IAWA Journal, Vol. 31 (2), 2010: 149–160

THE POTENTIAL OF IPÊ (Handroanthus SPP.) AND MAÇARANDUBA (MANILKARA SPP.) IN THE MANUFACTURE OF BOWS FOR STRING INSTRUMENTS

Eduardo Luiz Longui1*, Takashi Yojo2, Daniel Romeu Lombardi3 and Edenise Segala Alves4

SUMMARY While the Caesalpinia echinata (pernambuco wood) is traditionally used in the manufacture of bows for string instruments, wood of other gen- era such as Handroanthus (syn. ) and Manilkara are also used in bow making, but still on a very small scale. This study aims to evaluate the anatomical, chemical, physical, mechanical, and acoustic characteristics of these two latter woods, establishing their potential for bow making. Length, frequency of vessel elements and rays, and the higher percentage of fibers influence the density, modulus of elasticity, modulus of rupture, and the speed of sound propagation, whereas the content of lignin influence the sticks’ stiffness. It appears that Handroanthus bows can provide quality equivalent to that of pernambuco wood. Despite its appropriate heartwood color and texture, Manilkara provides bows of inferior quality. Key words: Wood anatomy, wood properties, violin bows, lignin, extrac- tives, Handroanthus, Manilkara.

INTRODUCTION

Since the 18th century, pernambuco wood (Caesalpinia echinata Lam.) has been used worldwide in the manufacture of bows for string instruments. François Tourte (1747– 1835), a famous French bow maker, established this wood as the best for bow manu- facture, because of its unique characteristics of resonance, density, durability and beauty, among many other favorable features (Alves et al. 2008a). However, as stated by the IBAMA (Brazilian Environment Institute) resolution #37-N, from April 1992, the is endangered (Rocha & Simabukuro 2008; Gasson et al. 2009), restricting its legal commercial use after the year 2007. Therefore, studies on alternative wood species or other materials for substituting pernambuco wood in the manufacturing of bows became necessary. Some alternative woods have also been tested. Matsunaga et al. (1996) evaluated the physical and me- chanical properties of Caesalpinia echinata and other species. They concluded that,

1) Instituto Florestal, CP 1322, CEP 02377-000, São Paulo, SP, . 2) Instituto de Pesquisas Tecnológicas do Estado de São Paulo, CP 0141-01064-970, CEP 05508- 901, São Paulo, SP, Brazil. 3) Arcos Lombardi (Lombardi atelier), São Paulo, SP, Brazil [www.lombardiarcos.com.br]. 4) Instituto de Botânica, CP 3005, CEP 01061-970, São Paulo, SP, Brazil. *) Corresponding author [E-mail: [email protected]].

Downloaded from Brill.com09/30/2021 11:16:26PM via free access 150 IAWA Journal, Vol. 31 (2), 2010 among the woods tested, Dialium spp. and Eucalyptus pilularis showed promising re- sults. Angyalossy et al. (2005) compared the anatomical features of pernambuco wood with the characteristics of eight other Brazilian species that have been used by a national bow maker. The authors concluded that the bow quality is directly related to the dimensions, distribution and proportion of the wood cells. Alves et al. (2008b) established some anatomical features and physical, mechanical and acoustic properties for pernambuco wood that allow the manufacture of high-quality bows and must be considered in the selection of samples of this species as well as other substitute woods. Considering the wide diversity of Brazilian wood species (Brunelli et al. 1997), it is expected that, at least some of them, could provide raw material of good quality. Therefore, the successful use of other woods in the manufacturing of bows depends on the recognition of their structural, chemical, physical, mechanical and acoustic charac- teristics. It also depends on the interest of the bow maker in producing test-bows, and of the musicians being confident in using these bows. Actually, the use of other woods would contribute to the conservation of pernambuco , and also expand the bow market by allowing the use of new colors and non-explored textures. Some alternative woods have been empirically tested in Brazil in the production of modern bows, such as ipê - Handroanthus spp. and maçaranduba - Manilkara spp. (Alves et al. 2008a). Many species of the Handroanthus () have a heavy wood, extremely hard and very resistant to rot (Rizzini 1986). Popularly, some Handro- anthus species are known as pau-d’arco, which translates to “wood arch” in English (Paula & Alves 2007). They have been used by the Indians in the production of arches for hunting, because of their elasticity and resistance. The woods of the genus Manilkara (Sapotaceae) are very heavy, with pinky-red heartwood and are employed in house construction and manufacture of furniture and floorboards (Mainieri & Chimelo 1989). The aim of this study was to analyze the structure and the physical, mechanical, chemical, and acoustic properties of Handroanthus spp. and Manilkara spp. woods, establishing their potential in bow manufacturing.

MATERIAL AND METHODS Sample selection Sticks (740 × 15 × 15 mm) were obtained from planks of ipê (Handroanthus spp.) and maçaranduba (Manilkara spp.), bought at the local market and compared with samples of the Forestry Institute xylarium (SPSFw). From these samples, three sticks of each species were selected, taking into account the highest values of density, speed of sound propagation and modulus of dynamic elasticity determined by non-destructive tests. These are desirable features for the woods used in bow manufacturing, as established by Alves et al. (2008b). The density was calculated by the ratio between the stick mass and its volume; the speed of sound propagation was determined by the Lucchi Tester (Lucchi 1986), as described in Alves et al. (2008b). Considering the values of density and sound speed propagation, it was possible to obtain the dynamic modulus of elasticity (Ed) of the wood using the equation:

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speed 2 Ed = –––––– density 100 Anatomical analysis Blocks of 1.5 cm³ were cut from the ends of the sticks. The blocks were softened in boiling water and glycerin (4 : 1), and 15–20 µm thick sections were prepared on a sliding microtome. The transverse and longitudinal sections were bleached with sodium hypochlorite (60%), washed in water, stained with astrablue and safranin (1%, 9 : 1) (Johansen 1940) and mounted in Permount®. Macerations were prepared using the modified Franklin’s method (Berlyn & Miksche 1976), stained with alcoholic safranin and mounted in a solution of water and glycerin (1 : 1). On the transverse section the proportions of the cell elements were established, meas- uring 60 successive areas using a 25-point grid. The terminology followed the IAWA List (IAWA Committee 1989). We considered a sample size of 30 as adequate. All measures were performed on a microscope equipped with image capturing and with a semi-automatic measurement system (Olympus BX 50 with an image analyzer software, Image-Pro Expression 4.0). The statistical analyses were performed employing the SigmaStat 3.5 software for Windows (SPSS Incorporation). Considering the sample size and distribution, we used the nonparametric Mann-Whitney test (Rank Sum Test).

Physical, mechanical and acoustic properties To validate the results of the non-destructive tests and to obtain other information about physical, mechanical and acoustic properties of the studied woods, destructive tests were performed, according to the Brazilian standards of material characterization (Brazilian norm NBR 7190/97 – Wood Structure Project of ABNT - Brazilian Asso- ciation of Technical Norms). A Universal Test Machine (Instron) was used to deter- mine the static modulus of elasticity, the modulus of rupture and the speed of sound propagation.

Modulus of elasticity 3 FLP L E = –––––––––– 3 4 b h δLP

Where: E (modulus of elasticity), FLP (force up to the proportional limit); L (stick sup- port span); b (stick width); h (stick height); δLP (deflection at the proportional limit).

Modulus of rupture 3 Fr L σr = ––––––– 2 b h2

Where: σr (modulus of rupture), Fr (rupture force), L (stick support span), b (stick width), h (stick height). After rupture, blocks of 2.5 cm³ were cut from the ends and the central regions of the sticks. These samples were used to obtain the wood density. The mass of each block

Downloaded from Brill.com09/30/2021 11:16:26PM via free access 152 IAWA Journal, Vol. 31 (2), 2010 was determined in an analytical scale, followed by immersion in a beaker containing mercury to determine the displaced volume. The stick´s density corresponded to the average of three sampled regions.

ρ 12 = ρn [1 + 0.005 (12 – n)]

Mn ρn = –––––––––––––––––––––––– Volume at moisture content n

Mn – Mo n = 100 ––––––––– Mo

Where: ρ12 (weight density at 12%), ρn (weight density at n%), Mn (weight of speci- men at moisture content of n%), M0 (weight of specimen at moisture content of 0%), n (moisture content).

The speed of sound propagation (v) was obtained with the values of the density and the modulus of elasticity, since these characteristics are correlated (Bucur 1995; Yojo, 2004), according to the formula: –– E ν = –– � ρ Where: E = modulus of elasticity and ρ = density.

Lignin and extractive content analysis Klason lignin and extractive content were determined from fragments of the samples used in the destructive tests. For determination of the Klason lignin content we fol- lowed the method described by Hatfieldet al. (1994). Samples with 2 g of powder were submitted to several organic solvents (as chloroform and acetone), acid and alcoholic solutions. The material was washed and centrifuged and the pellet was quantified with the use of an analytical scale. The values were expressed as percentage. To analyze the extractive content we used the method described by Matsunaga et al. (1996): samples with 3 g of powder were deposited on soxhlet extractors, using water or ethanol/ben- zene as solvent. The residue was dried in a stove and the mass was determined, cor- responding to the extractive content.

RESULTS Wood anatomy A bigger diameter and length of vessel elements were observed in samples of Manil- kara, but the highest vessel frequency occurred in Handroanthus samples (Fig. 1, 2, 5 & 7). The height and frequency of the rays were also greater in samples of Manilkara, while the width did not statistically differ between the two woods (Fig. 3 & 4). When compared with Handroanthus, Manilkara samples have longer and thicker-walled fibers, as well as higher fiber diameter, with no differences in fiber lumen diameter (Fig. 6 & 8; Table 1).

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Higher volume of axial parenchyma and rays were found in the samples of Manilkara and higher percentage of vessels and fibers were found in the Handroanthus samples (Table 2).

Figures 1–8. Anatomical features of Handroanthus spp. (1, 3, 5 & 6) and Manilkara spp. (2, 4, 7 & 8). – 1 & 2: Transverse sections. – 3 & 4: Tangential sections. – 5 & 7: Vessel elements. – 6 & 8: Fibers. — Scale bars for 1–4 = 200 µm, for 5 & 7 = 100 µm, for 6 & 8 = 10 µm.

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Table 1. Wood anatomical features of Caesalpinia echinata, Handroanthus spp. and Manil- kara spp. sticks.

S p e c i e s –––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– Wood anatomy *Caesalpinia Handroanthus spp. Manilkara spp. features echinata (class A)

Vessels diameter (µm) 108 109 b (93–119) 119 a (104–134) element length (µm) 354 316 b (298–333) 683 a (589–773) frequency (mm-2) 13 14 a (12–15) 8 b (7–9)

Rays height (µm) 230 192 b (180–201) 399 a (297–512) width (µm) 19 33 a (30–36) 32 a (28–36) frequency (mm) 10 6 b (6–7) 9 a (8–10)

Fibers length (µm) 1159 1226 b (1115–1335) 1409 a (1218–1558) diameter (µm) 17 14 b (13–15) 25 a (23–27) lumen diameter (µm) 5 2 a (2–3) 2 a (1.5–2) wall thickness (µm) 6 6 b (5–6) 12 a (10–13)

Median values (p.25% – p.75%). Distinct letters indicate significant differences at the p < 0.05 level (Mann-Whitney test). – *Alves et al. (2008b). Class A = high quality sticks for bows.

Table 2. Tissue percentages of Caesalpinia echinata, Handroanthus spp. and Manilkara spp. sticks.

S p e c i e s –––––––––––––––––––––––––––––––––––––––––––––––––––––––– Cellular components (%) *Caesalpinia echinata Handroanthus spp. Manilkara spp. (class A) Axial parenchyma 18 15 16.5 Vessels 16.9 21.7 20.1 Fibers 58.8 54.9 50.4 Rays 6 8.3 12.8

*Alves et al. (2008b). Class A = high quality sticks for bows.

Physical, mechanical and acoustic properties Except for density, which was higher in Manilkara, Handroanthus had the highest values of all the analyzed properties: static and dynamic modulus of elasticity, speed of sound propagation, and modulus of rupture (Table 3).

Lignin and extractive contents The samples of Handroanthus had a higher percentage of Klason lignin, while Manil- kara showed higher quantities of hydrosoluble and ethanol/benzene soluble extractives (Table 4).

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Table 3. Physical, mechanical and acoustic properties of Caesalpinia echinata, Handro- anthus spp. and Manilkara spp. sticks. S p e c i e s –––––––––––––––––––––––––––––––––––––––––––––––––––––––– Properties *Caesalpinia echinata Handroanthus spp. Manilkara spp. (class A) # Weight density at 12% m.c. 1004 970 1064 (kg m-3) 1005 961 1081 1019 954 1058 • Weight density (kg m-3) 1000 1000 1140 1000 1000 1130 1010 1000 1120 # Modulus of elasticity (MPa) 18619 20583 16758 18844 26904 17492 23077 21153 17796 • Modulus of elasticity (MPa) 27755 27184 25650 28490 28659 23755 28995 28268 23953 # Speed of sound (m s-1) 4348 4651 4007 4372 5343 4062 4805 4755 4141 • Speed of sound (m s-1) 5320 5265 4790 5390 5406 4630 5410 5369 4670 # Modulus of rupture (MPa) 207 177 162 200 186 168 240 177 155 # NBR 7190/70; • Non-destructive methods. *Alves et al. (2008b). Class A = high quality sticks for bows.

Table 4. Contents of Klason lignin and extractives of Caesalpinia echinata, Handroanthus spp. and Manilkara spp. S p e c i e s –––––––––––––––––––––––––––––––––––––––––––––––––––– Contents (%) *Caesalpinia echinata Handroanthus spp. Manilkara spp. (class A) Klason lignin. 70.3 80.3 70.1 Hydrosoluble extractives 22.6 14.6 20.6 Extractives soluble in ethanol/benzene 22.3 16.6 21.6 *Alves et al. (2008b). Class A = high quality sticks for bows.

DISCUSSION

According to Woodhouse (1993a, b) the factors that influence the playability of a bow are related to its shape, equilibrium point, and wood properties, especially the density, the stiffness and vibration decay.

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By experience, bow makers know that harder samples have a higher potential to fur- nish good quality bows (Alves et al. 2008a). Sticks of high density and stiffness allow for the manufacture of thinner bows, also employing less material. These bows have ideal stability and weight, which confer them optimal playability (Alves et al. 2008b). Wegst (2006) established that woods for high quality bows have a density around 1000 kg m-3. Alves et al. (2008b) showed that pernambuco wood bows of high qual- ity had densities between 1000 to 1040 kg m-3, when calculated by mass/volume ratio, and 1004 to 1019 kg m-3, when determined according to the technical norm NBR 7190/97. Handroanthus sticks evaluated in this study had adequate densities, while Manil- kara sticks showed higher than the ideal density values proposed by Alves et al. (2008b). Considering that bows for violins have a pre-determined weight, between 60 and 64 g (Alves et al. 2008a), the use of more dense sticks implies they should be thinner in order to do not surpass the allowed weight, which leads to a loss of stability. Therefore, high density does not guarantee high quality of the stick, since it may not be homogeneously distributed. The ratio of different cell types, their dimensions, the thickness of the cell wall, and the presence of contents can be responsible for the wide variation observed in the wood properties (Panshin & de Zeeuw 1964; Kollmann & Côté Jr. 1968; Walker et al. 1993). High densities have been related to low frequency of vessels (Basson 1987; Rao et al. 1997; Green et al. 1999), higher percentage of longer fibers and thicker walls (Basson 1987; Downes et al. 1997) and rays of smaller dimensions and lower frequency (Fujiwara et al. 1991). The highest density of Manilkara sticks results from the lower frequency of vessels and fibers with thicker walls when compared to Handroanthus sticks. Despite its importance, the density is not the only parameter determining the quality of the sticks. Another key property is the modulus of elasticity (Lucchi 1986; Follmann 1995), which indicates the stiffness of the material. Sticks with low stiffness and con- sequently higher flexibility cause problems with the tension of the horsehair bow, af- fecting their dynamics and playability (Wegst 2006). On the other hand, sticks with high stiffness allow a better use of the energy imposed by the musician, allowing less physical effort. Handroanthus sticks had a higher modulus of elasticity, which indicates that they are stiffer than the Manilkara sticks. These results are at least in part determined by the higher percentage of fibers and higher lignin content detected inHandroanthus sticks. Lignin is a polymer that confers higher stiffness and resistance to cell wall degradation, influencing the dynamic properties of the wood (Obataya et al.1998; Carpita & Mc- Cann 2000; Jordão & Andrade 2000; Bergander & Salmén 2002). The elastic modulus of Handroanthus sticks was similar to Caesalpinia echinata sticks, previously estab- lished by Alves et al. (2008b), and traditionally considered the best wood for bows manufacturing. When compared with Manilkara, Handroanthus sticks are more homogeneous, and have lower and less frequent rays and a lower proportion of axial parenchyma. On the other hand, Manilkara sticks have higher stiffness because of higher density of rays and fibers with thicker walls, and also taller rays. These are the characteristics limit-

Downloaded from Brill.com09/30/2021 11:16:26PM via free access Longui et al. — Violin bows from Handroanthus and Manilkara wood 157 ing the bow quality, probably related to the non-uniformity of this wood regarding the distribution of density and stiffness. The speed of sound propagation has been shown to be of great importance for sticks (Alves et al. 2008a). Some authors observed higher speed of sound propagation in woods with longer fibers, bearing thicker walls and higher density (Bucur 1988; Feeney et al. 1998; Bucur et al., 2002; Oliveira & Sales 2006). Higher densities with lower values of speed of sound propagation were also described (Lucchi 1986; Calegari et al. 2007). On the other hand, Wegst (2006) reported high speeds in both woods with high density such as Caesalpinia echinata and Manilkara sp. and in woods with low density such as Pinus sylvestris and sp. Brancheriau et al. (2006a, 2006b), studying woods for xylophones, mention that the short, homogeneous rays with low frequency, paratracheal axial parenchyma and stor- ied structure provide material with optimal acoustic quality for the manufacturing of this instrument. Manilkara had apotracheal axial parenchyma, when compared to the paratracheal axial parenchyma of Handroanthus spp. and Caesalpinia echinata. Handroanthus showed higher speed of sound propagation than Manilkara sticks. Besides the lower density, this wood also had lower ray height and frequency, a higher percentage of fibers, higher lignin content and higher stiffness. Carrasco and Azevedo Júnior (2003) men- tion that the speed of sound propagation is more correlated to stiffness than to density, which was confirmed by the results obtained in this study. Another important feature is the modulus of rupture. The bow can break accidentally in a fall or as a result of internal cracks, originated from repetitive efforts of tension. The resistance to rupture was higher in the Handroanthus sticks, even though the values were lower than those found by Alves et al. (2008b) for pernambuco wood. It is possible that the higher percentage of fibers in the Handroanthus sticks, compared to Manilkara sticks, contributes to the increased resistance of such sticks. Alves et al. (2008b) found a higher percentage of fibers in sticks ofC. echinata with better quality, reinforcing the relationship between resistance quality and percentage of fibers. According to Matsunaga et al. (1996), the extractive contents in C. echinata wood also interfere in the quality of the bow. Minato et al. (1997), Sakai et al. (1999), and Matsunaga et al. (2000) observed that the impregnation of extractives obtained from this wood diminished the vibration decay in other wood species. A stick with high modulus of elasticity and low vibration decay, vibrates less when the horsehair bow are frictioned on the violin chords (Matsunaga et al. 1996). Alves et al. (2008b) stud- ied C. echinata sticks of different quality and did not find any correlation between the extractive content and the quality of the sticks, since all of the sticks of low quality also had a high extractive contents. In this study, Manilkara had the higher extractive contents. However, when compared to Handroanthus, this species was less adequate for the production of bows. In agree- ment with the previous reports, no relationship was observed between the extractives of Manilkara and Handroanthus and the quality of the sticks. Handroanthus bows have been bought and used by professional musicians, includ- ing soloists from important Brazilian orchestras. It is important to mention that at the

Downloaded from Brill.com09/30/2021 11:16:26PM via free access 158 IAWA Journal, Vol. 31 (2), 2010 time of purchase of bows, these musicians had the opportunity to choose Caesalpinia echinata bows, but they declined in favor of Handroanthus bows. However, Manilkara bows were not chosen by the professional musicians, possibly because of the higher density and lower stability of the bows.

CONCLUSION

We conclude that the Handroanthus sticks have similar or superior physical, mechani- cal and acoustic properties when compared to Caesalpinia echinata wood. Besides, Handroanthus samples showed a homogeneous anatomical structure that favorably influences the stick quality. Restrictive use ofHandroanthus is related to the color and texture instead of to the physical, mechanical and acoustic properties. Handroanthus wood has tones, contrasting to the traditional red color of C. echinata wood. The sticks of Manilkara have an inferior quality compared to those of Handroanthus, but might have some potential for bow manufacturing for beginner musicians. Manilkara bows are an option because of the suitable texture, color and final bow appearance for this market segment.

ACKNOWLEDGEMENTS

We are very grateful to FAPESP (The State of São Paulo Research Foundation) for the grant support to E.L. Longui. We also thank CNPq (National Council for Scientific and Technological Development) for the research fellow grant supporting E.S. Alves. We are grateful to the IPT (São Paulo Techno- logical Research Foundation), especially to the researchers Dr. Nilson Franco and Dr. Geraldo José Zenid for technical assistance and suggestions. We thank Itiberê M.S. Suckow (IF-Forestry Institute) for assistance in the photo preparation. Antonio Carlos Franco Barbosa and Paulo de Assis (IPT) for laboratory assistance and Dr. Veronica Angyalossy for useful suggestions have our special gratitude. This paper is part of the MSc of E.L. Longui.

REFERENCES

Alves, E.S., V. Angyalossy, E.L. Longui, D.R. Lombardi, E. Amano & A. Vargas. 2008a. O arco: arte e ciência. In: R.C.L.F. Ribeiro, C.J. Barbedo, E.S. Alves, M. Domingos & M.R. Braga (orgs.), Pau-brasil, da semente à madeira conhecer para conservar: 169–183. Instituto de Botânica, São Paulo. Alves, E.S., E.L. Longui & E. Amano. 2008b. Pernambuco wood (Caesalpinia echinata) used in the manufacture of bows for string instruments. IAWA J. 29: 323–335. Angyalossy, V., E. Amano & E.S. Alves. 2005. Madeiras utilizadas na fabricação de arcos para instrumentos de corda: aspectos anatômicos. Acta Bot. Bras. 19: 819–834. Associação Brasileira de Normas Técnicas. 1997. Projeto de Estruturas de Madeira NBR–7190/97. ABNT, Rio de Janeiro. Basson, P. 1987. Some implications of anatomical variations in the wood of pedunculate (Quercus robur L.) including comparisons with comoron (Fagus sylvatica L.). IAWA Bull. n.s. 8: 149–166. Bergander, A. & L. Salmén. 2002. Cell wall properties and their effects on the mechanical properties of fibers. J. Mater. Sci. 37: 151–156. Berlyn, G.P. & J.P. Miksche. 1976. Botanical microtechnique and cytochemistry. The Iowa University Press, Iowa.

Downloaded from Brill.com09/30/2021 11:16:26PM via free access Longui et al. — Violin bows from Handroanthus and Manilkara wood 159

Brancheriau, L., H. Baillères, P. Détienne, J. Gril & R. Kronland. 2006a. Key signal and wood anatomy parameters related to the acoustic quality of wood for xylophone- percussion instruments. J. Wood Sci. 52: 270–273. Brancheriau, L., H. Baillères, P. Détienne, R. Kronland & B. Metzger. 2006b. Classifying xylo- phone bar materials by perceptual, signal processing and wood anatomy analysis. Ann. Sci. 63: 73–81. Brunelli, A.A., J.J. Leal & F.G. Longo (coords.). 1997. Madeiras: material para o design. SCTDE, São Paulo. Bucur, V. 1988. Wood structure anisotropy estimated by acoustic invariants. IAWA Bull. n.s. 9: 67–74. Bucur, V. 1995. Acoustics of wood. CRC Press, Boca Raton. Bucur, V., P. Lanceleur & B. Roge. 2002. Acoustic properties of wood in tridimensional repre- sentation of slowness surfaces. Ultrasonics 40: 537–541. Calegari, L., D.M. Stangerlin, E.J. Santini, C.R. Haselein, S.J. Longhi, P.I.O. Carmo, L.C.P. Silva Filho & D.A. Gatto. 2007. Monitoramento do teor de umidade de madeiras de Pinus elliottii Engelm. e Eucalyptus grandis W. Hill ex Maiden, sob diferentes temperaturas de secagem, através do ultra-som. Ciência Florestal 17: 399–408. Carpita, N. & M. McCann. 2000. The cell wall. In: B.B. Buchanan, W. Gruissem & R.L. Jones (eds.), Biochemistry and molecular biology of : 52–109. American Society of Physiologists, Rockville. Carrasco, E.V.M. & A.P. Azevedo Júnior. 2003. Avaliação não-destrutiva de propriedades mecânicas de madeiras através de ultra-som-fundamentos físicos e resultados experimen- tais. Cerne 9: 178–191. Downes, G.M., I.L. Hudson, C.A. Raymond, G.H. Daen, A.J. Michael, L.R. Schimleck, R. Evans & A. Muneri. 1997. Sampling plantation Eucalypts for wood and fibre properties. Collingwood. Feeney, F.E., R.C. Chivers, J.A. Evertsen & J. Keating. 1998. The influence of inhomogeneity on the propagation of ultrasound in wood. Ultrasonics 36: 449–453. Follmann, E.V. 1995. Consideration about the construction of bows for stringed instruments. Instrumentenbau-Zeitschrift 1: 45–48. Fujiwara, S., K. Sameshima, K. Kuroda & N. Takamura. 1991. Anatomy and properties of Japa- nese . I. Variation of dimensions of ray cells and their relation to basic density. IAWA Bull. n.s. 12: 419–424. Gasson, P., K. Warner & G. Lewis. 2009. Wood anatomy of Caesalpinia s.s., Coulteria, Erythro- stemon, Guilandina, Libidibia, Mezoneuron, Poincianella, Pomaria and Tara (Leguminosae, Caesalpinioideae, Caesalpinieae). IAWA J. 30: 247–276. Green, D.W., J.E. Winandy & D.E. Kretschmann. 1999. Mechanical properties of wood. In: Forest Products Laboratory (ed.), Wood handbook: wood as an engineering material. Gen. Tech. Rep. 113: 1–46. Forest Products Laboratory, Madison. Hatfield, r.d., H.J.G. jung, J. Ralph, D.R. Buxton & P.J. Weimer. 1994. A comparison of the insoluble residues proceded by Klason lignin and acid detergent lignin procedures. J. Sci. Food Agr. 65: 51–58. IAWA Committee. 1989. IAWA list of microscopic features for identification. IAWA Bull. n.s. 10: 219–332. Johansen, D.A. 1940. Plant microtechnique. McGraw-Hill Book Company Inc., New York. Jordão, B.Q. & C.G.T.J. Andrade. 2000. Célula Vegetal. In: L.C. Junqueira & J. Carneiro, Bio- logia celular e molecular: 244–271. Editora Guanabara Koogan, Rio de Janeiro. Kollmann, F. & W.A. Côté Jr. 1968. Principles of wood science and technology. Vol. 1. Solid wood. Springer, New York.

Downloaded from Brill.com09/30/2021 11:16:26PM via free access 160 IAWA Journal, Vol. 31 (2), 2010

Lucchi, G. 1986. The use of empirical and scientific methods to measure the velocity of propaga- tion of sound. J. Violin Soc. 9: 107–123. Mainieri, C. & J.P. Chimelo. 1989. Fichas de características das madeiras brasileiras. Instituto de Pesquisas Tecnológicas, São Paulo. Matsunaga, M., K. Sakai, H. Kamitakahara, K. Minato & F. Nakatsubo. 2000. Vibrational prop- erty changes of wood by impregnation with water-soluble extractives of pernambuco (Guilandina echinata Spreng.). II. Structural analysis of extractive components. J. Wood Sci. 46: 253–257. Matsunaga, M., M. Sugiyama, K. Minato & M. Norimoto. 1996. Physical and mechanical prop- erties required for violin bow materials. Holzforschung 50: 511–517. Minato, K., K. Sakai, M. Matsunaga & F. Nakatsubo. 1997. The vibrational properties of wood impregnated with extractives of some species of Leguminosae. Mokuzai Gakkaishi 43: 1035–1037. Obataya, E., M. Norimoto & J. Gril. 1998. The effects of adsorbed water on dynamic mechanical properties of wood. Polymer 39: 3059–3064. Oliveira, F.G.R. & A. Sales. 2006. Relationship between density and ultrasonic velocity in Bra- zilian tropical woods. Bioresource Technology 97: 2443–2446. Panshin, A.J. & C. de Zeeuw. 1964. Textbook of wood technology: structure, identification, properties and uses of the commercial woods of the United States and Canada. Ed. 3. McGraw-Hill, New York. Paula, J.E. & J.L.H. Alves. 2007. 897 Madeiras nativas do Brasil. Porto Alegre: Cinco Conti- nentes. Rao, R.V., D.P. Aebischer & M.P. Denne. 1997. Latewood density in relation to wood fibre diameter, wall thickness, and fibre and vessel percentages in Quercus robur. IAWA J. 18: 127–138. Rizzini, C.T. 1986. Árvores e madeiras úteis do Brasil. Manual de Dendrologia Brasileira. Editora Edgard Gomide Blucher, São Paulo. Rocha, Y.T. & E.A. Simabukuro. 2008. Estratégias de conservaçao in situ e ex situ do pau-brasil. In: R.C.L.F. Ribeiro, C.J. Barbedo, E.S. Alves, M. Domingos & M.R. Braga (orgs.), Pau- brasil, da semente à madeira conhecer para conservar: 102–113. Instituto de Botânica, São Paulo. Sakai, K., M. Matsunaga, K. Minato & F. Nakatsubo. 1999. Effects of impregnation of simple phenolic and natural polycyclic compounds on physical properties of wood. J. Wood Sci. 45: 227–232. Walker, J.C.F., B.G. Butterfield, T.A.G. Langrish, J.M. Harris & J.M. Uprichard. 1993. Primary wood processing: principles and practice. Chapman & Hall, London. Wegst, U.G.K. 2006. Wood for sound. Amer. J. Bot. 93: 1439–1448. Woodhouse, J. 1993a. On the playability of violins. Part I. Reflexion function. Acustica 78: 125– 136. Woodhouse, J. 1993b. On the playability of violins. Part II. Minimum bow force and transients. Acustica 78: 137–153. Yojo, T. 2004. Discussões sobre as propriedades acústicas e sua utilização em madeira. In: IX Encontro Brasileiro em Madeiras e em Estruturas de Madeira (EBRAMEM): 11–20. Editora da Universidade Federal do Mato Grosso – EdUFMT, Cuibá.

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