Continuing my exploration of the little green book…

Yeomans’ proposition (to grow forests as intrinsic elements in urban design) is followed by a long middle section which is essentially pedagogical.

I’ve not read Yeomans’ other books yet, but I am presuming that a lot of his teaching material in The City Forest is synthesised from his previously published research.

He delves into the ways that natural landscapes are formed by water flows, and how these “landscape-shapes” (ridges, valleys etc), in turn, influence water flows. It’s his basic curriculum for cracking the code of the planet’s operations. I’m trying to immerse myself in it, but I think it won’t make much sense until I get to experience it in practice, on a bit of land.

There are some enlightening concepts in this pedagogical section of the book. I found his so-called “Scale of Permanence” to be a fascinating way to begin thinking about landscape design.

Here’s his scale:

1. Climate
2. Land shape
3. Water
4. Roads
5. Trees
6. Buildings
7. Subdivision
8. Soil

Essentially, this list represents a “descending order of permanence” of these 8 factors. In other words, the elements at the top of the list are more permanent (relative to human timescales) than those towards the bottom.

He writes:

The first two factors, climate and land shape, are the more or less unalterable background of the landscape. Water, with its lines and its patterns of flow, is the first factor of the landscape design of Nature which we change. (p. 40)

That notion – how to go about judiciously changing water’s patterns of flow, seems to form the basis of much of Yeomans’ work.

The descending scale of permanence could come in handy when thinking about how any landscape comes into being. It’s a humble way of seeing humans in relation to the universal forces which make the surface of the planet how it is.

Of course, we now realise that Climate is not exactly as “permanent” as Yeomans’ scale might have it. But his schema is still correct in the sense that the climate of any particular local piece of landscape is not really something that we humans have the ability to intentionally influence. (Well OK, I could be wrong).

Not that this humility stops Yeomans’ from thinking in terms of large transformations. Even attempting to improve the lowliest item on his list – soil – can have big effects.

I wonder how much (if any) of this curriculum has been integrated into professional disciplines like landscape architecture and engineering? “Permanence” is not a concept which you hear about much – we’ve gotten used to the idea of 50 years as a long lifespan for any element of the human-built environment…