METHODS FOR ESTIMATING ROOT BIOMASS AND PRODUCTION IN FOREST AND WOODLAND ECOSYSTEM CARBON STUDIES: A review

1. A review
Sk Abidur Rahman
METHODS FOR ESTIMATING ROOT BIOMASS
AND PRODUCTION IN FOREST AND WOODLAND
ECOSYSTEM CARBON STUDIES:
MSc Students
Department of Environment and Forest Resources
Chungnam National University, South Korea

2. Over view of Article
**Shalom D. Addo-Danso
PhD
University of British Columbia.
*Cindy E. Prescott
Professor
Department of Forest and
Conservation Sciences
University of British Columbia.
Supported by
University of British Columbia
Doctoral Fellowship, NERC of UK,
Authors Journal Others
• Forest Ecology and Management
• The Impact Factor of this
journal is 3.558, ranking it 7 out
of 67 in Forestry
• Published 1 January 2016, and
the it’s cite 106 times till now.
• Key topics of article: Carbon
allocation; Coarse-root
production; Fine-root biomass;
Ground-Penetrating Radar;
Ingrowth-core; Soil-pit
methods.

3. Presentation Outline
Title Slide
Over view of article
Research Objectives
Hypothesis
Statistical Analysis
Results
Discussion
Conclusions
Reference Slide
01
02
03
04
05
06
07
08
09

4. Research Objectives
Objective #1
Methods use in fine root and coarse root biomass production in forest
Objective #2
synthesize and compare existing methods for root biomass
and production based on relevant criteria
Objective #3
Decide which methos is best for their purposes
Objective #4
Ccompare fine and coarse root biomass and production estimates
from different methods measured at the same sites.
The objectives of this review were to

5. B A S I C S
01
02
03
Fine roots:
• typically primary roots <2 mm diameter ,
• function of water and nutrient uptake.
• heavily branched and support mycorrhizas.
• short lived, but are replaced by the plant in an
ongoing process of root 'turnover'.
Coarse roots:
• secondary thickening and woody structure.
• some ability to absorb water and nutrients,
but their main function is transport and to
provide a structure to connect the smaller
diameter.
• Fine roots (62 mm in diameter) contribute
less than coarse roots to total root biomass.

6. 6
Hypothesis
01
02
03
This synthesis com- pares existing methods for root
biomass and production estimation based on relevant
criteria that include cost, labour requirements, time
efficiency and accuracy and, also compares fine- and
coarse-root biomass and production estimates from
different methods measured at the same sites.
Root excavation and soil-pit methods are commonly
used to estimate coarse-root biomass, despite the high
cost and labour required.
Ground-Penetrating Radar is a very promising indirect
approach to estimate coarse-root bio- mass, but may
not be suitable for ecosystems with dense understory
and soils with high organic matter and ion contents.

7. 7
Hypothesis
0
4
0
5
0
6
Soil-core remains the most preferred method to estimate
fine-root biomass.
Empirical models are accepted as fast and cost-effective
indirect approach to predict fine- and coarse-root
biomass and production.
0
7
Fine-root production is usually estimated with the (mini)
rhizotrons, sequential-coring and ingrowth-core
methods
Coarse-root biomass estimates were not significantly
different between soil-pit and soil-core methods. There
was a significant positive correlation (r2 = 0.91, p <
0.0001) between fine-root biomass estimates obtained
from soil-pit and soil-core methods. Fine-root
production estimates were lower in the ingrowth-core
0
8
Based on the reviewed literature and comparative
analysis we propose that (mini) rhizotrons should be
preferred over the others in estimating fine-root
production.

8. 8
Hypothesis
09
10
In situations where cost and site conditions preclude
their use, the sequential-coring and ingrowth-core
methods are suitable.
The ingrowth-core should be used with caution in sites
where root growth is slow and root biomass may be
influenced by strong seasonal fluctuation

9. Literature Review
9
01
02
03
The carbon transferred belowground is estimated to
account for 22–63% of the total gross primary productivity
of forests (Litton et al., 2007).
Estimation of fine and coarse root biomass and production
can be grouped into direct and indirect methods.
Fine-root biomass and production have been estimated
with direct methods that include

10. Tree R o o t Bio ma ss Est ima t io n M et ho ds
Fine Root
monolith
soil-pit empirical models
Indirect
(mini) rhizotrons
soil-core/sequential-
coring.
ingrowth-core
Direct

11. Coarse Root
root–shoot or belowground–
aboveground ratio
soil-pit/soil-pit
ingrowth
Size- mass
allometric
equations
Indirect
wall or trench pro-
files and soil-core
root excavation
Direct
Ground-Penetrating
Radar (GPR)
root bio- mass increment
or difference
root radial
increment
Tree R o o t Bio ma ss Est ima t io n M et ho ds
Soil core
Root radial
increment.
Fraction or percentage
ofwood production.

12. Literature Review
12
01
02
03
no consensus in the literature on how best to estimate
root biomass, production and turnover
cost, labor availability, site con- straints and individual
preferences rather than accuracy and precision

13. Method
13
With respect to
root sampling,
additional criteria
were
fine root
production
(Web of Science, Scirus,
JSTOR and Google
Scholar) and library sources
using keywords ‘fine root’,
‘coarse root’, ‘root biomass
and production’ and
‘belowground biomass
allocation’.
diameter used to define fine and
coarse roots; (iii) fine-roots were
sampled using at least two of the
direct methods (ingrowth-core,
(mini) rhizotrons and sequential-
coring) to estimate production;
(iv) fine-root production should
have lasted at least one vegetation
season or 12 months; and (v) data
were collected from a single site
and within the same period
:
Data was compiled
literature search
through a
58 observations ingrowth-
core and sequential-coring,
25 ingrowth-core and
(mini) rhizotrons.
11 sequential-coring and
(mini) rhizotron .
A total of 28 studies were
considered for fine root
production.

14. 14
• Regression analysis was used to evaluate correlations between fine
root biomass estimates from soil-pit and soil-core methods, and fine
root production estimates from sequential- coring and ingrowth-core,
ingrowth-core and (mini) rhizotrons, as well as sequential-coring and
(mini) rhizotrons methods.
• GraphPad Prism 6 (GraphPad
• significance level of p < 0.05.
• The difference between the average estimates among fine and coarse
root biomass and fine root production methods was tested by student
t-test and one-way analysis of variance.
Statistical Analysis

15. Results & Discussion
15
Coarse-root biomass and
production: Direct methods
This is a sample text.
You can replace this text.
Enter your text here
70%
60%
85%
01
02
03

16. be laborious and expensive (Danjon and
Reubens, 2008).
it could take a whole day for five people to
manually uproot twenty-four 50-year-old
Pinus pinaster roots in a sandy spodosol soil,
which is relatively well suited for excavation.
The excavation method may result in
sampling error as roots become broken or lost
during excavation
It’s a gas giant and has rings
Used to estimate coarse root biomass
(CRB) of individual trees and stands in
tropical.
the entire root system of an individual tree within a
designated radius is excavated manually or with
the help of machinery such as a tractor, backhoe or
power shovel
It allows
for direct harvesting of coarse roots
concentrated mostly around the base of the
stem
Root excavation
It’s the only method that will accurately
quantify CRB in individual trees and is
particularly recommended for sites with
high spatial heterogeneity of roots.

17. under-estimate CRB
Soil-pit sampling also mostly excludes
taproots, root crowns and lignotubers, thereby
under-estimating the total bio- mass of coarse
roots
not considered to be suitable for directly
sampling root bio- mass of individual trees
(Rau
It’s a gas giant and has rings
determine lateral-root distribution in
ecosystems
.
The soil-pit method allows roots to be collected
throughout the soil profile (Park et al., 2007), and
therefore deeper roots are included in the root-
biomass estimates (Rau et al., 2009).
belowground heterogeneity (Bledsoe et al.,
1999). A critical aspect
of this method is ensuring that soil pits are
excavated deep enough
to recover more than 90% of the roots
(Bledsoe et al., 1999).
Soil-pit/soil-pit ingrowth
Root production is assumed to be the
amount of root bio- mass accumulated
during the interval
.

18. be laborious and expensive (Danjon and
Reubens, 2008).
it could take a whole day for five people to
manually uproot twenty-four 50-year-old
Pinus pinaster roots in a sandy spodosol soil,
which is relatively well suited for excavation.
The excavation method may result in
sampling error as roots become broken or lost
during excavation
It’s a gas giant and has rings
spade or exca- vator in a stand to
expose the coarse roots.
Wall profiles can also be pho- tographed, and the
images assembled to map the soil profil
Wall or soil trench profile.
This method is less time-consuming than
other direct meth- ods and is non-
destructive, and therefore provides the
opportunity for investigators to quantify
root systems in situ over large time scales
(Curt et al., 2001). Curt et al. (2001) noted
that observation and counting of 74 root
profiles required about 30 person-days,
compared to the 100 person-days required
to completely excavate one mature tree.

19. Wall or soil trench profile
spade or exca- vator in a stand to expose
the coarse roots
Wall profiles can also be pho- tographed,
and the images assembled to map the
soil profil
This method is less time-consuming than
other direct meth- ods and is non-
destructive, and therefore provides the
opportunity for investigators to quantify
root systems in situ over large time scales
(Curt et al., 2001). Curt et al. (2001) noted
that observation and counting of 74 root
profiles required about 30 person-days,
compared to the 100 person-days required
to completely excavate one mature tree.

20. Soil-core
under-estimate CRB
For instance, in a Eucalyp- tus plantation in
Tasmania, Resh et al. (2003) found that soil
cores under-estimated CRB by 9%
compared to estimates from total-tree
excavation.
The cor- ing device can also be easily transported,
and therefore the soil- core method is efficient fo
sampling roots in remote sites where accessibility
heavy-duty equipment is limited (Rau

21. These indirect techniques include size-mass allometric
equations, root–shoot or belowground–aboveground ratio, GPR,
root biomass increment or difference, fraction or percentage of
wood production, and root radial increment.
Indirect methods
they provide quick and non-destructive
means to quantify the con- tributions offine
and coarse roots to total forest and
woodland bio- mass and carbon storage

22. Size-mass allometric equations

23. Root–shoot or belowground–aboveground
ratio
RSR is a practical and cost-effective approach to estimate
CRB. The method is being widely applied, especially in carbon
dynamics studies (

24. Ground-Penetrating Radar.
GPR is a geo-physical close-range remote-sensing technique,
which uses
electromagnetic waves (EM) to obtain root images
also detect and quantify coarse-root spatial
distribution (e.g. Hirano et al., 2012) and tree decay patterns
(Butnor et al., 2009), and determine the physical properties of trees
and soil depth
a radar control unit, an antenna and a display unit
also detect and quantify coarse-root spatial
distribution (e.g. Hirano et al., 2012) and tree
decay patterns
(Butnor et al., 2009), and determine the physical
properties of trees
and soil depth
GPR has some advantages that
make it promising for root stud-
ies. In soils with low organic matter
and ion contents, GPR can pro- duce
CRB estimates comparable with
other methods.
GPR can account for large spatial variability of tree roots within a short
time, and can be used to repeatedly monitor and characterize roots at
the same site
GPR can account for large
spatial variability of tree roots
within a short time, and can
be used to repeatedly monitor
and characterize roots at the
same site
estimates can only be achieved under comparab
environmental conditions (Butnor

25. GRP
GPR-based root-biomass studies have mainly been conducted
under controlled conditions
difficult to obtain accurate GPR data in a dense and highly d
It is also difficult to distinguish between live and
dead roots with GPR

26. Root biomass increment or difference
several limitations; for instance
because it is time-dependent

27. Fraction or percentage ofwood production
approach is simple, cost-effective and fast, and is increasingly
being applied in carbon cycling and allocation studies, particularly
in the tropics
captures only production of large structural roots (Malhi
under-estimate CRP since it usually captures only production of large structural roots

28. Root radial increment
this in situ approach, diameter tapes or dendrometer bands are
used to record the diameter increments of superficially growing
roots for a given period (Zach
However, this method suffers from the same limitation as allo-
metric equations (Section 3.1.1.2.1), since it fails to capture
small coarse roots
only superficial roots are usually considered (Zach et al., 2010),
but more coarse roots may be distributed in the deep layers of
the mineral soil (e.g.

29. Direct methods. 3.1.2.1.1. Soil-core
Fine-root biomass and production
Fine-root biomass (FRB) is commonly esti- mated by the soil-core method
Soil cores or augers are usually used to sample fine roots,
Commonly used core diameters range from 1.9 to 15 cm (
Recommended corers of diameter >10 cm to estimate FRB
soil cores are preferred for the study of annual and seasonal variations in FRB. Root-biomass data from the soil-
core method is also used to validate the efficiency and accuracy of other methods

30. cONTINUE
Soil compaction, which is a common problem with the use of
cores, can result in over-estimation of root biomass
The difficulty in separating organic debris from fine roots may
lead to over-estimation of root biomass
Extracting sample cores and root- processing (washing, sorting, weighing) takes considerable time, so in
most studies roots are under-sampled, which affects the reli- ability of FRB data (Metcalfe
In a young short-rotation Populus plantation in Belgium, Berhongaray et al. (2013) found that when
processing extracted cores that the time spent washing, sorting and weighing roots rep- resented 84–93%
of the total time needed to process root samples
The method requires cutting of a monolith (block) of the soil directly from the soil surface, or at different depths, from
the wall of a trench. Soil monoliths can also be excavated with frames constructed from wooden or metal- lic materials
they provide large soil sam-
ple volumes, which increase the accuracy of FRB estimates (Taylor et al., 2013), and reduce the n
replicates needed to secure good estimates of FRB (Levillain
Monoliths are also suited for sites where roots may be
distributed into the deep layers of the soil (Levillain
Apart from being time-consuming and laborious, it can produce erroneous estimates of FRB due to inapprop
oven-drying procedures. B

31. Soil compaction, which is a common problem with the use of
cores, can result in over-estimation of root biomass
The difficulty in separating organic debris from fine roots may
lead to over-estimation of root biomass
Extracting sample cores and root- processing (washing, sorting, weighing) takes considerable time, so in
most studies roots are under-sampled, which affects the reli- ability of FRB data (Metcalfe
In a young short-rotation Populus plantation in Belgium, Berhongaray et al. (2013) found that when
processing extracted cores that the time spent washing, sorting and weighing roots rep- resented 84–93%
of the total time needed to process root samples
The method requires cutting of a monolith (block) of the soil directly from the soil surface, or at different depths, from
the wall of a trench. Soil monoliths can also be excavated with frames constructed from wooden or metal- lic materials
they provide large soil sam-
ple volumes, which increase the accuracy of FRB estimates (Taylor et al., 2013), and reduce the number of
replicates needed to secure good estimates of FRB (Levillain
Monoliths are also suited for sites where roots may be
distributed into the deep layers of the soil (Levillain
Apart from being time-consuming and laborious, it can produce erroneous estimates of FRB due to inappropriate washing and
oven-drying procedures. B
The monolith method also requires considerable time for sorting and processing of fine roots

32. Ingrowth-core
one of the most commonly used
methods to estimate fine-root produc-
tion and turnover. The method
estimates the amount of fine root that
grows into a defined volume of root-
free soil within a specified period of
time.
it is inexpensive and
field-application is simple and
straightforward.

33. (Mini) rhizotrons.
Rhizotrons or minirhizotrons allow
for fast and continuous in situ measurement of roots and root
seg- ments with moderate disturbance to sites (Taylor
processes, which include installationroot image collection, data
processing, and conversion of root- growth parameters into
biomass production,
Minirhizotron involves inserting clear tubes (usually small in
size) into the ground at an angle, and a device such as camera is
used to observe and capture root-growth at the soil-tube
interface
root images or drawings are usually analyzed with software pro-
grams (Hendricks
higher FRP esti- mates for ingrowth-core compared to
minirhizotron in Ecuadorian tropical montane forests
Disadvantage the substantial
cost ($US 15,000) involved in acquiring
equipment and processing the root data

34. Sequential-coring.
sampling soil cores at specific-time intervals for at least one
year, and calculating the difference in biomass and necro- mass
between the two periods
can also be used to estimate mycorrhizal biomass and
production (Vogt
Sequential-coring is also expensive and
laborious, requiring a large number of soil-core
replicates to produce good estimates.

35. Indirect methods. 3.1.2.2.1. The pipe model
and others.
The pipe model has rarely been used to determine FRB (e.g.
FRB can also be estimated from other models based on easily
measurable aboveground metrics such as basal diameter, DBH, height and crown foliage

36. N budget.
measures FRP as the
product ofannual N allocation to fine roots and the C:N ratio in fine roots (Nadelhoffer
This technique has rarely been used to estimate FRP (see

38. Comparison of methods
3.2.1.
eleven sites evaluated during CRB from soil-pit and soil-
coremethods were not significantly different (t = 0.06, p = 0.96,
n = 11) (Fig. 1a), and were positively correlated (r2 = 0.32, p =
0.07, n = 11) (Fig. 1b). However,
Coarse-root biomass estimates from soil-pit and soil-core
methods
Fine-root biomass estimates from soil-pit and soil-core
methods
The mean FRB estimate from the dataset in Appendix A was
higher for soil cores (5.17 ± 0.93 Mg ha!1) than the estimate from soil pits (4.31 ± 0.08 Mg ha!1), but the difference was
not signifi- cant (t = 0.601, p = 0.556, n = 9) (Fig. 2a). Many

39. Fine-root production estimates from ingrowth-core, (mini)
rhizotrons and sequential-coring methods
The mean FRP estimate obtained from studies in Appendix B
was lower in the ingrowth-core method (2.06 ± 0.23 Mg ha!1 year!1, n = 73) compared to estimates provided by
(mini) rhi- zotrons (3.81 ± 0.46 Mg ha!1 year!1, n = 26) and sequential-coring methods (3.84 ± 0.93 Mg ha!1
year!1, n = 59) (Fig. 3), although the differences were not significant (F = 2.851, p = 0.061)

40. Conclusion
01
This is a sample text.
You can replace this text.
Enter your text here
Discussion
02
This is a sample text.
You can replace this text.
Enter your text here
Discussion
03
This is a sample text.
You can replace this text.
Enter your text here
Discussion
Many investigators prefer root-excavation and soil-pit methods
to estimate CRB, despite the high
cost and labor required.
GPR is a promising indirect approach to quantify CRB, but may not suitable for ecosystems with a dense understory and soils
with high organic matter and ion contents. Empirical models are widely used to predict fine- and coarse- root biomass and
production in carbon studies
For FRP, the ingrowth- core method consistently provided lower

41. Suggest Future Research
Suggestions
Suggestion #1
(i) the soil-pit method should be employed to estimate coarse-root biomass
because it can serve as a compromise between cost and efficiency
Suggestion #2
(mini) rhizotrons should be favored over the other methods to estimate fine-
root production;.
Suggestion #3
where cost and site conditions (e.g. in stony or on steep slopes) preclude the
use of (mini) rhizotrons, the sequential-coring and ingrowth-core methods
are suitable;

42. Suggest Future Research
Suggestions
Suggestion #1
(i multiple methods should be employed to esti- mate fine-root production,
and more comparative studies of different methods on the same sites are
needed
Suggestion #2
(iv) the ingrowth-core method should be used with caution in sites where
root growth is influenced by strong seasonal fluctuations, and when used,
the period between cores/nets installation and root sampling should be
extended to allow for maximum root col- onization; and
Suggestion #3

43. Limitations of
Your Study
Limitations of Your Study
Limitations of Your Study
03
02
01
06
05
04
Limitation1
This is a sample text. You simply add your own
text and description here.
Limitation 2
This is a sample text. You simply add
your own text and description here.
Limitation 3
This is a sample text. You simply add your own
text and description here.
Limitation 4
This is a sample text. You simply add your own
text and description here.
Limitation 5
This is a sample text. You simply add
your own text and description here.
Limitation 6
This is a sample text. You simply add your own
text and description here.

44. Future Research
44
01 This is a sample text. You can
replace this text. Enter your text
here
Research
02 This is a sample text. You can
replace this text. Enter your text
here
Research
03 This is a sample text. You can
replace this text. Enter your text
here
Research
04 This is a sample text. You can
replace this text. Enter your text
here
Research
05 This is a sample text. You can
replace this text. Enter your text
here
Research
06 This is a sample text. You can
replace this text. Enter your text
here
Research

45. Known Problems and Limitations
45
Problems Limitations
This is a sample text. You can replace
this text. Enter your text here
This is a sample text. You can replace
this text. Enter your text here
This is a sample text. You can replace
this text. Enter your text here
This is a sample text. You can replace
this text. Enter your text here
This is a sample text. You can replace
this text. Enter your text here
This is a sample text. You can replace
this text. Enter your text here
This is a sample text. You can replace
this text. Enter your text here
This is a sample text. You can replace
this text. Enter your text here

52. QUESTIONS

53. THANK YOU !
Methods for estimating root biomass and
production in forest and woodland ecosystem
carbon studies: A review
Abidur Rahman
MSc student
Department of Environment and Forest Resources
Chungnam National University