Enjoy!