What are your species diversity guidelines?
What are some of your best performers?
Nik: Portland undertook a street tree inventory in stages between 2010 and 2016 and
found that the maple and rose families were way overrepresented. We were found to have
5% ash trees and we're being more cautious with that genus going forward because of
EAB concerns. The overall goal of 5-10-20 (no more than 5% of any one species; no more
than 10% of any one genus; and no more than 20% of one family) is informing our planting
efforts.
Gina: We're on the lookout for trees that thrive during our rainy season but then can
tolerate the increasingly common drought spells. Two evergreens here, silverleaf oak
(Quercus hypoleucoides) and canyon live oak (Q. chrysolepsis), show that kind of versa-
tility. Chinese pistache (Pistacia chinensis) grows well here in a variety of situations, as
do parrotia (Parrotia persica), tupelo (Nyssa sylvatica), and ginkgo (Ginkgo biloba).
What are some of the technologies or tools you are employing?
Nik: We use i-Tree Eco for quantifying tree benefits and services. Our Heritage
Tree, street tree inventory, and park tree inventory databases are all avail-
able via an ArcGIS online map for the public. We also have an ArcGIS collector
on our mobile devices, so as we're planting or monitoring trees, we can note
tree condition, updating the tree inventory database in real time.
We partner with Portland State University (PSU)'s Sustaining Urban Places Research (SUPR)
Lab. PSU Urban Studies and Planning Professor Dr. Vivek Shandas combined LIDAR GIS
and Census data into super tools that allowed us to see where trees are concentrated
in Portland and which areas need more planting support. SUPR has also done on-the-
ground temperature monitoring to determine where urban heat island effect hot spots
are. This combined data has helped guide our tree selection and planting efforts.
We have partnered with the U.S. Forest Service on conducting Urban Forest Inventory &
Analysis (UFIA) with most of the analytic tools based in i-Tree; you can read more about
that here. A tool that will emerge from that work is the My City's Trees App that's affil-
iated with the UFIA, providing a publicly accessible report on our urban canopy. >>
32 CityTREES
We're on the lookout for trees that
thrive during our rainy season but
then can tolerate the increasingly
common drought spells.
