Secateurs are used to cut diseased branches from trees or bushes grown using the Farming skill. They can be bought at all farming shops. They can also be stored with the tool leprechauns.
The main purpose for cutting branches off of trees and bushes is to cure that tree or bush that has become diseased whilst growing. Alternately they can be used to obtain willow branches from farmed willow trees. Up to 6 willow branches can be cut at a time, after which the branches regrow one at a time at regular intervals of approximately 10 minutes.
Following release of Fossil Island, secateurs now have a new use with the Hunter skill.