compensating for the loss of a healthy tree: how many trees do you owe me?

Compensating for the Loss of a Healthy Tree: How Many Trees Do You Owe Me?

David J. Nowak US Forest Service

Syracuse, NY

2004

Google goes Public

Invest $10,000

Boris Badenov

**ONE HUNDRED EIGHTEEN**

**118**

Invest $10,000 – Offer: $12,800 (inflation)

Boris Badenov

**ONE HUNDRED EIGHTEEN**

**118**

Invest $10,000 – Current Value = $95,000

Boris Badenov

**ONE HUNDRED EIGHTEEN**

**118**

Tree Value?

Tree Value?

Fallacy of Tree ValueThere is no NASDAQ for treesWe do not know the true value of treesWe may never know the true value of trees

Proposed SolutionCompensate on equal trees, not $Calculate number small trees = removed treeSize based methods:

Method No. 1” trees to replace 30” tree

DBH 30Basal area 900Leaf area ~70

Proposed SolutionCompensate based on leaf areaMany tree values associated with leaf areaTends to increase through time (predictable)

IssueNeed to consider future values (lost or gained)

Net present value (NPV) of future leavesNPV of 1” DBH large, long-lived tree = 34,000 ft2Replace a 24” DBH large tree:

Years Remaining NPV leaves (3% rate) No. replacement trees1 6,000 ft2 0.250 187,000 ft2 5.6

Calculating Tree CompensationTree sizeLife spanGrowth rateDiscount rate

Tree SizeLarge: London planetree (Platanus hybrida) Small: crapemyrtle (Lagerostroemia indica).

0.2 in/yr; 100 years to death

Life SpanCombined DBH mortality curve with average DBH distribution

Life SpanAverage population mortality = 1,2,3 or 4%

Life Span

Long-lived = 87 years Mod. Long-lived = 50 yrs Mod. Short-lived = 34 yrs Short-lived = 26 yrs

Calculating Tree CompensationTree size (large vs. small)Life span (1-4% annual mortality rate)Growth rate (0.2 inches/year)Discount rate (2, 3, and 4%)

Compensation Rate by DBH (3%; Large Tree)

Replacing large tree with large tree

Maximum Compensation Values (3% rate)

Replacement tree : Large SmallExisting Tree L ML MS S L ML MS SLarge Long-lived (L) 6.6 12.2 20.9 31.5 13.6 19.5 29.9 41.1

Mod. Long-lived (ML) 4.4 8.1 14.0 21.1 9.1 13.0 20.0 27.5Mod. Short-lived (MS) 3.4 6.2 10.7 16.2 7.0 10.0 15.3 21.1Short-lived (S) 2.9 5.3 9.1 13.7 5.9 8.5 13.0 17.9

Small Long-lived (L) 0.9 1.6 2.8 4.1 1.8 2.6 3.9 5.4Mod. Long-lived (ML) 0.7 1.3 2.3 3.4 1.5 2.1 3.3 4.5Mod. Short-lived (MS) 0.6 1.1 1.9 2.9 1.3 1.8 2.8 3.8Short-lived (S) 0.5 1.0 1.7 2.5 1.1 1.5 2.4 3.3

Look-up TablesDBH (inch)

YRS TO DEATH 1 2 3 4 5 6 7 8 9 10

80 0.9 1.1 1.3 1.6 1.8 2.0 2.3 2.5 2.8 3.1 81 1.0 1.1 1.3 1.6 1.8 2.0 2.3 2.5 2.8 3.1 82 1.0 1.2 1.4 1.6 1.8 2.1 2.3 2.6 2.8 3.1 83 1.0 1.2 1.4 1.6 1.8 2.1 2.3 2.6 2.8 3.1 84 1.0 1.2 1.4 1.6 1.8 2.1 2.3 2.6 2.9 3.1 85 1.0 1.2 1.4 1.6 1.9 2.1 2.4 2.6 2.9 3.2 86 1.0 1.2 1.4 1.6 1.9 2.1 2.4 2.6 2.9 3.2 87 1.0 1.2 1.4 1.6 1.9 2.1 2.4 2.6 2.9 3.2 88 1.0 1.2 1.4 1.7 1.9 2.1 2.4 2.7 2.9 3.2 89 1.0 1.2 1.4 1.7 1.9 2.2 2.4 2.7 2.9 3.2 90 1.0 1.2 1.5 1.7 1.9 2.2 2.4 2.7 3.0 3.2

Bold = large, long-lived treereplaced with comparable tree

Replacement trees: Mod Short-lived Large Tree

LimitationsLikely minimum compensationDoes not include:

Social values (Grandpa planted tree; historical tree)Punitive damagesEffect of multiple surrounding trees (forests)Value of dead trees

CompensationDetermine number of trees based on size and life span remaining (look-up tables or program)Replant the trees, orCompensation in dollars based on cost of planting trees (not value of tree)

Example: owed 10 trees; cost of planting = $1,000 per tree (compensation = $10,000)

Summary

dnowak@fs.fed.us nrs.fs.fed.us/units/urban

Tree compensation:Can be calculated based on NPV of leaf areaVaries with tree size and life span remainingCan be converted to dollars based on cost of planting new trees