Forest Survey of India
Ministry of Environment, Forest & Climate
Change, Government of India
Dehradun, Uttarakhand
Forest Inventory & Biomass Estimation
Presenter:
Kamal Pandey (ISS-2008)
Deputy Director,
Forest Survey of India
A. Forest Inventory
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Objective
Designing Forest Inventory
Sampling Design/Method
Sample Size determination
Sampling intensity
Laying out Plots in field
Estimation and Assessment
Inventory Report
B. Biomass Estimation
1.
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3.
4.
5.
Basic Concepts
Simple Indices of Biomass
Estimator for Actual Biomass Estimation
Sample Counts
Assessment of Biomass in a Sample Plot
Forest Inventory
“Forest inventory refers to both the tabulated forest
information and to the process of measuring and
analyzing the data on which the tabulated
information is based” (FAO 2010)
Global :
National:
Local :
International concern (GFRA)
Strategic planning and policy making (NFI)
Operative management (Working Plan)
Capturing Information for further analysis in
various field forms
 Forest Biometrics is science of forest (Bio) measurement
(metrics).
 It is used to determine growth in a forest.
 The quantification of biological and physical characteristics
information about trees can be made on various
parameters as listed below:
Species ,DBH, height, site quality, age, size, shape ,
insects, disease, wildlife, topography, soils , climate and
various other parameters etc
Steps/Object
Inventory objectives/desired information
 Natural Resources Survey
 Assessment of potential for forest and wood based
industry development
 Wood based industry feasibility study.
 Management plan for a forest - long term and short
term.
Development of sampling design and methods.
Data collection (field surveys, remote sensing data
analysis and other sources).
Data analysis and publication of the results.
 Purpose & Scale of inventory are main factors
determining the overall methodology.
 Cost and time constraints
CHOICE OF THE KIND OF ENUMERATION
Total or complete enumeration Partial (or sample) enumeration
Extent of the area to be covered
Variation in composition and density
Intensity of management, degree of accuracy
Resources of labour, time and funds available
Ratio of sample to the whole population is called sampling
fraction or intensity of sampling (expressed as %) eg 5%,
10% or 20%.
For example; Sample of 100 ha selected from 1000 ha.
Intensity of sampling is 10%.
CHOICE OF THE KIND OF ENUMERATION
• Total enumeration is carried where
– Crop composition and density varies greatly (miscellaneous
forests):- total enumerations
– Smaller forest areas where Intensity of management (high),
greater accuracy is required:-
• Extensive areas and all other cases:- Partial or sample
enumeration
– Reduced cost, saving of time
– Relative accuracy
– Knowledge of error & greater scope
• Resources of labour, time and funds available dictate
which method of enumeration can be carried out.
SAMPLING DESIGNS
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Objective of the inventory
Desired precision
Time and money available
Topography & accessibility
Availability of personnel and equipments
Availability of satellite imageries, aerial photographs,
and maps, data processing units.
 Results of previous survey
Information of precision level desired, time and money
available for the work provides the foundation for sampling
design.
Operational Efficiency
SAMPLE SIZE DETERMINATION
 Optimum sample size is essential for any inventory
design.
 Level of precision required (5–10% permissible error)
 Variability of main characteristic under study
 Through pilot survey
 Past study
 Correlated variable
 Cost of enumeration per sample plot
Working Plan prescribes following factors for determination of
sample size :
Volume/ha
Allowable error
Time and Cost factor
Refer: FSI’s Technical information Series (TISS)
Volume 2 No. 3, 2020 on intensity of sample size.
Determination of sample size
Shape & Size of the Sampling Units/Plots
 Small sampling units (area of plots) are more efficient
than larger ones
 Larger the number of independent sampling units (no. of
plots) observed, the better the precision.
 Square and rectangular plots are most commonly used in
forest surveys.
 Circular plot is very easy to lay on level ground once its
center and radius are fixed.
 Usual size of the plots is 0.1 hectare but bigger plots of
1.0 hectare are often laid in mature crops.
 Working Plan prescribes laying out of 0.1ha square plot
(NWPC, 2014) whereas Circular plots are laid as per
NWPC 2023.
 Thumb rule: Size of sampling unit should be large enough
to include at least 20 measurable trees.
Sampling
Random Sampling
Non-aligned Systematic Sampling
Aligned Systematic Sampling
Cluster Sampling
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Types of sampling plots
Temporary sampling plots
Permanent sampling plots
Temporary sampling plots:
 Generally used for the enumeration surveys
 Measurements carried out once only
Permanent sampling plots:
 forest dynamics
 Growth Parameters
Permanent sample plots
Permanent sampling plots can be used for:
Repeated measurements at regular interval
Used for preparation of yield tables.
To study the all stages of development of
even aged crop
Including crop volume and increment.
To study the same type of crops in different localities.
To study the influence on crop increment of different methods
of regeneration.
Working Plan Code 2014 Inventory designs
 Working Plan is a written document : Describing the forests,
 Results of the past management practices and
 Proposal for the future forest management
interventions for a forest area.
Evidence based
‘Planning and Management Mechanism’
Working Plan Code 2014 plot design
New NFI 2016 onwards & NWPC 2023
Coverage of NFI
India map (5x5km grids)
Sampling of grids on 5 yr cycle
1st yr – all 1s 2nd yr- all 3s 3rd yr – all 5s
4th yr – all 2s 5th yr- all 4s 6th yr- all 1s
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National Forest Inventory
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Assessment of forest resources at 95% precision
for National Estimation (90% for Sub-National)
Data needs of different organizations e.g NITI
Aayog, Finance Commission, SFDs, Universities
and Research Organisations
International reporting e.g. GFRA, UNFCCC,
NATCOM etc.
(contd…)
INDIA
5x5 km grids
Inventory cycle duration
• 05 years for forests and 10 years for TOF
• Approx 100 variables recorded
Outcomes of Invetory of Forest & TOF
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approx 7,000 forested & 10,000 TOF grids to be
inventoried/ year
estimate growing stock (stems and volume) inside and outside forest areas
estimate biomass and carbon stock in the India’s forest
estimate Growth and productivity
inventory of Important NTFPs
growing stock of bamboo
estimate important characteristic of forest such as regeneration, grazing, fire
incidence etc.
New National Forest Inventory
Design
INDIA GRID 5Km x 5Km
8m
900
5m
40m
40
m
900
8m
40
40m
40m
8m
Single Grid of 5Kmx 5Km
5m
m
900
8m 900
5m
5m
40 m
60 m
NFI Plot Design
Concentric circular plots at a distance of 5.0m from center of sub-plot
at 90° in east direction
Stump & Dead wood
(2.8m radius)
Sub-Plot 2
Sample Tree Form
Information
Woody Litter, Shrubs,
Climbers, Tree Regeneration
(1.7m radius)
Non clump
forming bamboo
Plot (half of subplot 2)
Sub-Plot 1
(central sub plot)
Herbs ( 0.6m radius)
Sub-Plot
3
1mX1m plot for forest floor and
soil at a distance of 20m from
central sub plot
Sub-Plot
4
PDF Form
Information
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Concentric circular plots at a distance of 5.0m from center of sub-plot at 90° in east
direction
Stump & Dead
wood (2.8m
radius)
Sub-Plot 2
Sample Tree Form
Information
Non clump
forming bamboo
Plot (half of subplot 2)
Woody Litter, Shrubs, Climbers, Tree
Regeneration (1.7m radius)
Herbs ( 0.6m radius)
Sub-Plot
3
1mX1m plot for forest floor and soil at a
distance of 20m from central sub plot
Sub-Plot 1
(central sub plot)
Sub-Plot
4
PDF Form
Information
F. No.
1.
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Name
9.
Plot Approach Form
Plot Description Form
Plot Enumeration Form
Sample Tree Form
Bamboo Clump Analysis Form
Bamboo Enumeration and Analysis Form (nonclump forming)
Bamboo Weight Form
NTFPs (Herbs, Shrubs and Climbers) and
Regeneration Form
Soil and Forest Floor Carbon Form
10
Stump, Dead Wood and Woody Litter Form
7.
8.
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Data Collection
Soil depth
Area under different
land use classes
Rockiness
Humus
Intensity of
regeneration
Origin of
stand
Incidence of fire
Injuries to crop
Crop
Composition
Grazing
Bamboo
density
Presence of weeds
Bamboo
quality
Presence of grass
Soil erosion
Plantation
potential
Etc.
Size class
Biotic
influence
60m radius (1.13 ha) Circular
plot for qualitative
information like – land use,
crop composition, origin of
stand, fire incidence, soil,
regeneration, grazing etc.
Cluster of 4 sub-plots
of 8m radius are for
tree measurements like dbh, height,
species name, crowndiameter etc.
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Variables to be recorded in field forms
Location / Accessibility
• GPS Point (Latitude,
Longitude, Altitude)
• Legal status
• Ownership
• Land use
• Agro-ecological Zone Layer
Terrain Type
• General topography
• Altitude (m)
• Slope (%)
• Aspect
• Rockiness
Soil
•Litter
•Humus layer
•Soil depth
•Soil color
•Soil texture / structure
•Organic Carbon
•Drainage Class
•Soil erosion status
Variables to be recorded in field forms
Dendrometric Parameters
• Origin of Stand
• Crop Composition
• Size Classes
• Species
• Dominance
• DBH (Over bark)
• Bark thickness (double)
• Bark void
• Tree height (total)
• Merchantable height (bole
height)
• Dominant height/ Top height
• Crown width
NTFP species
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Dead trees, cause?
Basal area (tree or stand)
Bamboo Occurrence
Bamboo Density, quality,
regeneration
Plantation potential
Forest type
Layer / strata
Species under regeneration /
herbs / shrubs
Dead wood
Rotten/missing cull
Compacted crown length
Clear bole height
Medicinal plants
Variables to be recorded in field forms (contd…)
Forest Disturbances
• Hazards
• Forest fires
• Wild animal damage
• Girdling or illicit felling
• Grazing
• Lopping
• Biotic/abiotic influences
Water resources
• Availability of stream
• Distance from stream
• Seasonal or perennial
• Number of springs
• Small water bodies
Forest health and vitality
• Presence of undergrowth
• Presence of grass
• Invasive species (two with
extant)
• Incidence of insects
• Incidence of diseases
• Mortality
• Decay class
Variables to be recorded in field forms (contd…)
Status of regeneration
• Intensity of regeneration
• Species under regeneration
• Vertical Stratification
• Presence of wildlife habitats
• Sustainable Forest
Management
• Growing Stock/biomass
• Succession Stage
• Conversion of Forest to Other
Land Uses
• Conversion of other land uses
to forests
• Forest utilization
• NWFP collection
Water utilization by nearby
communities
• Electricity generation
• Fuel wood collection
• Timber extraction (from
plantations)
• Cultural and religious importance
• Presence of archaeological
sites/monuments
• Presence of religious places
• Presence of religious important
trees
• Biodiversity /Forest regeneration
• Name of the species and quantity
Fields Forms (Forest Inventory)
Field Form
No.
Item
1.
Plot Approach
Form
2.
Plot Description
Form
3.
Plot Enumeration
Form
Description
The information recorded in this field form
describes how the plot was approached
The information recorded in this field form
pertains to the general description of forest
on an area of 1.13 ha (2 ha) i.e. 60m (80m)
radius around the centre of the plot.
In this form data of trees above 10cm dbh
and bamboo clumps are recorded which
are found in all sub-plots of 8 m radius (0.1
ha) plot.
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Fields Forms (Forest Inventory) – contd.
Field Form
No.
3.
4.
Item
Description
In this form data on dominance of trees of
10cm and above, double bark thickness,
Sample Tree Form tree height and crown width of trees are
recorded from sub-plot 2 (north-quadrant
(one-fourth area)) of the plot.
In this form data of each individual culms
occurring in certain selected clumps in the
Bamboo Clump
plot is recorded.
Analysis Form
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Fields Forms (Forest Inventory) – contd.
Field Form
No.
Item
5.
Bamboo
Enumeration and
Analysis Form (nonclump forming)
Description
In this form information is collected for
non-clump forming bamboos occurring in
the sample plot.
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Fields Forms (Forest Inventory) – contd.
Field Form
No.
6.
Item
Description
The data regarding herbs are collected from
four square sub-plots of 0.6 m radius
(1mx1m) laid out at 5m (30m from the
centre of main plot) distance from centre of
Herbs, Shrubs and all sub-plots. Similarly, the data regarding
Regeneration Form shrubs and regeneration are collected from
four square plots of 1.7 m radius (3mx3m)
laid out at a distance of 5 m (30m from the
centre of the main plots) from centre of all
sub-plots.
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Fields Forms (Forest Inventory) – contd.
Field
Form
No.
7.
Item
Description
For forest floor data fresh, partially and fully
decomposed leaves, twigs and branches are
collected from any of two sub-plots of 1mx1m laid
Soil and Forest
out at distance of 20m from centre of sub-plot 1
Floor Carbon
(north-east and south-west corners of the main
Form
plot). For collection of soil sample data pits of
(optional)
30cmx30cmx30cm in the above two plots are dug
out and a composite sample of 200gms is collected
for estimating soil carbon.
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Fields Forms (Forest Inventory) – contd.
Field Form
No.
8.
9.
Item
Description
Data is to be collected from all sub plots, in
Stump, dead wood the concentric circular plots of size 1.7 m
& woody litter Form (woody litter) and 2.8 m (stump and dead
wood).
(optional)
Data is to be collected from all sub-plots, in
Shrubs, climber & the concentric circular of size 0.6 m (Herbs)
Herb biomass form & 1.7 (Shrubs & climbers).
(optional)
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Forest Inventory – Pre-requisities
0.Objectives
1.Past Records:-Working Plans having information (Growing Stock, Volume
of wood, Tree species etc.)
- FSI Reports (ISFR, TIS)
2. Resources:-Manpower
-Finance
-Equipment (tools)
-Time-Line
3. Generation of Sample Size
4. Adequate Placing and Planning work
5. Analysis, Processing and Reporting of Results
Lay out of Plots in field
Laying out surround
Demarcation of plot boundary
Marking cross marks
Numbering of trees in the plot
Preparing a plot chart
Showing layout of plot and trees in plot
Surround: Area maintained around the Sample Plot
 All trees in the surround are generally marked by white
paint rings.
 Boundary lines of the plot are selected so that as far as
possible projections of the crowns of the border line trees
fall within the plot
Demarcation and Numbering:
Boundary line of the plots selected and marked by trench
around it (or at corners) by wooden post
Thank
You
Visit us at: www.fsi.nic.in
Kamal Pandey, ISS
Deputy Director,
Forest Survey of India
Email id:- pandey.kamal@nic.in
Whatsapp contact:- 0-9718671757