by Jesse Batty, Neighborhood Trees Senior Specialist; ISA Certified Arborist
Planting a tree is a relatively simple act. Ensuring that a tree survives the first growing season and the subsequent years thereafter is more difficult. The goal of FOT’s Neighborhood Trees monitoring program is to provide proper tree planting education and after-planting care assistance to new tree owners so that a tree will survive its first growing season and ideally become an asset to the community during the many years to come. With the help of over 180 volunteers, Friends of Trees is proud to report another successful monitoring season. Below are a few highlights from the past season of summer inspecting (read the entire Monitoring Report here):
- The total number of trees planted within the City of Portland during the 2015-16 planting season was 2,781 trees. The 2,781 trees represent 63 genera and 174 species of trees, which highlights FOT’s dedication to planting a diverse urban forest.
- Of the trees monitored in Portland, a total of 97 trees did not survive their first summer season in the ground. That equates to a mortality rate of 3.6% for the monitored tree set, or a 96.4% survival rate if viewed in a more positive light. Those trees that died represent 41 species.
- Of the 174 different species and cultivars planted, 41 species had at least one incidence of mortality. Goldenrain tree, Oregon White Oak, Scarlet Oak, and Western Redbud showed the highest mortality rates of trees planted in high quantities (more than ten total).
- FOT will continue to record historical knowledge of tree inventory; continue its vigilance while maintaining bare root and b&b stock prior to planting and during transport; continue to monitor performance of different species; continue to adhere to an inclement weather protocol; continue to improve stewardship education, particularly to those who receive trees at no cost; and continue to send additional watering reminders in the form of email and postcard to supplement the visits of summer inspectors.
- FOT continued its study of a sample of 10% of trees that were planted two seasons prior, also known as Tier II inspections. This subset of trees showed a 3.5% mortality rate, which is in line with the mortality rate seen in previous years of 2 year old trees.
- FOT also began a study of a sample of 10% of trees that were planted three seasons prior, also known as Tier Gamma inspections. This subset showed a 7.55% mortality rate. This confirms FoT’s belief that year 3 is a “make or break” year for the establishment of young trees. We have expanded our outreach around young tree establishment to include the first three seasons as opposed to the first two.
- We also continued our study of 10% of the trees planted during the 2009-10 planting season, also known as Tier Omega inspections. This subset of trees showed a 3.7% mortality rate during Year 7. It is promising to note that 73.66% of all Tier Gamma trees are rated Good or OK after 7 years in the ground.
All of these findings will help FOT continue to provide appropriate & accurate tree care advice for homeowners who acquire trees through our program. A huge thank you is owed to our volunteer Summer Inspectors who provide tree care guidance to homeowners and accurate data reporting to FOT staff to help keep FOT’s mortality rates low.