UKTC Archive

Re: Whacky? a change of subject line - Miyawaki

Subject: Re: Whacky? a change of subject line - Miyawaki
From: AV Arboriculture
Date: Nov 30 2021 18:49:05
Hi Jon,

I can't say I have read everything and I didn't want to lead anyone to any 
particular article or paper.

I gave a couple of links in a previous email: 'Urban Forests Company' have 
collated many (if not all) research papers relating to the Miyawaki Method 
and have published it here:

http://urban-forests.com/wp-content/uploads/2020/05/Urban-Forests-Scientific-research-on-urban-forests-created-with-the-Miyawaki-method-around-the-world.pdf

They have also summarised the research findings here:

Urban Forests Company, The Miyawaki method – Data & concepts, 2020: 
http://urban-forests.com/wp-content/uploads/2020/05/Urban-Forests-report-The-Miyawaki-method-–-Data-concepts.pdf

Between those two, I'm guessing you'll find what you need.

Regarding density, the trees will have smaller diameters initially and they 
tend to stop gaining in height at around 20 metres but will obviously 
continue to put on girth.  I haven't researched this aspect much though.  
There are plenty of photos of these forests and they seem to be thriving.  
The ones planted in the 70s and 80s (mainly from Japan and India) don't seem 
to have fallen over and haven't ended up as sticks.

It is not a m monoculture so they are not all competing for the same light.  
What is planted is a mixture of different trees, shrubs and ground layer 
plants, so different plants can occupy different spaces - it's not the same 
sort of competition you get in a monoculture.  Also, there is initial 
competition but then I guess mutualism through myccorhizal connections.  Some 
plants will get shaded or resourced out and will create more gaps for 
remaining plants.

"Growth stabilisation": this is a new term to me as well but I took it to 
mean peak height.  This can also be interpreted as a form of maturity, i.e. 
mature height.    

This method has been around for 50 years, has resulted in something like 2000 
new forests and is still being adopted as a planting method; if it was a 
failure then I very much doubt there would be any interest in in today.  
However it is fair to seek evidence.  If you look at photos of the many 
Miyawaki forests you will see that the plants do not stagnate or die off.  I 
am sure there will also be long-term research papers among the Urban Forests 
Company's collection.  As I said, I haven't read them all.  I only came 
across this method earlier this year and am still learning, but I can see 
from various images that the results are good.  Also, see the video link 
below.

Of course, any human planting isn't 'natural', hence the term 
'quasi-natural'.  It is trying to be as close to nature as possible by using 
many species of plants that occupy different layers and are classed as PNV 
(potential natural vegetation), so basically indigenous species.  They are 
more or less unmanaged and they create a healthy soil.  This seems a lot 
closer to nature than traditional planting methods.

I'm struggling to find images of older Miyawaki Forests - they may be in 
Japanese language websites - but there is a video of one he planted in 1976 
in Yokohama here:

https://www.youtube.com/watch?v=tybYS2R8FfY

I can't tell you exactly where the data for growth rates is, but it will 
likely be in that collection of research papers.  In any case, you can see 
from the video (and various before and after photos available in many places 
online, including IVN's website and Youtube videos) how quickly these forests 
grow.

I hope that gives you enough to go on!

Mike




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