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t 255 (2008) 2244–2250
Forest Ecology and ManagemenA new instrument for measurement and collection of quantitative
samples of the litter layer in forests
Ben Hur Marimon-Junior 1, John D. Hay *
Departamento de Ecologia, Universidade de Brasılia, Campus Universitario Darcy Ribeiro, 70.910-900 Brasılia, DF, Brazil
Received 10 May 2007; received in revised form 20 December 2007; accepted 1 January 2008
Abstract
The litter layer plays an important role in the maintenance of tropical forests. The evaluation of parameters such as thickness or water content
can reveal forest conditions that are of global relevance (for example carbon stock) or of local importance such as the conservation of nutrients in
native forests or plantations. However, there is no specific instrument or protocol for quantitative collection of the litter layer. We developed an
instrument composed of two parts that permits measurement and collection of the litter layer, following a simple protocol. The method was tested in
two forest types and we verified the greater accuracy and ease of use of the instrument compared to two other commonly used litter collection
methods.
# 2008 Elsevier B.V. All rights reserved.
Keywords: Litter thickness; Nutrient cycling; Brazil
1. Introduction
The litter layer plays a fundamental role in the maintenance
of tropical forests (Vitousek, 1982; Jordan, 1985; Vitousek and
Sanford, 1986; Cuevas and Medina, 1988) impeding the loss of
nutrients due to the strong weathering in the tropics (Herrera
et al., 1978; Stark and Jordan, 1978; Jordan and Escalante,
1980; Jordan and Herrera, 1981) and acting in the maintenance
of the chemical and physical properties of the soil that are
important for the equilibrium and sustainability of the
vegetation (Nill and Nill, 1993; Park et al., 1998; Gonzales-
Sosa et al., 1999; Swift and Bignell, 2000; Lavelle et al., 2001;
Lavelle and Spain, 2002; Hairiah et al., 2006). The quantitative
measurement of the parameters of the litter layer is a powerful
tool for the determination of diverse ecological conditions that
are of relevant interest in a world context of tropical forests
(Sampaio et al., 1993; Tapia-Coral et al., 2005). The physical
and chemical properties and biological of the litter layer are
important as indicators of local conditions in forest plantations
such as nutrient stock (Smith et al., 1998; Cunha et al., 2005),
* Corresponding author. Tel.: +55 61 3307 2592.
E-mail address: jhay@unb.br (J.D. Hay).1 Present address: Departamento de Ciencias Biologicas, Universidade do
Estado de Mato Grosso, UNEMAT, Rod. BR 158 km 145, 78690-000 Nova
Xavantina, MT, Brazil.
0378-1127/$ – see front matter # 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.foreco.2008.01.037
soil humidity (Marimon-Junior, 2007) or in the formation of
organic matter, all important aspects in evaluation of forest
conditions, especially in degraded areas undergoing regenera-
tion (Souza and Davide, 2001).
The thickness of the litter layer is a reflection of the balance
between the inputs and decomposition of organic matter and
can be an excellent indicator of the diverse conditions of
maintenance and equilibrium in forests (Vorobeichik, 1997).
Litter also has a strong influence on the soil profile, especially
the A horizon, protecting it against destruction of soil
aggregates and sealing the pores in regard to water infiltration
(Nill and Nill, 1993) nutrient loss due to leaching (Hairiah et al.,
2006) and loss of water vapor by evaporation due to the direct
incidence of solar radiation on the soil surface (Park et al.,
1998; Gonzales-Sosa et al., 1999). Another important benefit of
the litter layer is through the redistribution of organic matter
due to the action of soil arthropods (Swift and Bignell, 2000).
In spite of the importance of the evaluation of these aspects
and the increase of interest in forest monitoring there is no
specific instrument for quantitative measurement and collection
of samples of the litter layer. Besides the lack of an adequate
collection instrument there is also a lack of a standardized
collection methodology or protocol. Studies of the litter layer in
Brazil and other countries are still based on rudimentary
methods for the measurement of the thickness of the litter layer
and sample collection. These included collection of leaves with
Fig. 1. Photograph of the Marimon–Hay litter collector showing: (A) base,
formed by a base of multiple tines used to collect the litter from the forest floor
and (B) measuring fork. The ruler is graduated in cm. The collection device
shown has 42 tines.
B.H. Marimon-Junior, J.D. Hay / Forest Ecology and Management 255 (2008) 2244–2250 2245
a spike (Molofsky and Augspurger, 1992; Torti et al., 2001),
also called a litter probe (Mayor and Henkel, 2006), or by
estimates of depth with a ruler (Muscolo et al., 2007; Roovers,
2005; Portela and Santos, 2007).
In order to resolve this problem, we designed and
constructed an instrument for the measurement of the thickness
of the litter layer and quantitative collection of litter samples in
forests. We compared our instrument with the two traditional
litter collection methods cited above.
2. Materials and methods
2.1. Study area
Collection was done in two areas of native forest on the Vera
Cruz farm (property of Jairo Machado Rezende) in the
municipality of Nova Xavantina, eastern Mato Grosso, Brazil.
The first area was a monodominant forest (1485004700S latitude
and 5280803700W longitude), with Brosimum rubescens Taub.
accounting for over 80% of the above-ground biomass
(Marimon, 2005). The other forest area (1484903200S latitude
and 5280602000W longitude) was a mixed species forest where
B. rubescens was rare. Both forest areas are on flat terrain and
the annual litter input in both forests was similar, approximately
7.75 t/ha (Marimon-Junior, 2007). This region is a pre-
Amazonian transitional forest, with contact with the cerrado.
The climate is tropical with well-defined rainy and dry seasons.
The mean annual precipitation is 1500 mm and mean
temperature is 24.8 8C, with a mean minimum temperature
of 10 8C and a mean maximum of 37.4 8C. The soil is a
Plintosoil in the Brazilian soil classification system
(EMBRAPA, 1999), aeolic and concretionary with low cation
exchange capacity, base saturation and water retention, and has
a continuous lateritic layer at 80 cm depth. All data were
collected in previously established plots in each forest type (for
a detailed description of the sites see Marimon et al., 2001;
Marimon, 2005).
2.2. Description of the Marimon–Hay litter collector
The new instrument tested in the present study is called the
Marimon–Hay litter collector or multiple tine collector,
hereafter referred to as M–H. It is composed of two pieces,
a base and a fork that intersect (Fig. 1). The base is used in the
collection of the litter on the forest floor and the fork is used to
measure the thickness. The collector design was discussed and
developed in the ecology laboratories of the University of
Brasilia and the State University of the State of Mato Grosso
during 2 years and was patented in Brazil (Fundacao
Universidade de Brasılia, 2005). The base of the collector
measures 15 cm � 12.5 cm (187.5 cm2) and may have 35 or 42
tines (approximately 15 cm in length). The fork has seven teeth
for the 42 tine collector and six for the 35 tine collector. Both
pieces are made of steel and the tines are welded onto the base.
The handles of the base and the fork are covered with molded
rubber padding. The total weight of the instrument is
approximately 0.9 kg.
2.3. Sample collection protocol
The collection protocol is composed of two steps. The first in
the field and the second in the laboratory, if determination of
water content or nutrient content of the litter is desired. In the
field, the following sequence should be followed:
(1) L
ocalization of the sampling point, based on the area of thecollector a minimum of 30 points/ha should be collected.
(2) C
ollection (Fig. 2A) and removal of the litter sample fromthe forest floor.
(3) V
isual verification of the sampled point (Fig. 2B). Thisverification is important to confirm that when the sample is
lifted off the forest floor the root mat should be exposed,
indicating that the sample corresponds only to the L and F
layers leaving the H layer intact, following the division of
Hoover and Lunt (1952). The H layer should not be
removed since it contains a mixture of mineral soil and
other material. If part of the H layer or part of the root mat is
removed the sample should be discarded and the procedure
repeated at another point.
(4) M
easurement of the thickness of the sample. Insert the forkbetween the tines and lift it until it touches, without
compressing the base of the collected material. Read the
thickness of the litter layer on the ruler (Fig. 2C).
(5) I
f litter samples are also being collected for determinationof moisture or nutrient content the following procedure
should be followed. After measurement of the thickness of
the litter layer the sample should be firmly compressed
against the base of the collector using the fork. Any excess
material that extends beyond the sides of the collector
should be trimmed with scissors or pruning shears (Fig. 2D)
and discarded and the remaining litter on the base should be
Fig. 2. Collection and measurement of litter with the M–H collector in the field, showing: (A) sample collection; (B) visual verification of the sample site; (C)
measurement of the thickness of the litter on the included scale; (D) removal of excess material to obtain a quantitative sample. Data collected on the Vera Cruz farm,
Nova Xavantina, Mato Grosso, Brazil.
B.H. Marimon-Junior, J.D. Hay / Forest Ecology and Management 255 (2008) 2244–22502246
removed and placed in a previously tared recipient that can
be sealed to prevent water vapor loss.
In the laboratory, the protocol should follow the following
steps:
(1) U
sing an analytical or semi-analytical balance weigh eachsample to obtain its fresh weight.
(2) D
ry the samples in a forced draft oven until constant weight(minimum of 48 h at 70 8C).
(3) U
sing standard methods, prepare and process the samplesfor nutrient analysis.
This laboratory protocol will permit the determination of the
percent water in the litter; additionally the volume of the litter can
be calculated by multiplying the thickness of the layer by the area
of the collector. Aside from calculation of percent moisture in the
litter this procedure permits the estimation of density and litter
biomass per hectare. After determination of nutrient concentra-
tions the values per hectare may also be calculated.
2.4. Comparison of methods
To test collection efficiency we compared our collector
with two frequently used methods for measuring the thickness
of the litter layer. The thickness of the litter layer was
determined at 30 randomly selected points in each forest for
each method. All data were collected on 15 February 2006
and the monthly litterfall at both sites was similar during
this month (Marimon-Junior, 2007). The first method used
a rigid horizontal bar (HB) made of aluminum
(100 cm � 2 cm � 2 cm). The bar was placed on top of the
litter layer to serve as a reference and the thickness of
the litter layer was measured (Fig. 3A) at four points along the
bar by gently removing the F and H layers and then measuring
the distance from the base of the bar to the H layer with a
ruler. The second method used was a single tine (ST) of 30 cm
length (0.2 cm diameter) inserted into a wooden handle. In
this method the tine was inserted through the litter layer,
subsequently removed and the number of leaves on the tine
was counted. All the leaves on the tine were vertically
Fig. 3. Measurement of litter thickness: (A) using the horizontal bar method
(HB) and (B) using the single tine method (ST).
Table 1
Mean thickness of the litter layer (cm), standard deviation (S.D.) and coefficient
of variation (CV) for the three collection methods in both forest types,
Brosimum rubescens (MB) and mixed forest (MM) on the Vera Cruz farm,
Nova Xavantiva, Mato Grosso, Brazil
Forest type HB ST M–H
MB
Mean 1.92 ab 1.67 a 2.16 b
S.D. 0.46 0.72 0.38
CV 23.8 42.9 17.4
MM
Mean 2.06 a 2.29 a 2.28 a
S.D. 0.66 0.74 0.49
CV 31.9 50.2 16.3
Means with the same letter (within the same line) are not significantly different
at p < 0.05. HB, horizontal bar; ST = single tine; M–H = Marimon–Hay col-
lector.
Fig. 4. Mean length of time (min) necessary to collect samples with each
method in each forest as a function of mean litter thickness. HB = horizontal
bar, ST = single tine, M–H = Marimon–Hay collector. Data collected on the
Vera Cruz farm, Nova Xavantina, Mato Grosso, Brazil.
B.H. Marimon-Junior, J.D. Hay / Forest Ecology and Management 255 (2008) 2244–2250 2247
compressed to remove any space between the leaves and then the
thickness of the layer was measured with calipers (Fig. 3B).
Each method was repeated by three students (n = 10 for each
method) in each forest type to test for possible bias due to the
person making the collection. The total time spent by each
student to make the measurements with each method was also
recorded. Each student also made 10 measurements with the
M–H collector for a total of 30 randomly chosen points in each
forest types and the time required for each student to complete
these measurements was also recorded.
2.5. Data analysis
The following data were compared: (1) thickness of the litter
layer determined by each method, (2) the time necessary to
collect the data with each method and (3) differences among
students. Data were analyzed using SYSTAT 11.0 (SYSTAT
Inc., 2004) and Statistix 8.0 (Analytical Software, 2003).
Means are presented �1S.D.
3. Results
3.1. Comparison among methods
3.1.1. Thickness of the litter layer
The thickness of the litter layer measured with the three
methods was statistically different in the monodominant forest
but not in the mixed species forest (Table 1). In both forests the
standard deviation and coefficient of variation around the mean
was smaller for data collected with the M–H collector.
3.1.2. Time
The total time necessary for measurement of litter thickness
varied from 30 min (M–H) to 66 min (HB). In both forests the
sequence of mean time spent in data collection was the same,
M–H < ST < HB (Fig. 4). The mean length of time necessary
to make measurements of the litter layer in the monodominant
forest with the M–H collector was significantly lower than for
the BH method but was not different than for the ST method
(H0 = 6.48, p = 0.04). In the mixed species forest the same
result was observed (H0 = 7.2, p = 0.02).
3.2. Comparison among students
The M–H collector was the only method that did not have
significant differences in the depth of the litter layer among the
students in either area (H0 = 5.5, p = 0.06 in the monodominant
Fig. 5. Mean depth of the litter layer measured by different collectors using the
three methods (N = 10 for each method for each collector) in two forest types,
HB = horizontal bar, ST = single tine, MT = HB collector. Data collected on the
Vera Cruz farm, Nova Xavantina, Mato Grosso, Brazil. A = monodominant
forest, B = mixed species forest.
B.H. Marimon-Junior, J.D. Hay / Forest Ecology and Management 255 (2008) 2244–22502248
forest and H0 = 4.60, p = 0.10 in the mixed forest). The ST
method had significant differences among students in both
forest areas (H0 = 10.55, p = 0.005 in the monodominant forest
and H0 = 11.94, p = 0.003 in the mixed forest) but the sequence
of students differed between areas. The HB method was not
different among students in the monodominant forest
(H0 = 3.02, p = 0.22) (Fig. 5A) but was different in the mixed
forest (H0 = 20.57, p = 0.000) (Fig. 5B).
3.3. Difference between forests
The thickness of the litter layer in the monodominant forest,
measured by all three methods was smaller than in the mixed
species forest, however only for the ST method was the
difference statistically significant (H0 = 4.51, p = 0.03). The
mean number of leaves intercepted with the ST method was
higher in the monodominant forest than in the mixed species
forest (3.3 � 1.15 versus 2.9 � 0.84). However, the measured
thickness of the litter layer was not correlated with the number
of leaves in the monodominant forest (rs = 0.24, p = 0.195) but
did have a positive correlation in the mixed species forest
(rs = 0.55, p = 0.002) that characterizes a problem in extra-
polation of the results of this method.
4. Discussion
The higher degree of variability of the measurements of litter
thickness using the HB method may be explained by the
increase in the number of measurements per collection point
and by the difficulty in making the measurements since the
collector must lie on the forest floor to make the measurement.
This may also explain the significant difference in sampling
time of this method in relation to the other methods. An
independent estimate of litter thickness in both forests done in
the same month as the present study also indicated that mean
thickness was smaller in the monodominant forest (Marimon-
Junior, unpublished).
The increase in total time spent in the collection of
quantitative samples with the M–H collector in relation to
collection of data on litter thickness only was approximately
18 min for the 30 collection points. This was only 6 min slower
than the time required for data collection of litter thickness only
with the ST collector. The advantage of simultaneous collection
of quantitative samples of the litter layer is the possibility of
extrapolation in regard to nutrient and water concentration of
the litter. These parameters are important in view of the
importance of the litter layer in the maintenance of tropical
forests (see Vitousek and Sanford, 1986) and the maintenance
of the physical and chemical properties of the soil (see Hairiah
et al., 2006). If these data are adequately interpreted these
parameters are excellent aids for the determination of diverse
ecological conditions of great interest for tropical forests (for
example carbon stock) or local conditions (stock of nutrients in
different plantations).
An important advantage observed in the M–H collector
during field work was that generally the L and F layers were
removed at the transition point with the H layer (in>95% of the
samples). This is probably due to the extraction force of the
collector being greater than the retention force of the root mat at
the transition between these layers. A qualitative evaluation
indicated that the 42 tine collector should be used when the
litter layer is less than 5 cm thick since the material is more
securely held. For litter layer thicker than 5 cm the 35 tine
collector is recommended to lessen the possibility of
deformation of the litter layer and consequent under estimation
of its thickness (Marimon-Junior, unpublished).
According to Vorobeichik (1997) the thickness of the litter
layer is traditionally measured with low accuracy and is
dependent on the collector and studies in Brazil (Portela and
Santos, 2007) and in other countries are still based on
rudimentary methods (e.g. Molofsky and Augspurger, 1992;
Torti et al., 2001; Roovers, 2005; Mayor and Henkel, 2006).
The M–H collector makes an important contribution to the
resolution of this problem that normally makes field work
difficult and makes decreases the variation in the estimation of
the thickness of the litter layer. The use of a specialized
instrument for the measurement and collection of samples of
the litter layer fulfills a gap created by the non-utilization of a
B.H. Marimon-Junior, J.D. Hay / Forest Ecology and Management 255 (2008) 2244–2250 2249
specific instrument and lack of an established protocol. The
instrument and the sampling protocol presented here, if adopted
by other researchers makes possible the standardization of litter
collection in forest areas, facilitating comparison among areas
and studies.
Although our data show that our instrument is more efficient
and can reduce variability among samples there are several
limitations in regard to its use. This instrument will not be an
effective tool for collection in forests with litter thickness
greater than the length of the tines, such as might be
encountered in some temperate and boreal forests. It is possible
to increase the length of the tines, but this would probably make
the instrument too heavy for easy use. Another restriction is
related to the forest floor surface. If the surface presents
exposed rocks, has high microtopographic variability or has a
high cover of succulents, such as bromeliads, the insertion of
the tines through the litter layer might be compromised.
Differences or variability in leaf texture should not be a
problem for collection with this instrument since the tines have
a sharp point which can pierce the leaves but if the leaves have a
mean width narrower than the distance between the rows of the
tines then this might introduce a source of error into the results.
5. Conclusions
Our field tests showed that the M–H collector was more
accurate than two commonly used litter collection methods. In
two forest types the time spent in measurement of the thickness
of the litter layer was significantly shorter using the M–H
collector than for the horizontal bar but similar to the single
tine. The protocol suggested in the present study for
measurement of the litter layer and simultaneous collection
of quantitative litter samples was rapid and efficient, allowing
the collection of samples for physical and chemical analysis.
Another important advantage of the collector is the collection
of the L and F layers without the inclusion of the H layer.
Acknowledgements
The authors would like to thank the Fundacao Universidade
do Estado de Mato Grosso (UNEMAT) and the Coordenacao de
Aperfeicoamento de Pessoal do Ensino Superior do Ministerio
da Educacao (CAPES) for financial support of the Doctoral
thesis of the first author. The undergraduate students Bruno
Jordao, Louremberg Alves Peres and Rosemari Craco of the
biology course of UFMT assisted in data collection in the field.
Also to the CDT of the University of Brasilia for assistance in
obtaining the patent.
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