Featured Research

from universities, journals, and other organizations

El Nino Triggers Tropical Forest Reproduction

Date:
December 9, 1999
Source:
University Of Michigan
Summary:
On the island of Borneo, the world's second largest tropical rain forest is dying. Its death will mean the disappearance of a unique ecosystem where trees time their reproduction to the periodic arrival of El Nino. Loss of the forest could have a global financial impact, according a University of Michigan scientist.

El Nino triggers Indonesian tropical forest reproduction, says U-M scientist. Logging is destroying forest ecosystem, threatens local economy and global exports.

Contact: Sally Pobojewski
Phone: (734) 647-1844
Email: pobo@umich.edu

EDITORS: Color slides of Gunung Palung National Park are available on request.

ANN ARBOR --- On the island of Borneo, the world's second largest tropical rain forest is dying.

Its death will mean the disappearance of a unique ecosystem where trees time their reproduction to match the periodic arrival of El Nino. Loss of the forest also could have a global financial impact, since timber exports contribute as much as $8 billion annually to the Indonesian economy and provide 80 percent of plywood used in the U.S. home construction industry.

According to a study published in the Dec. 10 issue of Science by an international research team led by U-M tropical ecologist Lisa M. Curran, this ecological and economic resource is being destroyed by human activity, which has intensified the effects of regional climate change.

From 1985 to 1999, Curran and her colleagues studied Dipterocarpaca---the main family of rain forest canopy trees in Indonesian Borneo. Field research covered a 57-square-mile area, but focused on six square miles in the Gunung Palung National Park. The research team also surveyed timber concessions throughout the surrounding province of West Kalimantan and studied 30 years of export records to determine the impact of logging in the region and on the park.

Curran's study is the first to document an ecosystem with a rare reproductive strategy called masting. More than 50 different species of Bornean dipterocarp trees synchronize their reproduction---limiting fruit and seed production to brief, intense periods. Curran discovered that these bursts of reproduction are initiated by the arrival of the El Nino Southern Oscillation or ENSO, a periodic shift in tropical Pacific circulation patterns that brings drought to Indonesia.

"We recorded four masting episodes from 1986 to 1999 with an average interval of 3.7 years," said Curran, an assistant professor of tropical ecology at the U-M. "With the possible exception of one very minor event in 1994, they all occurred during ENSO years. Climatic conditions of an El Nino year trigger simultaneous fruiting in dipterocarps, and are essential for regional seed production."

According to Curran, masting gives canopy trees an important survival advantage. In a typical six-week masting period, her research team collected 180 pounds of seed---ranging in size from a chestnut to a pistachio nut---from every acre of the six-square-mile survey area on the forest floor.

"It's like Thanksgiving in the forest," Curran said. Wild boar, orangutans, parakeets, jungle fowl, partridges, and other animals congregate to stuff themselves. Local villagers collect baskets of seeds called illipe nuts to sell as a cash crop. Because so much seed is produced simultaneously over such a large area, however, there is still enough leftover to germinate and produce a carpet of new seedlings on the forest floor.

In the Science article, Curran and her co-researchers describe how the forest in Gunung Palung is changing following a decade of intensive dipterocarp logging in huge timber concessions surrounding the park. From 1991 to 1998, production of mature, viable dipterocarp seed fell from 175 pounds per acre (196 kilograms per hectare) to 16.5 pounds per acre (18.5 kilograms per hectare). Despite a major fruiting event during the 1998 El Nino year, no new dipterocarp seedlings were found in the survey area.

"Even though the park is supposedly off-limits to logging, the forest is losing the ability to regenerate itself," Curran said. Because seed predators can't find food outside the park, they move inside to eat the dipterocarp seeds before they germinate, according to Curran. Massive forest fires on nearby logging plantations, which destroyed an area the size or Denmark or Costa Rica in 1997-98, brought pollution and intensified El Nino's drought killing the few remaining dipterocarp seedlings.

"It's very sad, but unless the Indonesian government implements sustainable forestry practices, creates financial incentives to harvest responsibly, and prevents clearing and burning for industrial plantations, this ecosystem will be unable to recover," Curran said. "The real injustice here is to the Indonesian people in Kalimantan, because the majority depend on the forest for their basic livelihood. They will bear the environmental and socioeconomic costs, but the benefits from this harvest went to a few timber tycoons."

The research was supported by the U.S. Agency for International Development, National Science Foundation, U-M, International Timber Trade Organization, Wildlife Conservation Society, World Wide Fund for Nature, Conservation International, W. Alton Jones Foundation, National Geographic Society, and the Conservation, Food and Health Foundation.

Collaborators in the research study include Gary Paoli, U-M graduate student; Izefri Caniago, from the U.S. Agency for International Development in West Kalimantan; Dwi Astianti, from the University of Tanjungpura in West Kalimantan; Monika Kusneti, from the World Wide Fund for Nature; Mark Leighton of Harvard University; C. Endah Nirarita, from Wetlands International in Indonesia; and Herman Haeruman from the Indonesian National Development Planning Agency.


Story Source:

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


Cite This Page:

University Of Michigan. "El Nino Triggers Tropical Forest Reproduction." ScienceDaily. ScienceDaily, 9 December 1999. <www.sciencedaily.com/releases/1999/12/991209044954.htm>.
University Of Michigan. (1999, December 9). El Nino Triggers Tropical Forest Reproduction. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/1999/12/991209044954.htm
University Of Michigan. "El Nino Triggers Tropical Forest Reproduction." ScienceDaily. www.sciencedaily.com/releases/1999/12/991209044954.htm (accessed October 23, 2014).

Share This



More Earth & Climate News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

Reuters - Light News Video Online (Oct. 22, 2014) — The pair of rare white northern rhinos bring hope for their species as only six remain in the world. Elly Park reports. Video provided by Reuters
Powered by NewsLook.com
Trick-or-Treating Banned Because of Polar Bears

Trick-or-Treating Banned Because of Polar Bears

Buzz60 (Oct. 21, 2014) — Mother Nature is pulling a trick on the kids of Arviat, Canada. As Mara Montalbano (@maramontalbano) tells us, the effects of global warming caused the town to ban trick-or-treating this Halloween. Video provided by Buzz60
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) — He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
How Detroit's Money Woes Led To U.N.-Condemned Water Cutoffs

How Detroit's Money Woes Led To U.N.-Condemned Water Cutoffs

Newsy (Oct. 20, 2014) — The United Nations says water is a human right, but should it be free? Detroit has cut off water to residents who can't pay, and the U.N. isn't happy. 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:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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