# Prediction Model of Wooden Logs Cutting Patterns and Its Efficiency in Practice
## 2 Materials and Methods  
In order to compare the calculated values of the proportion of products produced by sawing the logs with the actual values obtained by implementing a cutting pattern for a specific log, a test set of 9 logs (Figure 1) (3 pieces of spruce, 3 pieces of beech, 3 pieces of oak) was chosen. The logs had to meet the following parameters: a length of 4 to 4.2 m, a diameter of the thicker end of 35 cm to 45 cm and a saw log quality of class III.B. For spruce, this class is characterized as logs of a healthy raw timber of standard quality with several qualitative features, at an overall average quality. Sound knots up to 6 cm in diameter are allowed. Ring shakes up to 1/8 of the end diameter, heart shakes up to 1/4 of the end diameter and frost cracks are not allowed. Sweep is allowed up to 2 cm/m. Taper is allowed up to 2 cm/m. Stain is allowed as the core staining up to 1/3 of the end area. Rot is not allowed. The bark may be damaged mechanically. Defects caused by insects are allowed to a maximum depth of 3 mm. The log dimensions are at least 2 m.  
In the case of beech, this class is characterized as logs of a healthy raw timber of standard quality with qualitative features, at an overall average quality. Sound knots are allowed in 2 pieces per running meter up to a knot diameter of 10 cm. Decayed knots are not allowed. Ring shakes are not allowed, heart shakes are allowed up to 1/2 of the end diameter and a frost crack is allowed without signs of rot. Simple sweep is allowed up to 4 cm/m for logs shorter than 6 m. Stain is allowed up to 1/3 of the end diameter, and rot is not allowed. Defects caused by insects can be on the surface to a depth of 3 mm. In the case of oak, this class is characterized as logs of a healthy raw timber of standard quality with qualitative features, at an overall average quality. Sound knots are allowed in 2 pieces per running meter up to a diameter of 10 cm. Decayed knots are allowed in 1 piece up to 6 cm diameter. Ring shakes are allowed up to 1/4 of the end diameter, heart shakes are allowed up to 1/3 of the end diameter and a frost crack is allowed without signs of rot. Simple sweep is allowed up to 4 cm/m for logs shorter than 6 m. Heartwood color stain is not allowed, the sap stain is allowed to its thickness and rot is not allowed. Defects caused by insects can be on the surface to a depth of 3 mm, in the case of deep insect attacks, up to 10 bores per running meter are allowed. Subsequently, the dimensional characteristics of the selected log were measured in accordance with ISO 13059: 2011(en) Round timber--Requirements for the measurement of the dimensions and methods for the determination of the volume. Table 1 shows the measured parameters of the logs tested. \begin{table}
\begin{tabular}{c c c c c c} \hline \multirow{2}{*}{**Tree Species**} & \multirow{2}{*}{**Markings**} & **Diameter of** & **Diameter of** & **Diameter of the** & **Total Length** \\  & & **Thicker End** & **the Centre** & **Thinner End** & **(mm)** \\  & & **(mm)** & **(mm)** & **(mm)** & **(mm)** \\ \hline Spruce & 1.1 & 440 & 410 & 410 & 4080 \\ Spruce & 1.2 & 365 & 360 & 335 & 4090 \\ Spruce & 1.3 & 380 & 340 & 350 & 4110 \\ Beech & 2.1 & 375 & 350 & 350 & 4110 \\ Beech & 2.2 & 440 & 430 & 420 & 4120 \\ Beech & 2.3 & 395 & 390 & 380 & 4080 \\ Oak & 3.1 & 430 & 415 & 410 & 4110 \\ Oak & 3.2 & 380 & 370 & 360 & 4055 \\ Oak & 3.3 & 415 & 400 & 400 & 4060 \\ \hline \end{tabular}
\end{table} 
Table 1: Parameters of logs tested. Figure 1: Logs tested. The selected log was cut with a MEBOR 1000 HTZ horizontal band saw. The log was laid with its thinner end to the saw band on the working track, where it was hydraulically attached with fixation tips. At the head of the thinner end, the proposed cutting pattern was transferred. The MEBOR 1000 HTZ horizontal band saw is a semi-automatic type, with hydraulic log rotation, automatic greasing and saw blade tensioning and integrated sawdust suction into the hopper as well. Sawn timber thicknesses are entered into the sawing program.