Vpliv napadov poljske zapredkarice (Cephalcia arvensis) na debelinsko priraščanje smreke (Picea abies)

Tratar, Kian Nai (author), Levanič, Tomislav (mentor)

Leta 2009 so v Prevaljah zabeležili napad poljske zapredkarice (Cephalcia arvensis Panzer). V diplomskem delu smo ugotavljali vpliv napada na debelinski prirastek navadne smreke (Picea abies (L.) Karst.) ter njen odziv na pretekle klimatske razmere. Odvzeli smo izvrtke iz 20 napadenih in 16 referenčnih dreves na pobočju Riflovega vrha pri Prevaljah na Koroškem. Izvrtke smo ustrezno obdelali in jih skenirali s sistemom ATRICS. Širine branik smo izmerili s programom CooRecorder. Na podlagi teh meritev smo v programu PAST5 izdelali kronologije dreves. Na izvrtkih napadenih dreves smo zabeležili vse spremembe v makroskopskih značilnostih lesa branik, ki so se pojavile v času izbruha poljske zapredkarice. Pridobili smo meteorološke podatke iz glavne meteorološke postaje Šmartno pri Slovenj Gradcu za obdobje 1957-2025. Na podlagi kronologij širin branik in podatkov o vremenu smo določili negativna značilna leta 2003, 2015 ter 2022. Rast v 2009 in 2010 ni bila pogojena s klimo, zato smo spremembe v debelinski rasti pripisali napadu zapredkarice. Na debelinski prirastek količina padavin vpliva bolj kot temperatura. Ugotovili smo slabše zdravstveno stanje in večjo utesnjenost napadenih smrek, kar bi bil lahko razlog za izbruh. Referenčne smreke za razliko od napadenih v letih 2009 in 2010 niso kazale zmanjšanja debelinskega prirastka. Povprečni debelinski prirastek napadenih smrek je za približno 40 % manjši od debelinskega prirastka referenčnih. Vpliv C. arvensis smo zaznali v 62,5 % napadenih dreves. Viden je v omejeni tvorbi kasnega lesa (45,7 % sprememb), v tvorbi smolnih kanalov (25,0 %) ter v ožjih branikah v letu po napadu (17,5 %). Znakov napada v in po letu 2011 nismo več zaznali.

• Language: Slovenian
• Keywords: Picea abies (L.) Karst., Cephalcia arvensis Panzer, dendrokronologija, navzkrižno datiranje, značilna leta
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [K. N. Tratar]
• Year: 2025
• PID: 20.500.12556/RUL-173825
• UDC: 630*52:630*45(043.2)=163.6
• COBISS.SI-ID: 250415619
• Publication date in RUL: 24.09.2025

Secondary language

• Language: English
• Title: Effect of the spruce web-spinning sawfly (Cephalcia arvensis) attacks on Norway spruce (Picea abies) growth

Abstract

An outbreak of the spruce web-spinning sawfly (Cephalcia arvensis Panzer) occured in Prevalje in 2009. In this thesis, we aimed to determine the effect of this attack on radial growth of norway spruce (Picea abies (L.) Karst.) and its response to climate in the past. We took samples from 20 defoliated trees and 16 control trees on the hillside of Riflov vrh near Prevalje in the Koroška region. The cores were appropriately processed and then scanned using the ATRICS system. We measured tree ring width using CooRecorder. These measurements were used as an input in creating the chronologies in PAST5. We marked any macroscopic changes in the defoliated trees’ rings, that occured in the years of the spruce web-spinning sawfly outbreak. We gathered meteorological information from the Šmartno pri Slovenj Gradcu main station for the 1957-2025 period. Based on this data and the created chronologies, we concluded, that 2003, 2015 and 2022 were negative pointer years. Because radial growth in 2009 and 2010 wasn’t conditioned by climate, we assigned the changes in wood anatomy to the sawfly attack. Precipitation affected radial growth more significantly than temperature. The defoliated trees had lower vitality and their canopies were more cramped, which could have been the cause of the outbreak. Unlike the defoliated ones, the control spruces showed no sign of reduced radial growth in 2009 and 2010. On average, the radial growth of defoliated trees was about 40 % lower than that of control trees. The effect of the attack was detected in 62,5 % of the defoliated trees. Most common signs were obstructed latewood growth (45,7 % of the changes), resin canal formation (25,0 %) and lower tree ring width in the year following the attack (17,5 %). Signs of the attack in 2011 and onward were no longer visible.

• Keywords: Picea abies (L.) Karst., Cephalcia arvensis Panzer, dendrochronology, crossdating, pointer years