UKTC Archive

RE: neighbouring tree roots and RPAs

Subject: RE: neighbouring tree roots and RPAs
From: Jim Quaife
Date: Mar 04 2021 08:10:40
A good many years ago I bought a book 'The Supporting Roots of Trees and 
Woody plants: Form Function and Physiology'(1999) ISBN 0-7923-5964-X 
(ruinously expensive!) The attached image (from page 114) is of physically 
exposed roots of group-cultivated NS in the top 20cm of soil - minimum root 
diameter measured 5mm.
The arrows are root grafts. (Low resolution to 'fit' in uktc)
There is a lot of good stuff in it but this study is and has been 
particularly useful.
Jim

-----Original Message-----
From: uktc-request@xxxxxx.tree-care.info 
[mailto:uktc-request@xxxxxx.tree-care.info] On Behalf Of Jon Heuch
Sent: 03 March 2021 18:17
To: UK Tree Care
Subject: RE: neighbouring tree roots and RPAs

Barrier? Not really? But competition, yes.

 

If you plant trees in a spacing trial (i.e. the same species, preferably
uniform conditions as far as possible) with different plots having different
spacings initially all the trees should grow at the same rate; those planted
most closely will encounter competition more quickly than those planted at
wider spacings so stem diameter growth slows down. Taken to extreme and
using very wide spacing you can get "free" growth for longer periods of
time. But the trees don't stop growing when competition is observed - merely
slow their growth, unless competition is intense; the roots continue to
exploit the soil wherever it is; there is no advanced party of roots marking
up their boundary, but there will be parts of the soil dried and exploited
that may be less useful for a neighbouring tree so their roots will try
elsewhere, wherever that may be.

 

You will find diagrams from those who have actually bothered to dig up tree
roots that show no such "barrier". Biddle's Vol 1 page 25 shows such a
diagram. I believe there is one in TROBI but I can't see it at the moment.
Another one in one of the Harvard Forest papers.

 

I'm not sure of any of your references other than Hirons & I would
appreciate a full set of references if you have them..

 

Jon 

 




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Attachment: Exposed root systems.pdf
Description: Exposed root systems.pdf