Thursday, January 26, 2012

Permaculture Succession

This tiny apple seedling...

...will one day become a large tree, but it can take a decade.

When most of us think about landscape design, we think about what goes where. We think about three dimensions. Height. Width. Depth. The X-Y-Z axis... Will this plant "work" here or there? I think I will plant this shrub next to this tree for a specific benefit.

A few of us will think about seasonal changes... This deciduous tree will lose its leaves in Autumn and let sunlight through in the Winter. These bulbs will come up in early Spring, bloom, and die back before my other perennials really start growing tall enough to over-shadow them.

There are even fewer still who will think about the changes that take place over years or decades. This is the realm of Succussion.

Succession is a well known ecological concept.
We need to remember that Permaculture is about modeling the natural world...
so our designed ecosystems should at the minimum acknowledge succession.

Succession, in a Permaculture or Forest Gardening world, deals with the design of plant community changes and transformations over the fourth dimension... time. This is a massive topic. When we starts to think about it in depth, we can get easily overwhelmed. I just want to introduce the topic today. Future articles will tackle specific aspects of succession, but today, I just want to wrap our minds around the idea of design over years.

Let's just take the planting of a single tree. Let's make it a full-sized, or standard, apple tree. This tree will take up to eight years to begin producing and over a decade to begin producing full crops (yet another reason I need to get my land as soon as possible! but that is another story). In a Permaculture design, especially a Forest Garden, we need to remember that this tree will not be growing on its own in a field by itself. There will be other plants around it. There will be other trees nearby. But this tree when first planted is likely only a few years old and no more than a few feet tall... a spindly twiggy shadow of what it will be in future years.

The most important thing we need to do is plan for the future mature size of this tree. The biggest mistake people make in planting trees in a Forest Garden is to plant trees way too close together. This is done often because they have limited space and want to squeeze as many varieties of plants and trees in as they can, and this temptation is made easier when the trees are so small to begin. The second reason, closely related to the first, is that because the tree is so small in its young stage, it is hard to picture what it will be like when full grown. Its hard to see that one foot sapling black walnut as a towering 100 foot (30 meter) colossal tree.

I cannot overemphasize the importance of schematic sketches of our land. We need to have a rough sketch, at the minimum, even if you are not a great artist, of what the land will look like in 1 year, 5 years, 10 years, 20 years, etc. We need to keep in mind how things will change, because they will change! This is not a bad thing. In fact, it is what we want!

I've seen too many people get upset that, for instance, a ten year old raspberry patch just isn't producing anymore. They don't want to pull it out, because they are attached to it. But it isn't producing much anymore, and the birds eat what is produced. It then gets straggly and overgrown and frankly, quite ugly looking. Well, raspberries only have about a ten year useful life! What did you expect? Plan for that change!

How about this? Place that raspberry patch surrounding that young apple tree. We will be using that space that will one day be shaded out by that apple tree. We will be protecting that young apple tree by surrounding it with thorny plants to keep the deer away. We will be collecting a yield from that land until the apple tree really starts to produce. The raspberries will just be fading out as part of their normal life cycle just as the apple is coming into its own. We will be motivated to clear out the old raspberries, so we can harvest the apples easier.

This is the concept of succession. Start thinking in the fourth dimension!

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