VIU Milner Gardens and Woodland

Forest Dynamics

Forests Are Always Changing

The forest at Milner Woodland is the product of contrasting ecological forces: disturbance and recovery. Events such as wild fires or windstorms can be destructive, but such events have always occurred in the past, and the species of the forest have evolved ways to recover after a natural disturbance. In fact, some species require periodic disturbance to create the conditions they need to thrive. After a major disturbance that kills most of the trees over a large area the process of recovery begins. The new forest develops through four distinct structural stages:

  1. During the initiation stage, young pioneer trees become established in the open and sunny environment. Scattered veteran trees that survived the disturbance provide some shade. Many shrubs, grasses and flowering plants are present.
  2. As the trees grow, the forest canopy closes over and many smaller plants are shaded out. The forest enters the self-thinning stage, as the less vigorous trees die due to lack of light and the trees shed their lower branches.
  3. Occasionally a large tree will die, leaving a gap in the canopy and allowing more young trees or other plants to re-establish in the understory. The forest is in the re-initiation stage.
  4. Eventually, many of the original pioneer trees have died off. The forest is a mosaic of several ages and species of trees. Some very large old trees are present, as well as standing dead trees, and large fallen logs. Gaps in the canopy allow a diverse assortment of small trees, shrubs and ferns to thrive underneath. This is the rich and diverse old-growth stage. Due to human activity, old growth forests are very rare in the Coastal Douglas-fir zone.

All four structural stages are found in the Milner Woodland, and are identified at the various interpretive stops.


Biological diversity (biodiversity for short) means the diversity of life.

Diversity of Species

British Columbia is home to 458 species of fish, 20 amphibians, 19 reptiles, 448 birds, and 143 mammals. There are at least 2850 plant species and between 15,000 and 35,000 insects. Many of the smaller and rarer species of life have never been recognized by science, and no-one can even estimate how many species of fungi and microbes may exist.

Genetic Diversity

The number of species in British Columbia is only the tip of the iceberg. Within each species, there is genetic diversity. For example, the Douglas-fir trees in this forest are each genetically distinct, just as every person is unique. There is as much genetic diversity in most tree species as in the human race.

Ecosystem Diversity

An ecosystem is an assemblage of living organisms – plants, animals, fungi, and microbes – and the non-living environment around them, including the soils and climate. The ecosystem also includes functions,

Conserving Biodiversity

With human activities altering many natural environments of the earth, conserving biodiversity is necessary to protect the ecosystem functions we all depend on. Important forest functions include controlling global atmosphere and climate, providing habitat for wildlife, conserving soil, and supplying high quality drinking water. But regardless of human utility, many people value the diversity of life for its own sake.

Because there so many species of life, and genetic variations within species, it is impossible to conserve each one individually. A practical alternative is the “coarse-filter approach” which means conserving as many different types of ecosystems as possible. By protecting a rare type of old growth forest ecosystem, Milner Forest plays an important role in conserving British Columbia’s biodiversity.