Tag Archives: Forests

GUEST POST: Time to Map and Monitor Pakistan’s Forests at the National Scale – Transparency and Accuracy

In Pakistan, too often, forested lands are treated as “free wastelands”. Deforestation and forest degradation is occurring primarily due to institutional negligence. An eye-opening example is massive deforestation in just four months observed in National Zoo-cum Park & Botanical Garden, Bani Gala, right in the capital territory of Islamabad. (see Fig. 1).

Figure1

Figure 1: A massive deforestation in four months (May-Oct, 2016) in National Zoo-cum Park & Botanical Garden, Bani Gala, Islamabad (Source of satellite images: Google Earth)

In Pakistan, many people consider real estate as the best investment, and this gives incentives for encroachers to intrude on state-owned land. Forested lands, due to their natural beauty and as a source of a double benefit, i.e., timber and land, are especially threatened by illegal land grabbers. Another example of forest degradation in Murree, Galliat region can be seen in Fig. 2, where 7.58 km2 of forest land was destroyed by  housing societies.

Figure2

Figure 2: Illegal encroachments in state-owned forests from 2005 to 2011: Bahria Golf City (Above) and OGDC Housing Society (Below). (Source of satellite images: Google Earth). See more detail in this published research article.

On the bright side, in recent years Pakistan has taken gigantic steps towards tree plantation under national (Green Pakistan Programme) and provincial (Billion Tree Tsunami in Khyber Pakhtunkhwa) initiates. These initiates have been well received and recognised globally. As an example, in 2009, Pakistan received a certificate from Guinness Book of World Records in acknowledgment of planting 541,176 mangrove plants in a single day in Keti Bunder (Indus Delta), Thatta district, Sindh province (see Fig. 3).

Figure3

Figure 3: Monitoring mangrove plantations: Repeat terrestrial photographs taken on May 2010 and May 2015 (left) and satellite images showing afforestation and conversion of mudflats into new mangroves (right). (Source of photographs: WWF-Pakistan; source of satellite images: Google Earth).

We should not forget that since 2011, Pakistan is part of UN-REDD (United National- Reducing Emission from Deforestation and Forest Degradation) program. Under the REDD program, developing countries receive performance-based incentives (payments) for reducing emissions of greenhouse gasses from forestlands. National Forest Monitoring System (NFMS) and Forest Reference Emission Level (FREL) / Forest Reference Level (FRL) systems are mandatory elements for REDD reporting system to get the financial benefits. Accurate and up-to-date information about the size, distribution, composition, and condition of forests and woodlands is essential for developing and monitoring policies and guidance to support their sustainable management. Although, in Pakistan, many independent researchers and organizations are conducting a number of scattered and local studies (e.g. Mapping Deforestation and Forest Degradation Patterns in Western Himalaya, Pakistan), however, a fundamental question remains:

How can we, in a systematic and transparent manner, map and monitor wall to wall Pakistan land cover and forest areas at the national scale?

Over the years, the use of satellite remote sensing data has become most popular among researchers and policy makers, for both smaller and larger scales. Consistent time series medium resolution freely available remote sensing data (e.g. Landsat, Sentinel-2 etc.) provide frequent, synoptic, and accurate measurements, monitoring, and simulation of earth surface features, especially forests. Unbiased ground information (field surveys, photographs, forest inventory, etc.) are very much necessary for the accuracy and evaluation of any product derived from satellite images. Under the REDD program, for FREL/FRL construction and reporting, Pakistan has to follow the guidance and guidelines of IPCC and the UNFCCC. For reporting to international bodies, Pakistan has to combine remote sensing and ground-based forest carbon inventory approaches for estimating, as appropriate, anthropogenic forest-related greenhouse gas emissions by sources and removals by sinks, forest carbon stocks, and forest area changes.

So, in my view, without further delay, Pakistan needs to take five steps for better forest management and policy formulations on the national scale:

  1. To operationalize satellite-based annual forest monitoring system for spatial quantification of deforestation, forest degradation, and afforestation
  2. To conduct comprehensive forest inventories for accuracy assessment, current forest stock, and greenhouse gas inventory
  3. To assess satellite-based land cover and land use changes at 5 years interval as an activity data for FRL reporting
  4. To map forest type and biomass/carbon stocks through integration of satellite and forest inventory data for spatial identification and quantification of habitats of tree species
  5. To develop a web-based visualization and dissemination tool using geospatial and socio-economic data for transparency and consistency

Conflicts of Interest: The findings reported stand as scientific study and observations of the author and do not necessarily reflect as the views of author’s organizations.

About this post: This is a guest post by Hammad Gilani. Learn more about this blog’s authors here.

Advertisements

Measuring 3D Forest Structure through Radar Remote Sensing

3DWald_tomo_xl

Polarimetric L-band F-SAR image of the study site in southeastern Bavaria, Germany. The image is shown in false color: forest areas appear green, while surfaces with low vegetation are shown in blue / red. Image credit: DLR

Radar remote sensing can enable us to see and construct a full 3D view of forest structure and trees. In a joint research study conducted last year, NASA and DLR proved this concept in airborne flights over a test region in southeastern Bavaria, Germany, where both agencies flew their own airborne radar sensors over a period of a few days. NASA flew its well-known L-band UAVSAR sensor, while DLR flew its F-SAR system. The F-SAR system is unique as it does coincident radar imaging at L-, C-, and X- bands. Radar remote sensing analysts know well that lower frequencies like L-band can penetrate right down to the forest floor, C-band frequencies penetrate the canopy to some extent, while X-band frequencies are reflected from the top of the tree canopy. Utilizing these three frequencies simultaneously for forest imaging allows full 3D mapping of the forest, from the upper section of the forest crown, canopy, branches, down to the under-canopy vegetation and forest floor.

See the DLR official press release for more info.

3DWald_vertikal_xl

Example vertical profile of radar backscatter from F-SAR. Backscatter is scaled in shades of green. Solid green lines represent liar-measured heights of forest floor and crown. Image credit: DLR

Many other research groups are also pursuing similar goals to measure forests in 3D using SAR remote sensing. One such technique which can be applied to both airborne and spaceborne SAR sensors is POLinSAR (Polarimetric Interferometric SAR).

The Finnish Geodetic Institute is leading a research effort to measure 3D forest structure using a multiple active sensors, including SAR imagery from Sentinel-1, TerraSAR-X / TanDEM-X, and ALOS-2 PALSAR, along with optical satellite stereo imagery, and Airborne Laser Scanning (ALS). Learn more about their research here and here.

Global Forest Assessment Report 2015 Released

Forest

The Food and Agriculture Organization (FAO) of the United Nations has released its latest Global Forest Resources Assessment (FRA) Report, which aims to quantify how the world’s forests are changing. This important report is used and cited often by nearly all kind of people working with forests. This is demonstrated clearly in the preface statement of the Assessment Report: “Reliable and up-to-date information on the state of forest resources is crucial to support decision-making for investment and policymaking in forestry and sustainable development.”

Access the FRA 2015 report here.

GUEST POST: Forest AGB Estimation and Mapping through Hi-Res Satellite Imagery (<5m resolution) – A Global Review

There is no remote sensing method that can give direct measurement of Above Ground Biomass (AGB). In most studies of AGB utilizing remote sensing, field-measured biomass values are used to train methods in predicting AGB values, linking biophysical parameters extracted from remote sensing data. Design (sample extrapolation) or model (empirical and mechanistic) based remote sensing approaches are being commonly adopted for biomass assessment and mapping. Although coarse and medium spatial resolution data, such as MODIS or Landsat TM, provide the potential for AGB estimation at a sub-national to national to regional level, mixed pixels and data saturation are major problems in AGB estimation in sites with complex biophysical environments.

Figure 1: Geographical coverage of peer-reviewed published studies on forest AGB estimation using high-resolution satellite imagery (in the time span 2004-2015).

Figure 1: Geographical coverage of peer-reviewed published studies on forest AGB estimation using high-resolution satellite imagery (in the time span 2004-2015). The legend shows the satellite datasets used for different studies.

In terms of assessment and mapping of deforestation (area, location, type of change), forest degradation (reduction in production capacity i.e. timber volume / biomass) and proxies of forest degradation (canopy closure, canopy morphology, number of mature trees, number of preferred trees, density, species composition, wild fire, and soil surface erosion), high resolution images are capable of predicting accurate results. Apart from other tree parameters, high resolution satellite data are being used for the estimation and mapping of AGB.

For site specific or sub-national level AGB estimation, high resolution satellite data could provide better results. However, due to diversity of data sources, study locations, number of samples, statistical methods and modelling standards, it is difficult to compare studies, and there is still no agreement on best practices to estimate biomass. In research communities, high resolution satellite data is gaining increasing popularity, so this post gives a quick glance of 28 peer reviewed published studies of the last 11 years (2004 – 2015) in this field of study.

Out of 28 peer reviewed published articles, 12 have been on study sites in Asia, 8 in North America, 5 in Africa, 2 in Latin America and only 1 in Europe (Table-1). QuickBird and IKONOS satellite have mostly been used for estimation and mapping forest biomass. Even in some cases, either two different sensors are jointly used (e.g. GeoEye-1 & QuickBird and QuickBird & WorldView-1) or integrated with active and passive medium resolution optical data (e.g. Landsat, ASTER and LiDAR) or microwave remotely sensed data (e.g. SAR / InSAR). Figure-1 provides the geolocations of studied conducted in different parts of world.

Table 1: Continent-level specification of high-resolution imagery used for forest AGB estimation and mapping in the time span 2004-2015.

High resolution satellite sensor* Africa Asia Europe Latin America North America Grand Total
GeoEye-1 4 4
GeoEye-1 & QuickBird 1 1
IKONOS 2 2 1 1 6
QuickBird 1 3 1 5 10
QuickBird & WorldView-1 1 1
SPOT-5 2 1 1 4
WorldView-2 1 1 1
Grand Total 5 12 1 2 8 28

Conflicts of Interest: The findings reported stand as scientific study and observations of the author and do not necessarily reflect as the views of author’s organizations.

GUEST POST: Land and Forest Cover Mapping and Monitoring – Global Scale Products

This image is taken from a recent paper by Kim et al. (2014), accessible here: http://www.sciencedirect.com/science/article/pii/S0034425714003149

This image is taken from a recent paper by Kim et al. (2014), accessible here: http://www.sciencedirect.com/science/article/pii/S0034425714003149

The availability and accessibility of global land and forest cover data sets plays an important role in many global, regional and national change studies. Recent developments in earth observing satellite technology, information technology, computer hardware and software, and infrastructure development have helped in the development of better quality land cover data sets. As a result, such data sets are increasingly becoming available, the user-base is ever widening, application areas have been expanding, and the potential of many other applications are enormous.

Data Source Year Resolution Available@
Very Coarse Resolution Products Mathews Global Vegetation/Land Use 1983 1° x 1° http://www.giss.nasa.gov/
Olson Land Cover and Vegetation 1983 0.5° x 0.5° http://www.grid.unep.ch/
Willson and Henderson–Sellers Global Land Cover 1985 1° x 1° http://www.ngdc.noaa.gov/
Coarse Resolution Products DeFries/Townshend-Global Land Cover 1995 10 km x 10 km http://glcf.umiacs.umd.edu/
GLCC (IGBP DISCover) 1997 1 km x 1 km http://edcdaac.usgs.gov/
UMD Land Cover 2000 1 km x 1 km http://glcf.umiacs.umd.edu/
MODIS Land Cover 2003 1 km x 1 km http://edcdaac.usgs.gov/
Vegetation Continuous Fields 2003 1 km x 1 km http://glcf.umiacs.umd.edu/
GLC-2000 2003 1 km x 1 km http://www.gvm.sai.jrc.it/
MODIS vegetation continuous fields (VCF) 2011 250 m x 250 m http://glcf.umiacs.umd.edu/
GLOBCOVER 2009 300 m x 300 m http://www.esa.int/
MODIS Land Cover 2008 500 m x 500 m http://edcdaac.usgs.gov/
Medium Resolution Products JAXA global PALSAR mosaic and forest/non-forest map (2007-2010) 2013 25 m x 25 m JAXA EORC
GeoCover LCTM 2003 30 m x 30 m http://www.earthsat.com/
China Global Land Cover 2012 30 m x 30 m http://www.globallandcover.com/
Global Forest Watch 2013 30 m x 30 m http://www.globalforestwatch.org/
GEO US Global Land Cover 2013 30 m x 30 m http://landcover.usgs.gov/

How much is the South Asian region benefiting?

I think we can benefit at the regional and/or at the national level. In the South Asian region, as we are well aware, lack of data and information has been one of the major limitations on policy and decision makers in addressing regional environmental issues. These issues include the development of greenhouse gas (GHG) inventories, the evolution of reducing emissions from deforestation and forest degradation (REDD) mechanisms, and the assessment of land degradation, as well as optimal land use planning.

How accurate are these products?

At different platforms debates and collaborations are going on to make global products more accurate and acceptable. Global scale study can’t come up to the demands of the national level scale. But based on our interest (land and/or forest cover change), we can get hold of the above-mentioned products, and after a certain levels of personal validation, these can be used and further analysed, instead of starting from scratch.

Conflicts of Interest: The findings reported stand as scientific study and observations of the author and do not necessarily reflect as the views of author’s organizations.
About this post: This is a guest post by Hammad Gilani. Learn more about this blog’s authors here