Here are this year’s photos from the Bartlett Tree Lab study comparing different planting methods for urban trees. For comparison, check out last year’s set. And for a fuller chronological picture, you can see all the photos up to that point in this post.
This independent study was set up by Dr. Tom Smiley to test how well trees fare in different growing media. The trees are monitored and tracked from year to year to measure their leaf extensions, height, DBH, and more.
(Structural Soil twig on the left, Suspended Pavement twig on the right).
(Structural Soil tree on the left, Suspended Pavement tree on the right).
The research plots were set up so that that 12 trees planted grown in a suspended pavement system (which is identical in performance to the Silva Cell), 12 trees were planted in a stalite/soil mix, 12 trees were planted in compacted soil, 12 trees in pure stalite, and 12 trees in a gravel/soil mix. All trees had access to 189 ft3 of growing medium.
It’s clear from the size of the trees and the color and number of leaves that the trees in the Suspended Pavement treatment are outperforming those in Structural Soil by a significant margin. Our expectation is that this advantage, which is so marked even at such an early stage, will only continue to compound over the course of their lives and development. We’ll continue to monitor their progress each year to monitor continuing changes.
Bartlett Tree Lab study is not sponsored by DeepRoot. Bartlett is an independent lab that chooses their own test parameters, conditions, and technologies. DeepRoot did not influence, pay for, or at any point become involved in the planning or design of that study. We also have no sway over the results, which we expect Tom Smiley to continue to publish about over the coming years.
All images courtesy of Tom Smiley.