ANNUAL GROWTH RINGS THICKNESS AND TREES TOTAL VOLUME

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1 Proceeding of Wood Science and Engineering in the Third Millennium" - ICWSE 007. Brasov June 0 ANNUAL GROWTH RINGS THICKNESS AND TREES TOTAL VOLUME ESTIMATE OF Acacia melanoxylon IN PORTUGAL Andreia Rucha* 1, António Santos*, José Campos*, Ofélia Anjos** 1 and Mário Tavares*** ABSTRACT This text presents some results on the variation of Blackwood (Acacia melanoxylon R. Br.) annual growth rings thickness in Portugal, as well as the best models to evaluate total volumes stand trees, under or over-bark. Annual ring thickness evaluations were done on 61 wood sample disks collected at the usually used levels. With the purpose of obtaining those disks, 0 sample trees of 40cm dbh were harvested in four northwest sites of Portugal. The study of earlywood and latewood thickness leads to the conclusion that the wood type is responsible for 16% of ring size variance, and earlywood is 61% larger in average than latewood. The site, number of ring and its interaction are responsible for 1% of annual woody increment variation. Respective residuals are very relevant in both cases - 75 and 88%. Based on the study of those wood variables, the four places were arranged into three independent homogeneous groups. Differences between averages of earlywood and latewood thickness were significative, as well as those between North and South exposures. The selected model (v=β 1 *d β *h β3 ) that uses sites as dummy variables for stand tree volumes estimation is also presented. Maximum expected errors perform values between 155dm 3 to mean maximum volumes of 136dm 3 under-bark, and 169dm 3 to mean maximum volumes of 1459dm 3 over-bark. Keywords: Blackwood, earlywood, latewood, modelling, volumes estimates. 1. INTRODUCTION The models used to evaluate stand tree volumes of this species stands in Portugal are almost a non-existent tool. This fact may be a consequence of the prevailing idea that, like others in the same genus, they are aliens of forest spaces. However, it cannot be forgotten, at least by its eventual interest in carbon sequestration. Also, it will not be negligible as generative of biomass for energetic production in forest biomass factories with very interesting growth rates, and by its capacity of nitrogen fixation and soil fertility improvement (Tavares et al., 1999a; Tavares et al., 1999b). Moreover, its sand soils fixation and consequent protective action as well as its less inflammability than the high pyrophyte index woody species that mostly colonize forest soils the maritime pine and the eucalyptus (Santos et al., 006; Tavares et al., 1999a; Goes, 1991) -, must be mentioned. Recent studies have also shown that wood of acacia presents good paper potentialities, namely in the production of writing and printing papers (Santos et al., 006) as well as for solid wood products manufacturing (Nicholas et al., 00). The eventual utilization of this woody species induces the construction of a model to evaluate total volume of stand trees, with and without bark. The acacia-tree stands, which are frequently mixed with maritime pine, eucalyptus or other hardwood species, but are also pure stands, can be an option to profit from spaces potentiality where Blackwood spontaneously appears and imposes its presence, shortly producing long, thick and rectilinear stems. In the north of the country this species presents an annual diameter growth that will be greater than the one of maritime pine and will be close to the one of eucalyptus. Therefore, it is a strong

2 Proceeding of Wood Science and Engineering in the Third Millennium" - ICWSE 007. Brasov June 0 concurrent in wood producing (Freire et al., 003). Furthermore, its wood material properties present a contained variability, what sets up a good sign to the industrial processing (Santos et al. in press). There are some methodological examples in the bibliography used for gathering data and modelling the volumetric evaluation of this Genus species (Sousa, 1974; Veiga et al., 000). However, Schneider (003) uses dummy variables as a modelling method to the sampled places, which enables to identify individual growth differences between places and to minimize the estimative errors. This was also our methodology. The objective of this work was to understand the Acacia melanoxylon growth rings thickness standard and to construct equations to evaluate its total stand volume through annual diametric increasing estimates.. MATERIALS AND METHODS The 5 Acacia melanoxylon sample trees used to obtain disks at different levels (base, dbh, 50% of total height and at each m until the upper commercial level (d class=10cm)) were sampled for the following 4 sites in MNC N PFRSM Continental Portugal (Figure 1) the National Camarido Forest (MNC), the Forest Perimeter of Ovar Dunes Drain of Maceda PFDOVM PFC (PFDOVM), the Forest Perimeter of Rebordões de Santa Maria (PFRSM) and the Forest Perimeter of Crasto (PFC). This site selection was due to the fact that Blackwood is found in pure or mixed stands with significant dimensions. The general characteristics of each region are shown in Table 1. We can see that PFC is placed at the higher altitude, and that MNC and PFDOVM are almost at the sea level; this last place shows few more rainfall amounts than the other three sites. Nearby the littoral the annual mean temperatures are a bit higher than in the interior (PFC). Fig. 1 Geographical location of studied sites in Portugal. Table 1 Geomorphologic, climatic and forest characteristics of the studied places. Parameters Site MNC PFDOVM PFRSM PFC Latitude 41º 53 N 40º 57 N 41º 43 N 40º 41 N Longitude 8º 43 W 8º 34 W 8º 34 W 7º 56 W Altitude (m) Total rainfall (mm/year) Mean annual temperature (ºC) Predominant exposition East and flat Flat North South Stand age in 005 (years) Stand attainment Plantation Seedling Seedling Seedling Source of the meteorological information: Normal Climatic 61/90 P-CLIMA (1999). MNC and PFDOVM are sandy sites, while the others are granitic. All the stands are mixed with maritime pine, near aged and managed in irregular high stand regime.

3 Proceeding of Wood Science and Engineering in the Third Millennium" - ICWSE 007. Brasov June 0 Concerning inter and intra-species competition, the studied sites show that the smaller number of trees per hectare (N/ha) are found in PFC and PFDOVM (Table ). These sites combine woody production with recreation. The more dense stands are in MNC and PFRSM, the latter presenting the highest variability. Table Mean values of sample trees competition. Site dbh of concurrent Dist. to the N/ha (±sd) trees(cm) compet. trees (m) (n=5) MNC (±90) PFDOVM (±39) PFRSM (±1410) PFC (±97) sd standard deviation So, the competition found in PFDOVM site will be higher than the one of PFC, once being higher the mean N/ha, the mean distance between the trees is smaller. MNC is where the competition will be more relevant, seeing that this site shows the second highest density and, naturally, the more reduced distance among trees; this fact is in agreement with the lower mean dbh of the 4 closest trees. However, the competition must be considered high in all sites, because mean dbh of the trees that are around the sample trees are greater than 30cm, and the distances between the sample trees and the surrounding ones are greater than 4m. Sampling consisted of 5 trees of the 40cm dbh class per site. A semi-automatic evaluation of earlywood (Ew) and latewood (Lw) widths of the annual growth rings was carried out on the digital images of the 61 disks collected on these sample trees. A Kodak Megaplus Camera Model ES 1.0 with an objective COSMICAR/PENTAX TV 00m LENS 1,5mm 75mm (1:1,8) was used to acquire these images. Growth rings measurement was performed with Wood Ring Analysis 1.0. Bark widths were also measured on the analysed disks faces for each North and South generatrix. The estimation of both the radial annual increments and the annual volumes was realized by WinSTEM TM 005ª program. The reached variable values were used to study wood growth and to construct the over-bark (vob) and under-bark (vub) total volume (v(dm 3 )) estimation models. The dbh(cm) over-bark and total high (h(m)) were adopted as independent variables. Dummy variables represent the four different study sites MNC, PFRSM, PFC and PFDOVM. SPSS 14 and STATISTICA 6.0. programs allowed ANOVA and the Multiple Comparison Tests (mct) to run, respectively. The 17 tested models of Table 3 were already used by several authors with identical objectives. The first 8 are linear, the remaining non-linear. Table 3 Tested models. Mod.nº Model Reference 1 v=β 0 +β 1 *d *h v=β 0 +βb *d*h βb *d 3 v=β 0 +β 1 *d *h+β *1/ d 4 v=β 0 +β 1 *( d)*h+β *1/ d+β 3 *d 5 v=β 0 +β 1 *h +β *d +β 3 *1/ d 6 v=β 0 +β 1 *d +β *h+β 3 *d *h 7 v=β 0 +β 1 *d+β *d +β 3 *d*h+β 4 *d *h 8 v=β 0 +β 1 *d +β *d *h+β 3 *d*h +β 4 *h 9 v=e (β +β1*(ln(h))^+β*ln(d)) 10 v=e (β +β1*h+β*ln(d)) 11 v=e (β +β1*(ln(h))^+β*(ln(d))^) 1 v=e (β +β1*h+β*(ln(d))^) 13 v=β 1 *d β *h β3 14 v=d /(β 0 +β 1 /h) 15 v=d *(β 0 +β 1 *h) 16 v=d *h/(β 0 +β 1 *d) 17 v=β 1 *d β Utilized by Freire et al. (003) Utilized by Veiga et al. (000) Utilized by Freire et al. (003) v total volume (dm 3 ); d diameter at breast high over-bark (cm); h total high (m).

4 Proceeding of Wood Science and Engineering in the Third Millennium" - ICWSE 007. Brasov June 0 Levenberg-Marquardt (Eyng, 006) estimation method was used to perform the regressions to non linear models. Table 4 ANOVA for annual wood increments thickness. Type of wood Variation origin DF MS F p Var. (%) Local (L) Sentido (Si) Nº anel (N) Ew and Lw Tw Tipo de lenho (Tl) L.Si L.N Si.N L.Si.N L.Tl Si.Tl L.Si.Tl N.Tl L.N.Tl Si.N.Tl L.Si.N.Tl Resíduo Local (L) Sentido (Si) Nº anel (N) L.Si L.N Si.N L.Si.N Resíduo DF Degrees of freedom; MS Mean square; Var. (%) Expected variation proportion. 3. RESULTS AND DISCUSSION 3.1. Growth rings thickness variation The results obtained by ANOVA for the thicknesses of the two wood types, separately (Ew earlywood and Lw latewood) or added (Tw - total ring wood), are presented in Table 4. They show that the significances of the differences between all the factors in the expression of wood increments are diverse. However, the contributions are very different. In spite of being biologically relevant, in both analyses the factors variation (%) is quite small if compared with the relevance of the respective residue (75 and 88%). Separately, both types of wood explain about 16% of correspondent thicknesses variation, while the remaining factors and significative interactions amount to 8%. Tw value is about 1%. The mct (Fisher LSD test) for both mentioned woody growth evaluations (Table 5) disclose the same homogeneous grouping (hg) of sites in both cases PFRSM (hg.1), MNC e PFC (hg.) e PFDOVM (hg.3). The hg organization standard and its relative positions may be due to the fact that de sites on the north (PFRSM and MNC) are less rainy and PFC more coldly. This situation, in addition with higher stand densities of the first two sites (Table ), results in inferior dimensions of annual growth rings inside the wood. The Table 5 mct LSD tests sites. Kind of wood Site Thickness (mm) hg.1 hg. hg.3 Ew and Lw PFRSM 1.90 **** MNC.13 **** PFC.5 **** PFDOVM.51 **** Error MS=1.9453; DF=3133.0; Significance level α=0.050; Dependent variables: Ew and Lw; Homogeneous group: Hg. PFRSM 3.81 **** MNC 4.7 **** Tw PFC 4.50 **** PFDOVM 5.0 **** Error MS=5.0847; DF=1540.0; Significance level α=0.050; Dependent variable: Tw; Homogeneous group: Hg. constant differentiated position of PFDOVM will fit to its statute of rainier site and to the one with the most reduced stand densities.

5 Proceeding of Wood Science and Engineering in the Third Millennium" - ICWSE 007. Brasov June 0 North radius points out superior thickness mean values than those of the south in about 9%. This happens if the two types of wood are considered in separate or not (Table 6). Table 7 shows that Ew is significantly different from Lw; this one is about 60% superior. An evaluation to 40-year-old trees shows that annual diameter growth mean rates present Table 6 - mct LSD tests senses. Type of wood Sense Thickness (mm) hg.1 hg. Ew e Lw values of 0.8 to 0.9cm/year in total height. This is why they can be considered good ones. This fact also denounces considerable volume growths. The trees presenting superior mean ages also display more reduced mean growth rates and lead us to foresee the unavoidable relenting with age. 3.. Wood volume estimation The selected results to all models fittings (Table 3), under and over-bark, are presented in Tables 8 and 9. The multiple R aj, the maximum expected errors (e*) and residual mean square (RMS), the mean absolute residual error (MAR), the mean squares (MS), the significant tests F, and the mean residual errors (BIAS) are also expressed. For any of the models high R aj were registered (93 to 97%). With higher R aj and significative coefficients of the independent variables, models 13 and 14 were pre-selected for vub, while and 13 models were for vob. The election of one of these models, for each of the dependent variables, selected the one that presented the smaller e*, RMS and MAR values, higher MS and F, and BIAS near zero. The elected model should also deserve an acceptable appreciation of its residuals distribution plot. This analysis lead to the selection of the non-linear model number 13, seeing that it is the one that better fulfils those criteria, both for vub and for vob. 4. CONCLUSIONS S.09 **** N.8 **** Error MS=1.9453; DF=3133.0; Significance level α=0.050; Dependent variables: Ew e Lw. S 4.19 **** Tw N 4.56 **** Error MS=5.0847; DF=1540.0; Significance level α=0.050; Dependent variable: Tw. Table 7 mct LSD tests - type of wood. Type of wood Lw Ew Thickness (mm) hg.1 hg ****.70 **** Error MS=1.9453; DF=3133.0; Significance level α=0.050; Dependent variable: Ew and Lw. From the two studied aspects for the 4 considered sites the evaluation of early and latewood thicknesses evolution and the construction of stand trees volume estimation models -, some conclusions may be pointed out: - The explanation degree of the two types of wood thicknesses variations is much reduced. - About 16% of growth rings thickness variation is due to the type of wood. The greater proportion is the one of earlywood. - The variation of total annual wood amount is explained by its original site, by the number of the considered ring and by its respective interaction. - With regard to total wood and to its annual fractions, the factor site is arranged into three homogenous groups, to which correspond three significative differences concerning mean ring thickness.

6 Proceeding of Wood Science and Engineering in the Third Millennium" - ICWSE 007. Brasov June 0 - It is on the North geratrix that the greater mean ring thickness is shown about 9% superior to the one of the South. - Earlywood thickness is about 61% greater than the one of latewood. - The mean diameter (0.8 to 0.9cm/year) and total high growth rates (0.65 to 0.76m/year) that are noted on the trees can be considered enough good and point out appreciable volume increments. Older trees present inferior mean growth rates and already indicate the growth slowing with age. Table 8 Statistical fittings of models for volumes (dm 3 ) under-bark (vub). Mod. Equation R aj. e* RMS MAR MS F BIAS vub= *d *h *mnc *PFRSM *PFDOVM vub= *d*h +0.6*d *MNC *PFRSM *PFDOVM vub= *d *h *1/ d *mnc *PFRSM *PFDOVM vub= *( d)*h *1/ d+9.484* d *MNC *PFRSM *PFDOVM vub= *h *d *1/ d *MNC *PFRSM+.55*PFDOVM vub= *d +6.15*h+0.039*d *h *MNC *PFRSM-4.088*PFDOVM vub= *d *d +0.58*d*h+0.031*d *h *MNC *PFRSM *PFDOVM 8 vub= *d *d *h+0.049*d*h *h *MNC *PFRSM- 1.85*PFDOVM vub=e ( *(ln(h))^+1.54*ln(d) *MNC+0.118*PFRSM *PFDOVM) 10 vub=e ( *h+1.557*ln(d)-0.004*MNC+0.107*PFRSM *PFDOVM) vub=e ( *(ln(h))^+0.*(ln(d))^ *MNC+0.116*PFRSM *PFDOVM) vub=e ( *h+0.6*ln(d))^+0.004*MNC+0.103*PFRSM *PFDOVM) vub=0.0466*d *h *0.988 MNC *1.16 PFRSM * 1.03 PFDOVM vub=d /( /h-0.116*MNC-0.76*PFRSM- 0.10*PFDOVM) vub=d *( *h *MNC+0.05* PFRSM+0.18*PFDOVM) vub=d h/( *d-0.567*mnc-5.486*pfrsm *PFDOVM) vub=0.88*d.7 *1.01 MNC *1.489 PFRSM *1.475 PFDOVM The non significative coefficients are presented in italic. - The reached algebraic expressions to estimate total volumes (vub and vob(dm 3 )) using overbark dbh (d(cm)) and total high (h(m)) followed the model v=β 1*d β *h β3. In both situations the estimated volumes to PFC, MNC and PFDOVM sites are very similar and nearly 13 or 14% inferior to those of PFRSM.

7 Proceeding of Wood Science and Engineering in the Third Millennium" - ICWSE 007. Brasov June 0 Table 9 Statistical fittings of models for volumes (dm 3 ) over-bark (vob). Mod. Equation R aj. e* RMS MAR MS F BIAS vob= *d *h *mnc *PFRSM+37.4*PFDOVM vob= *d*h +0.77*d *MNC *PFRSM-4.3*PFDOVM vob= *d *h-4.806*1/ d+1.4*mnc *PFRSM+4.96*PFDOVM vob= *( d)*h *1/ d+0.514*d *MNC+87.03*PFRSM+5.587*PFDOVM vob= *h *d *1/ d+.518*mnc *pfrsm *pfdovm vob= *d +6.59*h *d *h *MNC *PFRSM-9.311*PFDOVM vob= *d-0.013*d *d*h+0.041*d *h- 8.86*MNC+39.84*PFRSM-3.95*PFDOVM vob= *d *d *h *d*h *h -0.78*MNC *PFRSM *PFDOVM vob=e ( *(ln(h))^+1.533*ln(d)-0.014*MNC+0.133*PFRSM *PFDOVM) vob=e ( *h+1.548*ln(d) *MNC+0.136*PFRSM *PFDOVM) vob=e ( *(ln(h))^+0.1*(ln(d))^ *MNC+0.13*PFRSM *PFDOVM) vob=e ( *h+0.4*ln(d))^-0.001*MNC+0.136*PFRSM *PFDOVM) vob=0.0488*d *h *0.985 MNC *1.144 P1FRSM * PFDOVM vob=d /( /h-0.108*MNC-0.79*PFRSM *PFDOVM) vob=d *( *h *MNC+ 0.36*PFRSM+0.15*PFDOVM) vob=d h/( *d-0.479*mnc-5.584*pfrsm-.58*pfdovm) vob=0.308*d.5 *1.19 MNC *1.517 PFRSM *1.46 PFDOVM The non significative coefficients are presented in italic. - Models maximum expected errors of 155.dm 3 for vub and 168,6dm 3 for vob point out to estimated maximum errors of 11.4 and 11.6% respectively, corresponding to maximum tree mean volumes of 136(±31)dm 3 and 1459(±39)dm 3. LITERATURE EYNG, E. (006). Controle feedforward baseado em redes neurais aplicado a coluna de absorção do processo de produção de etanol. Dissertação de Mestrado para obtenção do título de Mestre em Engenharia Química pela Universidade de Campinas. FREIRE, J. TAVARES, M. CAMPOS, J. (003). Ritmos de Crescimento das Espécies Pinus pinaster, Acacia melanoxylon e Acacia dealbata nas Dunas do Litoral Norte e Centro. Silva Lusitana 11 (1): NICHOLAS, I., BROWN, I. (00). Blackwood: A handbook for growers and users. Forest research bulletin. Rotorua, New Zealand. No p.

8 Proceeding of Wood Science and Engineering in the Third Millennium" - ICWSE 007. Brasov June 0 P-CLIMA (1999). Software Provedor de Dados Climatológicos para Portugal. Versão 1.. Projecto ALTENER XVII/4.1013/Z/ (Ed.) R. Aguiar, INETI / DER, Lisboa. SANTOS, A., ANJOS, O., SIMÕES, R. (006). Papermaking potencial of Acacia dealbata and Acacia melanoxylon. Appita Journal, 59 (1). SANTOS, A., TEIXEIRA, A., ANJOS, O., SIMÕES, R., NUNES, L., MACHADO, J., TAVARES, M. Utilização potencial do lenho de Acacia melanoxylon a crescer em povoamentos puros ou mistos com Pinus pinaster pela Indústria Florestal Portuguesa. Accepted in S. Lusitana. SCHNEIDER, P., TONINI, H. (003). Utilização de variáveis dummy em equações de volume para Acacia mearnsii De Wild. [Versão electrónica]. Ciência Florestal, 13 (). Acedido em 14 de Julho de 006, em SOUSA, A. (1974). Tabelas de volume para Acacia melanoxylon na Ilha de S. Miguel (Açores). Circunscrição Florestal de Ponta Delgada,. TAVARES, M., CAMPOS, J., SAPORITI, J., DANIEL, C. (1999a) Formas de valorização do material lenhoso das Acacia deabata, A. melanoxylon e A. longifolia. 1º Encontro Sobre Invasoras Lenhosas. Sociedade Portuguesa de Ciências Florestais, Gerês. I: 157. TAVARES, M., CAETANO, F., FREIRE, J., SILVA, C., CAMPOS, J. (1999b). Dinâmica de crescimento das A. deabata, A. melanoxylon e A. longifolia em terrenos de pinhal das dunas litorais. 1º Encontro Sobre Invasoras Lenhosas. Sociedade Portuguesa de Ciências Florestais, Gerês. 1º Volume. pp. 89. VEIGA, R., CARVALHO, C., BRASIL, M. (000). Determinação de equações de volume para árvores de Acacia mangium Willd [Versão electrónica]. CERNE, 6 (1): Acedido em 0 de Novembro 005, em Contact addresses: Andreia Rucha* 1, António Santos*, José Campos*, Ofélia Anjos** 1 and Mário Tavares*** *Forest Engineer, ** Forest Engineer, PhD Professor, ***Forest Senior Researcher. 1 Escola Superior Agrária de Castelo Branco, Quinta da Senhora de Mércules, Castelo Branco, Portugal Estação Florestal Nacional, Quinta do Marquês, Oeiras, Portugal Corresponding author: Mário Tavares (mario.tavares@efn.com.pt)