Most people know that trees yield many benefits; however, the value of trees is different.

Registered Consulting Arborists® are regularly retained by legal or insurance professionals, property managers, and concerned homeowners for matters that involve an often misunderstood topic; the value of trees. These conversations often begin with, “I have a situation,” followed by an explanation of a tree loss or damage scenario. In tree damage cases, questions tend to lean toward future tree health and safety, but also tend to miss the value of damage. On the other hand, in cases where total loss of a tree are concerned, the general question often posed is, “What’s a tree worth?” Whereas, the question that should be asked is, “What is THIS specific tree worth?”

Before going any further, it is probably best to get a couple of basic definitions out of the way. Although often related, there is a difference between value and benefits.
• A benefit is the profit(s) or advantage(s) gained from something
• The value of something refers to its worth or importance

Human Interest

Importantly, the defining relationship, or commonality between the two definitions is people. Simply, without people to perceive the benefits of a thing (advantages or profits) and no one to pay for (or value) a thing , both concepts have no meaning. Thus, the easiest way to appraise a thing (assess value or worth) is to assess how much people are generally paying for the thing requiring appraisal. In other words, what does it cost to buy a given thing.

Unfortunately for the value of trees, there does not seem to be a huge market for a 50-150ft. shade tree growing on a private property. We cannot simply visit eBay or Amazon, nor call our local nursery to check the going price for a 70ft willow oak or white pine tree, installed. Even if it were possible to readily obtain direct replacement costs for mature trees, it’s not likely that this would provide the most accurate (or reasonable) measure of current value. After all, with enough resources, undoubtedly, you can have a large tropical palm tree installed in a Northeastern location in no time. That does not mean that it will live for more than a season, it simply means that someone spent a remarkable sum of money for whatever purpose. As an amenity tree, a tropical palm tree in the Northeast may have little value. As a prop for a high-budget movie however, I imagine there would be significant repercussions to the tree’s premature loss.

This begs the question, how do consulting arborists appraise the value of trees when they are damaged or destroyed? To answer that question, we need to review some background and history.

History of tree appraisal

People have been arguing over the value of trees for many, many years. Just imagine two farmers a couple of centuries ago arguing over whether an apple tree’s value was only in its current crop, all its future crops, or all of its future crops plus lumber. Over time, this value would evolve to include the loss of certain amenity benefits, such as the utility of the farmer’s front porch in the afternoon sun, property curb appeal, privacy from the neighbor and so on. Unfortunate things will happen, people will argue, unique situations will unfold and be accounted for. As a result, methods and guidance have emerged, evolved, and continue to evolve.

In the early 1900s, Dr. George E. Stone (1860-1941), Professor of Botany at the Massachusetts Agricultural College (now University of Massachusetts Amherst), wrote about the failings of then-current methods of tree valuation. Dr. Stone further worked to refine and enhance those methods into what has become the foundation (or skeletal framework) for modern tree appraisal in North America.

Development in Tree Appraisal

After a century of refinement and evolution, the current methods used by consulting arborists to appraise the value of trees are outlined by the Council of Tree and Landscape Appraisers (CTLA). Established in 1975, the CTLA represents the consensus of seven major green industry organizations, all of whom possess a material interest in the accurate and fair valuation of trees. The CTLA consists of:

These methods have been widely adopted and regularly used to settle disputes between neighbors, in various litigation, and for insurance purposes throughout the United States. Further, as the CTLA methods are rooted within established appraisal principles, they are gaining traction in other countries across the globe.

Current methods of tree appraisal

In cases where trees are not used for production purposes, the value of a tree is calculated based upon the tree’s size, species, condition, and location. However, including how and where to measure a tree size, each of the factors considered can have a number of variables requiring the consulting arborist to use empirical information to exercise impartial judgement. In many cases, the variables involved draw upon diverse knowledge and experience in different aspects of arboriculture.

After all, a tree that demonstrates early symptoms of a fatal disease, or represents a high risk may possess little to no value due to very poor condition ratings. Likewise, a tree that requires abatement due to local ordinances may also have little to no value as a result of very poor location ratings. In these extreme cases, removal may be required to remedy a situation. Thus, CTLA guidance logically concludes a tree that must be removed may have a negative value if the salvageable raw materials from said tree do not exceed the costs of removal and clean up. However, in some cases, pruning, cabling or other treatment may be an option to resolve an underlying condition. Where applicable, the cost of these treatments should be accounted for in the tree appraisal.

Additionally, these factors can be used to determine the value of damage to trees through consideration of pre and post casualty changes. By reviewing the change in a factor such as condition rating before a contractor or other party mistreated a tree, then after, damages readily emerge from the simple math.

Current implications of tree values

Throughout the United States, there are numerous cases where single, well-placed trees on private properties are valued at tens of thousands of dollars. Moreover, in specific states with applicable statutes, courts have awarded double or treble damages for trees unlawfully removed or damaged. Amounts awarded under these circumstances can easily reach into six-figures. However, even without additional damages, when damages are multiplied by a number of trees on a large property or individual trees on multiple properties, the values can be staggering.

For example, the state of Florida’s effort to control a citrus tree pathogen removed many thousands of citrus trees from private properties. In various class-action suits against the state, it was determined that the state’s actions were unlawful and affected property owners have been awarded over $60 million (without double or treble damages) for their losses thus far.

Another example is DuPont’s Imprelis® herbicide, which damaged or killed tens of thousands of trees across the US. Available to turf professionals from October of 2010 until voluntarily removed from the market by DuPont in August of 2011, the herbicide was intended to control broadleaf weeds in turf at low concentrations with low, off-target toxicity. However, due to its physical properties, the active ingredient was able to move through soil to be absorbed by tree roots with very harmful results. The chemical company’s estimated settlement cost was $1.175 billion in tree damage claims, according to a May 2014 article published by Golf Course Superintendents Association of America.

Much needed change

There are numerous examples across the country of streets or entire neighborhoods where a large number of trees have been seemingly cut in half or otherwise permanently damaged (one common practice is “topping”). These damaging practices are usually performed by low-budget contractors often referring to themselves “tree experts” and are further propagated via a social learning (aka: neighbor see, neighbor do) combined with misinformation. The practitioners often possess little to no scientific or safety training, use older and poorly maintained (more dangerous) equipment, evade taxes, are inadequately insured, and possess the worst customer service and safety records. The costs associated with their activities in a single neighborhood can easily reach seven figures.

Interestingly, Dr. Stone voiced a very similar concern about the abusive practices committed by those masquerading as “tree experts” or “tree doctors” in his 1916 publication on the valuation of trees. Today, nearly 100 years later, accountability and monetary damages for poor workmanship and damaging treatments have seemed to go largely unaddressed. However, given the enormous amount of growing data supporting the positive impacts of trees on economic, human health, social, and environmental issues, it seems change is long overdue.

When trees are mistreated, not only can they be permanently damaged, property values and the health of the urban forest can be damaged as well. In short, healthy, well-maintained and located trees can yield considerable value and many benefits, not only for a single property, but for surrounding properties as well. As time passes and trees grow, their benefits and values increase exponentially.

 

 

 

 

 

 

Selected References

Bloch, Lew. 2007. Tree Law Cases in the USA (2nd ed). Bloch Consulting Group, Potomac, MD.

Brinkmann, P. 2014, October. Jury awards $20.7M in Orange County citrus canker class action. Retrieved April 14, 2015, from http://www.orlandosentinel.com/business/brinkmann-on-business/os-jury-awards-207m-in-orange-county-citrus-canker-class-action-20141007-post.html

Coder, Kim D. 2004. Amenity Trees: Defining Concepts In Use. University of Geogia
 Daniel B. Warnell School of Forest Resources Publication SFR04-4.

Council of Tree and Landscape Appraisers (CTLA). 2000. Guide for Plant Appraisal (9th ed.). International Society of Arboriculture, Champaign, IL.

Cullen, Scott. 2005. Tree appraisal: chronology of North American industry guidance. Journal of Arboriculture 31(4), 157–162.

Cullen, Scott. 2007. Putting a value on trees – CTLA guidance and methods. Arboricultural Journal 30:21-43.

Donovan, G., Butry, D. 2009. Trees in the city: Valuing street trees in Portland, Oregon. Landscape and Urban Planning, 94, 77-83. Retrieved April 17, 2015, from http://www.researchgate.net/profile/Geoffrey_Donovan/
publication/222551246_Trees_in_the_city_Valuing_street_trees_in_Portland_Oregon/links/
0912f50cba3aca4bb1000000.pdf

George Edward Stone Papers (RG 40/11 Stone). Special Collections and University Archives, University of Massachusetts Amherst Libraries.

Kallis v. Sones, 146 Cal. Rptr. 3d 419, (208 Cal. App. 4th 1274, 2012)

King, Gordon S. 1977. Plant material evaluation. Journal of Arboriculture. 3(4):61-64.

Richman, H. 2014, May. GCM May: Aftermath. Retrieved June 20, 2015, from http://www.gcsaa.org/gcm-magazine/2014/may/aftermath

Salisbury, S. 2011, November. Citrus canker nets $19 million in Palm Beach County. Retrieved April 17, 2015, from http://www.palmbeachpost.com/news/business/citrus-canker-nets-19-million-in-palm-beach-county/nLwhs/

Stone, George E. 1916. Valuation of shade trees, pp. 255– 258. In Shade Trees: Characteristics, Adaptation, Diseases and Care. Bulletin No. 170, Massachusetts Agricultural Experiment Station, Amherst, MA.

Tate, Robert. 1989. ISA tree valuation guide: A critical examination. Journal of. Arboriculture. 15(6):145–149.

Watson, Gary. 2001. A study of CTLA formula values. Journal of Arboriculture. 27(6):289-297.

Watson, Gary. 2002. Comparing formula methods of tree appraisal. Journal of Arboriculture. 28(1):11–18.

Wozniak, M. 2014, August. Lee homeowners win final judgment in citrus canker case. Retrieved April 14, 2015, from http://www.news-press.com/story/news/2014/08/31/lee-homeowners-win-final-judgment-citrus-canker-case/14885737/

Additional Resources

American Forests Champion Trees, Measuring Guidelines Handbook

i-Tree Design, online tree benefits calculator

Purdue University online tree and landscape appraisal articles with explanations of specific methods for appraisal from the CTLA guide:
Article 1
Article 2