An interesting programme on Radio 4 today. It concerned the subject of tree
root systems. (Plants from roots to riches).
Here is my memory of the programme - but I suggest that anyone really
interested listens to it on Iplayer as my recollection may not be 100% correct.
In the very high winds and storms of 1987 a particular oak tree at Kew was
totally lifted from the ground (including the root system) - but then it
dropped back in to the hole! (The tree had been planted in the 1700s). The
condition of the tree prior to the storms was causing some concern : thinning
crown, dead wood, and poor leaf growth
It took Kew three years to sort out the damage to the other trees from the
storms and the particular tree was left until the end in order to decide what
to do with it.
The staff were very surprised to find that the tree was now in much better
condition than what it had been before it was uprooted.
They concluded that the number of visitors had compacted he earth over the
years, over the root system - and that was what has caused the tree to be less
than perfect with little or no growth. They also checked various research and
were actually surprised to realise that the majority of tree roots tend to be
only between 1m and 2m deep (a fairly unknown fact) - and that hence all the
compaction had caused significant distress to the tree roots.
They embarked on a change of policy - and started to aerate the roots of their
trees - forcing compressed nitrogen (later air) in to the roots to a depth of
about a metre. They also forced water and various feeds in to the root system.
The results were astounding. They now use a modified process of forcing
compressed air in to the root systems of all of their trees.
I must admit I was gobsmacked with the comments about the depth of the root
systems: I always thought that the main root system were much deeper than one
or two meters.
I have since found a page which explains the process in more detail than my
poor memory:
http://www.forestryjournal.co.uk/new...9/Iss27Kew.pdf