Keywords: beech, live crown ratio, slenderness coefficient, stand stability. Ključne reči: bukva, relativna dužina žive krune, koefiicijent vitkosti, stabilnost application/pdf 652861 bytes http://creativecommons.org/licenses/by/4.0/legalcode https://unilib.phaidrabg.rs/o:8901 doi:10.5937/SustFor2592071R ISSN: 1821-1046 Sustainable Forestry startpage: 71 endpage: 83 2025 Abstract: This study investigates the applicability of the live crown ratio (LCR) and the slenderness coefficient (SC) as indicators of tree and stand stability of European beech (Fagus sylvatica L.). The research was conducted within the Forest Management Unit (FMU) "Lomnička Reka", managed by the Public Enterprise "Srbijašume". Data were obtained from the stand inventory of the analyzed FMU, conducted on a network of permanent sample plots. The analysis focused on five structurally uneven-aged stands, encompassing 103 beech trees belonging to the middle-aged silvicultural group across eight sample plots. For each measured tree, both the live crown ratio and the slenderness coefficient were determined. Logistic regression and Conditional Inference Tree (CIT) analyses were used to identify critical LCR thresholds distinguishing slender from nonslender trees, with bootstrap procedures employed to assess the stability of the results. The findings revealed a significant negative relationship between LCR and SC (p < 0.001), with a critical LCR threshold of approximately 0.36–0.40 identified as necessary to maintain tree stability. Both statistical approaches yielded consistent results, supporting the robustness of LCR as a reliable predictor of slenderness. The obtained results emphasize the importance of analyzing these parameters during the process of planning silvicultural measures, particularly thinning, aiming to enhance tree stability, and improve the overall resilience of beech stands. Sažetak: Ova studija istražuje primenljivost relativne dužine žive krune (LCR) i koeficijenta vitkosti (SC) kao pokazatelja stabilnosti stabala i sastojina evropske bukve (Fagus sylvatica L.). Istraživanje je sprovedeno u okviru gazdinske jedinice (FMU) „Lomnička Reka“, kojom upravlja Javno preduzeće „Srbijašume“. Podaci korišćeni u ovoj studiji dobijeni su iz sastojinske inventure analizirane gazdinske jedinice, sprovedene na mreži permanentnih primernih površina. Analiza je obuhvatila pet sastojina, strukturno raznodobnih, sa ukupno 103 stabla bukve na 8 primernih površina koje pripadaju srednjedobnoj uzgojnoj grupi. Za svako izmereno stablo određeni su relativna dužina žive krune i koeficijent vitkosti. Za identifikaciju kritičnih vrednosti LCR koje razdvajaju vitka od nevitkih stabala korišćene su logistička regresija i analiza uslovnog stabla zaključivanja (CIT), dok su bootstrap postupci primenjeni za procenu stabilnosti dobijenih rezultata. Rezultati ukazuju na značajnu negativnu vezu između LCR i SC (p < 0.001), pri čemu je utvrđen kritični prag LCR od približno 0.36–0.40 kao neophodan za održavanje stabilnosti stabala. Obe statističke metode dale su konzistentne rezultate, potvrđujući pouzdanost LCR kao prediktora vitkosti. Dobijeni rezultati ukazuju na potrebu da se ovi parametri analiziraju u postupku planiranja uzgojnih mera, posebno proreda, sa ciljem povećanja stabilnosti stabala i poboljšanja ukupne otpornosti sastojina bukve. Račić, Miloš Kanjevac, Branko Račić, Ivana Ljubičić, Janko Dobrosavljević, Jovan Martać, Nikola Petrović, Nenad eng Live crown ratio and slenderness coefficient as indicators of beech tree stability Institut za šuamrstvo info:eu-repo/semantics/article