PDC Day 6: Trees

Graham Calder discussing food forest succession

A stunning relationship between forests and rainfall: trees add 50-75% to the total precipitation in the world.

Moisture moves inland from the ocean only about 100 km. If it weren’t for the forests, the rest of the land would be desert.

So rainwater is like a seed that plants a new and more important part of the water cycle, thanks to trees.

Trees are water pumps that move water from deep in the ground up to the clouds,  propelled by wind and capillary action. When it rains, water gets filtered back to the ground via leaves and stems, washing nutrients to the ground.

I wonder if forests would get more respect if their importance were better taught in schools.

Building a food forest is a long-term project. To be successful, you have to think in terms of succession patterns in nature. By starting with pioneer nitrogen-fixing plants that will be overtaken by the desired trees later, you build soil fertility so that the high-value desired trees, such as apples or pears, will thrive.

The high-value tree is surrounded by a guild of plants that fill many functions. Some fix nitrogen. Others confuse pests, repel deer, mine the soil for minerals and provide a rich mulch, or attract pollinators.

There are many interesting and even unusual trees you could grow in a food forest.

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