Definition: The removal of weaker plants or trees to decrease competition for resources such as sunlight, nutrients, or water and ensure ideal spacing for healthy and vigorous growth.
Thinning in the Forest Garden:
Thinning is a necessary practice in agroforestry in the Forest Garden Approach. Farmers apply this technique in a few areas of their Forest Garden to ensure that they are spending their valuable time, water, and labor on healthy plants that will flourish.
One of the most common reasons for thinning begins in the nursery when propagating seeds. Farmers sow multiple seeds in a tree sack or sow a bareroot beds more densely than needed, as not all seeds are likely to germinate. In many cases more than one seed will germinate in a sack or the bed will overcrowd. Since only one seedling should be raised in each sack, farmers should examine and determine which seedling seems strongest, removing the others. If they all look healthy, the farmer can also transplant these other seedlings into a new sack or to one where no seeds germinated. In bareroot beds, stunted seedlings can be culled while healthy seedlings can be transplanted to provide adequate spacing between them.
This resource competition can also occur in living fences or alleys, especially those that are densely planted by direct seeding, so it is important for farmers to monitor the initial growth and make sure there is no overcrowding. A farmer might also eventually need to thin some of the older trees in an alley cropping system if they grow too large and their canopies begin to crowd each other out or to block crops between the alleys from getting the sunlight they need.