"Nick Maclaren" wrote in message
...

[snip]

In terms of direct sun, even our summer sun is rarely strong enough
to worry them - yes, I really DO mean that it is comparable to
the light levels in a tropical forest!

The light levels in the (sub)tropical forests of which I have knowledge are
very low indeed, except in locally around clearings. Much lower than our
summer sunlight provides.

[snip]

Franz