Observing forest succession at the Boreal Ecology Centre

By Graham Peters, Manitoba Conservation Science Coordinator

February 1, 2022

As you walk the trails of the Boreal Ecology Centre in East Braintree you are bound to notice the incredible diversity of the forest. Below your feet the ground is carpeted by mosses, flowers, and fungi, and above you jack pines and aspens tower on all sides.
But pay close attention and you may notice the plant life on display changes as you walk through the forest. When you take careful note of the communities of plants that persist from stand to stand you will find that this single forest is actually a mosaic of unique ecosystem types.

Left: 2006 ecounit map of the Boreal Ecology Centre property

The property was mapped to identify where the different forest types were. What is especially interesting is that those forest types did not stay there! Or perhaps a better way of saying it is that the forest changed over time, some forest types appearing to expand and others to recede.

This is a process known as succession, the way the community structure of a forest will change over time. Let me use an example from the centre to clarify. In the original map from 2006, you will notice a small strip north of the river identified as “old field habitat.” The area became dominated by a variety of grasses and wildflowers after it was no longer mowed and maintained. 

Above: “old field habitat” ecounit

In the original report where this is defined it notes; “Over time, forests and shrubs will once again dominate these open areas, if they are left unchecked.”* 

And sure enough, what we have observed is that trees and shrubs have returned to the space, creating a patch of “early seral mixed forest.” Interestingly, this report defines early seral mixed forest as being “previously cultivated and has been allowed to regenerate”. In other words, the old field habitat has become early seral mixed forest, a succession we have seen in other places on the property. One type of ecosystem gives way to another and the forest community changes.

Succession is exciting because it means that the forest is always active. Over time the forest will grow and promote conditions that are supportive to other plants. In the early stages of succession or primary succession, only the hardiest plants can survive. The soil is poor and the sun exposure is high, but once these more tolerant plants have taken root they are able to create a more hospitable environment for the next wave of plants; secondary succession. The first trees now block the sun for shade-tolerant plants and the increase in plant matter adds richness to the soil. Several species make space for others and so on, and the forest continues to support new life and new growth.

Above: 2020 updated ecounit map

So how do we keep track of how the forest is changing? By observing and recording populations of the trees, shrubs, and other plants over time. Now, monitoring an entire forest is a big job; after all, 220 acres is a lot of ground to keep track of. So we take samples, smaller sections of forest called quadrats that we can use to help us understand the forest as a whole. These quadrats serve as permanent monitoring sites where we can record plant populations, and observe changes; plant growth, and population shifts. The data will help us to say with confidence how our forest is changing and offer a metric for its health.

This is our plan for the future at the Boreal Ecology Centre; to continue to observe how our forest is changing. Succession is part of a healthy forest and by continuing to watch our forest as it changes we can help to ensure that this natural cycle continues.

*A Rocha: Christians in Conservation. 2006. Overview Environmental Inventory and Assessment for the Loewen Property: East Braintree, Manitoba.