A Miyawaki Forest – Restoring Native Growth in Calgary

There has been much press recently highlighting “green” projects, many of which have arisen as a response to pollution and environmental destruction. This month I would like to introduce readers to the concept of a Miyawaki Forest, along with a different format for The Bowtanical Garden.

Recently, I had a conversation with Bowness resident Rob Miller, who has been in discussion with The City of Calgary Parks concerning the planning and planting of a Miyawaki Forest in a section of Dale Hodges Park.

Beverley – Rob, I understand that a Miyawaki Forest is named after the late Akira Miyawaki, a Japanese botanist and ecologist, but what exactly is a Miyawaki Forest?

Rob – Beginning in the 1970s, Professor Miyawaki advocated strongly for “natural forests” and the need to restore them. His studies at the time revealed the majority of forests in Japan were populated by non-native species, primarily planted for timber to support the forest industry. In some instances, the native forests had been removed completely to support agriculture and construction projects, resulting in many instances of erosion and severe soil degradation. He then launched a series of test projects in Japan to reintroduce deciduous native trees, as well as accompanying natural vegetation in an effort to restore the original biodiversity.

The interesting part about these initial projects is that Professor Miyawaki observed some natural forests remained intact around temples, shrines and monasteries in Japan, which allowed him to study and catalogue them. He also collected their seeds, which were then used as the foundation for planting new natural forests.

Beverley – I understand these initial projects were very successful in Japan, and Professor Miyawaki went on to conduct similar projects in many other countries to restore their native forests. This makes me think he uncovered a number of benefits from using his methods.

Rob – Yes, there are many benefits to reintroducing a native forest, but the most significant one is that a planned and planted native forest consistently regenerates much faster than a monoculture of non-native species, Professor Miyawaki determined that a planting using his method became a thriving natural forest within 20 to 30 years, nearly 10 times faster than typical tree plantations in Japan. Another benefit is that once a natural forest is established, in about three to four years, no maintenance or chemical fertilizer is required. The forest sustains itself and supports local biodiversity – the wildlife returns and the soil gradually improves. It has also been recently determined that these reintroduced natural forests can absorb upwards of 30 times as much carbon dioxide as forests planted for timber. In many locations, natural forests are found to be more drought-tolerant and can mitigate flooding by absorbing more water.

Beverley – Most “greening” projects I’ve noticed in Calgary usually start on barren ground and are sparsely planted with a few trees braced on poles. I see a lot of dead trees lining our streets in the spring! As the establishment of Miyawaki Forests has been successful in many countries, is there a process that has been developed to increase the chances of achieving success?

Rob – Yes, Professor Miyawaki developed a five-step process for the planning and planting of a natural forest with an aim to create a layered effect of trees, shrubs and ground cover. This process has been successful for large deforested areas, along city streets and parks, and even for small backyard groves. The five-step process is:

  1. A site survey is made of existing vegetation in the area, including all types of plants, from places that are still in a relatively natural state. Soil testing is conducted to compare soil from the natural area to soil in the planting site.

  2. Professor Miyawaki also collected seeds from native plants and used these to grow seedlings in a nursery. Plants and trees can also be ordered from nurseries without the added step of collecting native seeds.

  3. Soil is prepared at the planting site, with up to 30 centimeters of organic matter selected to bring the plantation site closer to native soil composition.

  4. A mixture of multiple species of trees, shrubs and ground cover (up to 40 different species) are planted randomly and close together to encourage competitive growth.

  5. Watering (if required) is done for one to three years to allow for the plantings to take hold. After this point the site should be self-sustaining.

Beverley – This seems like a fairly straightforward approach, but not something that one or two people could tackle on their own. I understand you’ve been in discussions with The City’s Parks Department about possibly undertaking a Miyawaki restoration project in a portion of Dale Hodges Park. 

Rob – Yes, I have had a very positive response from Calgary Parks, as well as Drs. Jana Vamosi and Mindi Summers, two biodiversity scientists at the University of Calgary’s Department of Biological Sciences, who have agreed to help with the project. Mike Dorion of Living Soils Solutions in Calgary has also expressed interest in helping out with the soil testing, which will be a critical component when we start to plant. However, as this will be a big undertaking, we are looking for volunteers from Bowness and surrounding communities to get involved with this project.

We are planning a Bio Blitz for Monday, May 23 to photograph and catalogue native plants in the forest around Dale Hodges Park. We want to identify as much existing native vegetation as we can. This will give us a good indication of what types of trees and shrubs will be successful. Dr. Vamosi, and possibly some of her students, has volunteered to be on hand for the Bio Blitz, to help volunteers with plant identifications. It will be a fun experience for those who like being out in nature and learning about native trees and plants.

Beverley – I really enjoy Dale Hodges Park, and this is exciting as a possible next phase for restoration of that area. If people are interested in taking part in the Bio Blitz, who do they contact?

Rob – I love walking my dog in Dale Hodges Park! The landscape architects have done an award-winning job creating the wetlands and trails in the area. Anyone interested in participating in the Bio Blitz can send me an email at rmiller@winexus.com.

We’ve set up the project on iNaturalist.ca to allow people to upload their plant photos from Dale Hodges Park during the Bio Blitz, but if you can’t make the event, you can still participate on your own time. Just email me for details on how you can add your photos to the project.

  • Beverley Sheridan, The Bowtanical Garden

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