During this era of climatic change, shade trees are without a doubt very important in coffee farming. Their umbrella shaped canopies provide shade thus mitigating against excessive temperatures and heat stress that are responsible for flower and fruit abortion. Shade trees also provide numerous other benefits.
Deep rooted shade trees recover soil nutrients from deeper soil horizons and transport them to their leaves. When the leaves fall and rot, they provide organic matter or manure which is released to the coffee plantation. This organic matter improves the soil texture and water retention thus availing the much needed water to the coffee. Besides, deep rooted trees don’t compete with the coffee for water and other nutrients. In addition, shade trees of the leguminous species capture much needed Nitrogen from the atmosphere and convert it into nitrates which are used by the coffee for numerous purposes.
Shade trees act as windbreakers to protect the coffee trees from excessive and destructive winds and some even repel dangerous pests found in the environment.
Some shade trees are a source of foliage for domestic animals and at the same time an important source of firewood in rural households when they are pruned to regulate shade. This process is called pollarding.
Trees to avoid
However, the tree species with the following traits need to be avoided:
- Trees that are alternate hosts to the Black Coffee Twig Borer e.g. Avocado and Albizia chinensis.
- Hardwood trees that attract pit sawyers e.g. Grevillea robusta and Maesopsis emimii or Musizi in Luganda.
- Trees that take very long to grow e.g. Milicia excelsa or Muvule in Luganda
- Trees that can only provide conical shaped shade e.g. eucalyptus and jack fruit trees.
- Trees that have leaves that take very long to decompose.
- ·Trees that produce thorns as these are very difficult to tame e.g. Erythrina abyssinica or Ejjirikiti in Luganda·
- Poisonous trees,