DIGITALNA ARHIVA ŠUMARSKOG LISTA
prilagođeno pretraživanje po punom tekstu



ŠUMARSKI LIST 5-6/2022 str. 93     <-- 93 -->        PDF

al., 2007). This stress was often found to increase susceptibility to insect pests (Foggo et al., 1994; Koricheva et al., 1998), while evidence is more limited, or at least variable, when it comes to pathogens (Tubby and Webber, 2010). Canker/dieback pathogens are more likely to be positively associated with host stress, particularly drought stress, than some foliar pathogens (Diminić and Hrašovec, 2005, Desprez-Loustau et al., 2006). Therefore, the urban environment is hostile to the long-term health of trees and shrubs and early detection of emerging threats is vital. Conducting a tree inventory is often the first step. In recent decades there has been an increased interest in urban tree inventories, resulting from growing problems with pest and pathogen attack on the urban tree stock (Raupp et al. 2006) and growing awareness of the multiple ecosystem services which trees provide in the cityscape among the decision-makers (Hubacek and Kronenberg, 2013; Georgiev et al., 2017).
The comparison of this inventory with the inventory made in the 1967 (Em et al., 1968) demonstrated that 223 species are currently absent from the Dendropark. The number of the species of the three most represented families Pinaceae (21), Cupressaceae (16), and Rosaceae (18) encountered in 1967 inventory were 30, 15 and 51 respectively.
As previously mentioned, since the last inventory in 1967 (Em et al.,1968), the collective Dendropark around Faculty of Forestry building has suffered changes in its surface and its contents, caused by the construction of a several buildings on the site which had previously been occupied by the Dendropark. This is one of the main reasons for such a drastic reduction in the number of the species.
Comparisons of repeated inventories may be used to monitor the health status of urban trees, but in current study, the lack of information regarding the physical position of the trees in the inventory from 1967, was especially problematic circumstance with the extremely long period of almost fifty years between the two inventories. This period corresponds to the average lifespan of the most species from the Rosaceae family whose number was evidently reduced (from 51 species in 1967 to 18 species in 2014).
The importance of the monitoring and regular pest and disease surveys became clear when the invasive box tree moth, Cydalima perspectalis (Walker) was established in the Dendropark in 2015, the following year after the inventory was completed. This was another evidence that living plant collections at botanical gardens and arboreta around the world can serve as early warning systems to help predict and prevent the invasion of new pests (insects, pathogens, or plants) (Britton et al., 2010). In many ways, urban greenspace represents an extended form of ‘Sentinel Planting’ (Fagan et al., 2008) where many organisms with the capacity to devastate sections of our environment will be most likely to have a visible impact and therefore be picked up during the initial stages of establishment (Tubby and Webber, 2010). This is highly significant as early detection offers the only realistic prospect of eradication of pioneer populations (Tubby and Webber, 2010).
The 2014 survey indicated that 33.8% of the total number of the trees were rated as good, 1.8% as very good, 31.1% as fair, while 24.5% were poor. Approximately 4.1% were rated to be in a critical state (in a state of decline), and 4.7% of trees were dead (Figure 1).
The total number of pest records was 128, 59 for insects belonging to 9 families and 69 for pathogens belonging to 15 families. The most prevalent family was Erysiphaceae both in species diversity (7) and number of individual pathogen records (16). This also is not surprising given that the powdery mildews are some of the world’s most frequently encountered plant pathogenic fungi (Glawe, 2008).
Species belonging to the family Curculionidae, more precisely the bark beetles (Ips sexdentatus Börner, I. acuminatus Gyll., Pityogenes bidentatus (Herb.) and P. quadridens (Hart.)) were with the highest number of records among pest insects. Therefore it was not unexpected that in the poorest conditions were the species from the family Pinaceae from which 41.9% of all individuals were rated as poor.
Of the most commonly found tree species, the healthiest was Platanus orientalis L. with 22 trees of which 21 were rated as good and only one as fair. Apiognomonia veneta (Sacc. & Speg.) Höhn. was not present nor any wood-decaying fungi, only the plane leaf miner, Phyllonorycter platani Stgr. was recorded on almost all examined trees but with very low populations.
The data that have been collected and analyzed to develop this inventory contribute significant information about the tree population and can be utilized to guide the proactive management of that resource. Tree inventory data can be utilized to justify needed priority and proactive tree maintenance activities as well as tree planting and preservation initiatives.
This inventory could also be used as an educational tool, in public relations, to educate residents about the benefits of a healthy, well-managed urban forest, and to inform them about species best suited to the community.
Conclusion
ZAKLJUČAK
Urban forests provide a multitude of benefits to the society. To maximize these benefits an urban forest inventory is often needed for planning and management purposes. Urban forest inventories are a valuable asset to planners and decision makers and can provide needed information about the quality, quantity and location of natural resources in urban