Ontario Tree Marker Program - Opens in a new windowThe tree marking course covers topics such as silvicultural systems, silviculture, silvics, wildlife habitat, tree defects and tree vigour characteristics. Through this training, tree markers help ensure the sustainability of Ontario’s public and private woodlands by making ‘cut and leave’ decisions for individual trees. Tree marking, done in conjunction with good forestry practices, has the capacity to safeguard the wellbeing and longevity of a forest.