Think about what a properly structured forest is to you. Would you include things like a closed canopy and the need for large groupings of mature trees? Would you stress the need for species diversity and the ability to resist disease? All of these points are very important, but a proper forest structure really includes everything from the massive, mature trees to the smallest fungi hiding under fallen leaves on the forest floor.


 

In the urban forest we are often lacking many of these important structural aspects – focusing mainly on the need for mature trees. Don’t get me wrong – this is exceptionally important for the urban forest and provides us with much needed environmental benefits – but we require more than just that! We need there to be another generation of younger trees (seedlings and saplings) present underneath our beautiful shade trees, ready to take their place if, for any reason, the older trees fail.

 

Trillium

 

Our society’s obsession with a perfect Kentucky bluegrass lawn is a great hindrance to forest structure –creating a homogenous layer under the trees, choking out everything else. When you’re out hiking in a natural area, do you ever see (non-native) grass growing throughout the forest? I hope not. Instead, you should see leaves, fallen limbs, saplings, seedlings, flowers, mushrooms, and leafy green shade-loving forest plants.

 

This tiered structure plays a huge role in keeping the forest healthy (nitrogen anyone?) and is also a very important aspect in creating wildlife habitat. To increase the diversity within the urban forest, we need to focus on bringing back proper forest structure – both on public and private lands. How can you create these tiers in your own backyard you ask? Do you have a shade tree on your property? If not, that is your first and most important step.

 

Forest Structure

 

If you do, focus on keeping tree debris (i.e. leaves and even fallen branches) to allow for nitrogen recapture as well as getting understory plants into your garden. Pagoda dogwood is a great example of an understory tree that has a unique growing shape and provides food for songbirds (not that I’m showing favouritism…). You should also try to find native grasses and flowers that will flourish in the growing conditions of your yard and (hopefully) phase out the majority of Kentucky bluegrass on your property. You can even purchase a pet log to grow different fungi species!

 

Not sure where to get started? Come check out LEAF’s Learning Garden where you can see what a native garden can look like (and it’s smartphone friendly). If you’re worried about how much shade you already have in your backyard and think you don’t have as many options as sunny gardens, consider LEAF’s shade garden kits that have only shade-loving species (most flower as well), designed to create a beautiful “forest floor look” – even in the urban forest environment.

 

Native understorey perennials

 

No matter what your backyard looks like now, there are options available for you to create a proper forest structure within it! Contribute to the urban forest and wildlife habitat today by getting started!