Using deciduous branch wood and conifer spindle wood to manufacture panels with transverse structure

Abstract

The increasing demand on the wood market makes it necessary to use all secondary resources, including the wood branches and spindles. The properties of deciduous branches and softwood spindles were evaluated in order to create wood panels, highlighting the transverse texture with high value added. The research analyzed the properties of the wood from deciduous (beech, maple) branches and from conifer (spruce, fir) spindles. The methodology of obtaining panels with transversal structure was also presented. The production of minor wood (branches or spindles) was 254 m3/ha/year in the case of beech (branches) and 109 m3/ha/year in the case of spruce (spindles). The proportion of compression wood for spruce had an average value of 40.6%. A similar value of tension wood for beech was obtained. The modulus of elasticity for pine spindle wood was 71.7% lower than the modulus of elasticity for bending strength in the trunk. The quality index was 36.7% lower in the case of spindles than in the case of pine trunk, and the value of the quality ratio in branch maple wood was 2.61% lower than in trunk wood. Thus, even if it is not the only efficient solution, wood in the minor portions can be used to make high value-added panels such as those that highlight the transverse structure.

Cutting with Circular Saw of Traversal-Structured Panels Obtained from Spruce (Picea abies L.) Branches

“…The working hypothesis from which this research started were multiple. First of all, it started from the hypothesis that the transverse structure of the wood offers a more pleasant image to the finished product [9], and the combination of several transverse structures of the wood complemented and intensified the general image of the finished product [8,9]. Also, a second research hypothesis was related to spruce branches, which are processed similarly to any other piece of softwood timber [10], and the gluing of dry slats is acceptable from the point of view of gluing resistance and deformation of obtained panels [4].…”

“…Otherwise, the processing of these types of panels will be carried out with scraps of chips and fibers, reducing the quality of the processed surfaces. The second problem is that of the compression wood [8,9,[13][14][15]] that was at the exit end of the circular blade from the panel, which increased the chipping power and created chippings. Therefore, it is recommended to watch the panel carefully in order to identify the compression wood [14], in order to insert it with this end into the circular disc or to reduce the advance speed when compression wood is encountered, in order to reduce the cutting power and obtain a clean surface, without the plucking of chips and fibers.…”

“…From a microscopic point of view, the diameter of the cell, the thickness of the cell wall and the diameter of the lumen of the axial tracheid of Scots pine [8] are much smaller in the branches than in the trunk. Also, the density and other chemical and mechanical characteristics of pine are different from those of spruce, which make pine much more difficult to be processed than spruce.…”

“…[3][4][5]. A more efficient use of branches is that in the industry of agglomerated composite boards such as boards made of wood chips, as raw material, from which chips superior in quality to other types of lignocellulosic resources are obtained [4,[6][7][8][9]. That is why branches are considered a basic raw material in the chipboard, wood paper and fiber industry, with timber [10,11] having the percentage of participation in a raw material recipe/consumption of over 50%.…”

“…The compression wood from the spruce branches is less homogeneous, has areas with different densities within it and swells and contracts differently [30][31][32]. That is why, when forming the prisms from the spruce branches, it is recommended to use the prism with Forests 2024, 15, 685 2 of 21 compression wood on the same panel [8,9], in order to obtain stable panel structures. The panel structures made of branches can have sides with the longitudinal texture of the wood, or with the highlighting of the transverse texture of the wood [9].…”