I've recently returned from another trip to Kintamani, Bali where it's the pruning season for the coffee trees. I stayed for a week so that I could not only scout more farms in the Subak (co-op) but also so I could learn how to prune coffee trees.
Pruning is one of the earliest stages of quality development and it's a very forward-thinking, strategic process. You directly affect quality through good pruning practices. The goals of pruning are to:
- Generate new branches in order to maintain production levels
- Improve air circulation in order to protect against fungus development and high, trapped humidity
- Remove weak branches in order to redirect plant energy (nutrition) to better-producing branches
- Maintain or obtain a desirable shape for easy harvest and future maintenance
- Expose more of the tree to sunlight
Most high-quality coffee shrubs have a capped, single-stemmed (monocauly) shape, which supports efficient nutrition transfer from the roots to the branches.
The fruit is the economically viable part of the tree, therefore all maintenance is aimed at supporting quality fruit production. Pruning removes new growth that requires nutrition to support — nutrition that could be focused instead on quality fruit production.
Flower and fruit development is encouraged by exposure to sunlight and inhibited by shading. Overexposure to sunlight results in overproduction of fruit and more fruit means reduced complexity and sugar content in the fruit. Pruning is, therefore, part of the delicate balance between sun exposure and shading of tree parts inside the tree's canopy in order to control production levels and nutrition direction and consumption.
Pruning isn't an exact science. One of the first things the farmer told me as he was teaching me, was that when I talk to another farmer about pruning, he'll likely have a different philosophy on how to prune. The only way to know what is right for a specific farm is to experiment with different pruning techniques and monitor the tree's performance and health over the years. Like I said, this is a very forward-thinking, strategic process.