Hello,
I've been thinking about this paper:
https://hess.copernicus.org/articles/11/1013/2007/
It's a hypothesys explaining how old grown forests call for rain. The physics is a bit complex, but the effect is this: when the forest is 'awake' it sucks moist air from the seas into the
land.
Now, there are a few requirements for this feature to word. It needs a large and continuous
canopy made of tall
trees and full of life. That's what creates the conditions for the rain pump.
A point to note, the canopy will hold moist under it, protected against winds and the
greenhouse effect of the sun hitting humid air. In some sense, this canopy is the skin of the forest. Having clearings is equivalent to having bleeding wounds in our skin. In an orchard where no tree touches the next one, that's the equivalent of a skinned animal, chair exposed.
In most food forests I've seen, this large canopy does not exist. On the contrary, the interphase is sought, with plenty of spaces where trees meet grasses.
My understanding is that in real forests, not many edible crops can be grown, since little sun reaches the crops. This is why zone 5 is advocated to be left as wild as possible, among other things.
But I wonder, can we apply some of this knowledge to our design? In particular, the idea that the canopy is like a skin which keeps moisture inside.
In a recent
Geoff Lawton video, he shows an ancient
irrigation system which is shaded by palms. 25 kilometres of cultivated land, following one single water stream. These palms form a continous skin, but they are just a strip of the land, so there's still plenty of light for crops below.
Maybe this is why overplanting, then thinning, works so well. It keeps moisture inside while plants are still small.
5
