IAWA Journal, Vol. 20 (4), 1999: 405-417
RAYS IN JUVENILE WOOD OF ACER by
J.E. Dakak l , R. Keller l & V. Bucur 2
SUMMARY
Juvenile wood characteristics of multiseriate and uniseriate rays of five species of the genus Acer were studied on young trees from France and Canada. Ray height, width, number in width of cells and proportion/ mm2 were determined for the earlywood. Variance analysis was used to discriminate the variability of the characteristics of rays. Simple regres sion analysis shows some strong correlations between the character istics of multiseriate and uniseriate rays of each species. Except for A. saccharinum, no relationships were established between the ray char acteristics and the specific gravity. Except for A. pseudoplatanus, no relationships were established between annual ring width and ray char acteristics. Principal component analysis focused separatelyon multi seriate rays and on uniseriate rays revealed differences between A. sac charum and A. saccharinum (e.g., the proportion and the number of cells in multiseriate rays). Key words: Ray size, juvenile wood, earlywood, Acer campestre, Acer platanoides, Acer pseudoplatanus, Acer saccharum, Acer saccharinum.
INTRODUCTION
Anatomical descriptions of maple wood (Acer) are available in numerous reference books (Greguss 1945; Stark 1954; Jacquiot et al. 1973; Wagenführ 1974; Core et al. 1976; Butterfieid & Meylan 1980; Panshin & de Zeeuw 1980; Koch 1985). Rays in Acer are homocellular, uniseriate and multiseriate. In hard maples there are rays of two distinct widths. The size and distribution of rays and vessels in hardwoods affect wood quality and utilization, both for solid wood and paper and pulp. Wood figure in maple is related to the size and distribution of rays. The ray cells are short and usually thin-walled and so contribute little to the strength properties of paper. In solid wood the ray tissue con tributes to acoustic wave propagation in radial direction (Bucur 1995). In the U.S. sugar maple (Acer saccharum Marshall) and black maple (Acer negundo L.) are sold as hard maple. Soft maples, e. g. Acer rubrum L. and A. saccharinum L.,
1) Ecole Nationale du Genie Rural des Eaux et Forets, LRSF, 14 rue Girardet, F-54042 Naney, Franee. 2) Universite 'Henri Poineare', Faeulte des Seienees, LERMAB, BP 239, F-54506 Vandoeuvre les Nancy, France. Correspondenee to be addressed to V. Bueur, e-mail: [email protected]
Downloaded from Brill.com09/30/2021 05:39:25PM via free access 406 IAWA Journal, Vol. 20 (4), 1999 are distinguished fromAcer macrophyllum Pursh in that "the rays intergrade in size in these last-named species and the widest rays are not so broad" (panshin & de Zeeuw 1980). Ray width is considered a useful character for wood identification of species groups of the maple group (Acer spp.). Ray characteristics of five Acer species are given in Table 1. n is generally accepted that the juvenile wood is characterized by shorter elements and a higher microfibril angle when compared to the mature wood (pans hin & de Zeeuw 1980; Koch 1985; Zobel & Sprague 1998). As noted by Zobel (1981), Zobel and Jett (1995), and Zobel and Sprague (1998) the juvenile wood of temperate-zone diffuse-porous species is not markedly different from mature wood. Fukazawa (1984) suggested that juvenile wood in hardwoods can be defined as "a region up to 5-8 cm from pith, regardless of their growth rate." These words noted that the effect of growth rate on juvenile wood properties of diffuse-porous hardwoods generally is relatively small.
Table 1. Some characteristics of rays of Acer species, as noted by the literature.
Characteristics of rays References width height total no. 11m nO.of 11m nO.of of rays author with year cells ceIIs permm2
Acer campestre - Field maple 30-60 1-5 <500 Keller 1992 1-6 1-40 50-60 Gregus 1945 30 2-4 320-800 Freund 1970 Acer platanoides - Norway maple 40 1-5 10-40 Keller 1992 53 4-6 470-600 Freund 1970 1-3 60-70 multi 10-12 Greguss 1945 uni 16-18 Acer pseudoplatanus - Plane tree maple 40-80 1-8 > 1000 60 Keller 1992 1-3 1-60 50-60 Greguss 1945 56 5-8 480-1000 Freund 1970 17-74 122-765 Tabatabi et aI. 1962 480-1000 Schmidt 1941 Acer saccharum - Sugar maple 3-8 multi> 800 Panshin 1980 uni> 200 19-53 1218 Stark 1954 Acer saccharinum - Silver maple 1-3 1-70 80-90 Greguss 1945 20-27 3-4 612-812 41-59 Stark 1954
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In recent years, in North America and in Canada, a strong attack of Ceratocystis on Acer saccharum wood was observed. This attack can be avoided by drying the wood to a moisture content below 20%; A. saccharinum is not attacked by this fungus. Acer saccharum and A. saccharin um have a very similar anatomical structure and be cause of this it is very difficult to differentiate them macroscopically. Information is available on the rays of A. saccharum, A. saccharinum (Stark 1954; Koch 1985), and A. pseudoplatanus (Vasiljevic 1951). The importance of A. saccharum andA. saccha rinum wood is increasing, especially in the U. S., because of increased use of these species for veneer, furniture, flooring, etc. To our knowledge, no references were pub lished on the ray characteristics of young wood of Acer species of European origin. The aim of this research is to study the characteristics of rays in juvenile wood of Acer campestre L. (field maple), A. platanoides L. (Norway maple), A. pseudoplatanus L. (Plane tree maple), A. saccharum Marshall (sugar maple), and A. saccharinum L. (silver maple), and to further establish useful criteria for identification of different maples, especially A. saccharum and A. saccharin um.
MATERIALS AND METHODS
The investigations were conducted on young trees (diameter between 6 and 16 cm) from East France, Lorraine (A. campestre, A. platanoides, A. pseudoplatanus) and East Canada (A. saccharum, A. saccharinum). From each species three individuals were taken. In each tree, at 1.30 m height, one disk of 10 cm thick was cut. From this disk five sampIes (small wood blocks, 20 x 20 x 40 mm), located between the 15 th and the 20th annual ring, were prepared as microscopic specimens in longitudinal tangen tial plane of wood and for other physical properties measurements (basic density and annual ring width). For microscopic observations (Freund 1970), the blocks were embedded in polyethylene glycol 1500. The ray characteristics of the 15 th ring were analyzed. The microscopic sections measured 15 mm x 7 mm x 12 J.Ull. Five rnicro scopic fields were explored for each section, one located in the center and four 10- cated in each corner. All the microsections were located in the earlywood zone of the 15 th juvenile annual ring. More than 30,000 measurements were taken to characterize the rays. Photomicrographs (Dakak 1997) were taken from each field of the micro scopic sections stained with safranin and mounted in Canada balsam. Measurements were perforrned using a Zeiss optic microscope equipped with a camera. The following characteristics of rays (uniseriate and multiseriate) of the earlywood were measured on a reference microscopic surface of 1 mm2 of each sec tion: • height of ray in J.Ull (H for multiserate rays and h for uniseriate rays). Rays wider than three cells were considered multiseriate; • width of ray in mm (L for multiseriate rays and 1 for uniseriate rays); • number of cells in a ray at maximum width (N for multiseriate rays and n for uniseriate rays); • ratio between area of rays and the observed surface in % (P for multiseriate rays and p for uniseriate rays).
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The number of rays was manually counted in the microseopie screens of 1 mm2 in tangential longitudinal seetion of each growth ring. Specific gravity (s.g.) was based on green volume and ovendry weight and was expressed in kg/m3. The annual ring width (w) is expressed in mm, and represents the average annual ring width between the 15 th and 20th ring, assumed to be part of the juvenile wood zone. For statistical analysis, routine linear regression analysis, analysis of variance (ANOVA) and principal component analysis were used with SAS/Stat 1999 to study the variability of the population.
Table 2. Ray characteristics in juvenile wood of studied Acer.
Characteristics of rays
Values Multiseriate rays Uniseriate rays
H L H/L N P h h/l n p 11m 11m % 11m 11m % I. Acer campestre minimum 254 27.5 8.6 4.0 1.8 10.8 12.4 0.7 1.5 6.1 average 344 32.3 10.7 4.1 7.5 90.9 14.1 6.5 1.7 8.0 maximum 397 37.7 12.l 4.6 14.3 129.0 15.6 8.4 1.9 12.1 C.v. % 13 9 13 6 50 40 9 36 8 28
2. Acer platanoides minimum 372 34.0 7.6 4.2 5.3 81.0 11.0 7.1 1.3 1.8 average 432 42.3 10.5 4.8 8.8 113.0 14.0 8.0 1.6 4.3 maximum 579 57.0 13.8 5.5 12.4 140.0 16.6 8.9 2.0 6.8 c.v. % 15 20 23 9 28 18 14 7 16 40
3. Acer pseudoplatanus minimum 64 32.5 1.9 4.0 0.6 77.9 1.6 6.3 1.2 1.4 average 27 49.4 5.1 5.5 5.6 116.0 11.5 16.4 1.4 6.3 maximum 366 59.7 7.l 6.6 16.0 139.0 15.1 75.0 1.6 11.0 C.v. % 52 24 44 20 113 21 34 136 10 53
4. Acer saccharum minimum 412 37.9 8.2 5.4 8.8 59.8 9.6 6.2 1.1 1.0 average 547 49.0 11.6 6.4 11.9 68.9 1O.l 6.8 1.3 2.5 maximum 636 63.6 16.7 8.0 17.2 80.5 10.5 8.l 1.2 5.2 C.v. % 17 21 28 16 30 13 3 12 6 73
5. Acer saccharinum minimum 321 31.3 9.0 4.0 0.3 68.6 9.1 7.1 1.0 1.6 average 552 52.5 10.6 6.3 10.5 118.0 11.5 9.8 1.4 3.8 maximum 696 71.7 13.2 8.0 21.3 234.0 15.5 18.6 2.l 7.8 c.v. % 27 25 15 22 79 55 23 40 31 66
Multiseriate rays: H = height; L = width; H/L = ratio of height to width; N = number of cells; P = proportion of rays. Uniseriate rays: h = height; I = width; h/l = ratio of height to width; n = number of cells; p = pro- portion of rays.
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Table 3. Variability of the characteristics of rays in Acer species, expressed by variance analysis 'ANOVA' .
Variability Species Individual Specimen Field Parameters related to multiseriate rays: height *** *** ns ns width *** *** ns ns no. of cells at maximum width *** *** ns ns Parameters related to uniseriate rays: height *** *** *** ns width *** *** * ns no. of cells at maximum width *** *** ns ns Global parameters: total surface *** *** *** ns proportion (%) *** *** ** ns
*** = level of significance 0.1 %; ** = level of significance 1%; * = level of significance 5%; ns = not significant.
RESULTS
Ray characteristics measured on our specimens are more or less in the range given by the literature for Acer spp. (Table 2). For a11 species, the multiseriate rays are charac terized by the average of main parameters as fo11owing: height 428 f.Ull, width 43 f.Ull and 9% proportion on reference surface. Multiseriate ray height of A. saccharum and A. saccharinum differed markedly from the other three species studied. Ray width of A. saccharum and A. saccharin um, respectively 49 f.Ull and 46 f.Ull, is greater than in A. campestre, A. platanoides and A. pseudoplatanus, respectively 32 f.Ull, 41 f.Ull and 38 f.Ull. The coefficient of variation of the proportion of multiseriate rays ranges between 50% for A. campestre and 113% for A. pseudoplatanus. For the uniseriate rays, a11 parameters are sma11er than for multiseriate rays, their proportion on reference surface is 5% on average. The coefficient of variation ranges between 28 and 73 %. The width of uniseriate rays of A. saccharum and A. saccharinum is similar (10-11 f.Ull) and smaller than for other species. Results for the analysis of variance (ANOVA) are shown in Table 3. The variability induced by the field of microseopie inspection is not significant, but the variability induced by the rays proportion is significant for both multiseriate and uniseriate rays. The simple regression analysis shows (Table 4) for: • Acer campestre, A. platanoides and A. pseudoplatanus, no very strong correlations (significant at 0.1 %, ***) between the parameters of multi- and uniseriate rays. • Acer saccharum, no correlation at a11 at the level of significance 0.1 % between the parameters of multiseriate and uniseriate rays. At 1% significant level, correlations were established between H/L of multiseriate rays and the proportion of uniseriate rays. • Acer saccharinum, negative correlation significant at 1 % between the proportion of multiseriate rays and the height and number of cells of uniseriate rays.
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Table 4, Correlation matrix and regression coefficients (rx 10-3) established for each species studied.
Characteristics of rays Multiseriate rays Uniseriate rays
H L H/L N P h h/l n p
Acer campestre H L ns H/L 788*** ns N ns ns ns p ns ns ns ns h ns ns ns ns ns 1 ns ns ns -717 -807 ns h11 ns ns ns ns ns 989 ns n ns ns ns -728* -752* ns 989** ns p ns ns ns ns ns ns ns ns ns
Acer platanoides H L ns H/L ns -775*** 1 N ns 842** -838** p ns ns ns ns h 648* ns ns ns ns 1 ns ns ns ns ns 939*** h/l 806** ns ns ns ns 722* ns n ns ns ns ns ns 925*** 946 ns p ns ns ns ns ns ns ns ns ns
Acer pseudoplatanus H L 910* H/L 983* ns N ns 984** ns P 873* 995*** ns .993*** h -971 * -935* -934* ns -918* 1 -973** ns -975* ns ns 890* h11 ns ns ns ns ns 890* ns n -920*** -940*- 958* ns -905* -956* 973** ns p -948* -948* -892* -902* -914* 897* 949** ns 981**
Acer saccharum H L ns H/L ns ns N ns 983*** ns p ns 866* ns .860* h ns -817* 866* ns ns 1 ns ns ns ns ns ns h11 ns -823* 965** ns ns 970*** ns n ns -782 ns ns ns 888* ns ns p ns -886* 944** -811* ns 949** ns 989*** ns (continued on next page)
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(Table 4 continued)
Characteristics of rays Multiseriate rays Uniseriate rays
H L HJL N P h h11 n p
Acer saccharinum H L 802* HJL ns ns N 919** 970*** ns P 857** 934** ns .936** h ns ns ns -852* -994*** I ns ns ns -717* -807 ns h11 ns -835* ns -822* -930** 996*** 982*** n ns -802* ns -783* -898** 999*** 994*** 996*** P ns ns ns ns -845* 984* 980*** 977*** 982*** Significant correlation coefficient at the following levels: * = 5%, ** = 1%, *** = 0.1 %.
The relationships between specific gravity and some characteristics of rays were cal culated (Table 5). Only A. saccharinum had significant relationships between both the proportion of multiseriate rays (P) and uniseriate rays (p) with specific gravity. In the first case r = 0.87*** and the variabilty explained by the regression coefficient r 2 is 75.8% In the second case r = 0.85*** and the variability explained by the regres sion is 72.3%. No correlations were found between the characteristics of rays and specific gravity for all other species. This suggests that for most of the Acer species studied here there is no influence of rays on the specific gravity. This finding agrees with data published by Fujiwara (1992). He noted that the "influence of rays on the specific gravity de pends upon species, that is, the difference in effect of rays on the specific gravity of
Table 5. Regression equations between ray characteristics, specific gravity (s.g.) and annual ring width (w), for species with significant correlation coefficients.
Variables Correlation coefficient Equation r r2
Acer saccharinum P and S.g. 0.87*** 0.758 P = -48.547 + 104.951 s.g. p and s.g. 0.85*** 0.723 p = 28.496 - 43.328 s.g.
Acer pseudoplatanus Pand w 0.85*** 0.732 P = 6.826 + 2.644 w
P = proportion of multiseriate rays in %; p = proportion of uniseriate rays in %; s. g. in kg/m 3; winmm.
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Table 6. Variance table in principal components analysis.
Variability explained by the components Rays Component 1 Component 2 Cumulative
All species studied All rays 0.57 0.19 0.76 Multiseriate 0.84 0.11 0.96 Uniseriate 0.53 0.29 0.82
Acer saccharum & A. saccharinum Multiseriate 0.84 0.13 0.97 Uniseriate 0.84 0.12 0.96
wood is attributable to difference in ray volume, dimension of ray cells and the ratio of volume of procumbent to upright ray cells." For beech, Keller and Thiercelin (1975) did not observe significant correlations between specific gravity and the proportion of rays or the number of rays per unit surface. Annual ring width is correlated with the proportion of multiseriate rays in A. pseudoplatanus (r = 0.85***). No other species studied had a significant correlation. Lev-Yadun (1998) noted for Pinus halepensis and P. pinea the lack of correlation between growth ring width and the size and number of rays for young trees. Principal component analysis as described by Cooper and Weekes (1991) is the next step in our statistical analysis. The aim of this analysis is to search for the asso ciation between variables and to summarize the co-variation among variables as ac curately as possible, using few components. All variables considered previously in Table 2 were taken as vectors to explain the variance of the population. Table 6 shows that for multiseriate rays, and for all species studied, the theoretic component no 1, or axis 1, explains 84% of the variability and the theoretic component no 2, or axis 2, explains only 11 %. The cumulative variance explained is 96%. For uniseriate rays the component no 1 explains 53% of the variability and the component no 2 explains 29% of the variability. In this case, the cumulative variance explanation is 82%. Finally, the multiseriate rays explain variability among Acer species better than uni seriate rays. When only A. saccharum and A. saccharin um are compared, the cumu lative explanation of variance is 0.97 for multiseriate rays and 0.96 for uniseriate rays. Figures 1 through 5 illustrate the concepts of principal component analysis related to the results presented here. In Figure 1 all species are compared with all vectors and three significant groups are distinguished. The vectors related to multiseriate rays are oriented to positive axis 1, while the vectors related to uniseriate rays are oriented to negative axis 1. The group composed of A. saccharum and A. saccharinum is oriented to positive axis 1 while A. pseudoplatanus is oriented to the negative direction of the same axis. Acer campestre and A. platanoides are oriented more or less around axis 2.
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3 .2 _._. .1 - 2 / ,- ,2 .2 Acer campestre .5 .1 1 1 'i (~, '.2 \ Acer platanoides .5 ...... ----..... i ,1 11 - / .3 1 /3-...... -----/ 1 ~-lfl:'t... H~~2 \ ...... - .. -", n " H .21 r"-,,- 0 \ , / h P'iJ Ne· "21 .3ej4· 4 .4 _/ I' ~ / 5 .S.4"? N .3 /-- hlr- 5 ., .5'\ / ' ...... :.; i '4.4 ~4 -1 'i3 / ,--"- \ / ,,_,,_,,?., .. 5 / -4 ~ - -5 i-- - -6 - - 3 • 1 -7 1 1 1 1 1 -6 -5 -4 -3 -2 -1 o 2 3 4 Component 1 Fig. I. Principal component analysis, for all species studied with all variables as vectors, Legends: I '" Acer campestre, 2 '" A. platanoides, 3 '" A. pseudoplatanus, 4 '" A. saccharum, 5 '" A. saccharinum. * '" original vectors; • '" principal components. 1.8 1 1 1 1 1 1 I 1.6 .4 - 1.4 - ,".2 \'\ 1.2 Acer campestre - .. /~ 1 .2 j Acer platanoides .~./ • 1 ,- Acer saccharum - I - . 1 i c- Acer saccharinum _ 0.8 I * \'.!4 .2 0.6 r- ( .1 1 ... 2 H/L ) \,- \, r-' N 0.4 i-- ", 2././ i- ~ 0.2 r- . .1 / 1 !* H /' i_ § 0~ ______-_'-_,-_~_,-~-_·_~:~~1 __1~!~5 __ ~ ____~.~5 __4i ____~ P- ..., 4 • .5 § -0,2 i-- i'-'3-{j5, : t~\.5 - u -0 4 r- '. 3" "'-. - , \ 3 3 "" .2 i' 5 \ -0.6 r- i, '. _,,_, P * .2j \ - -0.8 -"-"-"-"_ '-"- .3 /.4 .4 \ - ----'. 3 \ i \ -1 Acer pseudoplatanus I,'_..i - .3 i.. i - -1.2 \. .4 -1.4 .5 ! - "- '-"- } -1.6 - "- .. - ,. 3 -1.8 '----'----'----'----'-----''-----''-----'----'----'I I I I I 1 -5 -4 -3 -2 -1 0 1 2 3 4 Component 1 Fig. 2, Principa1 component analysis focused on multiseriate rays for all species studied (for 1egends, see Fig. 1). * '" original vectors; • '" principal components. Downloaded from Brill.com09/30/2021 05:39:25PM via free access 414 IAWA Journal, Vol. 20 (4), 1999 8 .3 7 I- - 6 I- - 5 - N 4 - 1:: Fig. 3. Principal component analysis focused on uniseriate rays for all species studied (for legends, see Fig. 1). * = original vectors; • = principal components. 1.8 I I I • 4 1.6 I- - 1.4 I- - 1.2 I- - .5 1 I- - .4 0.8 I- 4• - * H/L .4 0.6 I- - N 1:: 0.4 I- - Fig. 4. Principal component analysis focused on multiseriate rays for Acer saccharum (4) and A. saccharinum (5). * = original vectors; • = principal components. Downloaded from Brill.com09/30/2021 05:39:25PM via free access Dakak, Keller & Bueur - Rays in Aeer 415 3 I I I I I .5 2 r-- - Acer saccharinum ("'-'--", * h/l 1.. 5..p 5\.11.. *h .·-'::-.,..,5 •••• 5 ) ( '-'.,. \... ~~.. _q._~::.:.:j. .41 p / .5 -"-.. .' hc Acer saccharum I -1 ~ - -2 I I I I I .5 -2 -1 o 2 3 4 5 Component I Fig. 5. Prineipal eomponent analysis foeused on uniseriate rays for Acer saccharum (4) and A. saccharinum (5). * = original veetors; • = principal eomponents. Table 7. Principal components analysis, the projection of the eigenvectors on axes. Parameters of rays Component Height Width Ratio No. of ceHs Proportion H L H/L N P All species studied Multiseriate rays Component 1 0.47 0.46 0.39 0.48 0.43 Component 2 0.26 -0.28 0.76 -0.15 -0.49 Uniseriate rays Component 1 0.44 0.51 -0.004 0.58 0.46 Component 2 0.34 -0.44 0.80 0.004 0.22 Acer saccharum & A. saccharin um Multiseriate rays Component 1 0.47 0.47 0.38 0.48 0.42 Component 2 0.23 -0.25 0.76 -0.11 -0.54 Uniseriate rays Component 1 0.46 0.45 0.41 0.46 0.45 Component 2 0.39 -0.40 0.70 -0.35 -0.26 Downloaded from Brill.com09/30/2021 05:39:25PM via free access 416 IAWA Journal, Vol. 20 (4), 1999 When the analysis for multiseriate rays is performed (Fig. 2), Acampestre and A platanoides are organized around the theoretie eomponent 2 (axis 2). This axis is related to the ratio of the height to the width of rays. In the same plane, A saccharum and A. saccharinum form a group oriented in positive direetion to axis 1. The number of eeIls, H, Wand P are the parameters having the greatest influenee on axis 1. Acer pseudoplatanus has a distinet position in negative direetion ofaxis 1 and axis 2. The analysis performed for uniseriate rays (Fig. 3) shows a distinet position of speeies of Canadian origin, A. saccharum and A saccharinum negative to axis 1, A. campestre, A platanoides and A pseudoplatanus positive to axis 1. Axis 2 explained 29% of the variability of the population. The projeetion (Table 7) of height, width and number of eells on axis 1 is very similar (respeetively 0.47, 0.46 and 0.48). This means that all these veetors have a similar influenee on the variability of the multiseriate rays. For the population of uniseriate rays, the most important veetor is the number of eells in tangential diree tion of wood (0.58) followed by the width of rays (0.51). In the area above axis 2, the ratio height/width has quite the same influenee in multiseriate (0.76) and in uniseriate (0.80). It is impossible to distinguish A saccharum and A saccharinum using the results presented only in these two figures. Analysis of A saccharum and A saccharinum by themselves was used to clarify differenees in the eharaeteristies of their rays (Fig. 4 & 5). It seems that the differenee is marked by the eharaeteristies of the uniseriate rays onl y. The group A. saccharinum is predominantly influeneed by the height (h) and the ratio h/l of rays while the group Asaccharum is more influeneed by the proportion, number of eells and width of rays. CONCLUSION The eharaeteristies of multiseriate and uniseriate rays of juvenile wood of Acer spe eies grown in Franee and in Canada were: the width and height of rays, maximum width of the rays in eell number and the proportion of rays observed on a referenee surfaee of 1 mm2. Analysis of varianee diseriminated the high variability of the ehar aeteristies of rays between species induced by the trees and specimens. Furthermore simple regression analysis showed some strong correlations between the characteris ties of multiseriate and uniseriate rays of eaeh speeies. Exeept for A. saccharinum, no relationships between ray characteristics and the speeifie gravity were established. Except for A pseudoplatanus, no relationships between annual ring width and rays characteristics were established. The position of A. pseudoplatanus is weIl defined in prineipal component analysis performed with the focus on uniseriate rays. 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