PHYSICAL-MECHANICAL WOOD PROPERTIES OF Myracrodruon urundeuva IN HOMOGENEOUS PLANTING

Abstract

As a result of its high density and durability, wood of Myracrodruon
urundeuva (aroeira) is highly valued, and its exploitation in Brazilian primary forests
has been prohibited by law since 1991. One way to maintain this status and,
at the same time, supply the increased demand for this wood is through the
establishment of plantations. Therefore, the knowledge of M. urundeuva wood
properties in plantations with young trees is essential. Thus, we evaluated we evaluated some
physical and mechanical properties of wood from 20-year-old M. urundeuva (aroeira)
twelve trees in a homogenous plantation. Basic density was 770 kg m-3 and apparent
density was 984 kg m-3. The anisotropy coefficient of 1.69 is considered regular,
indicating that wood can be used in the manufacture of fine furniture, frames, boats,
musical instruments, sports equipment or flooring. The wood presented good
mechanical behavior, with an average strength for parallel compression of 53.84 MPa,
MOE of 12632 MPa and MOR of 123.58 MPa. The wood was identified as class 40,
thus showing potential for use in medium-sized structures and construction.
Basic density and apparent density correlated positively with compression parallel to
the grain and MOR. Wood quality, a positive characteristic, added to good technology,
even in young trees, shows that values of physical and mechanical properties are
suitable for various uses when compared to the same values of older trees based on
specialized literature. Our results confirmed that this homogeneous planting was adequate to
obtain M. urundeuva wood with such quality. Devido à alta densidade e durabilidade, a madeira de Myracrodruon
urundeuva (aroeira) é muito valorizada, e sua exploração em florestas nativas brasileiras
é proibida desde 1991. O estabelecimento de plantações é uma maneira de manter
essa situação e, ao mesmo tempo, fornecer o aumento da demanda por essa madeira.
Assim, o conhecimento das propriedades da madeira de M. urundeuva em
plantações com árvores jovens é essencial. Portanto, avaliamos algumas propriedades
físicas e mecânicas da madeira em árvores de M. urundeuva com 20 anos em
uma plantação homogênea. A densidade básica foi 770 kg m-3 e a densidade
aparente foi 984 kg m-3. O coeficiente de anisotropia de 1,69 é considerado normal,
indicando que a madeira pode ser utilizada na fabricação de móveis finos, quadros,
barcos, instrumentos musicais, equipamentos esportivos, pisos etc. A madeira apresentou
bom comportamento mecânico, com uma resistência média à compressão paralela de
53,84 MPa, MOE de 12632 MPa e MOR de 123,58 MPa. A madeira foi classificada
na classe C40, apresentando potencial para uso em estruturas e na construção civil.
A densidade básica e densidade aparente se relacionaram positivamente com a
compressão paralela às fibras e com o MOR. Um aspecto positivo é a
qualificação de madeira, com bom potencial tecnológico, mesmo em árvores jovens,
mostrando que os valores das propriedades físicas e mecânicas foram adequados para
vários usos, quando comparados com os valores de árvores mais velhas com
base na literatura. O plantio homogêneo foi adequado para obter madeira M. urundeuva com
qualidade.

Full text

PHYSICAL-MECHANICAL WOOD PROPERTIES OF
Myracrodruon urundeuva IN HOMOGENEOUS PLANTING1
PROPRIEDADES FÍSICO-MECÂNICAS DA MADEIRA DE
Myracrodruon urundeuva EM PLANTIO HOMOGÊNEO
Andressa KELLER2; Adriano Wagner BALLARIN2;
Miguel Luiz Menezes FREITAS3; Antonio Carlos Scatena ZANATTO3;
Eduardo Luiz LONGUI3, 4
ABSTRACT – As a result of its high density and durability, wood of Myracrodruon
urundeuva (aroeira) is highly valued, and its exploitation in Brazilian primary forests
has been prohibited by law since 1991. One way to maintain this status and,
at the same time, supply the increased demand for this wood is through the
establishment of plantations. Therefore, the knowledge of M. urundeuva wood
properties in plantations with young trees is essential. Thus, we evaluated we evaluated some
physical and mechanical properties of wood from 20-year-old M. urundeuva (aroeira)
twelve trees in a homogenous plantation. Basic density was 770 kg m-3 and apparent
density was 984 kg m-3. The anisotropy coecient of 1.69 is considered regular,
indicating that wood can be used in the manufacture of ne furniture, frames, boats,
musical instruments, sports equipment or ooring. The wood presented good
mechanical behavior, with an average strength for parallel compression of 53.84 MPa,
MOE of 12632 MPa and MOR of 123.58 MPa. The wood was identied as class 40,
thus showing potential for use in medium-sized structures and construction.
Basic density and apparent density correlated positively with compression parallel to
the grain and MOR. Wood quality, a positive characteristic, added to good technology,
even in young trees, shows that values of physical and mechanical properties are
suitable for various uses when compared to the same values of older trees based on
specialized literature. Our results conrmed that this homogeneous planting was adequate to
obtain M. urundeuva wood with such quality.
Keywords: aroeira; physical and mechanical properties of wood; wood technological potential.
______
1Recebido para análise em 01.06.17. Aceito para publicação em 14.12.17.
2Universidade Estadual Paulista "Júlio de Mesquita Filho" – UNESP, Faculdade de Ciências Agrônomicas, Av. Universitária, 3780, Altos do Paraíso, 18610-034,
Botucatu, SP, Brazil.
3Instituto Florestal, Rua do Horto, 931, 02377-000, São Paulo, SP, Brazil.
4Corresponding author: Eduardo Luiz Longui – edulongui@gmail.com
Rev. Inst. Flor. v. 29 n. 2 p. 239-251 dez. 2017
http://dx.doi.org/10.24278/2178-5031.201729208
ISSN impresso 0103-2674/on-line 2178-5031

Rev. Inst. Flor. v. 29 n. 2 p. 239-251 dez. 2017
240
KELLER, A. et al. Wood properties of Myracrodruon urundeuva.
RESUMO – Devido à alta densidade e durabilidade, a madeira de Myracrodruon
urundeuva (aroeira) é muito valorizada, e sua exploração em orestas nativas brasileiras
é proibida desde 1991. O estabelecimento de plantações é uma maneira de manter
essa situação e, ao mesmo tempo, fornecer o aumento da demanda por essa madeira.
Assim, o conhecimento das propriedades da madeira de M. urundeuva em
plantações com árvores jovens é essencial. Portanto, avaliamos algumas propriedades
físicas e mecânicas da madeira em árvores de M. urundeuva com 20 anos em
uma plantação homogênea. A densidade básica foi 770 kg m-3 e a densidade
aparente foi 984 kg m-3. O coeciente de anisotropia de 1,69 é considerado normal,
indicando que a madeira pode ser utilizada na fabricação de móveis nos, quadros,
barcos, instrumentos musicais, equipamentos esportivos, pisos etc. A madeira apresentou
bom comportamento mecânico, com uma resistência média à compressão paralela de
53,84 MPa, MOE de 12632 MPa e MOR de 123,58 MPa. A madeira foi classicada
na classe C40, apresentando potencial para uso em estruturas e na construção civil.
A densidade básica e densidade aparente se relacionaram positivamente com a
compressão paralela às bras e com o MOR. Um aspecto positivo é a
qualicação de madeira, com bom potencial tecnológico, mesmo em árvores jovens,
mostrando que os valores das propriedades físicas e mecânicas foram adequados para
vários usos, quando comparados com os valores de árvores mais velhas com
base na literatura. O plantio homogêneo foi adequado para obter madeira M. urundeuva com
qualidade.
Palavras-chave: aroeira; propriedades físicas e mecânicas da madeira; potencial
tecnológico da madeira.
1 INTRODUCTION
In recent years, the forest sector has
gained increasing recognition owing to the
importance and contribution of planted forests to
the countryʼs sustainable development. Indeed,
forest plantations have promoted changes in
regional and local economies, particularly those
that were previously based on extractivism, an
activity that has degraded vast regions of native
forest and subsistence agriculture. Thus, planted
forests play important roles, such as reduction of
pressure on native forests, reuse of land degraded
by agriculture, carbon sequestration, soil and water
protection, greater homogeneity of forest products
and development of forestry machinery optimizing
aspects of wood production (Nahuz, 2013).
Plantations should be designed to meet
these market requirements and needs, and the wood of
plantation species must have characteristics
that are equivalent or higher to those previously
used and derived from the exploitation of native
forests. Properties vary among species; therefore,
when selecting wood for a particular use,
physical and mechanical requirements must be
considered to guarantee that the wood will
perform adequately. This analysis is very important,
especially in tropical countries, with great
biodiversity, considering the variety and the
number of forest timber species (Nahuz, 2013).
In the present study, we investigated
the wood of Myracrodruon urundeuva Allemão
(Anacardiaceae). According to Silva-Luz and
Pirani (2017), a native, but not endemic,
Brazilian species, which presents geographic
distribution in all regions of Brazil in the
biomes of Caatinga, Cerrado and Atlantic Forest.
As a result of its high density and durability,
wood of M. urundeuva is highly valued and can
be used as lumber in civil construction, ooring,
furniture and turned parts, as well as external
construction, such as small bridges, posts,
stands, corrals and railway sleepers (Lorenzi, 2002).
It was the favorite wood for making fences in the
interior of Brazil (Heringer and Ferreira, 1973),
and it is still being used in rural areas. According to
Nogueira (2010), this wood of São Paulo state
presents the greatest durability.

Rev. Inst. Flor. v. 29 n. 2 p. 239-251 dez. 2017
241
KELLER, A. et al. Wood properties of Myracrodruon urundeuva.
Exploitation of M. urundeuva in Brazilian
primary forests has been prohibited by law since
1991. The use of its wood can only be exploited by
means of a Sustainable Forest Management Plan
and by a project previously approved by Instituto
Brasileiro do Meio Ambiente e dos Recursos
Naturais Renováveis – IBAMA (IBAMA, 2017).
In this context, the study of practices that make
it feasible to plant exotic and native species,
such as M. urundeuva, should be encouraged.
Such practices will contribute to the preservation of
natural ecosystems, reinforce the laws that prevent
predatory exploitation, and generate social and
economic benets, thus allowing the fulllment of
market requirements regarding potential species,
taking into account the sustainability.
M. urundeuva presents slow to
moderate growth, reaching annual increment of
5.50 m3. ha-1. year-1, and for best results in
trunk form, planting in full sunlight is
not recommended, while mixed planting with a
fast-growth pioneer species has been proposed
(Carvalho, 2003).
Apart from these proposals, the knowledge of
M. urundeuva wood properties in plantations with
young trees is scarce. Therefore, we aimed to
determine some physical and mechanical
properties of this species in a homogeneous
planting in the belief that the outcome would
provide knowledge for the potential use of young
wood and preserve remnants of native forest without
impeding exploitation in commercial plantations,
thus meeting market demands. To accomplish this,
we adopted a simplied characterization,
determining retractibility, compression parallel
to grain, modulus of elasticity (MOE) and
modulus of rupture (MOR), as recommended by
standard of the American Society for Testing and
Materials - ASTM D143-94 (ASTM, 2007).
2 MATERIAL AND METHODS
2.1 Planting Area and Sampling
The planting was established at a spacing of
3 x 2 m at the Luiz Antônio Experimental Station,
Luiz Antônio City, São Paulo (21o40ʼS, 47o49ʼW,
elevation 550 m). The average annual rainfall is
1,365 mm over oxisols or sandy textured soils.
Climate is Aw in the Köppen-Geiger classication
(Centro de Pesquisas Meteorológicas e Climáticas
Aplicadas à Agricultura – CEPAGRI, 2017).
In February 2011, we collected 12 trees (Table 1),
about 20 years old, and from each tree,
a log (1 meter in length) was cut at the region
immediately below the breast height. From logs,
central blocks were cut, and from these blocks,
we cut four specimens with cross section of
50 x 50 mm² (Figure 1).
Table 1. Dendrometric data of Myracrodruon urundeuva trees. DBH = diameter at breast height (1.3 m from the ground).
Tabela 1. Dados dendrométricos das árvores de Myracrodruon urundeuva. DAP = diâmetro à altura do peito (1,3 m do solo).
Tree Height (m) DBH (cm)
118.6 28
2 18.1 23
3 19.0 26
4 20.1 28
5 19.0 25
619.5 20
7 17.8 22
8 18.0 19
9 19.9 27
10 18.6 21
11 16.2 20
12 19.1 20
Mean 18.6 23.2

Rev. Inst. Flor. v. 29 n. 2 p. 239-251 dez. 2017
242
KELLER, A. et al. Wood properties of Myracrodruon urundeuva.
Specimens were conditioned to
equilibrium in a climate-controlled room under
65% of relative humidity and 21 oC (approximately
12% to 14% EMC). After acclimatization,
specimens in nominal dimension were prepared
according to the ASTM D 143 secondary method
(ASTM, 2007), owing to the impossibility of
obtaining clear specimens 50 by 50 mm.
The physical and mechanical properties
evaluated were as follows: basic density;
apparent density at EMC; longitudinal, radial,
tangential and volumetric shrinkage; strength in
compression parallel to the grain; modulus of
elasticity (MOE) and modulus of rupture (MOR).
Mechanical tests were performed in a
computer-controlled 300 kN eletromechanical
testing machine. All the variables of mechanical
tests were adopted according to ASTM D 143
(ASTM, 2007). Initial results of strength and
elastic properties (modulus of elasticity) were
corrected to the EMC (12%) using a conversion
coecient of 3% (of variation per 1% of
MC variation) for strength properties and 2% for
elastic properties.
Figure 1. Schematic representation of a sample cutting for physical and mechanical tests of Myracrodruon
urundeuva wood.
Figura 1. Representação esquemática do corte de uma amostra para os ensaios físicos e mecânicos.
The characteristic 5-percentile value of
each strength property was estimated according
to the simplied expression (Eq. 1), as dened
by the Brazilian standard NBR 7190 (Associação
Brasileira de Normas Técnicas – ABNT, 1997;
Eufrade Júnior et al., 2015), in order to determine
structural classication of wood in strength
classes, those being hardwoods from C20 to
C60 (Table 2), according to NBR 7190 (ABNT, 1997).
1
2
2
12
...
2 1,1
1
2
n
n
kn
σσ σ
σσ
−

+++

=× −×


−

Eq. 1
where σk is the characteristic value of strength of
the wood to the test considered, and n is the
number of specimens.
3 RESULTS AND DISCUSSION
The values of apparent density and
mechanical properties were corrected for the
reference humidity of 12% (Table 3).

Rev. Inst. Flor. v. 29 n. 2 p. 239-251 dez. 2017
243
KELLER, A. et al. Wood properties of Myracrodruon urundeuva.
Table 2. Strength classes and characteristic values for hardwoods at 12 % m.c., according to NBR 7190.
Tabela 2. Classes de resistência e valores característicos para as madeiras de eudicotiledôneas a 12% de teor de umidade,
de acordo com a NBR 7190.
Hardwoods
Classes fc0,k (MPa) fv0,k (MPa) Ec0,m (MPa) ρbas (g.cm-3)ρ12 (g.cm-3)
C20 20 4 9500 0.500 0.650
C30 30 5 14,500 0.650 0.800
C40 40 619,500 0.750 0.950
C60 60 8 24,500 0.800 1.000
fc0,k = compression parallel to the grain; fv0,k = shear parallel to the grain; Ec0,m = modulus of elasticity (in compression
parallel to grain; mean value); ρbas = basic density; ρ12 = apparent density at 12% moisture content (mass and volume at
12% MC).
fc0,k = compressão paralela às bras; fv0,k = cisalhamento paralelo às bras; Ec0,m = módulo de elasticidade (na compressão
paralela às bras; valor médio); ρbas = densidade básica; ρ12 = densidade aparente a 12% de teor de umidade (massa e
volume a 12% de teor de umidade).
Table 3. Physical and mechanical properties and failure types of 20-year-old Myracrodruon urundeuva wood.
Tabela 3. Propriedades físicas e mecânicas e os tipos de ruptura da madeira de Myracrodruon urundeuva aos 20 anos de idade.
Sample
ρ
12
(1)
ρ
bas
(2) fc0
(3) Ftc(4) MOE(5) MOR(6) Ftr(7)
1968 759 51.77 ws 13280 131.96 cgt
2 899 711 39.01 ws 11947 118.07 cgt
3 830 662 34.64 ws 11376 87.69 cgt
41162 891 75.30 ws 13028 145.33 cgt
5 924 729 56.85 ws 11259 109.28 cgt
6895 708 45.64 ws 10843 92.16 cgt
7 1104 852 66.91 c 11234 125.79 cgt
8 933 735 54.71 ws 11285 120.16 cgt
9 1143 879 65.40 ws 9564 118.37 cgt
10 1044 811 46.93 ws 11884 135.20 cgt
11 920 726 54.21 ws 16461 118.49 cgt
12 942 741 47.65 ws 11468 113.20 cgt
13 966 758 49.57 ws 13112 150.16 cgt
14 889 704 42.60 ws 13597 116.41 cgt
15 1020 795 45.52 ws 8350 78.28 st
16 987 772 57.55 ws 16608 146.78 cgt
17 1034 805 58.57 ws 12619 150.77 cgt
18 899 711 50.71 ws 16965 149.08 cgt
19 933 734 51.57 ws 15444 134.99 cgt
20 1015 792 61.64 ws 13101 154.82 cgt
21 925 729 54.53 ws 17059 138.16 cgt
22 888 703 51.29 ws 7929 68.12 st
23 976 765 49.75 ws 15160 139.96 cgt
to be continued
continua

Rev. Inst. Flor. v. 29 n. 2 p. 239-251 dez. 2017
244
KELLER, A. et al. Wood properties of Myracrodruon urundeuva.
The mean basic density was 770 kg.m-3,
while the density at 12% moisture (
ρ
12) was
984 kg.m-3. Density is inuenced by anatomical
variations, and these, in turn, vary according
to age, axial and radial positions, spacing
between trees, climatic and soil conditions. Thus,
comparing density values with other studies,
we noticed some variations. For example,
Tung et al. (2011), studying M. urundeuva at the
age of 20 years, also cultivated in a homogeneous
plantation (spacing 3 m x 3 m), in Selvíria,
Mato Grosso do Sul, reported a basic density of
750 kg.m-3, lower than the present value. However,
climatic and spacing diferences (3 m x 2 m in
our study) between plantations could account for
this. Lisboa et al. (2016) studied M. urundeuva
wood for plywood production, and trees were
collected in a natural cerrado area in the southwest
of Goiás state. Although no information is
provided about age, these trees had, on average,
11.6 cm in DBH, height 28 m and basic density of
820 kg.m-3. Thus, these trees had greater height
and smaller diameter than those of the present
study (Table 1). Palharini et al. (2014) reported basic
24 911 719 49.54 ws 11168 103.50 cgt
25 919 725 45.71 ws 13490 105.86 cgt
26 991 775 53.36 ws 14257 129.51 cgt
27 934 735 50.80 ws 15765 135.88 cgt
28 1026 799 58.06 ws 12735 108.77 cgt
29 1060 823 62,02 ws 10771 110.94 cgt
30 1054 818 68.88 ws 12030 154.17 cgt
31 954 750 45.87 s 8967 103.46 st
32 893 706 40.75 ws 10914 102.98 cgt
33 1004 784 56.99 ws 12456 130.99 cgt
34 1045 812 52.44 ws 11784 133.17 cgt
35 1155 887 68.38 ws 12958 130.52 cgt
36 1171 897 73.17 ws 13878 155.79 cgt
Mean 984 770 53.84 12632 123.58
(1) ρ12 = apparent density at 12% moisture content; (2) ρbas = basic density; (3) fc0 = compression parallel to the grain;
(4) Ftc = failure types in compression; (5) MOE = modulus of elasticity (bending); (6) MOR = modulus of rupture;
(7) Ftr = failure types static in bending. Ft = failure types; ws = wedge split; c = crushing; s = shearing; cgt = cross-grain
tension; st = splintering tension;
(1) ρ12 = densidade aparente a 12% de teor de umidade; (2) ρbas = densidade básica; (3) fc0 = compressão paralela às bras;
(4) Ftc = tipos de ruptura na compressão; (5) MOE = módulo de elasticidade (exão); (6) MOR = módulo de ruptura;
(7) Ftr = tipos de ruptura estáticos na exão. Ft = tipos de ruptura; ws = fenda em cunha; c = esmagamento;
s = compressão com cisalhamento; cgt = tração desviada – grã cruzada; st = tração com desbramento.
continuation – Table 3
continuação – Tabela 3
Sample
ρ
12
(1)
ρ
bas
(2) fc0
(3) Ftc(4) MOE(5) MOR(6) Ftr(7)
density of 863 kg.m-3 in M. urundeuva samples
collected in the City of Santa Luz, Piauí state,
but, again, the age of trees was not mentioned.
In these last two studies, the density was higher
than our mean value (770 kg.m-3)
Mainieri and Chimelo (1989) and
Lorenzi (1992) reported a mean density at
15% MC of 1,190 kg.m-3 (905 kg.m-3 when the
value is converted to the base of basic density),
but without age, spacing or sampling area data.
The much higher values suggest that the trees
were older than those of the present study.
According to Finger and Logsdon (2004),
the values of apparent density and basic density
allow the identication, in a simplied way,
of species into one of the resistance classes,
as dened by NBR 7190/97 (ABNT, 1997), and
allow estimation of wood quality for structural use.
Accordingly, this basic density value allowed us
to categorize M. urundeuva wood into resistance
class C40 (basic density higher than 750 kg.m-3),
i.e., medium to high mechanical resistance, which is
indicated for use in medium-sized structures.

Rev. Inst. Flor. v. 29 n. 2 p. 239-251 dez. 2017
245
KELLER, A. et al. Wood properties of Myracrodruon urundeuva.
Characterization of rupture type,
performed according to ASTM D143/94
(ASTM, 2007), indicated that “wedge split”
type represented more than 94% of the samples,
without rejecting any results obtained and
indicating the homogeneity and regular pattern
of sample rupture. The wedge split rupture is
considered regular and quite common in
compression tests.
The average value of compression
parallel to the grain was 53.84 MPa. This value is
lower than that presented by Mainieri and
Chimelo (1989) of 90.0 MPa; however, the age
and planting conditions were not mentioned.
Then, based on our results, the wood of
M. urundeuva could be classied into structural
class C40 - hardwood (fc0,k ≥ 40 MPa), evidencing the
good mechanical performance of the species at
20 years old. The results indicate that M. urundeuva
wood can be used in wood structures, since this
result puts it in the higher strength classes,
as dened by NBR 7190 (ABNT, 1997) for
hardwoods (Table 2).
The mean value of MOE, 12632 MPa,
is lower than that available in the NBR 7190
table (ABNT, 1997), which presents 23393 MPa.
However, like compressive strength, age and
tree occurrence are dierent in the two studies.
The mean value of MOR was 123.58 MPa. Longui
et al. (unpublished data) determined some properties
of 20-year-old M. urundeuva grown in two types
of agrosilvopastoral system which reported MOE
between 9722 - 9900 MPa and MOR between
105.5 and 110.9 MPa, lower values than those
in the present study. In this case, other factors,
such as seed origin and climatic and soil conditions,
could have inuenced the results. Therefore,
both MOE and MOR values allow us to again
classify 20-year-old M. urundeuva wood into the
C40 strength class, among the resistance classes
dened by NBR 7190 (ABNT, 1997) for hardwoods.
The types of rupture found did not
lead to rejection of any results. The cross-grain
tension type represented more than 91% of the
samples, indicating homogeneity and the normal
pattern of rupture. Cross-grain tension rupture
is characteristic of trees that present growth
stresses or samples of juvenile wood near the pith.
Our samples come from relatively young
M. urundeuva trees with smaller diameter compared
to older trees.
We highlight that these results come
from 20-year-old trees, which are relatively
young for the species and can grow for many
decades. According to Nogueira (2010), older trees
reach up to 30 m in high and 1 m in diameter.
Therefore, the species cultivated in homogeneous
plantations can provide quality wood in a relatively
short time. However, tree spacing and
edaphoclimatic conditions will inuence heartwood
and sapwood percentage and wood density.
In addition, after cutting, some trees presented
regrowth, which provides continuity in wood
exploitation, potentially with dierent uses than
originally planned. Thus, thinning could be partial,
obtaining materials with dierent ages.
Our average values of shrinkage
(Table 4) in trees with mean DBH of 23.2 cm
were 0.62% for longitudinal shrinkage,
7.32% tangential, 4.51% radial, 13.64% volumetric
shrinkage and 1.69 anisotropy coecient.
Guimarães Júnior et al. (2016), in a study with
dierent diameter classes (5-12; 12-18.9 and
25.9-32.9 cm) in M. urundeuva collected in a
Deciduous Seasonal Forest, in the municipality
of Jataí, Goiás state, found values of 10.34,
11.16 and 5.82% for tangential shrinkage; 6.45,
7.41 and 3.99% for radial shrinkage; 16.30,
14.78 and 9.46% for volumetric shrinkage and 1.65,
1.50 and 1.49 for anisotropy coecient. Palharini
et al. (2014), in samples of M. urundeuva at
dierent commercial heights, collected in the
municipality of Santa Luz, Piauí state, reported a
mean tangential shrinkage of 8.67%, mean radial
shrinkage of 5.36% and anisotropy coecient of 1.62.
The age of the trees was not mentioned in
either of these two studies, and the results were
established by Brazilian standard NBR 7190
(ABNT, 1997). Our values were higher compared to
the largest diameter class of Guimarães Júnior et
al. (2016), the class closest to our diameter classes,
except for the value of anisotropy coecient,
which was lower in our study. Our values of
tangential and radial shrinkage were lower,
while our anisotropy coecient values were higher
compared to Palharini et al. (2014).

Rev. Inst. Flor. v. 29 n. 2 p. 239-251 dez. 2017
246
KELLER, A. et al. Wood properties of Myracrodruon urundeuva.
Table 4. Shrinkage values (%) and anisotropy coecient from green to oven-dry moisture content of 20-year-old
Myracrodruon urundeuva wood.
Tabela 4. Valores de retração (%) e coeciente de anisotropia do teor de umidade verde ao seco em estufa da madeira de
Myracrodruon urundeuva aos 20 anos de idade.
Sample Longitudinal Tangential Radial Volumetric Anisotropy coecient
1 0.71 5.47 2.80 9.61 1.95
2 0.77 6.38 5.15 13.49 1.24
30.36 9.45 5.85 17.71 1.62
4 -0.02 9.74 4.20 15.62 2.32
5 0.95 6.28 3.59 11.74 1.75
60.83 7.25 5.29 14.78 1.37
7 0.33 5.57 3.17 9.73 1.76
8 0.10 8.49 5.13 15.30 1.65
9 0.53 7.42 5.01 14.32 1.48
10 1.06 9.11 4.73 16.71 1.93
11 0.41 8.60 5.17 15.84 1.66
12 0.48 7.68 4.69 14.20 1.64
13 0.70 6.24 2.65 10.32 2.35
14 0.91 6.05 3.95 11.83 1.53
15 0.93 8.97 9.42 22.42 0.95
16 ---- 9.81 5.94 1.65
17 0.82 6.41 3.07 11.14 2.09
18 0.62 7.69 4.15 13.72 1.85
19 0.51 8.30 5.40 15.87 1.54
20 0.45 8.04 4.26 14.10 1.89
21 0.20 9.03 5.94 17.10 1.52
22 0.30 6.06 3,27 10.38 1.85
23 0.37 9.54 5.64 17.59 1.69
24 0.66 5.56 3.38 10.32 1.64
25 1.22 7.50 3.75 13.71 2.00
26 0.53 8.76 4.26 15.09 2.06
27 0.38 9.55 5.20 17.07 1.84
to be continued
continua

Rev. Inst. Flor. v. 29 n. 2 p. 239-251 dez. 2017
247
KELLER, A. et al. Wood properties of Myracrodruon urundeuva.
The study of wood shrinkage is essential
to determine use since pieces that must be embedded
or need precision should not present great variation
in their dimensions. According to Silva (2002),
values between 1.2 - 1.5 are considered excellent,
between 1.5 - 2.0 are regular, and above 2.0 are bad.
However, the anisotropic factor, taken alone, does
not characterize a wood as being stable, causing,
instead, a false impression of stability (Potulski,
2010). Ideally, wood should present anisotropy
coecient as close to the unit as possible and low
volumetric shrinkage.
The anisotropy coecient, as dened
by the relationship between tangential and
radial shrinkage (T/R) of M. urundeuva in the
present study, was 1.69 (mean of the
36 test specimens). The strength values obtained
allow us to state that M. urundeuva wood is
indicated for structures, in general, and building
ne furniture, boats, musical instruments,
and sports equipment, among others. Lucena
et al. (2011) emphasize the use of wood for
building fences and as fuel in northeastern Brazil.
The basic density and the apparent
density were positively related to the compression
parallel to the grain and MOR (Figure 2).
Usually, mechanical properties tend to be related
to wood density (Zhang, 1994). For this reason,
wood density is often used to predict mechanical
properties (Hoadley, 2000). Based on the studies
of other groups, we emphasize the trend whereby
density (physical property) increases with age in
Brazilian native woods (Longui et al., 2010;
Lima et al., 2011; Longui et al., 2014), which,
consequently, will inuence the mechanical
properties, especially when we compare the
regions near the pith with those close to the bark.
On the other hand, Zhang (1995) compared
hard- and softwoods and reported that the
physico-mechanical properties in the hardwoods
studied were remarkably less inuenced by
growth rate. The author further reported that
growth rate has a signicant eect on mechanical
properties which can be attributed to wood density.
Thus, the values of mechanical properties tend to
increase as M. urundeuva trees grow.
continuation – Table 4
continuação – Tabela 4
Sample Longitudinal Tangential Radial Volumetric Anisotropy coecient
28 1.36 4.96 3.74 10.81 1.33
29 0.57 7.24 3.71 12.60 1.95
30 0.49 4.57 3.20 8.78 1.43
31 0.76 4.82 7.25 14.14 0.66
32 1.01 5.86 3.71 11.45 1.58
33 0.91 7.25 3.48 12.72 2.08
34 0.60 8.95 4.89 16.18 1.83
35 0.56 6.61 3.31 11.36 2.00
36 0.48 4.44 4.06 9.60 1.09
Mean 0.62 7.32 4.51 13.64 1.69

Rev. Inst. Flor. v. 29 n. 2 p. 239-251 dez. 2017
248
KELLER, A. et al. Wood properties of Myracrodruon urundeuva.
Figure 2. Relationships among properties of Myracrodruon urundeuva wood. a) Compression parallel to grain (CPG)
as a function of apparent density (AD). b) Modulus of rupture (MOR) as a function of apparent density (AD).
c) Compression parallel to grain (CPG) as a function of basic density (BD). d) Modulus of rupture (MOR) as a function
of basic density (BD).
Figura 2. Relações entre propriedades da madeira de Myracrodruon urundeuva. a) Compressão paralela à
grã (CPG) em função da densidade aparente (AD). b) Módulo de ruptura (MOR) em função da densidade aparente (AD).
c) Compressão paralela à grã (CPG) em função da densidade básica (BD). d) Módulo de ruptura (MOR) em função da
densidade básica (BD).

Rev. Inst. Flor. v. 29 n. 2 p. 239-251 dez. 2017
249
KELLER, A. et al. Wood properties of Myracrodruon urundeuva.
4 CONCLUSIONS
Basic density was 770 kg m-3, and
apparent density at EMC was 984 kg m-3.
The anisotropy coecient of 1.69 is considered
“regular”, indicating that wood can be used
in the manufacture of ne furniture, frames,
boats, musical instruments, or sports equipment.
The wood presented good mechanical behavior,
with an average strength for parallel compression of
53.84 MPa, MOE of 12632 MPa and MOR of
123.58 MPa. Mechanical properties were identied
as class 40, which shows the potential for use
in medium-sized structures and construction.
Basic density and specic gravity correlate
positively with compression parallel to the
grain and MOR. Wood quality, a positive
characteristic, added to good technology, even
in young trees, shows that values of physical and
mechanical properties are suitable for various
uses when compared to the values of older trees.
Overall, our results conrmed that this
homogeneous planting was adequate to obtain
M. urundeuva wood with such quality,
thus maintaining the sustainability of native stands.
ACKNOWLEDGMENTS
The authors thank Israel Luiz de
Lima for eldwork (Forestry Institute – IF),
as well as Ailton de Lima Lucas (UNESP - Botucatu)
for laboratory assistance.
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