The Karri

Karri (Eucalyptus diversicilor) grows only in the south-west of Western Australia.
It occurs in a variaty of soils but it is at its best in conditions such as around there - deep red earths and lots of rain (above 1'250 mm per year).

Karri Fun Facts


Karri is a gum tree, one of 500 or so eucalypts that grow in Australia.
The name "Karri" comes from an aboriginal language.


Karri is the largest tree in Western Australia reaching 88 metres.
It is the 2nd tallest hardwood tree in the world.
Another Eucalypt, the Mountain Ash in Victoria and Tasmania is bigger by 10 metres.
It is ranked in the top 10 largest living things on the planet and can weigh up to 150 tones.


Occasionally it lives for 350 years.
Karri reaches full height at about 75 years.
Most pristine forest is aged 150-200 years.


Smooth white bark is shed in strips to reveal salmon pink bark each autumn.


Up to 70% of the leaves can be shed and regrown each year.
Leaves are full of eucalyptus oil and are very flammable.


It takes 4 years for flower buds to develop into gumnuts with ripe seed.
A tree sets flower each year but has a bumper crop every 4-7 years.
The whole forest produces a bumper crop about every 10 years.
It then needs to build up its food reserves before the next bumper crop.
One tree can yield 1 kg of honey.

One tree can produce 250,000 flowers of which 1/5 will become gumnuts, each wirth one seed inside.
Only 1/4 of these seed will survive to germinate.
Only 1 /10 of the germinates will survive the first year.
Only 1/150 of these seedlings will live to old age because of fierce competition between the trees.
In other words - there is a lot of life eating, munching and living on karri.


One tree needs an average of 170 liters of water per day.
Scientists stilt don't know how a tree can pump water 88 metres from the roots into the treetops.
This requires a pressure of 300 lbs per square inch - terrific force.


One Karri can produce enough timber to build 2 1 /2 houses.
And is worth $9,000 in 1989 sawn timber values.
Only 5% of the Chipmill intake is Karri, the rest is sawmill residue or Marri (redgum) - 1989 figures.
Decaying wood in the heart of most karri trees support a thriving community of fungi and insects.


Gumnuts with ripe seed on the tree are stimulated to open 2-3 days after a hot fire has passed.
Seed that falls onto ashbeds grows much faster and stronger than off ashbeds.
With bark and laves shed each year, forest litter builds up at a quick rate, 3 tones per hectare per year.
A long unburnt area would have 50 tonnes of leaves, bark and twigs that would reach to your waist in dead stuff.


Although dominated by the huge karri trees themselves, karri forest is home to a vast array of plants and animals.
Many of these are endemic to the south-west, that is, they are found nowhere else.
Almost all of the animals that are known to have occurred in the karri forest at the time of European settlement are still found here.


16% of the Karri Forest was cleared for agricultur.
About 48% of the remainder will be excluded from logging either as National Parks or Conservation areas and special care zones (1989 figures):
The karri forest covers about 200'000 hectares, of which 174'000 hectares are DEC managed land.
Of these, 53'000 hectares are in Nature Reserves or National Parks, including 40'000 hectares of virgin forest.
A further 28'000 hectares are in stream and road reserves not harvested for timber.

The rest is secured under State Forest and is managed on a sustained yield basis and protected to ensure a karri forest remains on this land forever.




No liability for timeliness, integrity and correctness of this document is accepted.
Last updated: Wednesday, 18.06.2008 1:36 PM