Old-growth forest reserves offer the potential to facilitate the maintenance of multiple ecosystem services (ES), such as carbon storage, water and recreation, in managed landscapes. However, substantial challenges exist with regard to defining and identifying old-growth forests, and suitably locating priority areas for old-growth conservation. To address these issues, I developed a structure-based old-growth index using field and LiDAR metrics that allowed old-growth values to be estimated at a fine grain across a landscape. I then used a spatial prioritization tool to simulate old-growth reserves for multiple ESs. Using this framework I evaluated trade-offs between forest ESs including timber. This thesis contributes to the management of old-growth forests by providing a quantitative and repeatable framework to identify, assess and monitor old-growth values while indicating the scope for the establishment of old-growth reserves for multiple ESs.