The incidence of mistletoe (Viscum album ssp. abietis) on silver fir (Abies alba) in Croatia

Abstract

Abstract:The research on incidence of mistletoe (Viscum album ssp. abietis) on silver fir (Abies alba) was carried out in natural fir stands in Croatia. In the area of Gorski Kotar 32.8 % of the examined dominant fir trees were infected with mistletoe. The mistletoe incidence was presented according to the damage degrees of silver fir from 0 (healthy trees) to 4 (dead trees), rated by the crown defoliation and needle discoloration. With the increase of incidence, mistletoe spreads more onto more vital, i.e. less damaged trees. In the Dinaric Alps 28.6% of the examined fir trees were infected, this percentage amounting to 27.1% for the mountainous regions between the Sava and Drava rivers. The site and stand parameters (exposure, elevation, site quality, forest community and crown closure) were analysed in order to establish whether there was a correlation between these parameters and mistletoe incidence. There was a negative correlation between the elevation and mistletoe incidence. Among the compartments with a closed stands there were considerably less compartments with higher mistletoe incidence than among compartments with a sparsely closed and understocked stands. The other analysed site and stand parameters individually had no significant influence on mistletoe incidence. The correlation of silver fir mortality in 2004 and mistletoe incidence in 2002/03 was analysed, and their strong correlation was established. Mistletoe could be considered as a bioindicator of silver fir decline, and probably a significant contributor to that decline. In the areas where mistletoe incidence is great it can be presumed that silver fir is significantly damaged.

Impact of Common Mistletoe (Viscum album L.) on Scots Pine Forests—A Call for Action

“…abietis (white mistletoe) is one of the most significant biotic factors affecting Silver fir in natural forests. In the last 60 years in Europe, many reports were made about mistletoe affecting Silver fir: in France [15,16]; in Switzerland in the 1970's, 1980's, and 2000's [17,18]; in Croatia [19]; in the Spanish Pyrenees [20]; and in the Romanian Carpathians [21]. Mistletoe is also a major problem in the fir forests on Mount Parnis, Greece [22].…”

“…Mistletoe is also a major problem in the fir forests on Mount Parnis, Greece [22]. More than 30% of firs in some regions of Croatia (e.g., in Gorski Kotar, 32.8%) were infected by mistletoe [19], and in the Romanian Carpathians the infection rate reaches 42% [21]. There is a lack of consensus regarding the effects of V. album subsp.…”

Individual vulnerability factors of Silver fir (Abies alba Mill.) to parasitism by two contrasting biotic agents: mistletoe (Viscum album L. ssp. abietis) and bark beetles (Coleoptera: Curculionidae: Scolytinae) during a decline process

“…This allows the maintenance of an osmotic pressure gradient to promote tree sap flow into the parasite, except for during severe drought periods in which such a mechanism is not sufficient to prevent mistletoe decline before the decline of its host (Escher et al 2008). In the context of climate change, V. album is expected to act as a bio-indicator of silver fir decline (Idžojtic et al 2008).…”

Impact of White Mistletoe (Viscum album ssp. abietis) Infection on Needles and Crown Morphology of Silver Fir (Abies alba Mill.)

“…In the last sixty years several scientists investigated silver fir infection with mistletoe across Europe: in France (Plagnat, 1950;Plagnat and Brossier, 1969), in Switzerland (Hofstetter, 1988;Noetzli et al, 2003), in Greece (Tsopelas et al, 2004), in Spain (Oliva and Colinas, 2007) and in Croatia (Idžojtić et al, 2008).…”