Tree planting in Portland, Oregon is associated with decreases in non-accidental and cardiovascular mortality, and the magnitude of this association increased as trees aged and grew.
Look, I’m a huge proponent of planting trees but you gotta be careful about correlation and causation. The article itself admits that “It is an observational study, so it cannot establish a causal relationship between trees and mortality.” Yet you’d believe the study established causation based on the monetary claims about the value of tree planting if you only read the abstract, which claims, “Using US EPA estimates of a value of a statistical life, we estimated that planting a tree in each of Portland’s 140 Census tracts would generate $14.2 million in annual benefits (95 % CI: $8.0 million to $20.4 million).” You cannot make this estimate if you do not know it to be a causal relationship.
I get really pissed when environmentalists mislead the public towards their preferred outcome using faulty or over-interpreted data*. I wrote a report about single-use items a few years ago, and the deeper I dug into statements about straws and such that were listed on environmental advocacy sites, the more of a sham they turned out to be. I wound up doing a literature review to find valid, empirical evidence in support of our paper, and uncovered that compostable packaging actually has greater impacts when it is not composted — which is often!
Tell people to plant trees because they clean the air, provide shade, and reduce flooding, but don’t lie and tell them planting a tree will make them live longer.
*There are many reasons for this in the scientific literature, but at the core comes down to two challenges: science is insufficiently funded and researchers are rewarded for significant findings. See also: Imagining a better way — for everything
