Much like our own communities, our forests are diverse, or at least, they should be.
What is forest biodiversity?
According to the Convention on Biological Diversity (CBD), forest biodiversity refers to the variety of all life forms within a given forest, including everything from micro-organisms to plants and animals. Beyond their presence in a forest, it also refers to the complex interactions they form amongst themselves. Why is this important? A thriving and diverse forest offers environmental, economic, social and cultural value to our communities.
So, what makes forests naturally diverse? There are many levels of diversity that contribute to a forest’s overall biodiversity. Here are four key ones to consider:
1. Keystone Species and Diversity
Within each ecosystem, there are often one or more species crucial to the health of that ecosystem. These species are often referred to as keystone species. Whether it is a plant, an insect or an animal, the survival of other species within the ecosystem would be compromised without them.
A naturally diverse forest offers incredible ecological value – of which trees are a major contributor. Not only do trees offer a habitat to a variety of organisms, but they also create environments conducive to new plant growth. For example, aspen trees are considered keystone species in the Boreal forest because of the habitat they provide to fungi, insects and birds.
2. Species Diversity
The variety of species that live within a forest contributes to its resistance and adaptability to change. This is particularly true of tree species as well. When a forest lacks diversity in the types of trees planted, it becomes more vulnerable to damage caused by pests or a changing climate.
An example of this can be made from the effects of Dutch elm disease. Across North America, elm trees have been dying off since first exposed to the pathogen in the 1930s. Although there are ways to protect and reduce the spread of Dutch elm disease, it is costly and time consuming. Given that Dutch elm disease targets elm trees specifically, a forest made up solely of elm trees would be much more vulnerable against exposure to the pathogen, compared to one rich in a variety of tree species that could compensate for loss of susceptible trees.
3. Genetic Diversity
According to Bioversity International, genetic diversity supports the growth and general survival rates of a tree population. How? Genetic variation in a tree population can help protect against stressors and climate change, which could otherwise compromise the sustainability of the population.
Given the importance of genetic diversity, the Canadian Forest Service has created the National Tree Seed Centre in an effort to preserve genetic diversity within Canadian forests.
4. Age Diversity
The cycle of life plays a critical role in any living population. Be it humans or trees, a population is at its strongest when there is diversity in age. When it comes to managing forests for long-term viability, a tree population that is diverse in age structure is an important consideration. Having a diverse age structure can help to buffer the forest against stressors that impact trees at different life stages. For example, younger trees can grow into the gaps left by older trees as they complete their lifespan.
Each age class plays an important role in the forest canopy. One benefit of older and taller trees is that they can offer a larger canopy of protection for organisms living below it, while young trees can provide habitat complexity and wildlife shelter lower in the canopy. When it comes to carbon absorption, both mature and young trees absorb and retain carbon. However, they do so at different rates.
Embracing Nature’s Diversity
Evidently, there are many levels that contribute to a forest’s overall biodiversity. Embracing these diversities and taking them into consideration is key to optimizing a forest’s health and longevity.
Let’s Help Keep Our Forests Naturally Diverse, Together.
Want to help us build diverse and resilient forests across Canada? Donate towards the planting and care of an urban tree in your community. With the purchase of a $40 urban tree, you will help Tree Canada in creating greener cities and towns for years to come.