Tree Assessment and Valuation

Slide 1 Tree Assessment LHAP 305 D.Ballard 2025 Slide 2 What will we cover? Tree risk assessments Levels of tree risk assessment Risk mitigation Methods of tree valuation Tree inventory systems Codes and regulations Slide 3 Tree Risk Assessment Qualification Also known as TRAQ As an ISA certified arborist, you could take training to become TRAQ certified. https://www.isa-arbor.com/Credentials/ISA-Tree-Risk-Assessment-Qualification Arboriculture Canada also has the Comprehensive Tree Risk Management Qualification course https://www.arborcanada.com/courses-1/comprehensive-tree-risk-management-qualification Slide 4 What is Tree Risk Assessment? Tree Risk Assessment - The process used to identify, analyze, and evaluate tree risk. Tree Risk Management - is the application of policies, procedures, and practices used to identify, evaluate, mitigate, monitor, and communicate tree risk. The Farmer Fred Rant. (2010, June 03). Tree Goes boom. Film at 11. The Farmer Fred Rant. Retrieved Oct 31, 2025 Slide 5 Levels of Tree Risk Assessment Level 1 - Limited visual assessment of 1 or more trees. Identify trees and the location Find the best route for inspection Assess from one perspective - walking by, driving by Record what trees need mitigation or further assessment Evaluate the risk based on what you saw Submit report with recommendations Washington Tree Services. (n.d.). Tree Inspection & Evaluation. Washington Tree Services. Retrieved Oct 31, 2025 Slide 6 Levels of Tree Risk Assessment Level 2 - Basic assessment - Detailed visual inspection of the tree, its surroundings and the targets involved. Locate and identify trees Determine targets and target zone Inspect the site and review site history Visual inspection of tree - binoculars, mallet, probe or trowel Assess tree loads, leans, and general tree health Record observations Determine likelihood of failure, as well as impact and consequences Submit report with mitigation options and degree of risk involved Frey, F. (n.d.). 5 Signs It’s Time to Schedule a Tree Risk Assessment (TRA). Vintage Tree Care INC. Retrieved Oct 31, 2025 Slide 7 Levels of Tree Risk Assessment Level 3 - Advanced assessment - detailed information on tree parts, defects, targets and site conditions Aerial inspections - Climbers, drones, UAV photographs Detailed target assessment - values, occupancy rates Detailed site assessment - history, soil testing Decay testing - boring, high end technologies Health evaluation - from roots to shoots Storm/ wind analysis Assessing trunk leans Load testing- hand pulls, pull test with sensors Lab tests Green Leaf Tree Services LTD. (n.d.). Certified Tree Risk Assessment. Green Leaf Tree Services LTD. Retrieved Oct 31, 2025 Samsara Tree Care. (n.d.). Tree Inspections & Arborist Reports By Samsara. Samsara Tree Care. Retrieved Oct 31, 2025 Slide 8 Tree Risk Assessment Risk - combination of likelihood of tree failure, likelihood of impact, and consequences of failure. Tree risk assessment - Process used to identify, analyze, and evaluate tree risk. Tree risk evaluation - Comparing the risk involved with a tree against the standards of a client Diameter at breast height (DBH) also known as diameter at standard height (DSH) measured at 1.4 meters above the ground Find circumference of trunk Then calculate DBH or DSH = circumference / π (Pi) Slide 9 Tree Risk Assessment - Targets Targets - Anything, that during the course of a tree failure, can be harmed or damaged Static targets Movable targets Mobile targets Target Zone - area in which the tree or branch is likely to strike Occupancy rates - amount of time targets are within the target zone Constant, frequent, occasional, rare Likelihood of Impact - High to very low Consequences of failure -Severe, significant, minor, negligible Durand-Wood, E. (2023, June 29). An Inconvenient Tree. Strong Towns. Retrieved Oct 31, 2025 Slide 10 Example - Targets A large Poplar Tree is growing alone in a Park, in Calgary. It is a Saturday in the middle of summer. It has a large dead limb overhanging the sidewalk. What are the targets? What are the assumed occupancy rates? What is the Likelihood of Impact? What consequences could we assume? What level of consequences would you put this under? Marrickville Municipality. (2015, Aug 16). Our poor poplar trees. Saving Our trees - Marrickville Municipality. Retrieved Oct 31, 2025 Slide 11 Tree Risk Assessment - Tree Failure Tree failure- Breakage of a stem, branch, or roots, or loss of mechanical support in the root system Anderson, J. (n.d.). Stump the Forester: What Are Codominant Stems? Florida urban Forestry Council. Retrieved Oct 31, 2025 Lester, D. (2015, Feb 14). Storm-damaged trees require careful assessment for care. Recordonline.com. Retrieved Oct 31, 2025 Slide 12 Tree Risk Assessment - Tree Failure Likelihood of failure - The chance of a tree or tree part failure occurring in a specified time frame. Defects and structural conditions Loads Site conditions Weather Time frame Imminent, probable, possible, Improbable Slide 13 Tree Risk Assessment - Site Inspection History of failures Typical weather for the area Tree experiencing new exposures Evidence of root damage Evidence of drought or flooding New soil conditions Trees growing on slopes New construction in area Restrictions on tree Slide 14 Steps to Develop a Tree Risk Rating Identify possible targets Identify tree parts that could fail Categorize the likelihood of failure Categorize the likelihood of impact For each failure/target combination Categorize the likelihood of failure and impact Assess consequences of failure Categorize the risk. Managing Tree Risk 101. (n.d.). TRAQ Tree Risk Management Methodology. Managing Tree Risk 101. Retrieved Oct 30, 2025 Slide 15 Risk Mitigation Mitigation - action taken to reduce risk. Target management Tree based mitigation Residual risk - The risks remaining after or caused by the mitigation attempt. Slide 16 Tree Valuation Know your trees worth Slide 17 Tree Valuation Tree valuation is how we put a dollar value on a tree in a landscape Reasons to have a tree valued Unexpected losses Tort Claims Insurance Claims Tax deductions Real estate assessment Proactive planning Slide 18 Tree Valuation What do we look for when appraising a tree? The species The condition The Size The Location Slide 19 Depreciation of Value Depreciation is the loss of value to estimate the actual value of a tree in a landscape. Depreciation depends on; Condition of the tree Functional Limitations External Limitations Slide 20 Tree Appraisal Methods There are a few methods for doing so Sales comparison approach Income approach Cost approach Replacement Cost Approach Trunk formula technique (TFT) Slide 21 Tree Valuation Sales comparison approach Estimates the value of having trees on the property by comparing it to a similar properties value without the trees. Not commonly used because it's unlikely to find properties that are similar enough. Slide 22 Tree Valuation Income Approach Value is based on the economic benefits of the tree. Both current and future incomes from it. Example A peach tree produces 100 kg of peaches in a year. The grower makes an income of $5 per kg each year. The tree was expected to last 8 years before it was sprayed with roundup by a disgruntled employee. Slide 23 Tree Valuation Cost Approach Determines value based on current costs to replace or reproduce a tree of the same species and of similar size. Replacement cost method Trunk Formula Method. Slide 24 Tree Valuation Cost Approach - Replacement cost Method Used when the nursery can supply the client with a tree that is the same species and of the same caliper. Value = Cost of purchase + cost of planting Slide 25 Tree Valuation Trunk Formula Technique (TFT) or Trunk Formula Method Meant for valuing large trees that would be difficult to replace with one of equal species and size. Slide 26 Tree Valuation Find CSA of subject tree calculate DBH = circumference / π (Pi) CSA = Diameter x Diameter X .7854 (.7854 is a constant) Find unit tree cost - cost per square inch of replacement tree Find cost of new tree and cost to transport and install Find caliper size of tree you will purchase FInd CSA = Diameter x Diameter X .7854 Find Basic reproduction cost (CSA of subject tree/ CSA of replacement tree) x total replacement cost = basic reproduction costs Purcell, L. (n.d.). Tree Appraisal and the Value of Trees. Purdue Extension. Retrieved September 15, 2025 Slide 27 Tree Valuation Condition rating - Overall tree health condition in percentage Good health and structure - 100% Defects over half of the tree - 50% Functional limitations - Characteristics of the tree itself that reduce its practical value Messy fruiting tree or trees prone to branches breaking Growing into power lines or against a building Minor inconvenience- 5% reduction Major Inconvenience- up to 50% External limitations - problems out of the owners control that affect the tree. Easements or right-of-ways. Minor restriction - 5% reduction Major conflicts - up to 50% Purcell, L. (n.d.). Tree Appraisal and the Value of Trees. Purdue Extension. Retrieved September 15, 2025 Slide 28 Tree Valuation Now that you have all these values, you can find your depreciated reproduction cost Multiply the basic reproduction cost by all depreciation percentages BRC x CR X FL X EL Add in any additional costs Post planting care, old tree removal This will give you your appraisal value Purcell, L. (n.d.). Tree Appraisal and the Value of Trees. Purdue Extension. Retrieved September 15, 2025 Slide 29 Lets try an example An Ohio Buckeye is growing beside an office building. The tree has great structure and no defects. It is growing well with lots of space and no external obstructions. (Assume no depreciation). The owners would like a value on the tree. You measure circumference at 1.4 meters from the ground and find it to be 100cm. The local nursery has 10 cm caliper Ohio Buckeyes that will cost $1000 for purchase and install. There are no additional costs. Find a value for the Ohio Buckeye to the nearest $1000. Slide 30 Tree Inventory Systems Record of species, locations, characteristics, and assessments of trees and groups of trees in a defined area (Street, park, urban centre, etc) These inventories are used to Find number of trees Find value of trees Variety of species in an area IPM Budgeting Planning and development These inventories likely include Tree species and diameter Location Condition Past maintenance More advanced inventories include Site information Crown dimensions Maintenance schedule Risk assessment Value https://www.itreetools.org/ https://maps.calgary.ca/TreeSchedule/ Slide 31 Codes and Regulations ANSI 300 https://sullivansisland.sc.gov/sites/sullivansisland/files/Documents/Tree%20Preservation/ANSI%20300-%20Pruning%20Standards.pdf ANSI Z133 https://cdn.ymaws.com/www.ohioforest.org/resource/resmgr/masterlogger/z133.pdf OHS - Part 34 and 39 https://kings-printer.alberta.ca/documents/OHS/OHS Code_March_31,_2025_(rep_s850)_only.pdf Slide 32 Bibliography Anderson, J. (n.d.). Stump the Forester: What Are Codominant Stems? Florida urban Forestry Council. Retrieved Oct 31, 2025, from https://fufc.org/what-are-codominant-stems/ Dunster, J. A., Smiley, E. T., Matheny, N. P., & Lilly, S. (2017). Tree Risk Assessment Manual. International Society of Arboriculture. Durand-Wood, E. (2023, June 29). An Inconvenient Tree. Strong Towns. Retrieved Oct 31, 2025, from https://archive.strongtowns.org/journal/2023/6/29/an-inconvenient-tree Frey, F. (n.d.). 5 Signs It’s Time to Schedule a Tree Risk Assessment (TRA). Vintage Tree Care INC. Retrieved Oct 31, 2025, from https://www.vintagetreecare.com/signs-to-schedule-a-tree-risk-assessment Green Leaf Tree Services LTD. (n.d.). Certified Tree Risk Assessment. Green Leaf Tree Services LTD. Retrieved Oct 31, 2025, from https://www.greenleaftree.ca/tree-risk-assessment Lester, D. (2015, Feb 14). Storm-damaged trees require careful assessment for care. Recordonline.com. Retrieved Oct 31, 2025, from https://www.recordonline.com/story/lifestyle/home-garden/2015/02/14/storm-damaged-trees-require-careful/35189115007/ Managing Tree Risk 101. (n.d.). TRAQ Tree Risk Management Methodology. Managing Tree Risk 101. Retrieved Oct 30, 2025, from https://managingtreerisk101.net/traq-tree-risk-management-methodology/ Marrickville Municipality. (2015, Aug 16). Our poor poplar trees. Saving Our trees - Marrickville Municipality. Retrieved Oct 31, 2025, from https://savingourtrees.wordpress.com/2015/08/16/our-poor-poplar-trees/ Purcell, L. (n.d.). Tree Appraisal and the Value of Trees. Purdue Extension. Retrieved September 15, 2025, from https://www.extension.purdue.edu/extmedia/fnr/FNR-473-W.pdf Samsara Tree Care. (n.d.). Tree Inspections & Arborist Reports By Samsara. Samsara Tree Care. Retrieved Oct 31, 2025, from https://samsaratreecare.com/tree-inspections-arborist-reports/ The Farmer Fred Rant. (2010, June 03). Tree Goes boom. Film at 11. The Farmer Fred Rant. Retrieved Oct 31, 2025, from http://farmerfredrant.blogspot.com/2010/06/tree-goes-boom-film-at-11.html Washington Tree Services. (n.d.). Tree Inspection & Evaluation. Washington Tree Services. Retrieved Oct 31, 2025, from https://www.washingtontreeservices.com/tree-services/tree-inspection-and-evaluation/