Theory 91/Urban & Built Environment/Street trees
Street Trees Need Soil
The claim
Urban tree survival is set by the ratio of soil volume to crown size, so a large crown on a small pit dies regardless of watering.
01Mechanism
Water and nutrients must be supplied from the rooting volume; the ratio determines whether supply meets transpiration demand.
02Prediction
Survival should track the ratio.
03Refutation
Survival tracking watering regime would remove volume.