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Programs aimed at developing clones of hybrid trees are commonly established in Brazil to meet the demands of various forest-based industries. These programs have continually improved the quality of Eucalyptus wood, which has the potential to reduce deforestation by lowering demand for other, high value species. This is particularly true in the lumber market, however little is known about the resistance of Eucalyptus wood to biodegradation. The objective of this study was to evaluate variation in natural resistance of seven Eucalyptus grandis x Eucalyptus urophylla hybrid clones to decay by four wood-rot fungi and feeding by subterranean termites. In addition to mass loss, the relationship between density and durability was also examined. Results showed significant differences among the various clones both in density, as well as resistance to fungi and termites, although none of the clones had resistance to Trametes versicolor. Mass loss values ranged from 9.5-55.2% in the fungal tests and from 6...
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Variation in Natural Durability of
Seven Eucalyptus grandis 3Eucalyptus
urophylla Hybrid Clones
F. J. N. Franc¸a T. S. F. A. Franc¸a R. A. Arango
B. M. Woodward G. B. Vidaurre
Programs aimed at developing clones of hybrid trees are commonly established in Brazil to meet the demands of various
forest-based industries. These programs have continually improved the quality of eucalyptus wood, which has the potential to
reduce deforestation by lowering demand for other high-value species. This is particularly true in the lumber market, but little
is known about the resistance of eucalyptus wood to biodegradation. This study evaluated variation in natural resistance of
seven Eucalyptus grandis 3Eucalyptus urophylla hybrid clones to decay by four wood-rot fungi and feeding by subterranean
termites. In addition to mass loss, the relationship between density and durability was also examined. Results showed
significant differences among the various clones in density as well as in resistance to fungi and termites, although none of the
clones were resistant to Trametes versicolor. Mass loss in wood specimens ranged from 9 to 61 percent in the fungal tests and
from 6.9 to 20.5 percent in termite tests. Average density measurements among clone groups were calculated to be between
461 and 659 kg/m
. Among the clones, five of the seven showed resistance to fungal decay and termite feeding, which was
correlated with increased wood density. Based on these results, we suggest that certain clones, particularly those with higher
density values, may be considered for production of various lumber products.
Eucalyptus spp. are commonly used in reforestation
programs in Brazil to meet the demands of various forest-
based industries, with the majority used for pulp and paper
or charcoal. Species of this genus are popular because of
their fast growth, with trees able to be harvested between 6
and 7 years of age (Braz et al. 2014). In Brazil, numerous
cloning programs have been started to improve the quality
of this material, mainly through development of hybrid
species (Bassa et al. 2007, Alves et al. 2011, Brazilian
Association of Planted Forests Producers 2015). In partic-
ular, hybrid trees of Eucalyptus grandis 3Eucalyptus
urophylla represent the most commonly used hybrid by the
pulp and cellulose industry in Brazil (Busnardo 1981).
The crossing of these two Eucalyptus species permits fast
growth, a characteristic of E. grandis, as well as improved
physical properties of the wood (i.e., increased wood density
of between 460 and 650 kg/m
), which is characteristic of E.
urophylla. It is also thought that this hybrid is well adapted
to the ecological conditions in Brazil (Carvalho 2000).
Therefore, hybrid clones of E. grandis 3E. urophylla
possess ideal characteristics in terms of both growth and
density, with numerous industries continuing to invest in
research on genetic development of this hybrid (Brigatti et
al. 1983, Ikemori and Campinhos 1983, Bertolucci et al.
Recently, fluctuations in the price of pulp and paper and
the low value of charcoal have caused many of the major
forestry companies in Brazil to begin considering alternative
uses for eucalyptus wood. Factors such as scarcity and high
cost of native woods, as well as ecological pressures from
overharvesting, have contributed to the growth in utilization
of eucalyptus wood materials, particularly in the flooring
and lumber industry (Scanavaca and Garcia 2003). Al-
though the major properties of wood from E. grandis 3E.
urophylla hybrids have been reported in terms of pulp and
The authors are, respectively, Graduate Research Assistant and
Graduate Research Assistant, Dept. of Sustainable Bioproducts,
Mississippi State Univ., Mississippi State (, [corresponding author]); Research Entomologist
and Microbiologist, USDA Forest Products Lab., Madison, Wiscon-
sin (,; and Adjunct Profes-
sor III, Dept. of Forestry and Wood Sci., Jerˆ
onimo Monteiro, Federal
Univ. of Esp´
ırito Santo, Esp´
ırito Santo, Brazil (graziela.dambroz@ This paper was approved as journal article SB833 of the
Forest & Wildlife Research Center, Mississippi State University.
This paper was received for publication in June 2016. Article no.
ÓForest Products Society 2017.
Forest Prod. J. 67(3/4):230–235.
paper, studies specifically concerning the potential use of
these materials in lumber products are lacking. In particular,
little is known regarding the amount of variation that can
occur among the various hybrid clones and how this
variation can affect susceptibility to biological deterioration.
These types of studies are important as both genetics and
environmental factors can influence the physical properties
of the wood material (Beaudoin et al. 1992, Alzate et al.
2005). Thus, in addition to the studies related to physical
and mechanical properties of E. grandis 3E. urophylla
hybrids, examination of resistance to decay fungi and
termites is also necessary to gain a better understanding of
the possible applications of this material. The main
objective of this study was to evaluate the amount of
variation in hybrid E. grandis 3E. urophylla clones, with
specific focus on density and durability to wood-degrading
organisms, and to provide baseline data that could help
identify potential clones that might be used in production of
higher value products (e.g., lumber).
Materials and Methods
Test samples were obtained from 13-year-old clones of E.
grandis 3E. urophylla hybrid trees harvested from an
improvement test site for pulp production in an experimen-
tal plantation located in Alcobac¸a, Brazil. Clone trees were
planted randomly within the forest, and each tree was
labeled with information relating to clone number and
position within the forest for future reference. In this study,
7 of the 20 different clones were selected based on
dendrometric parameters, such as diameter at breast height,
crown size, and bark thickness, as identified in a previous
study (Franc¸ a 2014).
Samples were cut from each clone in the heartwood
section located directly beneath the bark of a 25-mm-thick
board (Fig. 1). Samples were cut across the center of the
cross section (see Fig. 1 in Choong and Barnes 1969) into
specimens that were 25 by 25 by 9 mm (tangential by radial
by longitudinal). For biological tests, six replicate samples
were selected from each clone for exposure to each of the
four fungi and for termite testing. All sample blocks were
conditioned to a constant weight at 6 percent equilibrium
moisture content (EMC) by maintaining wooden samples
under a constant temperature and relative humidity until
they reached the equilibrium moisture content. This was
done so that accurate measures of density and weight could
be determined before testing. Density was calculated by first
determining the weight of each block at 6 percent EMC and
then measuring block dimensions (cross-section size and
length) with a caliper.
Decay testing followed the ASTM D2017 standard
(ASTM International 2012). Specimens were exposed to a
total of four decay fungi, two brown-rot fungi (Gloeophyl-
lum trabeum and Postia placenta) and two white-rot fungi
(Irpex lacteus and Trametes versicolor), obtained from the
Forest Products Laboratory (Madison, Wisconsin) culture
collection. Southern pine (Pinus spp.) and sweetgum
(Liquidambar styraciflua) sapwood were used as controls
for exposure to brown-rot and white-rot fungi, respectively.
Test samples were exposed to decay fungi for a total of 14
weeks. After this period, blocks were removed from the
culture bottles, carefully brushed free of mycelia, and
allowed to air-dry overnight. Blocks were then conditioned
at 218C and 30 percent relative humidity (6% EMC) and
weighed, and percent mass loss was calculated. Classifica-
tion of decay resistance based on average percent mass loss
was then assigned to each clone group according to the scale
presented in the ASTM D2017 standard (Table 1).
Termite testing followed the American Wood Protection
Association (AWPA) E1-13 standard (AWPA 2014) using
the eastern subterranean termite, Reticulitermes flavipes
(Kollar). Termite species was confirmed both morpholog-
ically and genetically in previous studies (Arango 2015,
Arango et al. 2015). Termite collections were done the day
of test setup from dead logs and cardboard traps set out in a
small wooded area in Janesville, Wisconsin. Southern pine
and sweetgum samples were again used as controls. Test
specimens were placed in a plastic container with 50 g of
sterile, sifted sand and 8.5 mL of sterile water. One gram
(ca. 300 workers and 1% soldiers) of freshly collected R.
flavipes (third and fourth instar) was then added to each dish
and allowed to feed for 4 weeks. After 4 weeks, samples
were removed from the testing arena and cleaned using a
Figure 1.—Schematic cross-section of Eucalyptus grandis 3
Eucalyptus urophylla log identifying sampling locations.
Table 1.—ASTM classification of decay resistance according to
mass loss values.
Resistance class Average mass loss (%)
Highly resistant 0–10
Resistant 11–24
Moderately resistant 25–44
Slightly resistant or nonresistant 45
Adapted from ASTM International D2017 (2012).
small brush to remove sand particles. The number of live
termites after exposure was also recorded. Samples were
oven-dried overnight and reconditioned to a 6 percent EMC
to obtain a final weight, and then percent mass loss was
calculated. Each sample was also rated based on the visual
evaluation system provided by the AWPA E1-09 standard
(AWPA 2012; Table 2).
For statistical analysis, Pearson correlation coefficient
was used to determine the correlation between density and
percent mass loss for the fungal data and between density,
percent mass loss, and termite mortality for the termite data.
Differences in wood consumption of fungi among clones
and between fungi, as well as the difference in mass loss
between clones for termite tests, were compared using the
Tukey test (a¼0.05; SAS version 9.4, SAS Institute 2013).
Table 2.—American Wood Protection Association (AWPA)
classification for visual rating of test blocks exposed to
subterranean termites.
Visual rating classification Rating
Sound 10
Trace, surface nibbles permitted 9.5
Slight attack, up to 3% of cross sectional area affected 9
Moderate attack, 3%–10% of cross-sectional area affected 8
Moderate/severe attack, penetration, 10%–30% of cross-sectional
area affected 7
Severe attack, 30%–50% of cross-sectional area affected 6
Very severe attack, 50%–75% of cross-sectional area affected 4
Failure 0
Adapted from AWPA E1-09 (2012).
Figure 2.—Correlation between density and mass loss for the Eucalyptus grandis 3Eucalyptus urophylla hybrid clones against (a)
brown-rot fungi and (b) white-rot fungi.
Results from decay tests showed mass losses ranging
from 9 to 61 percent and from 53 to 95 percent for clone
specimens and control samples, respectively. Eucalyptus
grandis 3E. urophylla clones E6 and E7 were significantly
less resistant to all fungi tested compared with the other
clones, with the exception of clones exposed to T.
versicolor, where all clones showed significantly lower
resistance compared with the other three fungi tested.
Samples exposed to the other white-rot fungus I. lacteus,
however, showed analogous results with those exposed to
the two brown-rot fungi (Fig. 2). Compared with clones E1
through E5, results showed nearly three to four times higher
average mass loss in clones E6 and E7 (Table 3).
Test blocks exposed to feeding bysubterranean termites had
average mass losses ranging from 7 to 21 percent in clone
specimens, compared with 23 to 30 percent mass loss in
control samples. Termite mortality values ranged from 2.5 to
37 percent in hybrid clones, with 2.5 percent mortality in
control samples (Fig. 3). Based on the visual rating
classification of termite attack, clones E6 and E7 were
classified as having very severe attack and were the clones
most susceptible to termite feeding. Clones E1, E3, and E5
were classified as moderately attacked in the termite test and
had lower mass loss values then the other five clones (Table 4).
Average density values for the hybrid clones ranged from
461 to 659 kg/m
, with significantly higher density in clone
E1 and significantly lower density in E6, compared with the
other hybrid clones (Table 3). The relationship between
density and mass loss in decay tests suggests a negative
correlation in samples exposed to G. trabeum (P,0.0001),
P. placenta (P,0.0001), and I. lacteus (P,0.0001). Thus,
clones with higher density values had increased decay
resistance compared with clones with lower densities.
Results from the termite tests were comparable to those
from the decay tests. All hybrid clones were susceptible to
termite feeding, with significantly higher mass losses in
Table 3.—Average density, mass loss, and decay resistance class of the seven Eucalyptus grandis 3Eucalyptus urophylla hybrid
clones exposed to brown-rot and white-rot fungi.
Clone Density (kg/m
Gloeophyllum trabeum Postia placenta Irpex lacteus Trametes versicolor
Mass loss (%) Class Mass loss (%) Class Mass loss (%) Class Mass loss (%) Class
E1 659.6 A (28.2) 16.6 B c (6.8) R 20.7 C b (2.5) R 24.1 B b (7.2) R 50.1 A a (2.7) NR
E2 551.4 CD (50.2) 9.5 B c (4.1) HR 22.9 C b (8.4) R 28.9 B b (14.2) MR 51.4 A a (6.0) NR
E3 619.4 D (20.2) 22.5 B c (11.0) R 24.3 BC c (8.4) R 31.4 B b (6.3) MR 55.2 A a (4.3) NR
E4 542.5 CD (18.2) 14.3 B c (10.3) R 28.4 C b (6.5) MR 30.9 B b (7.4) MR 52.6 A a (2.5) NR
E5 568.2 C (6.5) 11.3 B c (6.1) R 17.5 C b (7.8) R 19.5 B b (5.4) R 49.9 A a (5.1) NR
E6 461.5 E (26.0) 51.8 A b (11.4) NR 55.0 A ab (8.9) NR 60.9 A a (12.3) NR 52.3 A b (4.6) NR
E7 521.0 D (26.0) 40.0 C b (11.4) NR 38.6 B b (8.9) NR 60.9 A a (12.3) NR 52.3 A b (4.6) NR
Avg. 560.6 23.7 29.6 36.7 52.0
SP 747.8 (9.4) 53.1 (1.1) NR 58.6 (1.9) NR
SG 655.9 (17.5) 94.7 (1.3) NR 66.8 (1.5) NR
Values are the means of six samples (standard deviations in parentheses). Means with the same letter designation are not significantly different (P.0.05),
where capital letters indicate comparisons between clones and lowercase letters indicate comparisons between fungi. Classes of decay resistance are based
on ASTM D2017 categories (ASTM International 2012). HR ¼highly resistant; R ¼resistant; MR ¼moderately resistant; NR ¼not resistant; SP ¼southern
pine; SG ¼sweetgum.
Figure 3.—Correlation between density, mass loss, and termite mortality in Eucalyptus grandis 3Eucalyptus urophylla hybrid clones
exposed to feeding by subterranean termites.
clones E6 and E7. Statistical analysis indicated a negative
correlation between density and mass loss (P,0.0001).
However, no statistical difference was found between clones
in terms of termite mortality, nor was a significant
correlation found between density and termite mortality
(Table 4).
Density is often one of the major properties of wood
associated with natural durability (Arango et al. 2006 and
references therein). Because E. grandis 3E. urophylla
clones are commonly used in pulp and cellulose production,
numerous researchers have examined density values, as well
as other characteristics associated with durability, specifi-
cally for this hybrid. In this study, clone density ranged from
462 to 660 kg/m
, which is comparable to values reported
from published literature (e.g., Bassa et al. 2007, Gonc¸ alves
et al. 2009). However, in a study on longitudinal variability
in wood density of different E. grandis 3E. urophylla
clones, Alzate et al. (2005) reported slightly lower density
values (Table 5).
Results from both fungal and termite testing in this study
were also comparable to those given by other researchers,
although published literature on decay and termite resis-
tance is limited. Mass loss values reported by Silva et al.
(2014) and Dytz (2014) for G. trabeum and P. placenta are
comparable to those shown here. However, mass loss values
reported by both Silva et al. (2014) and Dytz (2014) after
exposure to T. versicolor were lower than those from the
present study, with specimens classified as moderately
resistant. In one of the only studies on termite resistance of
E. grandis 3E. urophylla clones, Lopes (2014) reported
similar mass loss values, but higher levels of termite
mortality, using the termite species Nasutitermes corniger.
A summary comparing values from published studies with
the results presented here is shown in Table 5.
Natural resistance to termites and decay has often been
correlated to levels of extractives in wood, which has the
potential to explain some of the variation in durability. Low
levels of extractives are ideal for pulp and cellulose
production but likely result in increased susceptibility to
biological degradation (e.g., decay and insect feeding).
Overall, hybrid E. grandis 3E. urophylla clones are thought
to be relatively low in extractives (average total extractives
of ;2.5% in Bassa et al. 2007 and ;3.5% in dos Santos and
ıgolo 2007), with higher levels of extractives in
heartwood compared with sapwood (7.6% vs. 3.7%,
respectively; Gominho et al. 2001). Although extractive
content was not measured in this study, Boa (2014) reported
total extractive content of E. grandis 3E. urophylla hybrid
clones to range from approximately 2.08 to 4.82 percent,
with clones E1, E3, and E5 having significantly higher
extractive content compared with the other clones. These
higher levels of extractives might explain the increased
resistance to decay and termite feeding observed in our
Overall, results show that E. grandis 3E. urophylla
hybrid clones vary in terms of biological resistance and
density, suggesting that clone variation is an important
consideration in choosing materials for new markets. In the
United States, natural resistance was determined to be a
major consideration of end users before purchasing lumber
products (Nicholls and Roos 2006). Based on statistical
analyses from this study, it might be possible to estimate
natural durability properties against fungal and termite
attack based on wood density values and then select for
clones with higher densities as potential alternative
materials to be used in the lumber products. Future studies
should focus on the correlation between density and
extractive content to determine if one or both of these
factors significantly improve resistance to biological
This study demonstrated one possible method for
selecting the best clones for lumber production based on
natural resistance to biological deterioration. Although E.
grandis 3E. urophylla hybrids showed variation between
Table 4.—Mass loss, termite mortality, and density of the seven
Eucalyptus grandis 3Eucalyptus urophylla hybrid clones
exposed to feeding by subterranean termites.
loss (%)
mortality (%)
E1 8.1 B (1.8) 29.6 A (38.0) 8 655.4 (25.7)
E2 9.6 B (2.1) 8.8 A (6.9) 7 541.6 (42.9)
E3 7.5 B (1.5) 36.7 A (36.7) 8 612.7 (23.7)
E4 8.4 B (1.8) 36.7 A (46.4) 7 544.3 (16.1)
E5 6.9 B (1.3) 22.5 A (32.1) 8 567.4 (4.7)
E6 20.5 A (4.4) 2.5 A (0.0) 4 457.8 (24.0)
E7 16.7 A (3.0) 2.5 A (0.0) 4 523.6 (24.1)
Avg. 11.1 19.9 7 557.5
SP 29.2 (0.04) 2.5 (0.0) 0 463.2 (20.4)
SG 23.0 (0.03) 2.5 (0.0) 0 653.04 (11.4)
Values are means (standard deviations in parentheses). Means with the
same letter are not significantly different (P.0.05). SP ¼southern pine;
SG ¼sweetgum.
Table 5.—Summary of termite and decay data as well as density values from published literature on hybrid Eucalyptus grandis 3
Eucalyptus urophylla clones.
density (kg/m
Average mass loss (%)
Average termite
mortality (%)
versicolor Termite
Present study 560.1 23.7 29.6 36.7 52.0 11.1 19.9
Alzate et al. (2005) 490.0
Bassa et al. (2007) 505.0
Gonc¸alves et al. (2009) 580.0
Silva et al. (2014) 26.1 26.8 28.6
Dytz (2014) 37.0 25.7
Lopes (2014) 15.7 55
clones in terms of resistance to fungi and subterranean
termite feeding, two of seven clones did show higher levels
of natural resistance. These results suggest that certain E.
grandis 3E. urophylla clones might have a future potential
use in lumber production, which has more added value than
pulp and paper products.
The authors would like to thank the USDA Forest Product
Laboratory for test facilities and technical support and
FIBRIA (Brazil) for providing of wood samples for the
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... In fact, density is often one of the major properties of wood associated with natural durability (Arango et al. 2006;Chave et al. 2009). Based on statistical analyses, França et al. (2017) highlighted that it might be possible to estimate Eucalyptus wood natural durability properties against fungal and termite attack based on wood density values and then select genus with higher densities as potential alternative materials to be used in the lumber products. Southam and Ehrlich (1943) suggested several possible ways in which tissue density may influence its decay resistance, e.g. ...
... Natural resistance to termites and decay has often been correlated to levels of extractives in wood, which has the potential to explain some of the variation in durability. Low levels of extractives are ideal for pulp and cellulose production but likely result in increased susceptibility to biological degradation (França et al. 2017). These higher levels of extractives might explain the increased resistance to decay and termite feeding observed in our study. ...
Eucalyptus trees have been adapted to the Tunisian climate. Now, they need to be economically valued. Tunisian Eucalyptus have great technological properties allowing us to use them as wooden material. However, there is large variability in the natural durability between heartwood Eucalyptus spp. The wood sustainability assessment provides reliable parameters to predict the service life of wood-based products. This study aimed to evaluate the wood deterioration of four North Tunisian fast-growing Eucalyptus spp. ( Eucalyptus maidenii , Eucalyptus saligna , Eucalyptus camaldulensis and Eucalyptus gomphocephala ) exposed to basidiomycetes ( Coniophora puteana and Trametes versicolor ) and termite ( Reticulitermes flavipes ) attacks. Among the four Eucalyptus woods, Eucalyptus gomphocephala presents the highest decay and termite resistance. The four Eucalyptus wood species are classified as very durable against fungal degradation and durable against termite attacks, expect for Eucalyptus saligna which is classified as sensible against termites. The natural durability of Eucalyptus seems to be mainly caused by extractives, and a lot of compounds are involved. Antifungal and anti-termite properties of these compounds were put in perspective with the natural durability of wood. Gas chromatography-mass spectrometry (GC-MS) analyses highlighted that Eucalyptus durability is mostly governed by gallic acid, fatty acid glycerides, fatty acid esters, phenolic compounds, sitosterol, catechin and ellagic acid.
... These variations are becoming more important with the shift from harvesting old-growth forests to short rotation plantation trees and native forest regrowth. Wood from plantation and regrowth forests are generally proving to be more susceptible to degradation compared to old growth trees due to a decrease in the presence of toxic chemicals or extractives [2,3]. ...
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New approaches for assessing wood durability are needed to help categorize decay resistance as timber utilization shifts towards plantations or native forest regrowth that may be less durable than original native forest resources. This study evaluated attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy combined with principal component analysis (PCA) for distinguishing between groups of Alaska yellow cedar (Cupressus nootkatensis) wood for susceptibility to two decay fungi (Gloeophyllum trabeum and Rhodonia placenta) and the eastern subterranean termite (Reticulitermes flavipes). Alaska yellow cedar durability varied with test organisms, but the majority of samples were highly resistant to fungal and termite attack. Weight losses and extractives yield using sequential extractions (toluene:ethanol > ethanol > hot water) showed moderate to weak relationships. PCA analysis revealed limited ability to distinguish amongst levels of wood durability to all tested organisms. The absence of non-resistant samples may have influenced the ability of the chemometric methods to accurately categorize durability.
... The action of fungi decomposes the wood cell wall biopolymers (cellulose, hemicelluloses, lignin), causing changes in the anatomical structure and, consequently, decreasing the wood properties (Pawlik et al., 2019). Studies have shown that mechanical properties of wood has a reduction with the action of decay fungi (Singh and Singh 2014;Witomski et al., 2016;Silva et al., 2019) and termites (França et al., 2017;Gallio et al., 2018). When external organisms consume of a wood component, an effective loss of material and therefore a reduction in mechanical properties (Kim et al., 2019). ...
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The use of Chromated Copper Borate (CCB) for wood treatment is known with several studies on a laboratory scale. However, there is a lack of field studies to analyze the effect of the CCB over time. This study aimed to evaluate the wood properties of Eucalyptus urophylla S.T. Blake x Eucalyptus grandis W. Mill ex Maiden (called E. urograndis), treated with CCB as well evaluate the leaching of chromium, copper and bore (Cr/Cu/B) in field test. The field experiment, with wood treated and untreated (no CCB application), was installed in 2016 and remained until 2018. Wood physico-mechanical properties were evaluated for each condition (treated and untreated) and at three different time: at 0, 1 and 2 years of field exposure. The elements (Cr/Cu/B) losses (leaching) were determined by the difference in the quantification of each element retained in the wood (retention), from year 0 (amount of original elements) in relation to years 1 and 2 of field exposure. The preservative treatment of E. urograndis wood with CCB was efficient to maintain its physical and mechanical properties (mass loss, basic density, rupture and elasticity modulus) during the 2 years of field exposure. The E. urograndis wood without CCB treatment showed reductions in the physical-mechanical properties, indicating their low natural durability. High leaching (close to 100%) for boron was observed. In addition, the total of CCB retention has not changed (statistically) after 2 years.
... All trees used in this study were processed at the same time to ensure similar conditions for all samples tested. The material came from logs 2 m in length obtained between 5 m and 7 m of the tree height described by França et al. (2017a). The 84 pieces selected for this study were cut from the sapwood section, located in the peripheral region of the logs, which is the section located under the bark (Fig. 1). ...
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Selecting clones with the best genetic materials is one goal of Eucalyptus breeding programs. Understanding the variations between the wood from different hybrid clones during drying is necessary to process improvement. This study aimed to select Eucalyptus clones for lumber production based on their drying defects. From a plantation in Brazil, 42 trees within the seven different clones were used, all trees were 13 years old. The effect of the genetic material on the apparent density of the clones was significant. It was possible to separate the clones into four groups. Even if the wood was from the same genotype, a load of boards made from Eucalyptus grandis × Eucalyptus urophylla wood exhibited heterogeneity in the drying rate due to factors inherent in the wood, especially the apparent density. The apparent density negatively affected the drying rate of the clones, i.e., approximately 70.5% of the drying rate was explained by the apparent density. Denser pieces exhibited lower drying rates. For a more homogeneous natural drying, it is recommended that the composition of the stacks use pieces with the same apparent density and thus similar initial moisture. The air-drying process is recommended to release any free water on Eucalyptus woods.
Natural durability remains one of the most attractive characteristics of wood, and helps wood obtain a premium price. A worldwide shift towards the use of younger trees from intensively managed forests has created greater concerns about wood quality, especially the wood's resistance to fungi and insects. Wood durability is assessed using a variety of standards. Some standards are based on destructive methods that measure weight loss after exposure to wood degrading organisms. These tests are useful but there are concerns about variabilities in durability classifications according to different testing methods. Furthermore, durability can be heavily influenced by variations within and between trees, sites, regions, genetic origin, and age. Thus, there is a need for a faster, non-destructive and economically viable technique for screening wood durability. Fourier transform infrared spectroscopy with attenuated total reflectance (ATR-FTIR) and near infrared spectroscopy (NIR), with chemometrics analysis was explored for classifying wood durability. The extractive contents of Alaska yellow cedar (Callitropsis nootkatensis) and western juniper (Juniperus occidentalis) were investigated to understand the variability that existed between and within trees, and the relationships between brown-rot decay (Gloeophyllum trabeum and Rhodonia placenta), termite (Reticulitermes flavipes) resistance, and the spectroscopic results were examined. FT-IR showed sensitivity in detecting to one of the extractive concentrations (carvacrol) as differences were observed on 3% concentration. The majority of the Alaska yellow cedar and western juniper samples were classified as resistant to highly resistant against decay fungi and termites. A moderate to poor correlation between extractives and mass loss to wood biodegradations agents (fungi and termites) was observed, indicating the possibility for other factors may contribute to wood superior durability. Chemometrics analysis using principal component analysis (PCA) and hierarchical cluster analysis (HCA) on the spectral data was unable to accurately classify wood based on their durability. Nevertheless, results suggest FT-IR and NIR can be used for analyzing wood extractives, as well as the possibility for producing more accurate predictions on species with greater variability in durability.
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This paper is aiming to evaluate the possibility of cooking mixtures of Eucalyptus grandis x Eucalyptus urophylla and Pinus taeda for the production of kraft pulp with specific characteristics. Proportions of Pinus taeda from 10% to 50% were considered. The results indicated a downward trend in total yield and screened yield values, in pulp viscosity, in the hexenuronic acid content, in solubility in NaOH 5%, in the number of fibers per gram of pulp, in the drainability and strength and burst indices, with the increasing proportion of Pinus taeda in the pulps. As the proportion of Pinus taeda increased in the pulps an increase was noticed for the parameters total lignin content in the pulp, length and width of the fibers, coarseness and tear indices. In conclusion, the addition of up to 10% of Pinus taeda to Eucalyptus can increase pulp quality for the tear index and drainability parameters speeding up the paper machines and resulting in higher productivity. These mixtures also allow the production of tailor-made pulp and special papers.
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This research aimed to test the deteriorating ability of fungi isolated from Eucalyptus spp. wood and perform chemical analysis of wood deteriorated, to verify which components of wood suffered major changes in the light of the attack. The experiment was conducted in the Laboratório de Biodeterioração da Madeira, Departamento de Ciências Florestais e da Madeira, Centro de Ciências Agrárias, Universidade Federal do Espírito Santo in the municipality of Jerônimo Monteiro, ES, Brazil. A total of 12 fungi were used, and nine of these came from pure cultures isolated from fragments of stumps of eucalypt woods deteriorated, collected in three distinct locations, and three with recognized capacity of deterioration that were used as the standard of comparison. The Basidiomycetous fungi 1 and 2 showed high capacity of deterioration of Eucalyptus spp. The heartwood of eucalypt showed a greater natural resistance than the sapwood, but the fungi were able to degrade both them. In general, there were, an increase in the content of extractives in wood damaged (heartwood and sapwood), for Basidiomycetous 1 and Basidiomycetous 2. The heartwood of Eucalyptus grandis there was a decrease in extractives content for both Basidiomycetes. To the holocelulose (cellulose and hemicelluloses), there were small differences between the healthy and damaged wood (mean variations around 1 %). The Fungi, Basidiomycetous 2 caused a greater degradation of lignin as compared to the Basidiomycetous 1.
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This work was developed in order to evaluate the mechanical breakage of trees and its relation to the dendrometric characteristics, the wood specific gravity and bending (MOE, MOR and work to maximum load) in order to select clones more tolerant to wind action. The mechanical resistance of the trees to break was determined by the simulation of the effect of wind on them, getting the strength to break the trees. Ten clones of Eucalyptus urophylla x Eucalyptus grandis hybrid with 30 and 35 months in forest plantations in the lowlands were evaluated. The average force to break the trees was 79.00 kgf, the average height of 2.99 m. The average wood density was 0.40 g/cm³. MOE, MOR and work to maximum load in static bending tests were equal to 60,965 kgf/cm², 544 kgf/cm² and10 J, respectively. The CNB017 showed the best results in the resistance of trees to break test and in the physical and mechanical parameters evaluated, being considered the most suitable clone for the areas subjected to wind breakage of trees. © 2014 Universidade Federal de Santa Maria. All rights reserved.
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The objective of this study was to document current areas of subterranean termite activity in Wisconsin and to evaluate genetic characteristics of these northern, peripheral colonies. Here, amplified fragment-length polymorphism was used to characterize levels of inbreeding, expected heterozygosity, and percent polymorphism within colonies as well as genetic structure among populations sampled. Genetic analysis revealed two species of termites occur in Wisconsin, Reticulitermes flavipes (Kollar) and Reticulitermes tibialis Banks, both found in the southern half of the state. Colonies of both species in Wisconsin are thought to represent the northern boundary of their current distributions. Measurements of within colony genetic variation showed the proportion of polymorphic loci to be between 52.9-63.9% and expected heterozygosity to range from 0.122-0.189. Consistent with geographical isolation, strong intercolony genetic differences were observed, with over 50% of FST values above 0.25 and the remaining showing moderate levels of genetic differentiation. Combined with low levels of inbreeding in most collection locations (FIS 0.042-0.123), we hypothesize termites were introduced numerous times in the state, likely by anthropogenic means. We discuss the potential effects of these genetic characteristics on successful colony establishment of termites along the northern boundary compared with termites in the core region of their distribution. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.
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Fast growing species as those belonging to the gender Eucalyptus present serious problems during the various phases of sawing, drying and processing. Thus, this work aimed to study the physical wood properties of a clonal hybrid of Eucalyptus urophylla x Eucalyptus grandis at two ages originated from coppice and replacement regeneration at different thinning intensities, with diameters between 28.0 and 30.0 cm. The results showed that the extract of older aged wood with two thinning interventions (E2) presented the highest mean values for specific gravity along the stem and in the position pith to bark, as well as lower average volumetric contractions and lower average anisotropic factor (1.66). Although extract E1, with coppice at the age of 70 months and anisotropic factor equal to 1.92, was close to extract E3, with only one replacement at the age of 70 months and anisotropic factor equal to 2.04 along the stem, it presented the lowest specific gravity and average shrinkage values for log 1 in relation to log 2. The same behavior was verified for volumetric contraction. The anisotropy factor in log 1 was lower in relation to log 2 in extracts E1 and E3.
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Environmental pressure has resulted in voluntary removal of chromated copper arsenate (CCA) from wood preservatives in residential applications in the United States. A new generation of copper organic preservatives was formulated as replacements, but these preservatives may not provide a permanent solution to all related problems. Some of these issues include concern over copper in aquatic environments and corrosion of fasteners. Copper preservatives in general are also poor inhibitors of mould. Therefore, we still need to evaluate alternative solutions in order to address current inadequacies of copper organic wood preservatives. In this study, six hardwoods and six softwoods were evaluated for their ability to resist termite damage by Reticulitermes flavipes. Mass loss versus specific gravity showed an inverse correlation in tropical hardwood species, but a slightly positive correlation in native softwood species. Also, southern yellow pine and Douglas-fir wood blocks were evaluated after treatment with 0.1% copper borate, water-borne (WB) copper naphthanate, and N′N-naphthaloylhydroxylamine (NHA). Erisma, juniper, ipe, and white-cedar were highly resistant. The NHA-protected Douglas-fir and southern pine resisted attack as effectively as copper borate or WB copper naphthanate treatment. These results indicate that selected naturally durable wood species, both tropical and native, inhibit R. flavipes damage as effectively as preservative treatment.
A 7-year plantation of Eucalyptus grandis x urophylla hybrid established in the vicinity of Mogi Guaçu, SP, and managed to supply raw material to the pulp and paper industry was harvested in a differentiated way to produce wood for multiple purposes. The wood was graded into three fractions for different uses (F-I: sawnwood for "clear blocks"; F-II: pulpwood and F-III: fuelwood). In addition to yield analysis and product quality, a research was conducted among producers. This research aimed to identify specifications and prices of "clear blocks", small dimension sawnwood free of defects, produced for the export market. The study produced "clear blocks", woodpulp or cellulose, and fuelwood in experimental form. The combined yields of these products were analyzed in comparison with the results obtained in a standard operation aimed solely at the production of pulpwood. The analysis of the pulp production material showed high quality and yield results (about 53%). The "clear blocks" production yielded about 30%. The multiple products production of was compared to the standard production of pulp in a simulated market operation. The results favour the diversification of products as an important alternative in situations where the pulp market price is low.
The purpose of this study was to evaluate the quality of Eucalyptus benthamii wood for kraft pulp production. A hybrid of Eucalyptus urophylla x Eucalyptus grandis, probably the most planted Eucalyptus clone in Brazil, was also analyzed for comparison purposes. Basic density, chemical composition and fiber dimensions were determined for the two species. The Eucalyptus benthamii wood presented an anatomical structure, basic density and fiber dimensions quite similar to those of other species planted by the Brazilian pulp industry. However, it presented poorer wood quality characteristics when compared to the hybrid urograndis species, with higher amounts of extractives and lignin, lower amount of glucans, more galactans and lower S/G ratio, characteristics leading to lower pulping yield. Additional studies should be carried out to establish its pulping, bleaching and paper strength properties.
The study analyzed the wood basic density effect in two Eucalyptus grandis x Eucalyptus urophylla hybrid clones (440 kg/m3 e 508 kg/m 3) on bleached pulp quality (fiber dimensions and physical-mechanical properties). The woods performance on pulping, bleaching and beating results were analyzed. The Kraft pulping was carried out in forced circulation digester in order to obtain 17±1 kappa number targets. The pulps were bleached to 90±1 using delignification oxygen and D0EOPD 1 bleaching sequence. Bleached pulp of low basic density clone showed, significantly, lowest revolutions number in the PFI mill to reach tensile index of 70 N.m/g, low Schopper Riegler degree and generated sheets with higher values to bulk and opacity. These characteristics and properties allow concluding that bleached pulp of low basic density clone was the most indicated to produce printing and writing sheets. The bleached pulp of high basic density clone showed higher values of bulk and capillarity Klemm and lower water retention value when analyzed without beating. The bleached pulp of high basic density clone showed more favorable characteristics to the production of tissue papers.
A progeny test of Eucalyptus urophylla, nineteen years old, was used in order to quantify the influences of growth stress and taper in sawed wood yield. Six trees per progeny were selected (two trees per plot, with three repetitions). Growth stress was measured indirectly through the log end splitting and end splitting board measurements. Yield was calculated quantifying the log and sawed pieces volumes. There was no significant statistical difference among the progenies for growth stress, taper or for yield in sawed wood. There was no correlation between log end splitting and end splitting board, and no correlation of growth stress and diameter of the logs. Therefore, tree selection for sawmill at this age, should be based exclusively on silvicultural parameters. Sawed wood yield average was 42.54%.