Presence Of Heartwood Research Articles

Heartwood formation and its relationship with basic density and green moisture content of young small-leaf mahogany trees

Swietenia mahogani (L.) Jacq. is one of Indonesia’s commercially valuable timbers. We investigated the time or age at which heartwood formation begins, and observed and determined whether the occurrence of heartwood formation was affected by age or diameter. The presence of heartwood from the bottom to the top (at various axial positions) of the stem was observed, and the basic density (BD) and green moisture content (GMC) were measured. The area of heartwood and sapwood was determined based on the colour differences in the cross-section. The results showed that the formation of the heartwood begins when the tree is four years old. In the axial position, the heartwood can be found in up to 65% of the tree height. The analysis of variance (ANOVA) test showed that heartwood proportion was determined more by diameter than by age. Therefore this can be a consideration for tree breeding programmes to select trees with larger diameters. Harvesting of young, fast-growing mahogany trees with large diameters from tree breeding can be expected to produce wood with good beauty and durability. Furthermore, BD in the heartwood was lower than in the sapwood, although there was a positive correlation between the proportion of heartwood and BD.

The Methods for Measuring the Area of Heartwood and Sapwood

The presence of heartwood is one of the most important parameters in economic value that can affect the final use of wood. For construction materials, the presence of a large heartwood is very necessary, considering this will have a positive effect on the basic properties of the wood. Meanwhile, its heartwood proportion has a negative impact on the quality of pulp and paper. Therefore, this study aims to review the methods of calculating the area of the heartwood by using suitable heartwood measurement methods for better stand management and selection of raw materials in the industry. The results of the review showed that non-destructive methods were developed to measure the area of heartwood-sapwood such as computer tomography (CT-image), electrical resistivity tomography (ERT), x-ray densitometry, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and near-infrared spectroscopy (NIRS), so far. This is different from the destructive methods that are commonly used for visual inspection of wood color and anatomical features. During the selection of methods, the factors to be considered include cost, time, tree damage, number of samples, and efficiency in applying the methods. The visual inspection is the best option for determining the area of heartwood and sapwood. But, when the heartwood and sapwood boundaries color is unclear, chemical indicators can be performed. In addition, the ERT method can be the second alternative for tropics species. Furthermore, the method used in a study of the presence of heartwood depends on the five limiting factors mentioned previously.

Deciduous oak/chestnut: Differential shrinkage of wood during charcoalification? Preliminary experimental results and implications for wood diameter study in anthracology

Recent methodological developments in dendro-anthracology offer many new techniques to address the historical practices associated with the exploitation of wood as a fuel and to better understand the reciprocal interests of forest landscapes and societies. The study of wood diameter in dendro-anthracology involves three fundamental stages: i) to measure the position of charcoal pieces in relation to the heart of the wood, known as charcoal-pith distance ii) to correct the data, taking into account the error associated with using measurement as a tool and wood shrinkage, iii) to interpret the data in terms of original diameters exploited. Each of these steps has been, and continues to be, the basis of numerous research projects, notably by using experimental approaches in order to perfect the pith estimation tools (used to measure the distance between the charcoal fragment and the centre of the stem, refine experimental techniques and improve methodologies. This article is focused on estimating suitable correction factors related to wood shrinkage. Although this phenomenonis very well understood for a great number of species as regards the drying process, it remains more difficult to quantify a precise correction factor for shrinkage during the wood burning process. The experimental approach presented in this study involves a comparative analysis of wood shrinkage in oak and chestnut in charring conditions close to those observed in a charcoal-making context (charring in a low-oxygen environment, at temperatures between 400 °C and 600 °C). The charring of wood sections in a muffle furnace clearly shows an increase in the difference in radial shrinkage between dried and charcoalified wood. During drying, shrinkage in oak is only 2% greater than in chestnut. By contrast, the difference in shrinkage between the two taxa is 7% after charring. In addition, these experiments highlight the significant influences of temperature and of the presence of heartwood on the extent of wood shrinkage that occurs when wood is burned. The results of this study provide a better understanding of the phenomenon of shrinkage and also enable correction factors for these two taxa, more suitable for application in an archaeological context, to be proposed.

Evaluation of chemical compositions, air-dry, preservation and workability of eight fastgrowing plantation species in Costa Rica

Costa Rica has successfully planted various forestry species for wood production. However, the use of their wood is limited, due to poor knowledge about their chemical properties, air-dry, preserved and workability performance. The present study details information of these properties for the species: Alnus acuminata (Aa), Acacia mangium (Am), Bombacopsis quinata (Bq), Cupressus lusitanica (Cl), Swietenia macrophylla (Sm), Terminalia amazonia (Ta), Terminalia oblonga (To) and Vochysia guatemalensis (Vg). Among the results obtained, it was found that the wood of these species is in general slightly acidic, except Bq, which presented tendency to be basic. Different species show considerable variability in the content of holocellulose, lignin and extractable micronutrients. Regarding micronutrients, and in relation to other species it was found a high percentage in Vg. The use of boron as a preservative, may be applied in the 8 plantation species. The presence of heartwood in some species made it not possible to be preserved by the vacuum-pressure method, but the sapwood was possible to preserve in all species. The drying rate increased with increasing board thickness and drying time was different among species. The fastest drying rate was found in Ta and Am, followed by Sm, To, Aa and Cl with intermediate values and Vg with the slowest air-drying rate. Am, Bq, Cl, Sm and To present from excellent to good planing, sanding , drilling and molding, but Ta, Bq, Aa and Vg, especially Aa and Vg, in the workability operations were catalogued as poor or very poor quality.Evaluación de la composición química, secado al aire, preservación y trabajabilidad de ocho especies de rápido crecimiento en plantación de Costa RicaEn Costa Rica se han plantado con éxito varias especies forestales para la producción de madera. No obstante, el uso de la madera es limitado debido al poco conocimiento acerca de sus propiedades químicas, secado al aire, preservado y trabajabilidad. En el presente estudio se detalla información de esas propiedades para las especies: Alnus acuminata (Aa), Acacia mangium (Am), Bombacopsis quinata (Bq), Cupressus lusitanica (Cl), Swietenia macrophylla (Sm), Terminalia amazonia (Ta), Terminalia oblonga (To) and Vochysia guatemalensis (Vg). Dentro de los resultados obtenidos, se encontró que la madera presenta un pH ligeramente ácido, a excepción de Bq, con tendencia a ser básica. Las diferentes especies muestran una considerable variabilidad en el contenido de holocelulosa, lignina, extraíbles y micronutrientes; con respecto a los micronutrientes, y en relación con las otras especies se encontró un alto porcentaje en Vg. El uso de boro como preservador, puede ser aplicado en las 8 especies de plantación. Las especies con presencia de duramen no fue posible preservarlas con el método vacío-presión; sin embargo, la albura sí es posible de preservar en todas las especies. El tiempo de secado incrementa con el incremento de espesor de la tabla y presenta variación entre especies. El menor tiempo de secado se encontró para Ta y Am, seguido por Sm, To, Aa y Cl, con valores intermedios y Vg con el secado al aire más lento. Am, Bq, Cl, Sm y To presentan de excelentes a buenas propiedades de cepillado, lijado, taladrado y moldurado, pero el resto de las especies (Ta, Bq, Aa and Vg), en especial para Aa y Vg, en las operaciones de trabajabilidad son catalogadas como de mala o muy pobre calidad.

Circumferential variation of heartwood and stem quality in maritime pine stems

Maritime pine (Pinus pinaster Ait.) is an important timber and pulpwood species covering about 4 million ha in Portugal, Spain and France. This work studied the cross-sectional distribution of heartwood and sapwood along the stem using 3D modelling on 20 trees. The target was to assess the potential of this species for the industrial production of heartwood sawn products. The maritime pine stems were characterized by wide sapwood of 10 cm, in average, and the presence of heartwood at all height levels with constant diameter up to 35 % tree height, decreasing afterwards. In the radial section, the heartwood follows a circumferential-like shape which changes along the stem. Pith eccentricity index values were low and homogeneous regarding to stem and higher for heartwood. Heartwood cross-sectional shape was constant up to 45 % of total height of the tree and more elongated upwards. The constant heartwood diameter, low taper and pith eccentricity index, and an approximate circular shape up to 10 m height indicated these species’ potential to produce solid wood products made out of heartwood.

Influence of blue stain on density and dimensional stability of Pinus radiata timber from northern Galicia (Spain)

Abstract The presence of blue-stain fungi considerably decreases the value of Pinus radiata timber, which is commercially important in Galicia (NW Spain). For this study, seven young pine trees growing in four different plantations were felled, and 20 discs were sampled from different heights in the stems. Parts of the discs were discoloured as a result of fungal infection. The discs were cut into small specimens. Defect-free specimens (controls) were selected for determining density and dimensional stability both in the volume and in the axial direction. Physical properties of fully blue-stained specimens and the controls were compared for each disc based on one-factor analysis of variance. As the factor was blue-stain, the other sources of variation were suppressed, such as tree source, height in the stem, ring width, cambial age and presence of heartwood or sapwood. Most of the physical properties analysed on some sample discs differed significantly between discoloured and unstained wood. The variables most affected by blue stain were basic density and volumetric shrinkage: blue-stained wood was 1.1% lighter and volumetric shrinkage was 5% higher in blue-stained wood than in the controls.

Resistance of Selected Wood-Based Materials to Fungal and Termite Attack in Non–Soil Contact Exposures

The resistance of three naturally durable heartwood species and a stranded giant bamboo product to fungal and termite (Coptotermes formosanus) attack was evaluated at a test site located near Hilo, Hawaii. Merbau (Intsia bijuga or I. palembanica) and ipe (Tabebuia spp.) were both exceptionally resistant to fungal and termite attack, while western juniper (Juniperus occidentalis) heartwood was slightly less resistant to degradation. The presence of heartwood on western juniper samples had no noticeable effect on the performance of adjacent sapwood. The bamboo decking proved to the least durable of the materials and experienced substantial termite and fungal attack over the 32-month test period.

Spread of Heterobasidion annosum s.s. and Heterobasidion parviporum in Picea abies 15 years after stump inoculation

The tree pathogenic fungi Heterobasidion annosum s.s. and Heterobasidion parviporum cause root and butt rot in Norway spruce (Picea abies) and produce serious economic losses to the forest sector in Europe. We experimentally studied inter- and intraspecific differences between H. parviporum and H. annosum s.s. in the way they infect stumps and spread into neighbouring trees. Eleven H. parviporum and nine H. annosum s.s. isolates were artificially inoculated on stumps of two spruce stands after first thinning. After 15 years, the same isolates were reisolated from neighbouring trees. Heterobasidion parviporum spread more frequently from the inoculated stumps to the neighbouring trees than H. annosum s.s. The surroundings of H. annosum s.s. stumps that did not spread were often colonized by H. parviporum. Heterobasidion annosum s.s. spread was restricted mainly to the areas of the plot where no other Heterobasidion genotypes had been inoculated. In such cases, H. annosum s.s. tended to develop into bigger genets than H. parviporum. The probability of stump-to-tree spread of H. parviporum depended on the diameter of the stumps, suggesting that H. parviporum spread may relate to the presence of heartwood. Both H. parviporum and H. annosum s.s. proved to be strong pathogens on Norway spruce; however, when competing for the same trees, H. parviporum seemed capable of excluding H. annosum s.s. from the stand.

Modeling of sapwood and heartwood delignification kinetics of Eucalyptus globulus using consecutive and simultaneous approaches

Eucalyptus globulus sapwood and heartwood were delignified at 130°, 150°, or 170°C by kraft pulping. Pulp yields of heartwood were lower than those of sapwood (46.5% vs. 50.4% at 170°C). Delignification was modeled using consecutive and simultaneous kinetic models. The modeling was similar for heartwood and sapwood, and either approach could be used, with both yielding good correlations between experimental and model data. The consecutive model identified two delignification phases with similar reaction rates and activation energies for heartwood and sapwood at 150° and 170°C. At 130°C only one phase was identified. Three reactive types of lignin fractions were identified using the simultaneous model, without differences between heartwood and sapwood. Their reaction rates were 0.152, 0.138, and 0.003 min−1 at 170°C, and the activation energies were 132, 119, and 102 kJ.mol−1. The presence of heartwood did not influence the kinetic development of delignification. The negative impact of heartwood in pulping is related to the higher content of extractives (9.8% vs. 3.9% in heartwood and sapwood) and to their influence on the process, namely in the heating-totemperature phase when a substantial mass loss occurs (30% vs. 20% for heartwood and sapwood).

The influence of heartwood on the pulping properties of Acacia melanoxylon wood

The pulping wood quality of Acacia melanoxylon was evaluated in relation to the presence of heartwood. The sapwood and heartwood from 20 trees from four sites in Portugal were evaluated separately at 5% stem height level in terms of chemical composition and kraft pulping aptitude. Heartwood had more extractives than sapwood ranging from 7.4% to 9.5% and from 4.0% to 4.2%, respectively, and with a heartwood-to-sapwood ratio for extractives ranging from 1.9 to 2.3. The major component of heartwood extractives was made up of ethanol-soluble compounds (70% of total extractives). Lignin content was similar in sapwood and heartwood (21.5% and 20.7%, respectively) as well as the sugar composition. Site did not influence the chemical composition. Pulping heartwood differed from sapwood in chemical and optical terms: lower values of pulp yield (53% vs 56% respectively), higher kappa number (11 vs. 7), and lower brightness (28% vs 49%). Acacia melanoxylon wood showed an overall good pulping aptitude, but the presence of heartwood should be taken into account because it decreases the raw-material quality for pulping. Heartwood content should therefore be considered as a quality variable when using A. melanoxylon wood in pulp industries

The influence of irrigation and fertilization on heartwood and sapwood contents in 18-year-old Eucalyptus globulus trees

The quality of wood from 18-year-old Tasmanian bluegum (Eucalyptus globulus Labill.) trees was assessed in relation to heartwood content, accumulation of extractives, and pulp yield using two growth conditions: control (C) and growth optimized by irrigation and fertilization in the first 6 years of growth (IL). Within the tree, heartwood content decreased from the base upwards, representing, on average, 77.7% and 67.6% at the base and 7.0% and 4.8% at 29.3 m height for IL and C trees, respectively. Heartwood volume represented 65.6% and 55.6% of total tree volume for IL and C trees, respectively. Heartwood content was positively correlated with tree growth, while sapwood content remained rather constant, with a radial width of approximately 2 cm. Heartwood contained more extractives than sapwood (5.3% vs. 4.0%) and pulp yield was lower from heartwood than from sapwood (58.0% vs. 56.0%). Pulp yield was negatively correlated with content of extractives. No difference in extractives or pulp yield was found between IL and C trees. The presence of heartwood decreases the quality of raw material for pulping and should be regarded as a stem-quality variable in eucalypt forestry.

Pulping Yield and Delignification Kinetics of Heartwood and Sapwood of Maritime Pine

In maritime pine (Pinus pinaster Ait.), heartwood represents a substantial part of the tree stem at final harvest age (80 years) corresponding to 42% at the base of the stem wood diameter and decreasing upward. The rate of heartwood formation was estimated at 0.35 rings/year, beginning at 18 years of age. Differences in the chemical composition between heartwood and sapwood were mainly in the extractives, 19.7% and 5.8%, respectively. The lignin content was 23.1% and 24.5% in the heartwood and sapwood, respectively. Pulping yield of the heartwood was lower than that of the sapwood (40.0% vs. 49.7%) and was negatively correlated with the extractives content. Extraction of heartwood prior to pulping increased the pulp yield and the delignification (lower residual lignin in pulps). Pulping kinetics showed lower yields for heartwood at all pulping stages, the difference occurring especially in the initial reaction phase. However, delignification rate constants were similar for heartwood and sapwood (3.1×10−2 min−1 and 2.7×10−2 min−1 for the main delignification phase for sapwood and heartwood, respectively), with a lower activation energy for sapwood (68.3 vs. 90.0 kJ · mol−1). The presence of heartwood decreases the raw‐material quality for pulping and this should be taken into account when harvesting trees for pulping processes.

Influence of structural parameters on the nondestructive evaluation of ash timber (Fraxinus excelsior L.)

The aim of this project is to analyse the influence of wood structure of ash timber products — as a result from different growth rates — on their performance, if nondestructive evaluation is applied. To do this, 261 beams have been tested with the method of natural frequency on flexural vibration. The following anatomical and structural parameters have been documented as independent variables on all tested beams: annual ring width, proportion of latewood, ring position, grain orientation, presence or absence of heartwood and other discolourations as well as the positions and dimensions of knots. The values obtained from the nondestructive evaluation have been put into relation with the MOR obtained through final destructive 4-point-bending test of all beams. The influence of the wood structure on this relationship has been analysed either with univariate regressions between single structural parameters and MOR, or including more than one of these structural parameters in multivariate regression models. The regressions between nondestructive parameters and MOR present lower levels of determination than the usual determination levels reported for softwood timber. For the ringporous species ash the influence of the wood structure could be more significant than for the more homogeneous wood structure of coniferous species and, consequently, should be analysed in detail. The main results of this analysis show only minimal influence of the ring structure and of the grain angle on the relationship between nondestructive values and MOR. The presence of heartwood does not influence this relationship. By far the most important parameter is the presence or absence of knots. Different knot parameters were measured and included into the models: KAR and vectorial models of position and dimension of the knots. This detailed measurement of the knots and its inclusion into multiple regression models allow a significant increase of the total level of determination and consequently an improved nondestructive quality assessment of ash timber products. Consequences for the practical application of the results in industrial sawmilling are considered.