Fences are ubiquitous in most western societies and have a history spanning several millennia. Many are important historic heritage, recording changes in technology and attempts to settle and manage land. Various forms of log, brush and post-and-rail fences occur widely in south-eastern Australia. Although common in the 19th and early 20th centuries, most have been replaced by post-and-wire on farmlands. However, those that have survived, usually in forests, are now rare, are highly significant historic heritage, and are at severe risk from recurrent wildfires. Three examples illustrate the problems: chock-and-log fence (western NSW), cockatoo fence (south-eastern NSW), and log fences (central highlands of Tasmania). They are all likely to be more than 100 years old and are currently among the only known examples to survive. There is no realistic way to protect the fences from either wildfire or hazard-reduction burning. Ageing and rot predispose the logs to ignition by smouldering embers, and normal fire containment procedures make little allowance for historic heritage. The only approach is to record the fences before they go up in smoke. As fences are distributed world-wide, the problem is not restricted to Australia, and probably has not been recognised in other countries.