Tree Inventory & EAB

Yes, we are tired of the cold and snowy weather too.

While we wait for the weather to turn and the snow to melt we move to our next project. It is time to update our tree inventory.

Yesterday we spent the morning training our staff on tree identification and the items needed for the inventory.

We split the group into four groups of two to crawl the property and touch every tree. First we have to identify each tree by species. Next we measure the diameter of the tree to determine the age. Then we observe the tree and grade in on a scale of 1-4 (1-Poor, 2-Fair, 3-Good, 4-Excellent).

There should be no poor rated trees because of years of removing them or maintaining them to a healthier state. Fair rated trees are ones with drought stress or physical stress such as storm damage. Most trees will be rated Good due to consistent pruning. We expect more Excellent trees than the last inventory done in 2014 due to our plan.

Why do an inventory?

This is a great time update records and maintain goals with the tree management plan. Touching each tree on the property allows us to carefully inspect every tree. Most trees are visually inspected from a distance each year, unless they demand specific care. One of the other benefits to the inventory is to better prepare for known stresses in the future. One stress we are preparing for is the invasion of the Emerald Ash Borer (EAB).

As you may know, the insect has been identified in Boulder and Westminster. The insect will arrive in Denver some time soon, but it is unclear when. In preparation of EAB we are taking a few steps to ready for the insect. Evaluating each Ash tree on the property is critical to make the right call for each tree. Pinehurst has over 200 ash trees on the property, so it is important to have a plan in place.

Ash trees are popular trees on the Front Range. They are fast growing trees that were cheap and highly adaptable to our soils. Since Denver does not have many native trees, planting ash trees over the years became popular to increase shade and texture values in many neighborhoods, parks and golf courses. The downside to these trees is that the require a significant amount of maintenance. With their fast growth pattern, they require frequent pruning and with late spring snows they can incur a lot of snow weight damage.

When the EAB gets to town they usually sniff out the weaker or more mature trees first. They burrow underneath the bark and eat the tree from the inside until it dies.

The most common and most effective step to perform again EAB is to remove ash trees. An inventory and health evaluation will determine which trees should be removed from the property first. Removing the "low hanging fruit" will assist with the EAB to skip over our property and find more desirable ash trees elsewhere.

Some of the trees removed can be replaced with a different species in the nearby areas. Once the inventory is complete we can determine which species need to be planted and where on the property. In 2020 we will be planting more trees than the property has seen in almost ten years.

Some ash trees might be worth saving, at least in the short term. Young or mature ash trees that score a higher value due to location or health could be worth saving. There is one insecticide application that has shown some promising results. It is an application that is required every two years for the life of the tree.This can be a costly process especially once the EAB arrives, they do not go away. EAB can live in other trees but are not as devastating.

Most likely once the EAB gets to Denver, most if not all ash trees will be gone in 20-30 years. Once we notice that the EAB is below I70 we will begin to treat the ash trees we deem as salvageable. However we will have a back up plan in place if the chemical treatment is not enough to keep the tree alive.

Since we are planning to be golfing at Pinehurst for many generations, ultimately it is wise to plan on not having any ash trees on the property someday. This is a great opportunity to continue to diversify and strengthen our tree population.