Indian State of Forest Report and Forest Survey of India: Methodology, Frequency and Key Indicators

The Indian State of Forest Report (ISFR) is a biennial assessment published by the Forest Survey of India (FSI), an organization under the Ministry of Environment, Forest and Climate Change (MoEFCC). First published in 1987, the ISFR provides data on India’s forest cover, tree cover, mangrove cover, growing stock, and carbon stock. The assessment serves as a baseline for national environmental policies, international reporting to bodies like the Food and Agriculture Organization (FAO), and monitoring ecological targets under the National Forest Policy.

Forest Survey of India: Structure and Functions

Institutional Setup

• Establishment: Founded on June 1, 1981, succeeding the Pre-Investment Survey of Forest Resources (PISFR) initiated in 1965 with FAO and UNDP assistance.
• Headquarters: Dehradun, Uttarakhand.
• Regional Offices: Four zonal offices located at Shimla (Northern Zone), Kolkata (Eastern Zone), Nagpur (Central Zone), and Bengaluru (Southern Zone).
• Nodal Ministry: Functions as an attached office under the Ministry of Environment, Forest and Climate Change.

Mandate and Key Activities

• Prepares the biennial Indian State of Forest Report.
• Conducts national forest inventory (NFI) across forest and non-forest areas.
• Monitors forest fires using satellite remote sensing via the Near Real-Time Forest Fire Monitoring System.
• Maps forest canopy density, mangrove cover, and coral reef ecosystems.
• Implements training programs for forestry personnel in remote sensing, GIS, and field inventory techniques.

Methodology of Forest Cover Assessment

FSI employs a combination of satellite remote sensing, Geographic Information System (GIS) techniques, and ground truth verification to assess green cover.

Remote Sensing Technology

• Data Source: Uses Indian Remote Sensing (IRS) satellite data. Recent assessments rely on LISS-III (Linear Imaging Self-Scanning Sensor) sensors aboard IRS-P6 (Resourcesat-1) and Resourcesat-2 satellites.
• Spatial Resolution: Operates at a spatial resolution of 23.5 meters with a minimum mapping unit (MMU) of 1 hectare.
• Scale of Mapping: Assessment is conducted at a scale of 1:50,000.

Classification Scheme

The assessment categorizes canopy density into distinct technical classes based on tree canopy density percentage.

Ground Truth Verification and Quality Assurance

• Field Validation: Remote sensing interpretation is validated through ground truth checks across selected geographic coordinates.
• Accuracy Assessment: Employs an error matrix to ensure mapping accuracy standards, aiming for an overall accuracy threshold above 85%.

Key Indicators and Definitions

Forest Cover vs. Recorded Forest Area

• Forest Cover: Refers to all lands more than 1 hectare in area with a tree canopy density of more than 10%, irrespective of ownership and legal status. Includes orchards, bamboo, and palms.
• Recorded Forest Area (RFA): Refers to all geographic areas recorded as forest in government records (Reserved Forests, Protected Forests, and Unclassed Forests) under the Indian Forest Act, 1927 or local state acts.
• Trees Outside Forests (TOF): Trees found outside recorded forest areas, including linear plantations along roads, canals, farmlands, and urban parks.
• Tree Cover: An estimate of tree patches smaller than 1 hectare (including isolated trees) located outside recorded forest areas.

Growing Stock and Carbon Stock

• Growing Stock: Total volume of all living trees above a specified minimum diameter at breast height (DBH) in a given area.
• Forest Carbon Stock: Total amount of carbon stored in forest ecosystems, divided into five pools:
  • Above-Ground Biomass (AGB): All living vegetation above the soil (stems, branches, bark, foliage).
  • Below-Ground Biomass (BGB): All living roots of trees and woody plants.
  • Dead Wood: All non-living woody biomass not part of litter.
  • Litter: Non-living biomass of driver leaves, twigs, and small woody debris above soil.
  • Soil Organic Carbon (SOC): Organic carbon in mineral and organic soils to a specified depth; constitutes the largest share of India’s forest carbon pool.

Frequency and Evolution of ISFR Reports

• Assessment Cycle: Published every two years (biennial).
• First Assessment (1987): Based on visual interpretation of Landsat satellite imagery at 1:1,000,000 scale.
• Digital Processing Shift (1995): Shifted from visual interpretation to digital image processing techniques.
• Grid-based National Forest Inventory (2002): Introduced a systematic sampling design dividing the country into grids for detailed field inventory.
• Specialized Chapters: Recent editions include mapping of bamboo resources, forest fire vulnerability zones, carbon stock modeling, and climate change hot spots in forest areas.

Core Facts for Revision

• FSI Predecessor: Pre-Investment Survey of Forest Resources (PISFR), launched in 1965 with FAO and UNDP support.
• Parent Organization: Forest Survey of India is an attached office under MoEFCC, headquartered in Dehradun.
• First ISFR Edition: Published in 1987.
• Assessment Frequency: Biennial (published every two years).
• Primary Satellite Sensor: LISS-III sensor aboard Resourcesat satellites.
• Minimum Mapping Unit (MMU): 1 hectare (patches smaller than 1 ha with >10% canopy are classified under Tree Cover, not Forest Cover).
• Forest Cover Threshold: All land above 1 hectare with canopy density exceeding 10%, regardless of legal ownership or land-use rights.
• Scrub Classification: Land with tree canopy density under 10% (excluded from total forest cover calculation).
• Largest Carbon Pool Component: Soil Organic Carbon (SOC) accounts for the largest proportion of total forest carbon stock in India.
• Legal Definition (RFA): Recorded Forest Area comprises Reserved Forests, Protected Forests, and Unclassed Forests declared under the Indian Forest Act, 1927 or state laws.
• Forest Fire Monitoring: Conducted using real-time MODIS and VIIRS satellite sensors integrated with SNPP and Aqua/Terra systems.