Archive for July, 2010

Pruning Young Shade Trees

Wednesday, July 21st, 2010

How you prune a shade tree during its first few years will have a profound effect on its shape, strength, and life span. Proper pruning during the early years will save you money, and produce safer, healthier, more beautiful, and easier-to-maintain trees. Keys to proper pruning are:

1. Prune early in the life of a tree, but don’t start until the third year or so, unless there are broken limbs or twigs that need removal immediately.

2. Identify the best leader and lateral branches before you begin pruning, and remove any defective parts before pruning to form.

3. Keep pruning tools sharp. A clean cut assures faster healing of the pruning cut.

4. Prune with an eye to the future:

a. Remember that a branch does not move up the trunk as a tree grows. A branch 5′ off the ground now will still be 5′ off the ground                ten years from now – only thicker and longer than it is now.

b. Try to visualize the future shape that is desired and prune limbs that won’t fit that shape.

c. Remove branches that will cause an obvious problem in the future (e.g. a double leader).

d. Prune as lightly as possible, and only when there is good reason to prune.

e. Never remove more than one-fourth of a trees crown in one season.

Click on image to enlarge.

More On Tree Values

Monday, July 5th, 2010

Last time, I talked a little bit about the value of trees in the urban environment, noting that the greatest values of trees are the environmental benefits provided by the stately denizens. Right after I posted that blog, the July (2010) issue of the Missouri Conservationist Magazine published an article entitled “Street Trees Pay Us Back,” by Bill Graham and Helene Miller. In their article, they talk about how street trees not only provide environmental benefits, but they also report on how these benefits translate into economic value. I recommend the article to anyone interested in finding out how the economic benefits are calculated in the Kansas City area, and why the authors were inspired to say “It’s as if our urban trees were growing dollar bills instead of leaves.” Some of the information is truly mind boggling.

The value of trees varies from place to place, but the 415,000 trees growing on city rights-of-way in Kansas City provide an average benefit of $123 per tree, or more than $51 million annually! North Kansas City averages about $190 per tree per year, while Liberty averages  about $90 per tree per year due to smaller tree sizes overall and many that are just recovering from severe storm damage a few years back.

Some other fascinating findings in the article are:

1. Street trees that shade asphalt pavement can save a city up to 60% on road maintenance costs over 30 years.

2. Cars parked in the shade pollute the air less than vehicles parked in the open. The article explains why.

3. Tree-lined streets increase public safety. Studies show that drivers will slow down by up to 15 mph when driving such a thoroughfare because the trees make them think the street is narrower even when it’s not.

The article covers many more benefits and what they are worth in economic terms. Check it out. If you’re not a subscriber, The Conservationist can be found in the nearest public library, or can be viewed online at MDC’s website: MissouriConservation.org. You can also subscribe online, and The Conservationist is free to Missouri households.

Check out this tag placed on one of the KC study trees outlined by Graham and Miller. It was a project done in conjunction with The Heartland Tree Alliance; just one of the organizations extolling the virtues, and benefits, of trees in the urban environment. Pretty illuminating, eh?