The Forestry Corps was much less stringent about medical qualifications than the Infantry was. The Creston Review article that announced the formation of a Forestry Corps unit in Creston provided details: minimum height was 4 feet 11 inches; loss of hearing in one ear or sight in one eye was acceptable; men who had lost toes or fingers would be accepted as long as they were capable of five-mile walks and heavy labour. Maximum age was 48 - though we can easily see from the ages of those who enlisted in Creston that this was a fairly flexible requirement.
Nevertheless, there were limits. John Callahan, although he gave his age at enlistment as 45, was discharged at Creston in April 1917 as medically unfit due to overage; evidently, his age made him unable to carry out the hard work expected of Foresters overseas. Frank Clarke appears to have lied about his age to ensure his acceptance by the medical review board.
Clarke's attestation papers give his date of birth as 9 August 1871, making him just shy of his 46th birthday when he enlisted. However, we found a Canada Census record for him which indicates that he was born in 1868 - making him nearly 49 when he signed up with the Forestry Corps. He was certainly not the only one to be over the maximum age of 48; there was a handful of others, including the Commanding Officer. Clarke, however, seems to have struggled with his age. His service record makes a number of references to it, and he was finally discharged in October 1918 for being medically unfit due to senility.