Narberth Area Nature Stewards

Abstract/Summary:

Our neighborhood tree canopy is a revered part of what defines the community; these trees:

Established old growth trees are aging out, and attempts to replace them are pursued by shade tree commissions in both Lower Merion and Narberth. Narberth alone adds ~50+ young trees per year, but not all survive, and these young trees take decades to fully mature into canopy trees.

The Ivy Warriors project started with saving one tree on one street, then after a few walks on nearby blocks... this curiosity quickly turned into a borough area walking survey to gain an understanding of the issue. The outcome is a map of trees under threat of ivy. This map provides public visibility into scope of the current problem (see below).

This survey has made it clear that unmanaged ivy (and other vines) are quickly spreading across the borough. Some trees have already been lost and even more are only a few years away from this same fate. If left unchecked, it now seems apparent that a large portion of trees will succumb in less than 5 years, another large portion 5 years behind this. There will soon be an acceleration of tree loss at a rate that new plantings can not replace.

Ivy should be completely removed from community properties per the invasive species code, but this is not needed to save our tree canopy. Basic management that is good enough to save the trees is simple, easily taught, and only a once per year maintenance activity. Cutting all vines at ground level and continuing to restrict them will allow our trees to recover and also keep the ivy from going to seed and allowing local birds from spreading the seedlings to new properties

Snapshot of completed walking survey map:

The above is a snapshot of the map as of completion of the walking survey. If you want to see the live map and interact with it for closer inspection, or to track updates as progress is made, click here. Note: if you scroll to the bottom of the left column, you can toggle on a satellite image overlay which also adds street names to the map.

Survey Summary:

a curb walk survey was performed Dec 2022 - Jan 2023
area is bounded inside Montgomery Ave, Wynnewood Ave, & Bowman Ave.
about 3/4 of a square mile in area was covered, including all of Narberth
photo data was compared against google maps / street view and then plotted
544 markers placed on the map (516 related to trees actively under attack)

Survey strengths:

winter survey allowed for leafy english ivy vines to be observed while seasonal leaves are missing
comparing collected photos to google map/street view data provided increased location accuracy
historical timeline via google street view provided insight into speed of vine growth and in some cases lost trees due to ivy

Survey weaknesses:

only trees visible in direct line of sight from street curb could be observed, trees behind buildings or other items could not be surveyed
addresses are best guesses based on google maps house numbering and layout, the further the pin is from the street curb, the more difficult it was to make an educated guess at the exact location or address
map pins track any visible leafed vine climbing a tree, most is english ivy, but it does not cover other invasive vines that are leafless in the winter and are less visible
there is no rating for each point, it could be one attacked tree, or a small cluster. it could be an early stage attack or a fully mature one
photos were posted to provide insight into the worst examples, but not all... and there is no specific match between a photo and a specific marker on the map

Possible Next Steps:

general education of the public including a raised awareness:

of the value of our tree canopy: financial, health, and environmental
of the scope and intensity of the issue of vines attacking our tree canopy
that it is our citizen duty to completely remove english ivy from properties in compliance with recently passed local codes denoting english ivy as an invasive species

communication channels that could be leveraged:

social media channels related to shade tree commission, local government, local gardening, and other environmentally focused groups
local government newsletters and email channels
sponsored postcard mailers to residents
word of mouth, or door to door canvassing

call to action within these communications:

ask homeowners to remediate all climbing vines from trees by cutting a "one inch moat ring" around the base of the tree (on trunk close to ground, or around base of root flare on the ground) and maintain this yearly

advise that vines not be pulled from trees as this could damage trees further, but instead allow vines to die off and decay naturally

suggest that ivy (and other climbing vines) be completely removed from groundcover and property if possible
request reporting of areas where property owners need assistance with this and support these requests with a small volunteer group, create a channel to collect and track these requests
recruit a small group of volunteers across the borough to receive these requests providing consent to enter property and remediate for property owners in situations where they can't do it themselves
recruit a small group of volunteers to approach public parks and other properties where no specific owner can be held responsible for this effort

This blog will continue to provide updates as they are uncovered, come back to the homepage periodically to check up on our efforts.