permaculture

[Toby Hemenway <hemenway@jeffnet.org>]

Marsha wrote: 

> It is the tendency of all natural systems to grow.

and
 
>Ernst Gotsch, our "forest guru" talks of the "Law of otimization of
> life", that Natural systems will always increase in their life-support
> systems.

I'm uncomfortable with these statements. It's not true of individuals, who
grow in size for a short time, then spend most of their lives slowly
degenerating until they die (I'm not picking on you, Marsha, just trying to
refine some ideas). And it's not really true of ecosystems. Those ideas were
common in ecology until about 1980. They've been superseded by an
understanding that the "perfect world" those ideas require doesn't exist,
thus they can lead to erroneous assumptions or requirements about what
actually occurs, or what is sustainable. In nature, disturbance and
perturbation are the rule. A living system is _capable_ of long-term growth
or deepening complexity, but there is always a fire, disease, storm,
revolution, or some other setback that destroys biomass and resets the
system's trajectory along a new path. Always.

In study after study, the forest or animal or estuary under examination was
pole-axed by perturbations, and never got to follow the ideal trajectory.
For example, nearly all forests increase in mass (though diversity
fluctuates, it doesn't always increase) for some small fraction of the
theoretical lifespan, until they create conditions that are perfect for some
catastrophic fire or blight or bug, and then are destroyed well before
"climax." This is why old growth occurs mostly in small patches. Dawn points
out that scale is important, and at small scales--patches of trees or
whatever--things are _really_ chaotic with no trends evident. So most
ecologists have abandoned the idea that real ecosystems are headed toward a
more complex, diverse, or massive state. They are capable of it; they just
rarely make it very far on that path. This idea is reorganizing restoration
and forest ecology, and I think has use for permaculture. It means we need
not feel guilty about the "recombinant" ecologies we're creating by mixing
natives with exotics; disturbed, patchy ecosystems are the rule. Nor is
disturbance from harvest or logging a bad thing, if it is on a scale
appropriate to the local system.

Maybe it is only with human intervention that systems can be kept on the the
"ideal" constantly complexifying path, as in permaculture, where we cut back
brush, add new plants, move mulch from one site to another, etc, to keep
things growing nicely.

Toby