The harwood forest Hardwood forests typically feature unevenaged stands, which means that the trees are of different ages and heights. The composition of these stands varies greatly according to the nature and intensity of disturbances. For example, despite having less light to grow in, young saplings of shade-tolerant species will take advantage of small openings in the cover to grow quickly and replace older trees. Under the cover of these trees, shade-tolerant species regenerate, gradually building up a new forest consisting of sugar maple, yellow birch, oak, beech, basswood, hemlock or white spruce. Although mixedwood forests are dominated by balsam fir, they can include all softwood species and most hardwood species typically found in Qu bec forests.
Renewal often takes place as a result of insect epidemics or forest fires.
Generally, a ravaged stand is quickly replaced by balsam fir saplings that have already been established as an understorey. The composition of these mixedwood stands is influenced by local climate and soil conditions. Mixedwood forests constitute the richest portion of boreal forests, making for greater contrast and permitting good growth of yellow birch.