HomeMy WebLinkAboutTR_Tree_Replacement_Methodology_Memo_171221_v1
T ECHNICAL M EMORANDUM
Date: December 21, 2017
To: Kelly Purnell
From: Amber Mikluscak, PLA, GISP
TWC Project Number: 111103
Project Name: Energize Eastside Tree Replacement Plan - Renton
Subject: Proposed Tree Retention and Replacement Methodology for Energize Eastside – Renton Segment
As a linear corridor crossing multiple parcels, tree impacts associated with the Energize
Eastside project corridor cannot be analyzed using the standard City of Renton process. In
order to satisfy the intent of the process outlined in the Renton Municipal Code [RMC] 4-4-130
and in the City of Renton’s Tree Retention Worksheet, an alternate methodology must be
applied.
First, the bounds of the project corridor will serve as an effective “parcel” boundary, allowing
for analysis on a project-wide scale. Within the corridor, tree impacts will be analyzed using a
zonal approach; trees will be classified by zoning district, then aggregated according to the
tree retention factors that are stated in the Tree Retention Worksheet. After categorization into
zones, a Tree Retention Worksheet will be completed for each zone. Specifically, the zones
will be as follows:
• Zone 1 – Commercial and industrial zones (0.1 retention factor)
• Zone 2 – Residential zones outside of those specified for Zone 3 (0.2 retention factor)
• Zone 3 – Zones RC, R-1, R-4, R-6 or R-8 (0.3 retention factor)
Using information gathered in the arborist field inventory and the results of the Vegetation
Impact Analysis (VIA), completed December 2017, tree retention and impacts within each
zone will be calculated using the step-by-step process outlined in the Tree Retention
Worksheet.
To accompany each Worksheet, a map will be produced showing the extent of tree impacts
within the zone. In addition, a corresponding typical plan will be provided for each zone that
outlines the proposed replanting strategy that will be applied.
Once the required tree replacement for each zone is calculated, candidate areas for replanting
will be identified in an attempt to approach the necessary amount of required replacement
trees. In the event that there is insufficient area to achieve the required replacement quantity,
alternate strategies will be identified, such as in-lieu fee or private property owner outreach
strategies, such as tree giveaways or coupons for tree purchase, that will offset the aesthetic,
habitat, and/or other functions of the trees being impacted.