Usporedba dviju metoda za praćenje zdravstvenog stanja urbanih šuma

We compared the performance of two methods for monitoring urban forest health. The first was based on a systematic grid (ISM), and the second on non-linear transects (UFMO). Both methods were tested during July and August 2013 in the Rožnik urban forest in the Municipality of Ljubljana (MOL). We assessed crown condition and damaging agents on 15 ISM plots, surveying an area of 92 a (are = 100 m2) in 1,640 minutes. By comparison, the UFMO method was used to survey an area of 518 a in 1,700 minutes. The performance of the ISM and the UFMO methods was 17.8 min/a and 3.28 min/a, respectively. According to the time/area performance measure, the UFMO method performed 5.4 times better than the ISM method. The UFMO method recorded 1.5 times more damaging agents per hour, 2.7 times more trees per hour, and 13.4 times more dead standing trees per hour. It also suggested 7.0 times more management measures per hour. However, the density of the data gathered was 7.1 times higher for the ISM method. According to the chosen comparison measures, the overall performance of the UFMO method exceeded the ISM method in all chosen performance measures expressed in relative time except the amount of data gathered. We conclude that, for the same sampling cost, the ISM approach produces an unbiased, but imprecise, estimate of overall forest health, while the UFMO method produces a biased, but more precise, estimate. We discuss possible improvements and further limitations of the UFMO method with an emphasis on the differences between the two methods of monitoring and surveying forest health. We conclude, that the ISM monitoring method can be supplemented with the UFMO surveying method to capitalize on the potential synergies of combining both approaches.Usporedili smo izvedbu dviju metoda praćenja zdravstvenog stanja urbanih šuma. Prva se temelji na sustavnoj mreži (ISM), a druga na nelinearnim transektima (UFMO). Obje metode testirane su tijekom srpnja i kolovoza 2013. u urbanoj šumi Rožnik u općini Ljubljana (MOL). Procijenili smo stanje krošanja i štetnih čimbenika na 15 ISM ploha, istražujući površinu od 92 a u 1.640 minuta. Metoda UFMO korištena je za ispitivanje površine od 518 a za 1.700 minuta. Performanse ISM-a i UFMO metoda bile su 17,8 min/a odnosno 3,28 min/a. U skladu s mjerenjem performansi vremena/površina, UFMO metoda je provedena 5,4 puta brža od ISM metode. Metoda UFMO zabilježila je 1,5 puta više štetnih čimbenika po satu, 2,7 puta više stabala po satu i 13,4 puta više mrtvih stabala po satu. Također je predloženo 7,0 puta više mjera upravljanja po satu. Međutim, gustoća prikupljenih podataka bila je 7,1 puta veća za ISM metodu. Prema odabranim mjernim pokazateljima, ukupna uspješnost metode UFMO premašila je ISM metodu u svim odabranim mjerama uspješnosti izraženim u relativnom vremenu, osim količine prikupljenih podataka. Zaključujemo da, za isti trošak uzorkovanja, ISM pristup proizvodi nepristranu, ali nepreciznu procjenu ukupnog zdravlja šuma, dok metoda UFMO daje pristranu ali precizniju procjenu. Raspravljamo o mogućim poboljšanjima i daljnjim ograničenjima UFMO metode s naglaskom na razlike između dviju metoda praćenja zdravstvenog stanja šuma. Zaključujemo da se metoda praćenja ISM može dopuniti metodom mjerenja UFMO kako bi se iskoristile potencijalne prednosti kombiniranja oba pristupa

A new record of Rhizoctonia butinii associated with Picea glauca 'Conica' in Slovenia

In 2013, the death of needles of dwarf Alberta spruce (Picea glauca ‘Conica’) seedlings was observed in an arboretum in Slovenia. Needles on infected P. glauca ‘Conica’ twigs were covered with thick, yellowish brown hyphal cushions. The outgrowing mycelium was white and had completely overgrown some needles and connected them to each other. To definitively identify the fungus affecting P. glauca ‘Conica’, morphological examinations of isolated pure cultures were performed, and the internal transcribed spacer (ITS) region of the rDNA was sequenced. Based on morphological and molecular phylogenetic analyses together with the performed pathogenicity trial, we identified the causal agent of the observed symptoms as Rhizoctonia butinii – a recently described species. This report connects this fungus to a new locality and a new host plant