Featured Research

from universities, journals, and other organizations

Do Australia's giant fire-dependent trees belong in the rainforest?

Date:
November 1, 2012
Source:
Wiley
Summary:
Australia's giant eucalyptus trees are the tallest flowering plants on earth, yet their unique relationship with fire makes them a huge puzzle for ecologists. Now the first global assessment of these giants seeks to end a century of debate over the species' classification, a debate which may determine their future.

Australian mountain ash (Eucalyptus regnans) can grow to a height of over 100 metres (330 feet), making it one of the tallest tree species in the world.
Credit: Leanne C. / Fotolia

Australia's giant eucalyptus trees are the tallest flowering plants on earth, yet their unique relationship with fire makes them a huge puzzle for ecologists. Now the first global assessment of these giants, published in New Phytologist, seeks to end a century of debate over the species' classification, a debate which may determine their future.

Gigantic trees are as rare as they are awe inspiring. Of the 100,000 global tree species only 50, less than 0.005%, reach over 70 meters in height. While many of these giants live in Pacific North America, Borneo and similar habitats, 13 are eucalypts which live in Southern and Eastern Australia.

The tallest flowering plant to call Australia home is Eucalyptus regnans, with temperate eastern Victoria and Tasmania being home to the six tallest recorded species of the genus. One Tasmanian tree was measured at 99.6 m, while a tree in Victoria achieved the historic record of 114.3 m.

"The conifers of North America are often thought of as the largest trees on earth, yet the flowering eucalyptus trees of Australia reach comparable heights," Professor David Bowman, from the University of Tasmania's School of Plant Science. "This is surprising as Australia is the world's driest inhabited continent. Yet, this apparent paradox may explain the evolutionary advantage of gigantism in trees."

Wildfires are common in dry and arid environments such as Australia, but Eucalyptus regnans has evolved a unique dependency on fire for regeneration. While fire may kill the trees, their seeds are protected in aerial capsules, which are then released on to the scorched earth. The fire not only clears away potential seed predators and any forest canopy which may block sunlight; it also releases nutrients in the soil which encourages seed growth.

"This unique relationship with fire helps us understand how these giants evolved," said Bowman. "Our research suggests gigantism in eucalypts evolved opportunistically within the last 20 million when the ideal environmental conditions for rapid tree growth were combined with the presence of wildfire."

However, fire dependency now threatens the trees' future as much as it has shaped their past. Due to this trait foresters classify the tree as unique type of Australian vegetation, rather than considering it a rainforest tree.

"This classification has serious scientific and conservation implications for the remaining forests of mature (old growth) giant eucalypts," said Bowman. "Giant trees have huge value for the timber industry, yet there are strong environmental reasons for their protection. Classification as rainforest trees would support arguments in favour of conservation."

Dr Bowman's team presents a comparative analysis which clarifies the relationship between the giant eucalypts and other rain forest species. Their findings suggest that while the species has evolutionary advantages which allow it to outcompete other species, they do coexist on the margins of rainforests and should be considered part of that ecosystem.

"Our work seeks to resolve a century old dispute about rain forest classification," concluded Professor Bowman. "Rather than seeing them in isolation we place these giants into their global context by recognizing them as species of rainforest tree, albeit trees with a unique dependence on fire."


Story Source:

The above story is based on materials provided by Wiley. Note: Materials may be edited for content and length.


Journal Reference:

  1. D. Y. P. Tng, G. J. Williamson, G. J. Jordan, D. M. J. S. Bowman. Giant eucalypts - globally unique fire-adapted rain-forest trees? New Phytologist, 2012; DOI: 10.1111/j.1469-8137.2012.04359.x

Cite This Page:

Wiley. "Do Australia's giant fire-dependent trees belong in the rainforest?." ScienceDaily. ScienceDaily, 1 November 2012. <www.sciencedaily.com/releases/2012/10/121031214005.htm>.
Wiley. (2012, November 1). Do Australia's giant fire-dependent trees belong in the rainforest?. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2012/10/121031214005.htm
Wiley. "Do Australia's giant fire-dependent trees belong in the rainforest?." ScienceDaily. www.sciencedaily.com/releases/2012/10/121031214005.htm (accessed July 28, 2014).

Share This




More Plants & Animals News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Newsy (July 28, 2014) The asteroid that killed the dinosaurs struck at the worst time for them. A new study says that if it hit earlier or later, they might've survived. Video provided by Newsy
Powered by NewsLook.com
Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) Video provided by AP
Powered by NewsLook.com
Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins