Natural regeneration after 2014 ice storm - a stand in Rožnik

Objekt na katerem smo preučevali uspešnost naravnega pomlajevanja se nahaja v Mestni občini Ljubljana, GGE ZGS Ljubljana. Vrzel, ki je nastala v žledolomu 2014 leži na vznožju Rožnika. Na tej površini so bile meritve opravljene že v letih 2014 pred sanacijo sestoja in 2015 v času vegetacije. Podatke, ki smo jih pridobili na ploskvah v letu 2016, smo primerjali s podatki iz leta 2015. Na podlagi primerjave smo ugotavljali uspešnost naravnega pomlajevanja. Popis in meritve sem izvajal na 19 vzorčnih ploskvah. Čeprav se je številčnost mladja zmanjšala iz 130460 na 89045 osebkov na ha, ga je za normalno pomlajevanje še vedno dovolj. V mladju prevladujejo osebki dobre kvalitete. Zmanjšanje gostot gre pripisati zaostrenim ekološkim razmeram predvsem v višinskih razredih med 0 in 20 cm ter 21 in 50 cm. Delež vrst rodu Rubus se je izrazito povečal, ta namreč zavzema skoraj 70 % površine. V mladju sta prisotna tudi robinija in visoki pajesen, ki spadata med invazivne vrste. Pri rasti je robinija še posebej uspešna.Success of natural tree regeneration was studied in urban forest of Ljubljana. The canopy gap, which emerged during the ice storm in 2014 was located under Rožnik hilly area. On the same plots the measurements were already performed during the growing season in 2014 before and in 2015 after the salvage logging. Data for this study were acquired in 2016 and were then compared to the data from 2015. Measurements of regeneration tree species composition, density and height distribution were performed on 19 sample plots. The density of seedlings was reduced from 130,460 to 89,045, but was still estimated to be sufficient for normal stand development. The regeneration was of good quality. The reduction of the densities was attributed to more extreme ecological conditions inside regeneration layer in heights up to 50 cm. The proportion of bramble coverage increased distinctively, for it was present on almost 70 % of the surface. Invasive black locust and the tree of heaven were also present among the young trees. Black locust was especially successful in recruiting into upper regeneration layers