How Wood Quality Can Be Shaped: Results of 70 Years of Experience

Abstract

This experiment was conducted in the pine woods of central Europe at a research area established in 1951. The experimental area of 1.35 ha was set up in a 14-year-old pine tree stand, which was divided into lots, and the pruning procedure took place in different variants. Some lots constituted control lots without pruned trees. The trees were pruned in four variants, reducing the living tree crown by 1/4, 1/3, 1/2, and 2/3 of its length. The study’s main aim was to determine the influence of pruning forest trees on the tree tissue. Moreover, the study attempted to answer whether pruning was a significant procedure for wood valorisation, and if yes, then which variant was the optimal one for Scots pine growing on the European plain. The results indicated a significant impact of pruning young pine tree stands on the properties of wood tissue, which differed regarding the adopted pruning variant. Significant differences in the width of annual rings, the size of the particular areas of the annual rings (latewood or earlywood), and the wood density depending on the pruning variant were observed. Furthermore, the results indicated that pruning induced numerous processes, which optimised the physiological and mechanical functions of the tree trunks. The outcome of this optimisation was, among others, the diversification of the vascular and strengthening area of the annual ring as well as the wood density, which was a reaction to reducing a part of the assimilation apparatus. From the technical wood value viewpoint, the optimal pruning variant for pine was between 1/3 to 1/2 of the living crown.

Measuring the Canopy Architecture of Young Vegetation Using the Fastrak Polhemus 3D Digitizer

“…In suppressed trees, the ratio of height increments to branch increments was around 1 [ 66 ]. It should be added that branching is not very desirable in forestry [ 67 , 68 , 69 , 70 , 71 ]. The latter conclusion implies that in the case of shelterwood management, the regeneration of Scots pine can only be sufficiently rapid, and the quality of the individuals can only be ensured when the stand is considerably thinned.…”

Developing a Model for Curve-Fitting a Tree Stem’s Cross-Sectional Shape and Sapwood–Heartwood Transition in a Polar Diagram System Using Nonlinear Regression

“…All raw data points' polar coordinates (r i , θ i ) were tabulated on a spreadsheet. Statsoft Statistica 12, a nonlinear estimation of advanced linear/nonlinear models, was employed to estimate the (a, b, r o , θ o , and k) parameters in Equations ( 8), ( 16), ( 17) and (24); the loss function is the least square, and the iteration method is Levenberg-Marquardt. We chose the 10 −10 maximum convergence criteria, 10,000 maximum iterations, and varied starting values.…”

“…Dendrochronology reads annual tree-ring variations to analyze a tree's archaeological and historical structures for reconstructing past climates and significantly contributes to environmental science development [22]. Tree-ring chronologies, which may contain dimensional variations and circular shape deviations, provide high-frequency signals [23] that record a tree's responses to the silvicultural system [24,25] and its habitat's environmental condition history (i.e., climate [26][27][28][29][30][31][32][33][34], pollutants [35,36], and water-heat stress [37]) during its growing periods yielding the xylem.…”

“…The best fit estimated parameters of the sapwood (a) and heartwood (b) periphery curve-fit based on the rotated superellipse model in Equation(24).…”

“…The analysis of variance of the outer log circumference (a) and the sapwood-heartwood transition (b) curve-fit based on the rotated superellipse model in Equation(24).…”