You would normally collect the pieces that broke off and stick them back on again.
Otherwise you'd probably be best getting some epoxy modelling putty and using that to fill the missing sections. You'd probably have to colour it with something or else paint on top of it with some enamel paints to match the wood. Something like this: https://www.milliput.com/index.html
Last edited by Simon Barden; 19-01-2018 at 05:32 AM.