. 24/7 Space News .
EARTH OBSERVATION
Is That a Forest? That Depends on How You Define It
by Staff Writers
Greenbelt MD (SPX) Nov 27, 2015


For a larger version of the maps please go here.

After comparing eight satellite-derived global maps, researchers found that measurements of forest cover vary widely-as much as 6 percent of Earth's land area, or the equivalent area of China. But the biggest discovery was not the discrepancy; it was the reason behind it.

Using the first global, Landsat-based map of tree cover (at 30-meter resolution), researchers led by Joseph Sexton of the University of Maryland found that ambiguity in the use of the word "forest" leads to different assessments of the location and extent of forest cover on maps.

Ecologists have long understood the complexity and vagueries of the concept of "forest." Geographers have long called for the definition to be more standardized across national and international monitoring entities. But until now, no one had quantified the scope of the problem.

The maps of forest cover above illustrate how measurements can vary widely depending on the forest definition used. The two maps are based on Landsat data and use different definitions employed by the UN Framework Convention of Climate Change (UNFCCC).

The top map considers an area forested if 30 percent of the land is covered with trees; the second map claims a "forest" when there is 10 percent tree cover.

The difference in forest calculations derives mainly from areas of intermediate tree cover, such as savannahs, shrublands, mountain ridge forests, and boreal taiga. (Use the image comparison tool to see where major measurement differences occur.)

"Whereas previous studies mentioned the discrepancy, our analysis quantified and mapped it globally and connected it to estimates of biomass and economic value," said Sexton, who is part of UM's Global Land Cover Facility. The findings were published in Nature Climate Change.

Issues such as persistent cloud cover in the tropics, shadows from the tree canopy, and the complexity of forest structure can all lead to small errors in satellite-based forest maps. But those errors are small in comparison to those caused by the definition problem.

"It's not technology's fault" that forest maps are inconsistent, Sexton said. "Today's satellites provide us with a sufficient precision to make ecological measurements of forests."

But until the definitions get hammered out, it will be difficult to make proper land-cover assessments or conservation agreements related to greenhouse gas emissions, climate change, and biodiversity.

Sexton and colleagues propose that there should either be a single, unambiguous definition of forest/non-forest that can be used globally or, preferably, the research and conservation community should shift to maps of measureable ecological characteristics such as tree cover, canopy height, and biomass.

"Through advances in remote sensing, we increasingly have the technical capacity to estimate the structure, cover, and composition of terrestrial ecosystems from space," Sexton explained. If an international consortium of scientists agreed on a set of measurable forests characteristics, better estimates of carbon stocks (where and how much carbon is stored in vegetation) could be made.

Sexton, J.O. et al. (2015) Conservation policy and the measurement of forests. Nature Climate Change, advance online publication.


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


.


Related Links
Earth Observatory
Global Land Cover Facility
Earth Observation News - Suppiliers, Technology and Application






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
EARTH OBSERVATION
New satellite to measure plant health
Paris (ESA) Nov 22, 2015
ESA plans to track the health of the world's vegetation by detecting and measuring the faint glow that plants give off as they convert sunlight and the atmosphere's carbon dioxide into energy. Yielding information about the health and stress of the planet's vegetation is important as the growing global population places increasing demands on the production of food and animal feed. Fo ... read more


EARTH OBSERVATION
Gaia's sensors scan a lunar transit

SwRI scientists explain why moon rocks contain fewer volatiles than Earth's

All-female Russian crew starts Moon mission test

Russian moon mission would need 4 Angara-A5V launches

EARTH OBSERVATION
ExoMars has historical, practical significance for Russia, Europe

European payload selected for ExoMars 2018 surface platform

ExoMars prepares to leave Europe for launch site

Tracking down the 'missing' carbon from the Martian atmosphere

EARTH OBSERVATION
Orion's power system to be put to the test

The Ins and Outs of NASA's First Launch of SLS and Orion

Aerojet Rocketdyne tapped for spacecraft's crew module propulsion

Brits Aim for the Stars with Big Bucks on Offer to Conquer Final Frontier

EARTH OBSERVATION
China launches Yaogan-29 remote sensing satellite

China's indigenous SatNav performing well after tests

China's scientific satellites to enter uncharted territory

China to launch Dark Matter Satellite in mid-December

EARTH OBSERVATION
Getting Into the Flow on the ISS

Russian-US Space Collaboration Intact Despite Chill in Bilateral Ties

ISS EarthKAM ready for student imaging request

Partners in Science: Private Companies Conduct Valuable Research on the Space Station

EARTH OBSERVATION
"Cyg"-nificant Science Launching to Space Station

Aerojet Rocketdyne completes AJ60 solid booster for Atlas V launcher

Flight teams prepare for LISA Pathfinder liftoff

Rocket launch demonstrates new capability for testing technologies

EARTH OBSERVATION
Neptune-size exoplanet around a red dwarf star

Exiled exoplanet likely kicked out of star's neighborhood

Retro Exo and Its Originators

How DSCOVR Could Help in Exoplanet Hunting

EARTH OBSERVATION
Creating a new vision for multifunctional materials

Cryogenic testing from 1964 to the James Webb Space Telescope

SSL selected to provide new high throughput satellite to Telesat

Satellite Spectrum Is Central To Future Vision For Global Connectivity









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.