Sentence:  When a tree is to be <WSD>cottoned</WSD> the ends from the cops are brought together and tied in a rough knot, which is hitched to a twig. Then, with the tube held upright, the operator walks round the tree as many times as may be necessary to cover it with lines of cotton, raising the metal tube about three feet after each round. 
Meaning of the word marked with <WSD> tags:  To wrap with a protective layer of cotton fabric.