| Popis: |
V začetku februarja 1999 je sneg poškodoval veliko dreves v Mestni občini Ljubljana. Od 624 dreves, zajetih v naši raziskavi, je bilo kar 195 (31 %) poškodovanih zaradi snega. V povprečju smo zabeležili 1,7 odloma na drevo. Poškodovanih je bilo 17 drevesnih vrst. Najpogosteje zastopane so bile Aesculus hippocastanum L., Betula pendula ROTH. in Salix x sepulcralis SIMONK.Razkroj lesa je bil najpogostejša napaka na mestu odloma. Praviloma se je pojavljal v kombinaciji z vraslo skorjo in bližnjo mehansko poškodbo. Na mestu odloma je bil razkroj zabeležen pri 87 % vej in vrhov premera nad 20 cm.Raziskava je pokazala, da neugodne rastne posebnosti drevesa ter razkrojni procesi v lesu odločilneje vplivajo na lomljenje vej kot sama drevesna vrsta. Odlomljeni deli polovice v snegolomu poškodovanih dreves so ovirali promet alipa povzročili materialno škodo. Z opravljanjem rednega nadzora varnostnega stanja dreves bi bilo mogoče pravočasno odkriti in odstraniti potencialno nevarna drevesa ali njihove dele. Raziskava kaže na nujno uvedbo sistemskega varnostnega nadzora in nege urbanega drevja v Ljubljani. As a result of heavy snow in February 1999, trees were damaged in the City of Ljubljana, Slovenia. Of the investigated 624 trees, 195 (31%) were damaged by snow. On average, 1.7 branch and top per tree were broken. Snow damaged 17 tree species, affecting particularly Aesculus hippocastanum L. and, to a lesser extent, Betula pendula ROTH. and Salix x sepulcralis SIMONK. Decay was the most frequent defect at the failure location and was often associated withincluded bark and vicinity of old mechanical wounds. 87% of broken branches and tops with diameter exceeding 20 cm were decayed at failure location. The research showed that failures were associated rather with structural growth defects and wood decay than with tree species. Broken parts of half of all damaged trees impeded the traffic or caused material damages. Regular control of the trees' safety stage would enable early identification and removal of potentially hazardous trees and their parts. The research demonstrates a necessity for a systematic tree control and proper urban tree care in the City of Ljubljana. |
