Treneer was a Cornish teacher and well known author who wrote about Cornish life in various periodicals and published several volumes of autobiography on her life in Cornwall, Oxford, and Birmingham.
Trenner's father was the Headmaster of the village school, which she attended before joining St Austell County School. After leaving school, she trained as a teacher in Truro and taught in Cornwall for a number fo years. She later took an external course at London University during the First World War, then spent a year at Liverpool John Moores University, and took a postgraduate degree at the University of Oxford as a mature student. She taught for 17 years at King Edwards High School for Girls in Birmingham.
Her autobiography, published in three volumes, covers her early childhood in Cornwall until 1906, her time in Truro, Exmouth and Exeter, as well as Camborne, Liverpool and Lady Margaret Hall, Oxford, and ends with her time spent in Birmingham between 1931 and 1947. Treneer retired from teaching in 1948 and wrote a life of Humphrey Davy, The Mercurial Chemist: A Life of Sir Humphrey Davy, which was published in 1963. Treneer died in 1966.