Re: disappearing Angophora costata

Richard Starkeson wrote:
> 
> Our local paper the Chronicle (derogatively referred to by the natives
> as the Comical) had a 3 line item in it today about the disease and
> death of virtually all of this tree in the vicinity of Sydney.  I have
> not seen the tree, but it is known for its attractive smooth bark.  Does
> anyone in that part of the world recommend it as especially attractive?
> Flowering display?  Is it really headed down the road to near
> extinction?

Agophora costata (Smooth Barked Apple or Sydney Red Gum)
In my Australian Wildflower Catalogue this relative of the Eucalypts is
described  as "a beautiful specimen tree for its interesting form, but
only suitable for the large garden or park".
It has large clusters of snowy white flowers very similar to those of a
gum tree.
It needs some protection from strong winds because of brittle wood and
also from frost when young.

For average gardens there is apparently a smaller species (A hispida)
known as the 
Dwarf Apple) described as a spreading shrub or small tree with the young
growths and flower buds covered with velvety red hairs. When the flowers
open they are white and showy and they are followed by ornamental seed
capsules..

The disease which is destroying these trees evidently became apparent
later than 1987 when this book was published, as there is no metion of
any problems with growing them. In fact the dwarf species is described
as "resistant to disease and pests"

> For those not in California, we are experiencing a similar destruction
> of oak trees.  A new (to the area ) fungus - a type of Phytopthera, just
> identified, is suddenly and rapidly wiping out several species of Oaks
> (Quercus) in California .  The trees are actually finished off by
> beetles after being severely weakened.  So far no trees seem to survive
> long in infected areas. We have at the moment several million acres of
> woodland and wooded grassland of which these trees are the principal
> component.  The landscape will dramaticaly change.  If you have always
> wanted to see the golden oak studded hills of California, don't wait too
> long.  It will be interesting to see if any resistant strains remain.
> Some parasites seem to be actually too effective for thier own good  -
> witness the virtual elimination of Ulmus americana and Castanea dentata
> in North America.  Perhpas this species of Phytophthera has been happily
> living off trees in other parts of the globe, and was only recently
> intorduced to oaks.

The combination of beetle and fungus sounds reminiscent of the elm
disease, although in that case I understand it is the beetle which comes
first and actually spreads the disease. What a tragedy, I do hope some
trees do prove to be resistant.

Phytophthora species are well-known killers of a number of different
trees throughout the world, but I think the majority do not usually
attack fully-healthy trees but rather those weakened by stress,
including such things as poorly-drained soils.

We had a near wipeout of (exotic) Lombardy poplars in NZ some years ago
following the introduction of Poplar rust. For a few years there seemed
to be nothing but sick and dying trees, but eventually a hard core of
resistant forms were left and now some twenty years or so later there
seem to be plenty of poplars around again.

Moira
-- 
Tony & Moira Ryan <theryans@xtra.co.nz>
Wainuiomata (near Wellington, capital city of New Zealand)
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