has been the law in Alberta since 1966. Under legislation, a forestry company
must "treat" a harvested area within two years of logging.
"Treatment" means ensuring either natural regrowth or artificial
reforestation. With natural regrowth, or regeneration, a timber company ensures
that conditions are right for trees to grow back naturally. This means making
sure that existing trees produce adequate viable seeds; or in the case of aspen,
that conditions are favourable for sapling regeneration from roots. It also
means making sure that the seeds and very young trees have the proper conditions
to survive and grow. Currently, about 20 percent of the total harvested area in
the province is regenerated naturally.
reforestation is accomplished by replanting seedlings, or by direct seeding. The
type of reforestation treatment and activity is determined by the species
harvested as well as numerous site conditions. Replanting efforts have improved
considerably in recent years, both in the methods used and the quality of the
seedling stock. Today, replanting accounts for about 60 percent of the area
harvested annually. Direct seeding typically accounts for 20 percent of the
total area harvested. The total area treated using these techniques continues to
replanting, direct seeding or natural regeneration, the area must be surveyed
according to provincial standards. The surveys are done at specific times to
check for the types of species that are growing, tree density, stocking and tree
health, or vigour. The establishment survey is completed four to eight years
after harvest for coniferous and mixedwood sites, and three to five years for deciduous sites.
A second survey,
the performance survey, is completed eight to 14 years following harvest, on
coniferous and mixedwood sites. This survey indicates how well the new trees are
growing and identifies areas where the growth of trees is being slowed by
competing vegetation. Trees must reach specified heights and no longer face
competition from other vegetation to be considered "Free to Grow".
When a performance survey reveals areas where there are too few trees or where
trees fail to meet height requirements, the site must be retreated. This
treatment could mean planting seedlings or clearing away competing vegetation,
such as grasses, shrubs or trees. The reforestation success rate in Alberta is
generally above 92 percent for coniferous, deciduous and mixedwood areas.
Department of the Environment. State of the Environment Report, Terrestrial Ecosystems. Edmonton: n.p., 2001. With permission from Alberta Environment.