Here's a radical statement for the orthodox among us: "Plants need not occupy all the layers for a stand to be a forest or forest garden. One could design a garden that had two useful layers, say a fruit tree
canopy and a diverse herbaceous layer" (p 75) although he does go on to say this isn't taking full advantage and more layers are better, depending on your goals. Some of the most beautiful forests I've been in, like the Kaibab forests in Northern Arizona, have very sparse understory layers.
And another iconoclastic statement, at least with respect to some of the lore about
permaculture design: "There is no substantiation for higher edge-zone
productivity except in wetlands and midsuccession environments where the edge effect may not be the cause." (p 94) He goes on to say that the edges that seem to have the effect are much wider than we can generally accomplish in a home-scaled food forest, and note that they can become perfect corridors for invasive species, decreasing the diversity we are after. "Just remember that if you have more edge to work with, so too do the weeds that want in!" (p 95) Yeah, weeds are just what I need more of. "Edges are a fact of physical life and a possible tool, not a panacea." (p 96)
The discussion of following a plant's natural tendency for reproduction by clumping or wide seed dispersal makes a lot of sense for designing plant spacing. Why fight an iris patch that expands by its
roots? How many plants, how big of an area of one species is too much? I think of the nearby
Pando aspen grove, a single organism that covers over 100 acres. It's ok for a plant to have its own kind as a neighbor.
I really like Table 3.6, which ought to be titled, "How much is
enough?"
Native MOIST temperate deciduous forests have a maximum of 35-40 species per quarter acre. It's not hundreds, and thinking so makes it way harder than it has to be. We can always add more later if we are missing a function.
Robert's garden: it's hard to think about it when you are starting out, but if we want our work to extend beyond our lifetimes, we must consider things like aging in place and inheritance, or at least creating something that someone else could adopt and operate. Robert's gardens had few patches which limited his ability to care for his garden as he got more frail. And wouldn't it be great if there were a way to easily 3-D model the heights and density of a group of
trees from a prospective planting map? I once
started a thread on this very topic: "The problem: the shrubs usually got in the way of access to the fruit trees or blocked the available paths back and forth through the core of the garden. Perhaps this shrub distribution made the garden look forest like, but it was a major hassle to move around the place, not to mention to prune, harvest, and monitor insects." (p 118 ). I said it then, and having taken my share of tumbles on this property, I am even more insistent now that the design eliminate all tippy-toe harvesting. It's might be part of some people's rich fantasy life. I want my reality to involve as few trips to the ER as possible as I get older.
My DH and I also have to have the serious discussion about inheritance. I found this blog
article summarizing what has happened to Robert's garden and it's not what any of us dream of. Planning for succession of gardener is a topic that we don't ever discuss, but isn't part of the design process?
ETA link to thread I forgot to include.