Class Talk

A Class 2 tree is mitigated at a 0.7:1 rate versus 1:1 in the previous regulation.

I have made new additions to the website for everyone's convenience.  Until items can be placed on the official pages, I hope the information provided will help give some guidance on how to read through the new ordinance amendments which went into effect on July 2.

One of the most sought-after pieces of information is on how to calculate tree replacement and the fee payments which may be provided in lieu of planting.  The following has been in effect since July 2.

It is important to note some very important factors to the ordinance and fee rate changes:
Most trees on a development site not encroaching on floodplain or escarpment will be rated Class 2 or Class 3 trees and provide for mitigation reductions.  However, a stand with a large population of post oak will become much more valued for its woodland character and mitigation will increase for trees 12" and larger which would now be rated as significant.  Site selection and how it is developed will become important considerations.

The increase in the rate for the Reforestation Value is the first increase in over 20 years, and the formulation has been adjusted to more appropriately qualify larger trees at higher rates.  The classification of trees does adjust for this in most lots, but each property will differ.  Additional tools have been provided for the careful planning of sites to minimize the risk of tree mitigation.

The base rate for tree mitigation reforestation values will be posted in city ordinance.  It will vary only as the market warrants with changes to publications by the industry, and as approved by City Council.

Additional information can be provided by the city arborist's office.



  • A tree of any species that has a minimum diameter of EIGHT INCHES that is not classified as unprotected;
  • Any tree in a stand which projects a tree canopy over a building site when identified within a FOREST STAND DELINEATION review;
  • A tree planted as a replacement tree.

CLASSIFICATIONS (status for replacement):

HISTORIC TREES3:1 replacement ratio (RV: $579/in.)

SIGNIFICANT TREES 1.5:1 replacement ratio (RV: $290/in.)

  • 12” diameter and greater: Post oak
  • 24” diameter and greater: American elm, bois d’arc, cedar elm, chittamwood, common persimmon, eastern redcedar, green ash, all other oaks, pecan, all walnut species, and white ash.

CLASS 1 TREES 1:1 replacement ratio (RV$: $193/in.)
Associated with primary natural areas or geologically similar areas within 50 feet above the escarpment zone.

CLASS 2 TREES0.7:1 replacement ratio (RV$: $135/in.)
Species not otherwise associated with other classifications and unprotected trees.

CLASS 3 TREES0.4:1 replacement ratio (RV$: $77/in.)
Arizona ash, black willow, cottonwood, hackberry, honeylocust, mesquite, mimosa, mulberry, ornamentals, Pinus spp., Siberian elm, silver maple, sugarberry, or small tree (as defined).

Callery pear (all cultivars), chinaberry, Chinese tallow, Ilex species (except yaupon holly and Possumhaw), palm (all plants in Palmae), tree-of-heaven (Ailanthus), other trees listed as invasive plants; and trees with a diameter of less than 10 inches at the point on the trunk 4.5 feet above the ground, located on a lot with an existing single family or duplex use that is occupied at the time of removal.

The following is effective only when payment is to be made in lieu of other mitigation:

Reforestation Value (RV$): The fee is applicable only when payment is made in lieu of tree replacement by planting or other available means of mitigation. The Replacement Value per diameter inch of tree as of July 2, 2018: $193.00.

* Updated formula (derived from the Trunk Formula Method* located in the Guide for Plant Appraisal, 9th Edition, with the 2015 Texas Supplement) is now calculated for planting a 3” cal. Tree, being the specified Largest Commonly Available Transplantable Tree Size (LCA) for Texas, and with the standard rate of a tree at $82/inch.

Base formulation (using diameter of the tree):

  • (3” x 3”) x 0.7854 x $82/square in. = $579.63
  • $579.63 / 3” = $193.21 per diameter inch.
  • The rate per inch is rounded to the whole dollar as $193.00 (base rate at 1:1 ratio).
  • All classification reductions are calculated from the rounded base and rounded to the whole dollar (ex.: $135.10 = $135.00, and $77.20 = $77.00).

*The Trunk Formula Method is the formula for appraising “the monetary value of trees considered too large to be replaced with nursery or field-grown stock.” – Guide for Plant Appraisal, 9th Edition (p. 70).