This is a puzzle – a question, not an answer.
In our quest to heal the land – or our little piece of it, at any rate – my partner and I have been reading about permaculture and taking steps toward putting it into practice. We’ve planted ten fruit and nut trees to date, along with some berry bushes, and lots more are due to arrive this spring. We’re working on developing the “guilds” – assortments of plants to fill the other ecological niches – around them.
Permaculture (please excuse this abbreviated description of a very complex subject) is a way to accelerate the ecosystem succession (bare ground –> annual grasses –> perennials –> shrubs –> savanna –> climax forest) and then hold it at the savanna stage, which is considered the most varied and productive. At the moment, we’re working on hurrying along the bare ground and annual-grass areas and haven’t really dealt with the two-thirds of the land that is forested.
The name “permaculture,” and in fact the whole idea of sustainability, suggest that a balanced, self-equilibrating system is desirable and achievable. (Remember the “balance of nature” we learned about in school?)
But consider these quotes:
“Any level of secondary succession is determined by both those levels which precede and those levels which follow, the total ecosystem being the recurrent and regenerative pattern of youth and maturity. A dynamic balance is achieved through the periodic reestablishment of secondary succession initiated by fire. … It is the unnaturally protected, statically maintained forest, brush, or grassland climax environment that is nonhomeostatic.” (Henry T. Lewis, “Patterns of Indian Burning in California: Ecology and Ethnohistory”)
“One of the most important recent ecological insights is the critical role of periodic disturbance – fire, flooding, insects, windstorms, to name a few – in maintaining species and habitat diversity. Rather than an anomaly that occasionally disrupts climax communities, disturbance is now viewed as the key recurring factor that keeps a mosaic of habitats in different stages of vegetation development …. [and] assures the presence of plants and animals that characterize each phase of the change from open land to mature forest.” (Glenn Douglas Dreyer, “Understanding and Managing Vegetation Change”)
“Many wetland ecosystems are not only resilient to periodic disturbances but dependent on them. For example, the floodplains of rivers in the western United States used to support stands of cottonwood trees, which are now declining. The cottonwoods rely on spring flooding for the germination of their seeds. However, once irrigation reservoirs were built to capture the snowmelt, the floods ceased and so did cottonwood generation.” (C. Colston Burrell, “The Natural Water Garden”)
These ideas aren’t new – the quotes above are from the 1970s and 1990s. This is just the first time I’ve grappled with them. If a “stable” system is in fact dangerously unstable, maybe we shouldn’t be striving for a stable, self-perpetuating system but rather for a dynamic system made up of many small parts, in which each part goes through cycles of several hundred years.
Native American tribes seem to have managed this quite well, using fire as the agent of disturbance. But again (see previous post), their success was based on very low population density and a semi-nomadic lifestyle. Trying to apply these ideas to today’s densely populated, settled world is more than a little mind-boggling.