OP, I found this good summary online:
http://www.csespta.org/Programs/DrChase.pdf
The author breaks interventions into three groups: change the brain, change the environment, and teach EF skills.
For "change the brain" he includes things like getting enough sleep, and interestingly, mentioned "outdoors/nature" but doesn't elaborate.
I say "interestingly" because my child with EF difficulties spent 2 weeks outside all day at a nature camp, and I swear it seems that his brain HAS changed. I have noticed a great deal more maturity, calmness, ability to handle frustration, ability to switch gears, and ability to plan ahead.
I would happily sign him up for a few more weeks if offered, because I see it as very enjoyable therapy for him!