In article 509dcd5a-1351-4efb-8032-f9e30f6adbf5
@p16g2000yqd.googlegroups.com, says...

On Dec 24, 10:42*am, kay wrote:
NT;945627 Wrote:



On Dec 21, 10:38*am, Janet wrote:-
In article 7b359958-ee09-4751-a1be-
, says...

-

There are such in the wild in Britain, on woodland edge, eg
blackthorn
with blackberry growing under it.-

* *That natural combination is not a permanent sustainable planting
though; it's transitional.-

why do you say that?
-
* * Janet-

It's woodland *edge* - ie an open space on one side. Open spaces, left
to themselves, don't stay open. The next stage in success is scrub (eg
brambles and blackthorn) followed by trees which will eventually shade
out the brambles and blackthorn.

Trees put a lot of energy into developing a strong trunk to be self
supporting, so that they can over-top everything else and grab all the
light. Everything else is to a certain extent opportunistic, making use
of either *temporary gaps in the tree cover, or living in areas where
there isn't enough soil cover for trees (eg mountain tops, cliffs). They
avoid the need to put all that effort into building trunks, but have to
snatch what they can, where they can.

This is a gross simplification!

Permaculture is all about reproducing forest edge conditions, with
minimal management to effectively stabilise it.

Permaculture is about creating permanent, sustainable plantings. Which
forest edge never is in UK latitudes, because we have relatively low light
levels and just one relatively short frost-free growing season. In the UK,
if you plant permaculture layers (something like, leaf perennials, under
black currants, under apple trees) shade will eventually defeat at least
one layer.

It does work where it was designed for.. in countries with much higher
light levels and no frosts or a different pattern of growing seasons.

Janet.