Estimating and monitoring
forest carbon stock using
fixed sample plots

Tamotsu Sato, Kaoru Niiyama, Tatsuya Otani (FFPRI)
Nur Hajar bt. Zamah Shari, Wan Mohd Shukri bin Wan Ahmad,
Abd Rahman bin Kassim, Ismail bin Harun (FRIM)

Pasoh

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Background• To establish national forest monitoring systems, use a combination of
remote sensing and ground-based forest carbon inventory
approaches for estimating forest carbon stocks and forest areachanges.

LINKAGEForest area

Average carbon stock

Total carbon stock = Σ (Forest areai x Averaged carbon stocki)• “Carbon stocks per unit area” can be estimated by measuring fixedsample plots, or stand carbon stock estimation models can be used(please see Chapter 9 in REDD-plus Cookbook) .
• Fixed sampling plots method is widely applied2

Objective

To determine biomass and estimate carbon
stock by different forest type and logging
history using fixed sampling plots in
Peninsular Malaysia

Hill forest (> 300m asl)

Lowland forest (< 300m asl)

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Study area
• Six states (Johor; Negeri Sembilan;Selangor; Pahan; Trengganu; Klentan)
in Peninsular Malaysia
Kelantan

Terengganu• Lowland and hill dipterocarp forests are
our target forest types

PahangSelangor
Kuala Lumpur

Negeri
SembilanJohor• Both forest types also classify into
“unlogged” and “logged” categories
based on logging histories• We set up 91 plots (0.36-ha in each plot)
within above-mentioned 6 states4Fixed sampling plots allocation
State
Forest type

Total

Negeri
Sembilan

PahangLowland unlogged

295218Lowland logged ≥ 10years

7156331

Lowland logged < 10years

622

717Johor

Hill unlogged

3Hill logged ≥ 10 years

2Hill logged < 10 years
TotalKelantan

21
75

91626

Selangor Terengganu

5103

62

92312915

Design of fixed sampling plot
Numbering of sub-plots for tree locations

Nested plot

• All living trees larger than 10 cm in DBH are measured within a 0.36ha plot (60 m x 60 m)• Small trees ranged between 5 cm and 10 cm in DBH are measured
within a nested sub-plot (10 m x 20 m)

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Methods of carbon stock estimation
Aboveground biomass (AGB): Kato et al. (1978)
WStem = 0.313 (DBH2H) 0.9733
WBranch = 0.0390 (DBH2H) 1.041
1/WLeaf = 1/(0.124 WS 0.794 )+1/125
1/H = 1 / 2.0 DBH + 1/61
AGB = WStem + WBranch + WLeaf

Belowground biomass (BGB): Niiyama et al. (2010)
WRoot = 0.023 DBH 2.59
BGB= WRoot

After calculating tree biomass, carbon stock of a tree will beobtained by multiplication of 0.47 (IPCC)
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Approach to raise the estimating precision~Important key of successful monitoring~Set up distinct stakewithin each sampling plot

Mark measuringposition

Make clear rules for
DBH measuring• Efficient planning is essential to reduce unnecessary works,
costs and ensure reliable carbon estimates and carbon stockchanges.

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Results

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Carbon stock in total biomass (Mg-C/ha)

Comparison of C stock285.25250.87198.18200.88176.24156.80Unlogged

Logged≥ 10 yrs

Hill forests

Logged< 10 yrs

Unlogged

Logged≥ 10 yrs

Logged< 10 yrs

Lowland forests

10Relative percentage
based on biomass (%)

Comparison of species composition~Percentage of Dipterocarpaceae spp ~36.0

Unlogged31.8
22.0

21.5

Logged≥ 10 yrs

Logged< 10 yrs

Hill forests

Non-Dipterocarpaceae spp

23.0

Unlogged

Logged≥ 10 yrs

17.7
Logged< 10 yrs

Lowland forests

Dipterocarpaceae spp
11Percentage of C stock based on DBH class
Hill forests
Unlogged

Logged ≥ 10 yrs

Logged < 10 yrs

Small trees (less than 10 cm in DBH)
contribute small portion of C stock in all
Lowlandforest forests
types
UnloggedLogged ≥ 10 yrs

Logged < 10 yrs

12Carbon stock in total biomass (Mg-C/ha)

Large trees explain C stock variances

Hill forests

Lowland forests

Density of large trees (DBH ≥ 70 cm) /ha

Because large trees dominate forest C stock,accurate & precise measurement of DBH is
important in carbon monitoring system.
13Small trees contribute species diversity
Species number based on the maximum DBH class
Maximum DBH classSpecies #Relative %Less than 10cm

111

22.9

10 - 29.9 cm

193

39.8

30 - 49.9 cm

116

23.9

50 - 69.9 cm

357.2

70 – 89.9 cm

153.1

Larger than 90 cm

153.1

About one fourth species do not reach 10 cm in DBH inhill forest at Semangkok FR.
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Key messages• Carbon stock estimation using fixed sampling plots ispractical way unless it cost high.

• Monitoring of fixed sampling plots would provide us important
information to carbon stock changes• Although small size trees (i.e. less than 10 cm in DBH)
account small portion of C stock, their species composition
contribute to high plant species diversity

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This research was supported by projects funded by
the Forestry Agency, Japan and Ministry of theEnvironment, Japan
Lowland Dipterocarp Forest, Malaysia
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Stem number (n/ha)Comparison of stem number

Unlogged

Logged≥ 10 yrs

Hill forests

Logged< 10 yrs

Unlogged

Logged≥ 10 yrs

Logged< 10 yrs

Lowland forests18Maximum DBH (cm)Comparison of maximum DBH

105.9
99.3

97.9

87.9

85.7
82.5

Unlogged

Logged≥ 10 yrs

Hill forests

Logged< 10 yrs

Unlogged

Logged≥ 10 yrs

Logged< 10 yrs

Lowland forests

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Examples of fixed sampling plot
implementations
Papua New Guinea(Fox et al. 2010)

Cambodia(Samreth et al. 2012)

N = 59N = 2020

Basal area (m2/ha)

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Carbon stock in total biomass (Mg-C/ha)