Uporaba ultrazvoka za detekcijo notranjih anomalij v stoječih drevesih : magistrsko delo - (magistrski študij - 2. stopnja)

Krajnc, Luka (author), Kadunc, Aleš (mentor), Straže, Aleš (comentor)

V magistrski nalogi je preučena uporabnost ultrazvoka za zaznavanje notranjih anomalij v stoječih drevesih. V sestoju so bila z ultrazvokom izmerjena drevesa bukve in smreke ter popisane njihove zunanje značilnosti. Na licitaciji vrednejših sortimentov so bili z ultrazvokom izmerjeni sortimenti gorskega javorja z in brez rebraste teksture. Preizkušane so bile hitrosti prehoda v 7 smereh ter 2 ravninah. Oblikovanih je bilo 7 novih spremenljivk, izpeljanih iz frekvenčnega spektra, dobljenega s FFT. Prisotnost trohnobe v smreki in rdečega srca v bukvi statistično značilno vplivajo na hitrosti ultrazvoka in analizirane frekvenčne spremenljivke, v obeh primerih prisotnost anomalije zmanjša hitrost ultrazvoka. Verjetnost rdečega srca se povečuje s prsnim premerom in večvrhatostjo. Hitrosti ultrazvoka so neuporabne za napovedovanje rdečega srca v bukvi, vključitev frekvenčnih spremenljivk v binarno logistično regresijo izboljša pravilnost napovedovanja (iz 80 % na 81,8 %). Prisotnost poškodb oboda in zniževanje hitrosti v tangecialnih smereh zmanjša verjetnost prisotnosti trohnobe pri smreki, model pravilno uvrsti 88,5 % analiziranih dreves. Model smo izboljšali z vključitvijo frekvenčnih spremenljivk na 91,5 %. Postopek meritev v sestoju, ki smo ga pohitrili z izključitvijo hitrosti iz modela, pravilno uvršča 87,3 % analiziranih smrek. Med sortimenti gorskega javorja z in brez rebraste teksture so bile odkrite statistično značilne razlike v hitrosti ene izmed smeri in pri več frekvenčnih spremenljivkah.

• Language: Slovenian
• Keywords: ultrazvok, stoječa drevesa, trohnoba, rdeče srce, rebrasta tekstura, smreka, bukev, gorski javor
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [L. Krajnc]
• Year: 2015
• Number of pages: X f., 92 f., [5] f. pril.
• PID: 20.500.12556/RUL-125867
• UDC: 630*53:630*85(043.2)=163.6
• COBISS.SI-ID: 4171686
• Publication date in RUL: 08.04.2021

Secondary language

• Language: English
• Title: The use of ultrasound in standing trees to detect Inner anomalies : M. Sc. Thesis - (Master Study Programmes)

Abstract

In this master thesis the use of ultrasound on standing trees to detect inner anomalies has been studied. Standing trees of beech and Norway spruce were measured with ultrasound in forest stands, outer characteristics of trees were also recorded. Logs of sycamore maple with and without fiddleback figure were also measured using ultrasound. 7 measuring directions were tested in two planes. 7 new variables were created using frequency spectrum. Presence of rot in spruce and of red heart in beech significantly impact speed of sound and the frequency spectrum. Presence of anomalies lowered ultrasound velocity in both species. Probability of red heart presence increases with breast height diameter and number increased with tree forking. Speed of ultrasound is not usable in predicting presence of red heart in beech. Frequency spectrum variables contribute to predicting red heart presence, as model accuracy improves after including them from 80 % to 81,8 %. Presence of previously inflicted injuries and low speeds of sound in tangential plane increases probability of rot presence in spruce, the developed model accurately classifies 88,5 % cases. To speed up the measurement process speeds of ultrasound were excluded from the model, the new model is accurate in 87,3 % cases. Statistically significant differences were found in speed of sound in tangential wood direction and in some of the frequency spectrum variables between sycamore maples with or without fiddleback figure.

• Keywords: ultrasound, standing tree, rot, red heart, fiddleback figure, spruce, beech, sycamore