Review Tree Preservation Plan Request for Trott Brook North

At the June 28, 2021 Environmental Policy Board (EPB) meeting, the Board reviewed a request from a developer to utilize a Fixed Radius Plot (FRP) sampling technique to survey trees in a planted setting (a full tree inventory would be completed for all naturally occurring trees except those outside the development area, which is compliant with City Code).  The EPB raised questions about cost/time savings and accuracy of such a sampling technique.  The attached memorandum from Kjolhaug Environmental Services Company attempts to address those questions.

Summary of Proposed Development Plan

• Number of lots: 270
• Developable Acreage: 124 Acres
• Zoning: R-1 Residential (MUSA) (Single Family Homes with 80 foot wide lots)
• Comprehensive Plan: Low Density Residential
• Net Density: 2.2 Units/Acre
• Dedicated Park Area: 13.4 Acres

Summary of Proposed Sampling Technique
Per the attached memorandum, the proposed FRP sampling technique would only be utilized in an area where the trees were planted, rather than occurring naturally.  The FRP method would establish 1/10 acre plots within the roughly 17 acre planted area and all trees within that plot would be surveyed.  The results would be extrapolated out to the entire planted area to provide a per acre relative basal area (equivalent to diameter inches), relative species abundance, and relative health condition for the planted area stand of trees.

Additional Information from Developer
The proposed method is estimated to reduce the labor hours for surveying the approximately seventeen (17) acres of planted trees by almost 150 hours.  A cost savings was not provided (Staff has requested this information), but the estimated time savings does appear significant.

The EPB had requested additional information about the accuracy of this type of sampling as well.  The memorandum includes multiple attachments of various studies that have been conducted on sampling techniques and their accuracy.  FRP appears to be considered an accurate sampling technique.

Formal Process
Staff has reached out to the City Attorney regarding whether this type of sampling technique would require a formal variance.  As of the writing of this case, a response has not been received.  Staff hopes to be able to provide a verbal update on this at the meeting.

If a formal variance would be required, that would be routed through the EPB and then to the Planning Commission (authority on variances).  If a formal variance is not required, any recommendation of the EPB would be forwarded to City Council for consideration.

Based on discussion.