The Automatic treetap extracts and drops resin from resin holes on IC2's rubber trees. Resin holes get exhausted by this process and will not regenerate. The dropped resin is then collected by any Rubber Tree Harvester (now uses the Logger, any existing Rubber Tree Harvesters can be crafted into Loggers).
The Automatic treetap needs to be powered by a Buildcraft compatible engine. However if you want to use redstone engine you will probably need 5 of them to make this machine effective.