I can hear rumblings from down in the woods. I've heard them before."How do you know that the diagonally closed canopy is good?"
It's hard to know how anything is good. I cannot prove that having these diagonals is good. There are few standards or clear objectives for wildlife clearings. They ought to be good for wildlife but there are over 100 species in the neighborhood and grass will be good for field voles but probably bad for tree warblers. People want more of this species but fewer of that. Some people like them all; others are single-species enthusiasts. Good today? or good over a long period. At what cost?
I've toyed with designing an experiment to test their goodness. I could not decide whether to use pounds of fruit as the criterion or observed animals. I knew I could measure wind velocities inside and outside of the clearing edge and the difference but that was only one dimension of the concept. It had to be a small effect, subtle in terms of acorn production of variable sized oaks in the vegetative managed "dough nut" around the clearing. I could measure fruit yield from 15 plants, expect high variability, and know the results would be "more studies are needed."
I knew that the dry, sparsely vegetated zones at the tree borders of most clearings was not what I desired for fauna. I knew that varied plants would be better (food, cover, soil protection, etc.) I wanted fruiting plants in sunlight but could not afford central sun-exposed areas. That was for grass. I wanted proximity to cover, changing plants over time, and I wanted diverse conditions for songbirds and small mammals. I thought that sufficient studies (if I could design them and get their approvals) over a long period ( say 30 years, if I could assure data storage) would allow me to draw conclusions about carefully-stated "good" results in terms of abundance of 10 species at confidence levels of about 75%. The cost would be at least $20,000 a year. I doubted if I would ever see $600,000 of public money spent on such a question of proof.
I had to continue, based on consistency with known ecological principles, field observations of plants and animals, responses to small scale treatments, assessment of labor costs, and general assessments of public wants.