Charlottetown experiments with mini forests to speed up growth

The City of Charlottetown is experimenting with a new way of growing forests, using native species and denser planting to encourage faster growth. 

It's called the Miyawaki method, named for the Japanese ecologist and botanist who developed the idea of mini forests, and how to grow them, in the 1970s.

The technique is now being used in urban areas across Canada and around the world. 

"When we think about a forest, we're thinking about trees over four metres high, so hopefully within the decade we'll be at that point for a majority of this area," said Simon Wilmot, program co-ordinator for environment and sustainability team for Charlottetown.

"We're talking about creating forests in an urban or suburban area that can grow faster." 

Wilmot said the first step is to amend the soil, to simulate the kind of organic matter that would be found in a mature forest. That involves adding a lot of compost and mulch. 

"In this case, we added 12 cubic yards of wood chips to the site, and really tried to make sure the site was as healthy as possible in terms of the soil before we started planting," he said. 

It's not just a matter of richer soil. The trees in the mini forest are also planted closer together, a metre apart versus the three metres you'd observe in a more traditional planting, said Wilmot.

"That high density does a number of different things. Number one, there's the competition. The competition between the trees will force them to grow faster, quicker," he said.

"Secondly, they will squeeze out space for invasive species. Most of the urban watersheds, we have problems with invasive species, so it really doesn't allow them any room."

Wilmot said the method "allows nature to take its course with the trees," with the strongest thriving.  

"Those trees that don't make it, or die, will just feed the soil and provide organic material for the next generation."

Wilmot said his crew planted two mini forests in June, a larger one in Wright's Creek with 200 native trees and shrubs and a smaller one in the Ellen's Creek watershed.

"The downside to this method is, it is costly. It does cost a lot to take the time to amend the soil," he said.