The Access Code says:
Tree felling, timber extraction and haulage may affect an area of forest and forest roads for several months. Read any signs warning you of forest operations, such as tree felling and extraction, and follow any precautions taken by the land manager. This will ensure that you do not hinder these operations and ensure your safety and that of people working there. In some cases, signs may indicate that it is safe to go along a route if the activity has stopped, such as for the weekend.
If you come across machinery, keep a safe distance. Take extra care if you are walking, cycling or riding along forest tracks as heavy timber lorries might be using the tracks. Do not climb on to timber stacks and keep children away from them.