Assessments in relation to parallel regions is surely always going to
be problematical especially in this time of global warming. Here in
South Central Victoria, Australia we are currently experiencing the
hottest November on record although today we have suddenly received a
quite substantial dump of rain which is more than we have had for months.
Bearing in mind that this is equivalent to a northern May we have
had temperatures in the mid 30's C and not much further north up in the
40's. This region is normally considered cold climatic zone 9b and heat
zone 4 and thus reasonably mild. We are only in Spring and the leaves of
the Agapanthus have been burnt and many spring bulbs have lost their
leaves prematurely. As an indication of the way plants are feeling the
heat quite a few sedums have been cooked as have the leaves of some
echeveria. With the sedum the most vulnerable area seems to be from soil
level with the dead stem tissue progressing up to where the middle aged
leaves are situated. I have lost many young succulent plants even though
they have been fully exposed to the sun right through winter and early
spring and thus should be acclimatised.
With such changes occurring are we in a position to seriously find
parallel regions beyond a fairly arbitrary set of conditions which may
be compromised even with our extensive deliberations. In our current
situation we do not even have parallel region conditions in our local
area where history is being rewritten.
Don Journet