Trees and Parking Lots

Where are the roots going to go?

Often we need to park our cars to go to our favorite coffee shop or grocery store or even our own driveway.
Most of the time a suitable tree is planted in a small " tree island" for aesthetics and some shade. Sometimes large trees are preserved during the construction phase and they do well over time. During this construction phase it's important to set up a tree protection zone (TPZ).
In this zone there should not be anything but good soil and tree roots. Even better is to add a few inches of mulch and irrigate the tree periodically as construction continues. The TPZ should give the tree roots as much room as possible. (Remember the trees roots are growing in a plate type system, there really isn't any such thing as a tap root on an establishes tree.) It's recommend a foot of space from the trunk per inch of diameter of tree. For example, a 5 inch diameter tree should have 5ft radius of TPZ. If you have a larger tree, say 40 inches in diameter, this would require 40ft radius. Not always feasible in a confined location.
So what do you do? Hire a Certified Arborist that cares about trees and find the best approach for the tree and the construction project. It's often possible to find a solution.

Below are some pictures of a Doug Fir that has a parking lot around it.

Very sparse foliage, lots of dead branches. A sad sign.

There was no TPZ, and the soil that had roots in it was removed with grading and then compacted to lay asphalt. The likelihood this tree survives a couple more years is low.

Why?Absorbing roots were removed in the grading process and the remaining roots compacted in the soil.
Soil compaction removes vital air space in the soil that the trees utilize. Without it the roots deteriorate and are subject to pathogens and decay. This can eventually result in a weakened anchoring root system and perhaps the tree being windthrown. You'll notice trees begin to lose leaf or needle and large branches begin to dieback.  Bummer.

Take the time to care for your trees. They care for you in many ways (though they do it without thinking about it.)

Large dead branches resulting from soil compaction/lowering grade.

Not much room for tree roots. But I can park my car.