Treecology’s 6 Step Cost-Benefit Analysis of Emerald Ash Borer Planning

For HOA’s & Townhomes (this is a sample explanation, not specific for any property)

Step 1: Inventory all Ash Trees

1. Calculate how many ash trees on site (volume).
2. Calculate total percentage of ash trees on site as compared to all other species (diversity). Performing a GIS Inventory can provide the volume, diversity and location of ash trees on site. A GIS Inventory can also assist in the short-term and long-term management of the ash trees.

Step 2: Ash Tree Condition Assessment

1. Measure the size of each ash tree (trunk diameter).
2. Assess the individual health of each ash tree. There is a direct relation between the health of a tree and the effectiveness of treatment. Ash trees with a poor health ranking should not be treated.
3. Assess the structure of each ash tree for long-term structural viability. Ash trees that have major branching concerns or high potential for failure should not be considered. The ash tree (both pictures to the right) is an example of a tree that should not be considered a long-term viable tree due to the major splitting trunk.
4. Each tree should be given a ranking for location. If a tree is providing higher value specifically due to its location, it should have a higher location ranking.

Step 3: Determine individual and overall ash Tree Value

Tree Value = (Size) x (Health %) x (Structure %) x (Location %) x (Ash tree value per inch diameter)

1. Since there is no current way that an ash tree can survive an Emerald ash borer infestation with treatment, Tree Value represents the “cost of doing nothing”. Since all untreated ash trees will be killed from EAB, the entire Tree Value will be lost, plus the cost of removals.   Treating and protecting ash trees help retain the value of the trees while eliminating the cost of removal and replacement.

Step 4: Calculate the Value Differential

Value Differential = Tree Value – (cost of tree removal + cost of replacement)

1. For trees less than 5 inches in trunk diameter, there will be no Value Differential since smaller ash trees can be replaced. In other words, Tree Value = cost of removal & replacement.
2. For trees greater than 5 inches in trunk diameter, there will always be a Value Differential.   Since 5” trees are commonly the largest that can be planted in most cases, any ash larger than 5” in diameter will have a difference in value. The larger the ash tree, the greater the Value Differential.

*Some tree types will be available via tree spading in larger sizes than 5” but may be limited due to exact growing location (may not have access to plant).

Step 5: Assess treatment options

1. Soil applications are generally less expensive than trunk injections and provide 1 year of EAB protection. There are restrictions on how much chemical can be applied per acre per year.
2. Trunk injections are more expensive, but provide 2 years of protection. There are no chemical limitations, but injections will cause minor damage to the ash when drilling holes for injection sites.

Step 6: Calculate the Treatment Value (Value Differential factoring treatment pricing)

1. This calculation will identify how many years ash trees can be treated until the cost of treating ash trees exceeds the excess value of replacing the tree with a 5” replacement (cost of treatment > Value Differential).

Due to the increase in tree growth every year, there will be a yearly increase in Tree Value of approximately $200 / inch diameter. The cost of EAB treatment will also increase by $3-4 per inch. The increase in value will outgain the increased cost of treatment, so the Treatment Value increases over the course of many years.