RE: Eucalyptus Questions
- To: "medit-plants"
- Subject: RE: Eucalyptus Questions
- From: K* H*
- Date: Wed, 28 Mar 2001 04:13:34 -0800
- Importance: Normal
An old gardener down the road told me that the roots of Eucalyptus, probably
thinking of, for example, E. citridora and E. globulus, produce some growth
inhibiting materials. The leaves, however, certainly do make a good mulch.
Certainly, these two at least, are very effecient at gobling up whatever
water they can find.
-----Original Message-----
From: owner-medit-plants@ucdavis.edu
[o*@ucdavis.edu]On Behalf Of Margaret Moir
Sent: Friday, March 16, 2001 9:42 PM
To: medit-plants
Subject: Re: Eucalyptus Questions
----- Original Message -----
From: Glenn Breayley <valhalla@iafrica.com>
To: medit-plants <medit-plants@ucdavis.edu>
Sent: Wednesday, March 14, 2001 3:42 PM
Subject: Eucalyptus Questions
> While on the subject, does anyone have the answers to the following
> questions.
>
> 1/ Are Eucalyptus leaves & compost truly poisonous to underfloor plants ?
> Might not their bare floor areas rather be due to their superior water
> robbing capabilities. ?
>
> 2/ Does anyone have any knowledge of the Jarrah ( E. marginata ) being
grown
> commercially outside of Australia ? Being one of the worlds greatest &
most
> durable of timbers I was wondering if it has commercial possibilities.
>
> Regards
>
> Glenn Breayley. Ragnarok & Valhalla Research.
> POBox 26158, Hout Bay, 7872, Capetown, South Africa
> Ph/Fax SA 021 7904253 E-mail valhalla@iafrica.com
> Wholesale nurseryman & Tillandsia specialist wholesale & retail grower.
>
Glenn, I don't believe the leaves themselves, once parted company with the
tree, have any toxic properties at all. In common with many other species
many of them are allelopathic, and the canopies may also have a "toxic
drip"........rain leaches a chemical from the canopy that is a growth
retardant to other plants. This is not universal with all eucalypts, mostly
just the ones that have to be super-competitive in their own environments.
Your surmise, that like a lot of trees they drink a lot of water and
out-compete other plants is frequently the case when no allelopathy is
present.
The WA Jarrah/ Marri/ Karri forests are the overstorey for thousands if not
millions of plants, growing densely underneath the trees, no toxins there.
But once a tree is mature, it is almost impossible to get things back in the
understorey if it has been lost thro' grazing or whatever. However a fire
will release nutrients trapped in the humus and leaves and provide an
ash-bed that the re-generating plants can germinate in.
The reason the leaves are resistant to being composted is because they're
sclerophyllous and have a very hard waxy coating to make them resistant to
transpiration. If the leaves are chopped up, such as through mowing or a
mulching machine they break down much more quickly. In combination with a
high nitrogen plant matter such as lawn clippings, they can make a great
mulch/compost. Eventually, even if entire, they will crumble to a superb
leaf mould but in the natural environment this is much hastened by fungal
associations.
Jarrah? It's never been attempted as forestry plantings......the tree is
much too slow growing to interest any foresters. Probably about [this is
just a rough guess] 200 years old before millable.
Margaret.
Margaret River
Western Australia.
