File:Aboveground Woody Biomass in the United States 2011.jpg
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English: Trees are one of Earth’s largest banks for storing the carbon that gets emitted by natural processes and human activities. Forests cover about 30 percent of the planet’s land surface, and as much as 45 percent of the carbon stored on land is tied up in forests.
But did global forests hold more or less carbon in the past? And could they store more in the future? Does it matter where those trees are growing? Scientists really don’t know. But before they can find out, they’ll need a reliable inventory of what is growing today. Josef Kellndorfer and Wayne Walker of the Woods Hole Research Center (WHRC) recently worked with colleagues at the U.S. Forest Service and U.S. Geological Survey to create such an inventory for the United States. The map above was built from the National Biomass and Carbon Dataset (NBCD), released in 2011. It depicts the concentration of biomass—a measure of the amount of organic carbon—stored in the trunks, limbs, and leaves of trees. The darkest greens reveal the areas with the densest, tallest, and most robust forest growth. Over six years, researchers assembled the national forest map from space-based radar, satellite sensors, computer models, and a massive amount of ground-based data. It is possibly the highest resolution and most detailed view of forest structure and carbon storage ever assembled for any country. Forests in the U.S. were mapped down to a scale of 30 meters, or roughly 10 computer display pixels for every hectare of land (4 pixels per acre). They divided the country into 66 mapping zones and ended up mapping 265 million segments of the American land surface. Kellndorfer estimates that their mapping database includes measurements of about five million trees. “Forests are a key element for human activity,” says Kellndorfer. “Resource managers need to see forests down to the disturbance resolution—the scale at which parking lots or developments or farms are carved out by deforestation. We have to know how much we have, and where, in order to conduct sound management and harvesting.” Learn more about the creation of Kellndorfer’s map and other attempts to measure Earth's forests in our newest feature story: Seeing Forests for the Trees and the Carbon: Mapping the World’s Forests in Three Dimensions.Afrikaans: Bome tel onder die Aarde se vernaamste opgaarders van die koolstof wat deur natuurlike prosesse en menslike aktiwiteite vrygestel word. Woude bedek sowat 30 persent van die planeet se landoppervlak, en tot 45 persent van die koolstof wat op land gestoor word, is in woude vasgevang.
Maar sou globale woude voorheen meer of minder koolstof bevat het? En kan hulle voortaan meer stoor, en maak dit 'n verskil waar bome groei? Wetenskaplikes weet regtig nie en voordat hulle kan uitvind, benodig hulle 'n betroubare inventaris van huidige plantegroei. Josef Kellndorfer en Wayne Walker van die Woods Hole-navorsingsentrum (WHRC) het onlangs met kollegas by die V.S. Bosdiens en V.S.A. Geologiese Opname saamgewerk om juis so 'n inventaris vir die Verenigde State op te stel. Die kaart hierbo is uit die Nasionale Biomassa- en Koolstofdatastel (NBCD) berei wat in 2011 bekendgestel is. Dit beeld die biomassa-konsentrasie uit, 'n maatstaf van die hoeveelheid organiese koolstof wat in die stamme, takke en blare van bome gestoor word. Die donkerste datapunte stem met gebiede ooreen waar die digste, hoogste en mees lewenskragtige bosgroei voorkom. Navorsers het die nasionale woudkaart binne ses jaar uit ruimtegebaseerde radar, satellietsensordata, rekenaarmodelle en 'n geweldige hoeveelheid grondgebaseerde data saamgestel. Dit is moontlik die hoogste resolusie en mees gedetailleerde aansig van woudstruktuur en koolstofberging wat ooit vir enige land saamgestel is. Woude in die VSA is tot 'n skaal van 30 meter, of ongeveer 10 rekenaarskermpiksels vir elke hektaar grond (4 piksels per akker) gekarteer. Hulle het die land in 66 karteringsones onderverdeel en uiteindelik 265 miljoen segmente van die Amerikaanse landoppervlak gekarteer. Kellndorfer skat dat hul karteringdatabasis metings van sowat vyf miljoen bome insluit. "Woude is van sleutelbelang in menslike aktiwiteit," sê Kellndorfer. “Hulpbronbestuurders moet woude tot op die resolusie van die versteuringskaal kan moniteer, die skaal waarop parkeerterreine aangelê word, of ontbossing weens ontwikkeling of landbou plaasvind. Ons moet weet hoeveel ons besit en waar dit geleë is ten einde gesonde bestuur en benutting toe te pas.” Kyk ons nuutste temaverhaal om meer oor die samestelling van Kellndorfer se kaart en ander inisiatiewe rakende globale woudmonitering te wete te kom: Seeing Forests for the Trees and the Carbon (kartering van die wêreld se woude in drie dimensies). |
| 日期 | 在1999年1月1日到2002年12月31日之間 |
| 來源 | https://visibleearth.nasa.gov/view.php?id=76697 |
| 作者 | Map by Robert Simmon, based on multiple data sets compiled and analyzed by the Woods Hole Research Center. Data inputs include the Shuttle Radar Topography Mission, the National Land Cover Database (based on Landsat) and the Forest Inventory and Analysis of the U.S. Forest Service. Caption by Michael Carlowicz. |
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本作品由NASA創作，屬於公有領域。根據NASA的版權政策：“NASA的創作除非另有聲明否則不受版權保護。”（參見：Template:PD-USGov/zh，NASA版權政策或JPL圖像使用政策） |  |
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| 日期/時間 | 縮圖 | 尺寸 | 使用者 | 備註 | |
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| 目前 | 2012年1月17日 (二) 00:26 | | 4,457 × 2,809（5.65 MB） | Patrickneil | {{Information |Description ={{en|1=Map of the United States aboveground woody biomass with 66 ecoregions deliniated. It shows the tons of trees and thier forests by hectacre. Based on the map and palette created by NASA's Earth Observatory employee Rob |
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