Finding Where U.S. Forests Have Been Undisturbed for a Quarter Century

Forest in Yellowstone National Park

Dr. Chengquan Huang is a Research Professor in the University of Maryland’s Geographical Sciences Department. This afternoon at the 2015 AGU Fall Meeting, Dr. Huang presented a poster explaining where to find U.S. forests that have been undisturbed for last 25 years. His research relied on Landsat to both find these forests and understand forest disturbance trends in the U.S.

Figure 1. High concentrations of undisturbed forests are distributed mostly in the northeast, north central, and western U.S., often along ecoregion boundaries. Image credit: Huang et al.

Presentation title:Where are the forests in the United States “not disturbed” over a quarter century?

Figure 2. Percent forest remaining undisturbed (PFUD) within a time interval decreased following an exponential decay function in the conterminous U.S. and each of its four regions as the time interval increased. Image credit: Huang et al.

• About 1.7 million square kilometers, or two thirds of 2.6 million square kilometers of forest in the conterminous U.S. did not experience any detectable natural or anthropogenic disturbance during the quarter century between 1986 and 2010 (see figure 1)
• The northern states in the eastern U.S. have the highest percentage of forest remaining undisturbed, while those in the south have the lowest values
• At any given time interval, the percentage of forest remaining undisturbed decreases following an exponential decay function as the time interval increases (see figure 2)
• If forest disturbance rates remain relatively stable over time, the conterminous U.S. would have less than 20% forest remaining undisturbed in 100 years, which would become less than 4% in 200 years
• Management approaches aimed at reducing timber harvest rates in the south and mitigating fire risks in the west are needed in order to maintain higher levels of undisturbed forests.

What insight did you gain from Landsat that would have been impossible to glean otherwise?

• Without Landsat, we wouldn’t be able quantify the amount of forest undisturbed over multiple decades at local, regional, state, and national scales;
• We wouldn’t be able to reveal that the percentage of forest remaining undisturbed at any given time interval decreases following an exponential decay function as the time interval increases, and therefore wouldn’t be able to estimate how much forest would remain undisturbed over multiple centuries.

What are the major implications of your findings?

• Old growth forests (> 100-200 years): mostly in the north and west, very little in the south, may constrain the distribution of species that favor old growth forests;
• Forest carbon stock: because old growth forests typically have higher carbon density than young forests, the south have more potential to increase its forest carbon stock than other forested regions in conterminous U.S.;
• Management approaches aimed at reducing timber harvest rates in the south and mitigating fire risks in the west are needed in order to increase and maintain higher levels of undisturbed forests.

Source: NASA/Lansat images

Detailed maps of forest canopy height and carbon stock for the conterminous US

The Woods Hole Research Center has released the first hectare-scale maps of canopy height, above-ground biomass, and associated carbon stock for the forests and woodlands of the conterminous United States. The multi-year project, referred to as the National Biomass and Carbon Dataset (NBCD), produced maps of these key forest attributes at an unprecedented spatial resolution of 30 m.


According to Dr. Josef Kellndorfer, who led the project at WHRC, "We are excited about the completion of this mapping project. The dataset represents a comprehensive assessment of forest structure and carbon stock within the lower 48 States at the beginning of the third millennium, providing an important baseline with which to improve our understanding of the United States forest resources and its link to the terrestrial carbon flux in North America. This dataset will be useful to foresters, wildlife ecologists, resource managers, and scientists alike."

Volker Radeloff, professor at the University of Wisconsin-Madison, Department of Forest and Wildlife Ecology, added, "Vegetation structure data has been the holy grail for biodiversity science: absolutely essential, but unattainable for large areas. The NBCD data set fills this crucial gap and will advance of our understanding of why biodiversity is so much higher in some areas than others, and target biodiversity conservation efforts."

The project was initiated in 2005 with funding from NASA's Terrestrial Ecology Program as well as support from the USGS/LANDFIRE consortium. Collaborators included the U.S. Forest Service Forest Inventory and Analysis (FIA) Program, and the National Land Cover Database (NLCD 2001) and National Elevation Dataset (NED) project teams at the USGS EROS Data Center.

To produce this first-of-its-kind data set, NASA space-borne imagery (SRTM/Landsat-7), land use/land cover information (NLCD 2001), topographic survey data (NED), and extensive forest inventory data (FIA) were combined. Production of the NBCD followed an ecoregional mapping zone approach developed for the NLCD 2001 project. Across 66 individual mapping zones, spatial data, field observations, and statistical models were used to generate the canopy height, aboveground biomass, and carbon stock maps, which were then joined to form national-scale products.

"This effort is an excellent example of FIA partnering to marry ground and remotely-sensed data to provide natural resource information at resolutions much finer than the FIA sampling frame," said Dennis May, Forest Inventory and Analysis program manager with the U.S. Forest Service, Northern Research Station.

Dr. Wayne Walker, a Center scientist who also worked on the project, added, "Maps of key forest attributes like canopy height and carbon stock have not existed for the U.S. at this level of spatial detail and consistency. They will provide ecologists and land managers with new and better information to support biodiversity conservation, wildfire risk assessment, and timber production while helping climate scientists and others to better understand the role that U.S. forests play in the global carbon cycle."

According to Kellndorfer, "This dataset will advance our understanding of the United States natural resources, provide an invaluable circa year 2000 baseline against which to assess changes in the future, and help to improve our understanding of the drivers for change, and thus supporting good decision making. Naturally we are keen to produce the next generation data sets of this kind to assess in detail how carbon stock and forest structures are changing in this country, and internationally. We look forward to working¬¬ with an ever growing community of colleagues in the U.S. and abroad on pushing the science of understanding the World's forests forward."

Dr. Kellndorfer's research focuses on the monitoring and assessment of terrestrial and aquatic ecosystems, and the dissemination of Earth observation findings to policy makers through education and capacity building. Using geographic information systems (GIS), remote sensing, and modeling, he studies land-use, land cover and climate change on a regional and global scale. His projects include carbon and biomass mapping of the United States, mapping forest cover across the tropical forested regions of Africa, Latin and Asia through the generation of consistent data sets of high-resolution, cloud-free radar imagery. He is a Senior Scientist at the Center. Before joining the WHRC, Kellndorfer was a research scientist with the Radiation Laboratory in the Department of Electrical Engineering and Computer Science at the University of Michigan. He holds a diploma degree in physical geography and a doctorate in geosciences from the Ludwig-Maximilians-University in Munich, Germany. He serves on various expert working groups within NASA, the Group on Earth Observation, and GOFC-GOLD addressing forest carbon measurements in vegetation from remote sensing with existing and future remote sensing and field measurements.

Dr. Walker is an ecologist and remote sensing specialist interested in applications of satellite imagery to the assessment and monitoring of temperate and tropical ecosystems at regional to global scales. His research focuses on measuring and mapping forest structural attributes, land cover/land use change and terrestrial carbon stocks in support of habitat management, ecosystem conservation and carbon-cycle science. He is committed to building institutional capacity in the tools and techniques used to measure and monitor forests, working in collaboration with governments, NGOs and indigenous communities across the tropics. He is an Assistant Scientist at the Center. Walker holds degrees in forest ecology (M.S.) and remote sensing (Ph.D.) from the University of Michigan.

The digital raster data set is now freely accessible from the WHRC website atwww.whrc.org/nbcd



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The above post is reprinted from materials provided by Woods Hole Research Center. Note: Materials may be edited for content and length.

Article source: Science Daily

Putting the Trees Back on the Map: How GIS is Helping Reforest South America

BY DEVON REESER
GIS tools have revolutionized tracking in the sometimes hazy field of reforestation in developing countries. Deforestation contributes to more greenhouse gas emissions than the entire global transportation sector. Clean Development Mechanism (CDM) programs borne from the Kyoto Protocol have burst onto the international funding scene to pay forest-rich, poorer nations for forest ecosystem services, whether that means reforesting or not deforesting. Hundreds of other private businesses offset their carbon emissions by funding forest “carbon sinks” as well, as part of their corporate social responsibility charters, usually in partnership with NGOs.

Many, if not most, of the countries where reforestation is most viable have fuzzy systems of accountability, however, as well as gaps in technology know how and systems to implement tracking. Illegal logging often negates efforts. South America is home to more than a third of the world’s remaining rain forests and has possibly the most potential to reforest with a relatively low population and easily convertible land. But nearly all countries in South America score under 40 on a scale of 100 on Transparency International’s Corruption Index – and hence it has been difficult to ensure trees will stay put.

New, simplified Web-based GIS systems and UN trainings as part of the Reducing Emissions from Deforestation and Degradation (REDD) program of the UN Convention on Climate Change are revolutionizing forest tracking in South America. Here are three innovative examples from South America of how GIS is being used to strengthen and control forest monitoring to put – and to keep – the trees back on the map.

Monitoring Reforestation in Paraguay
Paraguay has suffered the most from deforestation for monoculture agriculture of any of its Latin neighbors. Only 10% of primary forest cover is left, gone in only 60 years, mostly for soy and cattle production by foreign entities.[i]The NGO, A Todo Pulmon, Paraguay Respira (With All Its Lungs, Paraguay Is Breathing) is tackling reforestation head on and using GIS to monitor and measure. The goal of the project, begun in 2009 by a national radio personality, was to plant 14 million trees – 85% to restore the Bosque Atlántico del Alto Paraná (BAAPA, the Atlantic Rainforest) and 15% for urban areas and schools as an educational initiative to spread the importance of reforesting the Atlantic Rainforest. It has planted 40 million.[ii]

The challenge now is to monitor to make sure they stay there. Paraguay is the most corrupt country in the Americas – it is the 27th most corrupt in the world on the Corruption Index, and has been in the top 10 in the new millennium. Though a “Zero Deforestation” law has been in existence for nearly a decade, officials often look the other way when illegal logging occurs. To date, the country has lacked the capacity to monitor and mitigate that corruption and crime. World Wildlife Federation is training every municipality in the forest districts to use GIS monitoring with satellite imagery from Brazil’s Space Research Institute.[iii] GIS satellite images are matched with the GPS coordinates of trees planted to track if reforested trees have been cut, and, if so, landowners pay heavy fines per national law and ramped up police monitoring spurred by enhanced media coverage and social consciousness.

Tracking Deforestation in Ecuador
With help from REDD, Ecuador is serving as a model country to input data into a simplified reforestation and deforestation Web-based GIS portal.[iv] A challenge for Ecuador in preserving the Amazon is a desire and need to develop petroleum resources within its most dense forest area. Not only does the portal easily show deforestation in protected areas and biodiversity corridors with petroleum and natural resource development, but it also shows overlap of reforested areas. The information helps policy makers and other investors immediately visualize effects of development and identify priority conservation areas. The web-based system does not require expensive software purchases and can hence be used across the nation by forest land managers and other specialists to keep one full, up to date resource publically available. The information was shared at a conference in Buenos Aires to replicate in Argentina.

ECUADOR REFORESTATION PLOTS FROM SISTEMA ÚNICO DE INFORMACIÓN AMBIENTAL.
Exposing Illegal Loggin Using GPS in Brazil

The ability of NGOs and the media to expose illegal activity is a new method of creating social accountability and transparency that supersedes corrupt policing and state-based systems. Greenpeace activists used covert GPS surveillance to track illegal logging in the Amazon. Activists placed GPS trackers on logging trucks to find their destinations, and then shockingly show with GIS satellite imagery illegal logging deep within protected forest. The Brazilian government is now being pressured to overturn a 2013 law weakening control.[v] The full report, The Amazon’s Silent Crisis: Night Terrors was published in October 2014 and is being read all over the world.

The prevalence and easy technology transfer of GPS and GIS has now made it possible to monitor and make sure that, even in the most unpoliced, corrupt areas of the world, trees meant to be on the map are put there and stay for good.

References
[i] Mongabay. 2014. Paraguay.

[ii] WWF Global. 2014. With All its Lungs, Paraguay is Breathing.

[iii] WWF. March 2011. Making a Pact to Tackle Deforestation in Paraguay (PDF).

[iv] UN REDD Programme. 2014. National Programmes in South America strengthen capacities on forest monitoring and web-based geographic information systems. REDD Programme Newsletter. September 2014.

[v] Carrington, Damian. 15 Oct. 2014. Activists Use GPS to Track Illegal Loggers in Brazil’s Amazon Rainforest. The Guardian.


Source: GIS Loung - Maps and GIS

Using Near-Infrared Aerial Imagery to Inventory Oak Trees

BY CAITLIN DEMPSEY MORAIS


The first ordinance passed by the California city of Santa Clarita after it was incorporated was the Oak Tree Ordinance. Thousands of oak trees cover the Santa Clarita Valley and the presence of the trees is an important part of the city’s landscape (the city logo prominently displays an oak tree). The ordinance covers oak trees of the Quercus species native to the area which includes Valley Oak, California Live Oak, Canyon Oak, Interior Live Oak, and Scrub Oak. As well as regulating the pruning, encroachment and removal of oak trees, the city sought to protect “heritage oaks” under the ordinance. Heritage oaks are the largest and oldest oaks in the city and are defined as oaks measuring at least 108 inches in circumference for a single trunk, or 72 inches in diameter for multiple trunks, at 4 1/2 feet above the ground.

Having been incorporated in 1987, the city of Santa Clarita is still experiencing significant growth and development. Development plans submitted to the city have to be carefully scrutinized to make sure they are in compliance with the Oak Tree Ordinance. Because of this, it had long been a priority of the city’s GIS group to develop a geographic layer identifying the location of oak trees within the city. When the GIS group began participating in Los Angeles County’s inaugural aerial imagery acquisition program (called LAR-IAC), the opportunity arose to experiment with remotely sensing tree locations.

After reviewing different academic and commercial options, the project manager, Edgardo David, along with the rest of the GIS team (Kristina Jacob, Anthony Calderon, and Kelly Minniti) opted to contract with the Los Angeles firm Engineering Systems. The goal of the project was to utilize 4-inch resolution near-infrared aerial imagery to extract the locations of specific oak tree species with the city. The challenge was in using aerial imagery to develop a spectral signature for the oak trees that could be automated in order to extract all tree locations.

FOR THE PILOT STUDY, OAK TREE LOCATIONS WERE IDENTIFIED BY THE CITY'S ARBORIST.

A pilot project was developed that involved the identification of oak trees by the City’s arborist for a single aerial tile. Staff at Engineering Systems then used those marked locations to create a polygon layer in AutoCAD of all oak trees present. Engineering Systems then developed an application using Microsoft .NET that scanned the TIFF image (a 000 x 8000 4-inch pixel grid comprising 64 million pixels). Those pixel within the polygons were extract and were analyzed to prepare histograms to represent the frequency of individual Red, Green and Blue (RGB) values to determine the peak values representing the spectral signature of the oak trees.

THREE HISTOGRAMS REPRESENTING FREQUENCIES OF RED, GREEN, AND BLUE VALUES.

The spectral signature was then used as input parameters for a second application that scanned the TIFF image tile and extracted pixels that matched the signature. The process went through several iterations matched against field surveys to verify that the correct species of trees were being selected. The overall analysis found that the spectral signature was accurate in identifying more mature oak trees but younger trees with smaller canopies were not being identified. Engineering Systems is working on refining the process to be able to identify those younger trees. Over 166,000 trees were located using this automated process.

The resulting geographic layer also identifies the diameter of the oak tree canopy. Since the oak tree locations are now georeferenced, the oak trees were spatially identified with the parcel number. This now allows the staff within the various city departments to know when a property has an oak tree and is subject to the constraints of the Oak Tree Ordinance when plans are submitted by developers and property owners.

IDENTIFIED OAK TREE LOCATIONS.

Source: GIS Lounge - Maps and GIS

Using Remote Sensing to Count Trees

Operational administration of green assets such as forests and urban green cover ordinarily necessitates reliable, timely and well-run information about its developments and current status. Tree count management is important for sustaining conservational stability and ecological biodiversity. A systematic tree inventory of the forested areas and in the urban areas can help us involvedly view the causes of decline of forests in the area, decline in green cover in urban areas etc. and assist in decision making. Customary methods for counting trees are labor-intensive catalogue in the field or on anelucidation of large scale aerial photographs. Nevertheless these methods are pricey, time consuming and not pertinent to large, sequestered areas. Remote sensing technology know-how is the operational method for management and monitoring of green resources.

Methods of Extracting Remotely Sensed Data
There are different methods of getting the remotely sensed data, like the ones listed below.

• LiDAR
• Satellite Images
• UAV/Drone Images
• Terrestrial Photogrammetry

LiDAR
LiDAR methods of data collection is progressively used in forestry applications but also employed in urban environments for green cover calculations, tree canopy mapping and tree counting. Vast point clouds are usually converted software specific readable formats and are used to do the mapping for the tree counting and urban forestry mapping.

Satellite Images
One of the most important resources in the earth that needs constant monitoring and needs to be accurately measured for effective management is forest resources. Remotely sensed high-resolution or very high resolution satellite image data are crucial in this management, since it provides detailed information to administrators and planners for better decision making

UAV/Drone Images
Hyperspectral remote sensing, which uses the modern satellite sensors ability to capture the data in multiple-bands, in amalgamation with a properly updated land information system is understood to be a worthy technique to assist in making fast decisions. The practice of using Unmanned Aerial Vehicle (UAV) platform for many remote sensing applications is done to combine the advantages of traditional remote sensing techniques and the inexpensiveness of operating such techniques. UAV drones can fly at varying altitudes subject to the objective of the mission and end-result type. This tractability allows for optimization of the procedures according the meteorological conditions over a given area and the user requirements.
Terrestrial Photogrammetry

Tree counting is crucial for cultivated area and environmental management, biodiversity monitoring and many other applications. Regardless of the factor that satellite and aerial images have been widely used to distinguish, demarcate and count individual tree in urban areas and forested lands, till such techniques becomes widely accessible and knowledge of processing such data is increased, the traditional methods still hold the sway and might be detrimental for the green cover we all wish to have.

About the Author
Anil Narendran Pillai – (Vice President – Geomatics @ SBL) Mr. Pillai heads the GSS (Geospatial Services) domain at SBL. He has worked in the digital mapping, remote sensing, and GIS industries for over 23 years. He has 23+ years experience managing and coordinating GIS projects and 12 years senior management experience. He has extensive experience in all aspects of aerial and satellite imaging technology and applications. He has utilized remotely sensed satellite and airborne imagery for a variety of environmental applications including site location analysis, forestry, telecommunications and utility corridor mapping. He has a strong background in management of GIS and Photogrammetry imaging projects to support Government and private industry needs.His Passion lies in Need Analysis and Documentation, Topographical Mapping (ArcGIS), Spatial Data Management, Integrity and Security, GIS Data transformations and projections from multiple sources, Image Processing Software user testing and documentation, Project Coordination and Tech. Support, Inter-agency communication and support, 3D Data Generation and Management,Project Management, Digital Photogrammetry, Satellite Image Processing, Pre-Sales Presentations.

See more about SBL Geospatial services http://www.sblcorp.com/geospatial-services

Source: GIS Lounge - Maps and GIS

Mapping Forest Disturbance with Landsat

BY CAITLIN DEMPSEY MORAIS

The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) takes advantage of the30 year Landsat archive to inventory recent disturbances and forest-cover change. Using mid-summer, cloud free Landsat data from the Global Land Survey (GLS) project, LEDAPS first corrects the images to remove atmospheric effects from surface reflectance (source code for LEDAPS) before applying change detection techniques to map out disturbance, regrowth, and permanent forest conversion across the continental United States.

One of the resulting products is a map of the continental United States and Canada showing forest disturbance rates from 1990-2000. Areas on the map that are green indicate the least amount of disturbance during that time period which pink to red areas indicated the highest amount of disturbance.

Data produced from NASA’s project is contribute to the North American Carbon Program (NACP), a component of the USGCRP Carbon Cycle Science Program. The NACP is a coalition of researchers seeking to better understand the carbon cycle such as carbon sources and sinks and changes in carbon stocks.

Disturbance data can be downloaded from North American Forest Dynamics (NAFD) product archive at ORNL DAAC.

LANDSAT-DERIVED FOREST DISTURBANCE RATE (STAND REPLACING), 1990-2000, AGGREGATED TO 500M GRID. SOURCE: NASA.

Reference


Goward, S.N., C. Huang, J.G. Masek, W.B. Cohen, G.G. Moisen and K. Schleeweis. 2012. NACP North American Forest Dynamics Project: Forest Disturbance and Regrowth Data. Available on-line [http://daac.ornl.gov] from ORNL DAAC, Oak Ridge, Tennessee, U.S.A.http://dx.doi.org/10.3334/ORNLDAAC/1077

Source: GIS Lounge - Maps and GIS

Cloud Computing Used to Analyze Landsat Imagery and Detect Deforestation

BY ZACHARY ROMANO


Cloud computing allows individuals, firms, and institutions to manage and process large amounts of data faster than ever before. Landsat, NASA’s longest running initiative for the acquisition of Earth imagery, has generated nearly 50 trillion pixels of data by capturing one image per season, of every place on Earth, for the past 43 years. Now, “the cloud” has allowed researchers like Matthew Hansen and Sam Goward to make use of this abundant imagery data.

Every time a disturbance occurs to a forest, the growth cycle restarts and this can be seen in satellite images of Earth. The challenge, however, comes when working with lower­ resolution imagery, as it requires at least a 30 meter resolution to track small­scale changes to a forest via imagery. Hansen and Goward were bound to this low­ resolution data for quite some time. If resources allowed, these researchers would want to develop a live forest tracking system, that alerted a locale when forest destruction reached a high level, to the point of identifying the exact cause of the deforestation. Eventually, the team obtained Landsat imagery but due to the high cost, they could only obtain what they could afford.

SINCE JANUARY 1, 2000, MORE THAN 4.3 MILLION SCENES HAVE BEEN CAPTURED BY LANDSAT SATELLITES AND MADE AVAILABLE TO THE PUBLIC. GRAPH BY JOSHUA STEVENS, USING DATA COLLECTED FROM THE U.S. GEOLOGICAL SURVEY ACQUISITIONS ARCHIVE.

At a conference in 2008, the University of Maryland team met Rebecca Moore, a Google developer, at a conference and realized the value in Google’s high­-powered computing ability for their 700,000 Landsat scenes (more: New Detailed Maps Show Changes in Earth’s Forests). The team worked with Google to process these images to analyze them and track whether a pixel was forested or not, and aggregated this information to better understand forest growth cycle trends. Many methods were utilized but the system has the ability to measure the levels of RGB color density in each image pixel. By doing so, this allows the research team to hone in on those small­scale changes by tracking the variation in this color density over time. In total, the analysis process required 10,000 central processing units and took 1 million hours ­ a process that would have taken 15 years on a single computer.

CHANGES IN THE LANDSCAPE CAN BE DETECTED AS SMALL AS THE SIZE OF A BASEBALL DIAMOND. THESE TWO SATELLITE IMAGES SHOW PRE (LEFT) AND POST (RIGHT) CLEARING OF A FOREST IN NORTHERN ALABAMA. (NASA EARTH OBSERVATORY IMAGE BY JOSHUA STEVENS, USING LANDSAT DATA FROM THE U.S. GEOLOGICAL SURVEY)

One of the first case studies for this method looked at the Democratic Republic of Congo and found significant deforestation between 2000­ to 2010. This amounted to 5,5­72 teragrams of carbon lost due to slash and burn for agriculture and the need for wood as a fuel source. For nation’s like DCR, which lack any form of a forest or tree inventory, there is incredible value to those making land use and resource planning decisions. These images offer policymakers the most succinct understanding of deforestation. As this method gets more refined, the University of Maryland team hopes to expand the application of this tree inventory to other areas like tracking human health, protected nature areas, and modeling biodiversity.

References
Big Data Helps Scientists Dig Deeper by Holly Riebeek, Earth Observatory, NASA. March 26, 2015.

Source: GIS Lounge - Maps and GIS

New software developed by the Polytechnic University of Valencia (UPV) can generate maps of forest areas with information on timber volume, biomass or height of the trees, among other variables.

The development of this software by the Group of Geoenvironmental Cartography and Remote Sensing is part of the INFOREST project coordinated by COTESA (Center for Observation and Spatial Remote Sensing S.A.U) and funded by the Spanish Ministry of Industry, Tourism and Trade. The other teams that have taken part in the research are the Social Capital Group and Sustainable Development at the University of Castilla-La Mancha and the Group of Inventory and Natural Resources Management at the Polytechnic University of Madrid.

According to Luis Ángel Ruiz, researcher at the UPV, this project has yielded key information for management of forests using data from Earth Observation at local, provincial and regional levels. He also states that its results are particularly relevant to ensure optimal maintenance and exploitation of forests from an ecological point of view.

The software integrates the entire LiDAR data treatment process (which was also developed by the researchers) from the generation of digital terrain models, feature extraction and model estimation of forest variables, to obtain the final maps.

'From airborne LiDAR data and software application, we generate maps that can improve knowledge about the evolution of a forest, how its structure and characteristics change, as well as its potential to absorb CO2 and its wood volume. All this has positive effects on its maintenance, fire prevention or sustainable use,' says Luis Ángel Ruiz.

LIDAR technology (Light Detection And Ranging) works by continuously sending energy pulses to the ground, that impact on Earth's surface and return to the sensor. The return time allows registering the position and coordinates of the recorded points and, therefore, measures terrain, vegetation, buildings and other elements in 3D. The final point cloud data can be processed and analyzed for use in various applications, including the study of forest stands.

To develop this procedure, the scientists conducted a comprehensive field survey and airborne LiDAR data was acquired in a mountain area of ​​4,100 hectares, located in the municipality of Cuenca (Spain), primarily with three species of pine: Pinus nigra, Pinus sylvestris and Pinus pinaster, in addition to shrubland and bare ground. Given the importance of forest management in the area, the project has been backed by the City of Cuenca and the Junta de Comunidades de Castilla-La Mancha.


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The above post is reprinted from materials provided by Asociación RUVID.Note: Materials may be edited for content and length.

Article source: Science Daily

Forest Atlas Informs How Woodland Changes Affect Earth

An interactive GIS atlas tells a story about what the world was like in the past, what it's like right now, and what we can ask of it in the future. The US Forest Service (USFS) has one such GIS atlas, the Forest Atlas of the United States.

The Forest Atlas "represents a new strategy and architecture for sharing data, information, and knowledge with policy makers, resource managers, landowners, and constituents," explained project manager and research soil scientist Charles "Hobie" Perry.

Built on Esri technology, the Forest Atlas is a resource for answering questions about how changes in forests affect people and the earth.

This 30-meter digital data of tree canopy cover has superseded William H. Brewer's map of woodland density from 1873.

A Bountiful Archive of Forest Maps
Forest maps have a long history in the United States. In 1873, William H. Brewer of the US Census Bureau produced one of the first maps of forests and woodlands. In 1898, George B. Sudworth, a dendrologist in the early Forest Service, published hisCheck List of the Forest Trees of the United States, Their Names and Ranges. From that, he and his team used contour maps of the United States to record where various forest flora could be found. The Forest Service and the US Geological Survey then published these maps in a loose-leaf volume in 1913—the firstForest Atlas of the National Forests of the United States.

But due to all the legwork that went into producing this, only one volume was published.

Forest Inventories Help Track Change
In 1928, the USFS began the Forest Inventory and Analysis (FIA) program, which manages information on forest conditions and reports on sylvan trends. FIA inventories describe the location, health, age, and tree species of forests. Forest managers need this information to write sustainable forest plans; understand the risks of fire, insect, and disease outbreaks; and schedule treatment activities such as harvests—all to maintain forest health.

This information has wider reaching applications as well. Water resource managers use forest data to trace water life cycles. State forest managers use it to track insects, diseases, and invasive species so they can implement effective treatments. Scientists rely on forest measurements to calculate how much carbon dioxide should be captured and stored for carbon sequestration. Natural resource planners also build strategies and design policies using forest changes measured over time.

Reviving the Forest Atlas
Because more forest analysts and scientists are incorporating geospatial analysis into their work, FIA is paying more attention to geospatial technology. Recently, the USFS decided to revive the Forest Atlas project to better organize its tremendous amounts of spatial data, and it used Esri technology to rebuild the resource.

The foundation for the new Forest Atlas is a set of highly accurate forest maps derived from FIA and other research projects. FIA inventories nearly 1,000 different plant species across 12 time zones, from Puerto Rico and the Virgin Islands in the Atlantic Ocean to the Marshall Islands and Palau in the Pacific Ocean. FIA recognizes species according to the US Department of Agriculture's Plants Database to eliminate the inherent biases that can arise when people inventory forests according to their own needs.

In addition to showcasing FIA inventory data, the Forest Atlas features datasets and information from across the agency. This includes the Forest Health Technology Enterprise Team's National Insect and Disease Risk Map, the Monitoring Trends in Burn Severity Program's burn severity and fire perimeter maps, and other researchers' historic tree species migration maps and future range projections.

In the Forest Atlas, this information is combined with other forest attributes to tell a comprehensive story about the forces shaping US forests and the ecosystem services they provide.

"Good data tells a very significant story," said FIA's national program manager Greg Reams. "This helps us demystify reasons why species shift in the forest. Geospatial analyses tell a story of change, [allowing] us to track invasive species and understand how these events are occurring."

The Forest Atlas addresses other related but broad forestry concerns as well, including changes in employment trends, biomass availability, land cover, and land use. It also helps the USFS, firefighters, and other responders better manage wildfires and aids scientists in analyzing carbon sequestration potential.

More Inclusive Fire Management Strategies
Fires are a natural event in any wooded landscape. When strategically managed, they help forests grow stronger and healthier. But native and invasive pests, overcrowded clusters of forest, and drought conditions reduce forests' resilience to fire and increase the likelihood that fires will be catastrophic.

The USFS and its partners need to integrate fire as a critical natural process in land and resource management but control wildfires that pass through properties with various ownership structures, all while implementing the best available science.

The Forest Atlas lets stakeholders and policy makers share essential knowledge for making environmentally sound and cost-effective fire management decisions. Sharing open data on GIS platforms ensures that everyone can understand and participate in these critical decisions.

Forecasting Carbon Sequestration Capabilities
US forests offset about 16 percent of the nation's annual carbon emissions, according to the USFS, making the Forest Atlas invaluable for designing carbon mitigation strategies.

People involved in discussions about climate change and carbon are very interested in forests' past; current; and, most of all, future carbon sequestration rates. These people are particularly keen on seeing various mapped-out scenarios that project carbon storage rates over the next 10 to 30 years.

Using Esri model building tools, researchers can construct simulations of future carbon sequestration based on variables such as population growth, fluctuations in gross domestic product, and changes in forest age and density. Forest Service scientists can also use projected climate scenarios—ranging from warm dry seasons to mild wet seasons—to calculate the effects these different conditions would have on future forest growth, including changing forest areas and carbon sequestration rates over the next 30 years. Analysts can then use these projections to forecast economic development such as housing starts, future lumber demand, and the quantity and quality of water that will be derived from forested ecosystems.

Complex and connected scenarios such as these are easier to understand when presented as geospatial displays. For example, positive and negative carbon storage levels can be represented as a range on a map so the resource community can see areas that need management action and policy makers and city planners can see what the effects will be.
Making the Forest Atlas Accessible

The Forest Atlas is available on the USFS GIS platform and is published in accordance with the Federal Geographic Data Committee's metadata standards. This makes it easy to integrate the information with other open data across government organizations.

"I see us aligning with other agencies, not just in a statistical manner but in a geospatial manner," Reams concluded. "Geographic metadata makes it easier to track monitoring information such as the shifts among land-use and land-cover categories, particularly forests, agriculture, and urban landscapes. The open-source data platform enables data integration among agencies in ways that will prove highly meaningful."

The general public can also access the atlas via ArcGIS Online and through the US government's open-source spatial data website.

Source: ESRI

Detailed maps of forest canopy height and carbon stock for the conterminous US

The Woods Hole Research Center has released the first hectare-scale maps of canopy height, above-ground biomass, and associated carbon stock for the forests and woodlands of the conterminous United States. The multi-year project, referred to as the National Biomass and Carbon Dataset (NBCD), produced maps of these key forest attributes at an unprecedented spatial resolution of 30 m.


According to Dr. Josef Kellndorfer, who led the project at WHRC, "We are excited about the completion of this mapping project. The dataset represents a comprehensive assessment of forest structure and carbon stock within the lower 48 States at the beginning of the third millennium, providing an important baseline with which to improve our understanding of the United States forest resources and its link to the terrestrial carbon flux in North America. This dataset will be useful to foresters, wildlife ecologists, resource managers, and scientists alike."

Volker Radeloff, professor at the University of Wisconsin-Madison, Department of Forest and Wildlife Ecology, added, "Vegetation structure data has been the holy grail for biodiversity science: absolutely essential, but unattainable for large areas. The NBCD data set fills this crucial gap and will advance of our understanding of why biodiversity is so much higher in some areas than others, and target biodiversity conservation efforts."

The project was initiated in 2005 with funding from NASA's Terrestrial Ecology Program as well as support from the USGS/LANDFIRE consortium. Collaborators included the U.S. Forest Service Forest Inventory and Analysis (FIA) Program, and the National Land Cover Database (NLCD 2001) and National Elevation Dataset (NED) project teams at the USGS EROS Data Center.

To produce this first-of-its-kind data set, NASA space-borne imagery (SRTM/Landsat-7), land use/land cover information (NLCD 2001), topographic survey data (NED), and extensive forest inventory data (FIA) were combined. Production of the NBCD followed an ecoregional mapping zone approach developed for the NLCD 2001 project. Across 66 individual mapping zones, spatial data, field observations, and statistical models were used to generate the canopy height, aboveground biomass, and carbon stock maps, which were then joined to form national-scale products.

"This effort is an excellent example of FIA partnering to marry ground and remotely-sensed data to provide natural resource information at resolutions much finer than the FIA sampling frame," said Dennis May, Forest Inventory and Analysis program manager with the U.S. Forest Service, Northern Research Station.

Dr. Wayne Walker, a Center scientist who also worked on the project, added, "Maps of key forest attributes like canopy height and carbon stock have not existed for the U.S. at this level of spatial detail and consistency. They will provide ecologists and land managers with new and better information to support biodiversity conservation, wildfire risk assessment, and timber production while helping climate scientists and others to better understand the role that U.S. forests play in the global carbon cycle."

According to Kellndorfer, "This dataset will advance our understanding of the United States natural resources, provide an invaluable circa year 2000 baseline against which to assess changes in the future, and help to improve our understanding of the drivers for change, and thus supporting good decision making. Naturally we are keen to produce the next generation data sets of this kind to assess in detail how carbon stock and forest structures are changing in this country, and internationally. We look forward to working¬¬ with an ever growing community of colleagues in the U.S. and abroad on pushing the science of understanding the World's forests forward."

Dr. Kellndorfer's research focuses on the monitoring and assessment of terrestrial and aquatic ecosystems, and the dissemination of Earth observation findings to policy makers through education and capacity building. Using geographic information systems (GIS), remote sensing, and modeling, he studies land-use, land cover and climate change on a regional and global scale. His projects include carbon and biomass mapping of the United States, mapping forest cover across the tropical forested regions of Africa, Latin and Asia through the generation of consistent data sets of high-resolution, cloud-free radar imagery. He is a Senior Scientist at the Center. Before joining the WHRC, Kellndorfer was a research scientist with the Radiation Laboratory in the Department of Electrical Engineering and Computer Science at the University of Michigan. He holds a diploma degree in physical geography and a doctorate in geosciences from the Ludwig-Maximilians-University in Munich, Germany. He serves on various expert working groups within NASA, the Group on Earth Observation, and GOFC-GOLD addressing forest carbon measurements in vegetation from remote sensing with existing and future remote sensing and field measurements.

Dr. Walker is an ecologist and remote sensing specialist interested in applications of satellite imagery to the assessment and monitoring of temperate and tropical ecosystems at regional to global scales. His research focuses on measuring and mapping forest structural attributes, land cover/land use change and terrestrial carbon stocks in support of habitat management, ecosystem conservation and carbon-cycle science. He is committed to building institutional capacity in the tools and techniques used to measure and monitor forests, working in collaboration with governments, NGOs and indigenous communities across the tropics. He is an Assistant Scientist at the Center. Walker holds degrees in forest ecology (M.S.) and remote sensing (Ph.D.) from the University of Michigan.

The digital raster data set is now freely accessible from the WHRC website atwww.whrc.org/nbcd

.

Story Source:

The above post is reprinted from materials provided by Woods Hole Research Center. Note: Materials may be edited for content and length.

Article Source: Science Daily

NASA map sees Earth's trees in a new light

Global map of forest height produced from NASA's ICESAT/GLAS, MODIS and TRMM sensors. The map will advance our understanding of Earth's forest habitats and their role in Earth's carbon cycle.
Credit: NASA/JPL-Caltech



A NASA-led science team has created an accurate, high-resolution map of the height of Earth's forests. The map will help scientists better understand the role forests play in climate change and how their heights influence wildlife habitats within them, while also helping them quantify the carbon stored in Earth's vegetation.


Scientists from NASA's Jet Propulsion Laboratory, Pasadena, Calif.; the University of Maryland, College Park; and Woods Hole Research Center, Falmouth, Mass., created the map using 2.5 million carefully screened, globally distributed laser pulse measurements from space. The light detection and ranging (lidar) data were collected in 2005 by the Geoscience Laser Altimeter System instrument on NASA's Ice, Cloud and land Elevation Satellite (ICESat).

"Knowing the height of Earth's forests is critical to estimating their biomass, or the amount of carbon they contain," said lead researcher Marc Simard of JPL. "Our map can be used to improve global efforts to monitor carbon. In addition, forest height is an integral characteristic of Earth's habitats, yet is poorly measured globally, so our results will also benefit studies of the varieties of life that are found in particular parts of the forest or habitats."

The map, available at http://lidarradar.jpl.nasa.gov, depicts the highest points in the forest canopy. Its spatial resolution is 0.6 miles (1 kilometer). The map was validated against data from a network of nearly 70 ground sites around the world.

The researchers found that, in general, forest heights decrease at higher elevations and are highest at low latitudes, decreasing in height the farther they are from the tropics. A major exception was found at around 40 degrees south latitude in southern tropical forests in Australia and New Zealand, where stands of eucalyptus, one of the world's tallest flowering plants, tower much higher than 130 feet (40 meters).

The researchers augmented the ICESat data with other types of data to compensate for the sparse lidar data, the effects of topography and cloud cover. These included estimates of the percentage of global tree cover from NASA's Moderate Resolution Imaging Spectroradiometer on NASA's Terra satellite, elevation data from NASA's Shuttle Radar Topography Mission, and temperature and precipitation maps from NASA's Tropical Rainfall Measuring Mission and the WorldClim database. WorldClim is a set of freely available, high-resolution global climate data that can be used for mapping and spatial modeling.

In general, estimates in the new map show forest heights were taller than in a previous ICESat-based map, particularly in the tropics and in boreal forests, and were shorter in mountainous regions. The accuracy of the new map varies across major ecological community types in the forests, and also depends on how much the forests have been disturbed by human activities and by variability in the forests' natural height.

"Our map contains one of the best descriptions of the height of Earth's forests currently available at regional and global scales," Simard said. "This study demonstrates the tremendous potential that spaceborne lidar holds for revealing new information about Earth's forests. However, to monitor the long-term health of Earth's forests and other ecosystems, new Earth observing satellites will be needed."

Results of the study were published recently in the Journal of Geophysical Research -- Biogeosciences.

JPL is managed for NASA by the California Institute of Technology in Pasadena.



Story Source:
The above post is reprinted from materials provided by NASA/Jet Propulsion Laboratory. Note: Materials may be edited for content and length.


Journal Reference:Marc Simard, Naiara Pinto, Joshua B. Fisher, Alessandro Baccini.Mapping forest canopy height globally with spaceborne lidar.Journal of Geophysical Research, 2011; 116 (G4) DOI:10.1029/2011JG001708

Article source: Science Daily

Forest satellite data & mapping project led by Ecometrica Gets $1M from GEF to Conserve Mexico Biodiversity Hotspot

An international project led by sustainability software and data firm Ecometrica and funded by the UK Space Agency's International Partnership Space Programme (IPSP) has helped local organisations in Mexico secure funding of over $1 million from the Global Environment Facility (GEF) to support conservation of the El Ocote Biosphere Reserve, an internationally recognised biodiversity hotspot in the state of Chiapas.

The IPSP project is providing new satellite data and mapping technology to local organisations to assist in the monitoring of land use change, fires and forest health. Satellite derived information will be analysed and delivered to local organisations via a network of regional Earth Observation (EO) labs, built on Ecometrica's cloud-based technology.

Project director Elsa Esquivel, of Mexican NGO Ambio, said: “Ecometrica's satellite data and mapping technology is helping to us to identify areas where community activities to promote forest-friendly agriculture are succeeding, or running into problems. Without this our team on the ground cannot continually cover the more than 100,000 hectares of the reserve and the surrounding areas of influence. It will also help us to report on the effectiveness of our actions to the GEF, as part of an ongoing cycle of monitoring, evaluation and learning. We also hope that the satellite data and mapping system will be expanded to other parts of Chiapas to help communities mitigate and adapt to climate change.”

Ambio is leading the El Ocote project and has been working with indigenous communities in and around the Biosphere Reserve for more than seven years. The GEF funding will ensure that Ambio has enough staff to liaise with local farmers over activities that impact on the forest – such as crop burning – and to tackle illegal activities, including logging.

Dr Richard Tipper, executive chairman of Ecometrica, said: “We are delighted that GEF has chosen to back this project and that IPSP's input was a catalyst for that decision. The satellite derived information should help to ensure the intervention is effective and efficient, because it allows conservationists on the ground to know what is happening and to deploy their resources accordingly in the challenging terrain.”

Dr Tipper said the IPSP is a great example of a programme that helps businesses with advanced technologies build relationships in countries that would not normally benefit. Earth observation technologies have great potential to support sustainable forestry, agriculture and natural resource management around the world.

“Through the IPSP we are showing that UK companies have solutions that are relevant to the very real challenges faced by developing and emerging economies,” he said.

Dr Tipper said El Ocote is hopefully the first of several local conservation and development activities in Mexico and Brazil to be assisted by the EO Lab technology.

Distributed by The Communications Business on behalf of Ecometrica and Ambio.

For further information, please contact:

Denise Hannestad
The Communications Business
Tel +44 131 208 1500
Email: Email Contact

About Ecometrica

• In October 2015 Ecometrica was appointed by the UK Space Agency to co-ordinate a major new international project to set up a network of virtual regional Earth Observation (EO) Labs to develop suitable products for the forest sector.
• Ecometrica will spearhead the use of satellite data for forest monitoring across the globe. It will initially work with Brazilian space research institute INPE and Mexican research group ECOSUR, as well as several of the UK's leading forest EO researchers and experts.

Ecometrica’s team of recognised experts in sustainability accounting and reporting has been named as one of the world’s top Sustainability and EH&S brands by industry analyst Verdantix. Ecometrica has unrivalled experience in environmental assessments and natural capital accounting, and the Ecometrica Platform brings clarity to environmental and natural resource challenges by combining earth observation data from satellites with local information and business intelligence.

Ecometrica supports all aspects of sustainability planning, operations and reporting by businesses and public organisations. Its sustainability data and software services are available worldwide through offices in Boston, Edinburgh, London and Montreal.

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To Take Earth’s Pulse, You Have to Fly High

Ecologist Greg Asner and his team at the Carnegie Institution for Science can measure the biomass of a forest from the air. In this false-color video of Amazon rain forest in Peru, the biggest, heaviest trees are red, while yellow, green, and blue trees are progressively lighter. Carnegie's research aircraft is equipped with a scanning lidar—a laser ranging device that works like radar—and imaging spectrometers.




Story by Peter Miller
THE VIEW OUT THE WINDOW WAS BAD ENOUGH. As his research plane flew over groves of California’s giant sequoias, some of the world’s tallest trees, Greg Asner could see the toll the state’s four-year drought had taken. “It looked wicked dry down there,” he said. But when he turned from the window to the video display in his flying lab, the view was even more alarming. In places, the forest was bright red. “It was showing shocking levels of stress,” he said.

The digital images were coming from a new 3-D scanning system that Asner, an ecologist with the Carnegie Institution for Science, had just installed in his turboprop aircraft. The scanner’s twin lasers pinged the trees, picking out individual branches from 7,000 feet up. Its twin imaging spectrometers, one built by NASA’s Jet Propulsion Laboratory (JPL), recorded hundreds of wavelengths of reflected sunlight, from the visible to the infrared, revealing detailed chemical signatures that identified each tree by species and even showed how much water it had absorbed—a key indicator of health. “It was like getting a blood test of the whole forest,” Asner said. The way he had chosen the display colors that day, trees starved of water were bright red.


As California's historic drought continues, scientists are turning to remote sensing from the skies. Orbiting satellites measure groundwater depletion, and aircraft monitor the snowpack and the tree canopy's chemical composition, bringing crucial information to those working to alleviate the drought—and to the people who depend on them.

Disturbing as the images were, they represented a powerful new way of looking at the planet. “The system produces maps that tell us more about an ecosystem in a single airborne overpass,” Asner wrote later, “than what might be achieved in a lifetime of work on the ground.” And his Carnegie Airborne Observatory is just the leading edge of a broader trend.

At a time when human impacts on the planet are unprecedented, technology offers a chance to truly understand them.

A half century after the first weather satellite sent back fuzzy pictures of cloudsswirling over the North Atlantic, advanced sensors are doing for scientists what medical scanners have done for doctors—giving them ever improving tools to track Earth’s vital signs. In 2014 and early 2015 NASA launched five major Earth-observing missions (including two new instruments on the space station), bringing its total to 19. Space agencies from Brazil, China, Europe, and elsewhere have joined in. “There’s no question we’re in a golden age for remote sensing,” said Michael Freilich, NASA’s earth science director.

Four years of drought have taken a harsh toll on California's farms and forests. Last spring Greg Asner and his team flew over the Sierra Nevada, home to sequoias and other giant trees. With the new instruments on their airplane, the researchers completed in days a damage survey that would have taken a lifetime from the ground.

PHOTOGRAPH BY GREGORY ASNER, CARNEGIE INSTITUTION FOR SCIENCE

Climate Change Is Here

Germany Could Be a Model for How We’ll Get Power in the Future

The news from all these eyes in the sky, it has to be said, is mostly not good. They bear witness to a world in the midst of rapid changes, from melting glaciers and shrinkingrain forests to rising seas and more. But at a time when human impacts on Earth are unprecedented, the latest sensors offer an unprecedented possibility to monitor and understand the impacts—not a cure for what ails the planet, but at least a better diagnosis. That in itself is a hopeful thing.

WHAT THIS IS It’s a map of atmospheric carbon dioxide over land last summer, made by NASA’s OCO-2 satellite. Red areas have a bit more CO₂, green areas a bit less, than the global average of 400 parts per million.

WHAT THIS TELLS US Forests and oceans have slowed global warming by soaking up some of the CO₂ we emit. OCO-2 will shed light on where exactly it’s going—and on how fast the planet could warm in the future.MAP BY NGM STAFF: SOURCE NASA/JPL

WATER IS EARTH’S LIFEBLOOD, and for the first time, high-flying sensors are giving scientists a way to follow it as it moves through every stage of its natural cycle: falling as rain or snow, running into rivers, being pumped from aquifers, or evaporating back into the atmosphere. Researchers are using what they’ve learned to predict droughts, warn of floods, protect drinking water, and improve crops.

Forest

WHAT THIS IS The Carnegie Airborne Observatory made this image of rain forest in Panama with its scanning lidar, which probes the trees’ size and shape, and a spectrometer that charts their chemical composition.

WHAT THIS TELLS US The technique allows Asner's team, flying at 7,000 feet, to identify individual trees from their chemical signatures—and even to say how healthy they are. The reddish trees here (the colors are arbitrary) are growing the fastest and absorbing the most CO₂.PHOTOGRAPH BY GREGORY ASNER, CARNEGIE INSTITUTION FOR SCIENCE

In California the water crisis has turned the state into something of a laboratory for remote-sensing projects. For the past three years a NASA team led by Tom Painter has been flying an instrument-packed aircraft over Yosemite National Park to measure the snowpack that feeds the Hetch Hetchy Reservoir, the primary source of water for San Francisco.
Until now, reservoir managers have estimated the amount of snow on surrounding peaks the old-fashioned way, using a few gauges and taking surveys on foot. They fed these data into a statistical model that forecast spring runoff based on historical experience. But lately, so little snow had fallen in the Sierra Nevada that history could offer no analogues. So Chris Graham, a water operations analyst at Hetch Hetchy, accepted the NASA scientists’ offer to measure the snowpack from the sky.

Water

WHAT THIS IS It’s an image of the Tambopata River in eastern Peru made by the scanning lidar aboard the Carnegie observatory.

WHAT THIS TELLS US The area in this image is actually covered with rain forest. Some lidar pulses penetrate the forest and reflect off the ground, revealing the subtle topography—red is a few feet higher than blue—and faint, abandoned river channels that have shaped the forest and helped create its rich biodiversity.

PHOTOGRAPH BY GREGORY ASNER, CARNEGIE INSTITUTION FOR SCIENCE
Painter’s Twin Otter aircraft, called the Airborne Snow Observatory, was equipped with a package of sensors similar to those in Greg Asner’s plane: a scanning lidar to measure the snow’s depth and an imaging spectrometer to analyze its properties. Lidar works like radar but with laser light, determining the plane’s distance to the snow from the time it takes the light to bounce back. By comparing snow-covered terrain with the same topography scanned on a snow-free summer day, Painter and his team could repeatedly measure exactly how much snow there was in the entire 460-square-mile watershed. Meanwhile the imaging spectrometer was revealing how big the snow grains were and how much dust was on the surface—both of which affect how quickly the snow will melt in the spring sun and produce runoff. “That’s data we’ve never had before,” Graham said.

Land

WHAT THIS IS NASA’s Aqua satellite captured these visible-light images of California and Nevada on March 27, 2010 (left), the most recent year with normal snowfall, and on March 29, 2015 (right).

WHAT THIS TELLS US After four years of drought, the snowpack in the Sierra Nevada—a crucial water reservoir for California—is just 5 percent of the historical average. Snow has virtually vanished from Nevada. And west of the Sierra, in the Central Valley, much of the fertile farmland is fallow and brown.

PHOTOGRAPHS COURTESY NASA
Painter also has been tracking shrinking snowpacks in the Rocky Mountains, which supply water to millions of people across the Southwest. Soon he plans to bring his technology to other mountainous regions around the world where snow-fed water supplies are at risk, such as the Himalayan watersheds of the Indus and Ganges Rivers. “By the end of the decade, nearly two billion people will be affected by changes in snowpacks,” he said. “It’s one of the biggest stories of climate change.”



WITH LESS WATER FLOWING into California’s rivers and reservoirs, officials have cut back on the amount of water supplied to the state’s farmers, who typically produce about half the fruits, nuts, and vegetables grown in the U.S. In response, growers have been pumping more water from wells to irrigate fields, causing water tables to fall. State officials normally monitor underground water supplies by lowering sensors into wells. But a team of scientists led by Jay Famiglietti, a hydrologist at the University of California, Irvine, and at JPL, has been working with a pair of satellites called GRACE(for Gravity Recovery and Climate Experiment) to “weigh” California’s groundwater from space.
Planet Probes
Earth's vital signs are monitored by NASA's 19 Earth-observing missions. Ten of the most critical, shown here, circle the globe up to 16 times a day, collecting data on climate, weather, and natural disasters.

MONICA SERRANO, NGM STAFF; TONY SCHICK
SOURCE: STEVEN E. PLATNICK AND CLAIRE L. PARKINSON, NASA GODDARD SPACE FLIGHT CENTER

The satellites do this by detecting how changes in the pull of Earth’s gravity alter the height of the satellites and the distance between them. “Say we’re flying over the Central Valley,” Famiglietti said, holding a cell phone in each hand and moving them overhead like one satellite trailing the other. “There’s a certain amount of water down there, which is heavy, and it pulls the first satellite away from the other.”

The GRACE satellites can measure that to within 1/25,000 of an inch. And a year later, after farmers have pumped more water out of the ground, and the pull on the first satellite has been ever so slightly diminished, the GRACE satellites will be able to detect that change too.

Depletion of the world’s aquifers, which supply at least one-third of humanity’s water, has become a serious danger, Famiglietti said. GRACE data show that more than half the world’s largest aquifers are being drained faster than they can refill, especially in the Arabian Peninsula, India, Pakistan, and North Africa.

Since California’s drought began in 2011, the state has been losing about four trillion gallons a year (more than three and a half cubic miles) from the Sacramento and San Joaquin River Basins, Famiglietti said. That’s more than the annual consumption of the state’s cities and towns. About two-thirds of the lost water has come from aquifers in the Central Valley, where pumping has caused another problem: Parts of the valley are sinking.

This concrete wellhead on Allan Clark’s almond farm at Chowchilla, east of Los Banos in California’s Central Valley, used to be flush with the ground. But groundwater pumping accelerated by drought has caused the land to sink—in some places, according to satellite measurements, by around a foot a year. Two of Clark’s irrigation wells have run dry; he’s on a waiting list to have one deepened.

PHOTOGRAPH BY MARK THIESSEN, NGM STAFF

The spectrometer view would be like “Star Trek technology”: We’d be able to see and name individual trees from space.

Tom Farr, a geologist at JPL, has been mapping this subsidence with radar data from a Canadian satellite orbiting some 500 miles up. The technique he used, originally developed to study earthquakes, can detect land deformations as small as an inch or two. Farr’s maps have shown that in places, the Central Valley has been sinking by around a foot a year.

One of those places was a small dam near the city of Los Banos that diverts water to farms in the area. “We knew there was a problem with the dam, because water was starting to flow up over its sides,” said Cannon Michael, president of Bowles Farming Company. “It wasn’t until we got the satellite data that we saw how huge the problem was.” Two sunken bowls had formed across a total of 3,600 square miles of farmland, threatening dams, bridges, canals, pipelines, and floodways—millions of dollars’ worth of infrastructure. In late 2014 California governor Jerry Brown signed the state’s first law phasing in restrictions on groundwater removal.

AS EVIDENCE HAS MOUNTED about Earth’s maladies—from rising temperatures and ocean acidification to deforestation and extreme weather—NASA has given priority to missions aimed at coping with the impacts. One of its newest satellites, a $916 million observatory called SMAP (for Soil Moisture Active Passive), was launched in January. It was designed to measure soil moisture both by bouncing a radar beam off the surface and by recording radiation emitted by the soil itself. In July the active radar stopped transmitting, but the passive radiometer is still doing its job. Its maps will help scientists forecast droughts, floods, crop yields, and famines.

No one gets a better look at how we’ve transformed Earth—and conquered night—than astronauts on the space station. The view here is to the north over Portugal and Spain. The green band is the aurora.

PHOTOGRAPH COURTESY NASA
“If we’d had SMAP data in 2012, we easily could have forecast the big Midwest drought that took so many people by surprise,” said Narendra N. Das, a research scientist at JPL. Few people expected the region to lose about $30 billion worth of crops that summer from a “flash drought”—a sudden heat wave combined with unusually low humidity. “SMAP data could have shown early on that the region’s soil moisture was already depleted and that if rains didn’t come, then crops were going to fail,” Das said. Farmers might not have bet so heavily on a bumper crop.

Climate change also is increasing the incidence of extreme rains—and SMAP helps with that risk too. It can tell officials when the ground has become so saturated that a landslide or a downstream flood is imminent. But too little water is a more pervasive and lasting threat. Without moisture in the soil, a healthy environment breaks down, as it has in California, leading to heat waves, drought, and wildfires. “Soil moisture is like human sweat,” Das said. “When it evaporates, it has a cooling effect. But when the soil is devoid of moisture, Earth’s surface heats up, like us getting heatstroke.”

DESPITE ALL THE CHALLENGES to Earth’s well-being, the planet so far has proved remarkably resilient. Of the 37 billion metric tons or so of carbon dioxide dumped into the atmosphere each year by human activities, oceans, forests, and grasslands continue to soak up about half. No one knows yet, however, at what point such sinks might become saturated. Until recently, researchers didn’t have a good way to measure the flow of carbon in and out of them.

That changed in July 2014, when NASA launched a spacecraft called the Orbiting Carbon Observatory-2. Designed to “watch the Earth breathe,” as managers put it, OCO-2 can measure with precision—down to one molecule per million—the amount of CO₂ being released or absorbed by any region of the world. The first global maps using OCO-2 data showed plumes of CO₂ coming from northern Australia, southern Africa, and eastern Brazil, where forests were being burned for agriculture. Future maps will seek to identify regions doing the opposite—removing CO₂ from the atmosphere.

Greg Asner and his team also have tackled the mystery of where all the carbon goes. Prior to flying over California’s woodlands, they spent years scanning 278,000 square miles of tropical forests in Peru to calculate the forests’ carbon content.

At the time, Peru was in discussions with international partners about ways to protect its rain forests. Asner was able to show that forest areas under the most pressure from logging, farming, or oil and gas development also were holding the most carbon—roughly seven billion tons. Preserving those areas would keep that carbon locked up, Asner said, and protect countless species. In late 2014 the government of Norway pledged up to $300 million to prevent deforestation in Peru.

Within the next few years NASA plans to launch five new missions to study the water cycle, hurricanes, and climate change, including a follow-up to GRACE. Smaller Earth-observing instruments, called CubeSats—some tiny enough to fit into the palm of a hand—will hitch rides into space on other missions. For scientists like Asner, the urgency is clear. “The world is in a state of rapid change,” he said. “Things are shifting in ways we don’t yet have the science for.”

Within the next decade or so the first imaging spectrometer, similar to the ones used by Asner and Painter, could be put into Earth orbit. It would be like “Star Trektechnology” compared with what’s up there now, Painter said. “We’ve orbited Jupiter, Saturn, and Mars with imaging spectrometers, but we haven’t had a committed program yet for our own planet,” he said. The view from such a device would be amazing: We’d be able to see and name individual trees from space. And we’d be reminded of the larger forest: We humans and our technology are the only hope for curing what we’ve caused.

Source: National Geographic Magazine