Wednesday, August 27, 2014

Tallest trees of the World - Eucalyptus Regnans

Australia's mountain ash (Eucalyptus regnans) is the second tallest growing tree species in the world. The tallest specimen – nicknamed 'Centurion' – stands at 99.6m in Tasmania's Arve Valley. It is the world's tallest flowering plant and known hardwood tree, most commonly found in Southeastern Australia. There are a number of different trees that use the name “mountain ash” and none of them are related. This particular tree, however, is a different species of Eucalyptus that can grow up to 230-400 feet tall. The tree is known for being the tallest flowering plant in the world. The ones pictured were seen outside of Marysville in Victoria, Australia.


Historically, the tallest recorded Mountain Ash (Eucalyptus regnans), also known as Swamp Gum, was a 115m tree felled in 1880 at Thorpdale in Victoria. Today, the tallest living example is across Bass Strait. The tree, nicknamed Centurion, was discovered in late 2008 in state forest in the Arve Valley near Geeveston, about 60km southwest of Hobart, and is the only known standing hardwood in the world measuring 100m. It is closed to visitors in spring because of nesting eagles.

The species grows extraordinarily quickly, reaching its maximum height in 200 years, a rate five times faster than the redwoods.

"The eucalypts do not live long enough to rival the redwoods in size. However, there may have been genetic 'freaks' that may have – and could in the future – reach over 100m tall," says Brett Mifsud, a specialist in finding and measuring tall trees.

Historic records show that in 1880 a felled mountain ash was recorded at 114.5m in Thorpdale, 137km south-east of Melbourne, making it the tallest tree in the world at the time.

The Andromeda stand is still the biggest stand of the tallest flowering plants on Earth, with three of the top five biggest hardwood trees, and more than a dozen specimens over 90m. Good fortune has seen it saved from logging since it was first identified in 1959. Even in the understorey everything is of giant proportions. The tree ferns rise 5m tall before the fronds flush sky high, blocking sunlight from reaching the forest floor. On the ground, fallen moss-covered tree trunks and limbs leave an obstacle course of rotting timber.

We make the journey into the forest the next day, with the rain cascading through the canopy. Together with fellow arborist Brett Mifsud, Greenwood has climbed and measured most of the tallest trees in this forest. Climbing involves shooting an arrow with a line over a top branch of the tree using a crossbow or giant slingshot. This line is used to pull a thicker string, and then a climbing rope, which is anchored to another tree to offset the weight of the climber. Today, after a failed attempt, Greenwood gets a fix and climbs more than 90m to rig up a descent line closer to the trunk.

Greenwood, who owns The Tree Works in Melbourne, inherited a love of nature from his father. “I did a degree in forestry and always had a general interest in tall trees, which expanded in 2000 when I was asked to measure some trees for Forestry Tasmania,” he says, recalling how the process used to involve a measuring stick and a tape measure but is now more likely to involve a laser.

Greenwood says the tallest Eucalyptus regnans today are most probably much smaller than the tallest that have existed. The tallest softwood tree, the Coast Redwood of North America, grows to about 115m.

Given time, Greenwood says, it’s possible that a hardwood eucalypt could grow to challenge the biggest of the redwoods. And if it does, he says, it will most likely be in Victoria, which is considered to have more favourable growing conditions.

To get there

The Styx Valley is 90km from Hobart, near Maydena. Accommodation is available in Maydena at Giants’ Table, www.giantstable.com.au; for more information see www.forestrytas.com.au