Findings from interviews of officers from different council departments in South-East Queensland confirmed that planners and engineers differ from tree managers in their perspectives and principles for street tree planting and CA-074 Me selection (Roy et al., 2017). It would be interesting to study whether other officers, including planners, urban designers, infrastructure engineers and landscape architects involved in municipal street tree planting programs across Australia share preferences for street tree planting and species selection principles similar to that of tree managers. Future research identifying the species characteristics responsible for specific services/disservices might help Australian tree managers to select street tree species based on environmental principles to alleviate the negative impacts of rapid urbanisation (e.g., evergreen, broad canopy trees to reduce urban heat island effect) (Shashua-Bar and Hoffman, 2000, 2004; Tsiros, 2010). It will also help tree managers to align street tree species selection principles and parameters (e.g., species characteristics, management and maintenance factors) with street tree planting rationale (e.g., environmental benefits, visual and aesthetic benefits) in council documents.
The author acknowledges the generosity of time, experience and knowledge offered by tree managers from 129 city councils across Australia in identifying the issues that informed street tree planting principles and species selection rationales within the city councils. The author thanks Associate Professor Jason Byrne and Professor Catherine Pickering from Griffith University, Dr. Aidan Davison from University of Tasmania, Dr. Johan Östberg from Swedish University of Agricultural Sciences and the anonymous reviewers for providing valuable feedbacks that have helped to improve the manuscript. The map showing the geographical distribution of city councils across Australia was prepared by Spatial Science Officer Meghamala Roy Basu. The funding for this research was made available by an Australian Postgraduate Award.
Common ragweed, (Ambrosia artemisiifolia L.), hereafter referred to as ‘ragweed’, is a wind-pollinated annual plant that is native to North America. Ragweed pollen has been detected in Canadian interglacial deposits that are more than 60,000 years old (Bassett and Teresmae, 1962). The massive spread of ragweed in different parts of the world has coincided with major socio-economic transitions that increased disturbed land areas. In 18th and 19th century Canada, European settlement led to increased agricultural activity. Large-scale deforestation and soil disturbance resulted in a hundredfold increase of ragweed pollen in these regions (Bassett and Crompton, 1975).
Ragweed was introduced to Europe at the end of the 19th century. Since then, this species has spread and naturalised across Europe (Kiss and Béres, 2006). The key factor in the introduction of ragweed in Europe was anthropogenic (Chauvel et al., 2006). Commercial trade between North America and Europe, as well as American troops transporting food products and war equipment during the First World War, contributed to the spread of ragweed (Kiss and Béres, 2006). Smith et al. (2013) summarised most existing knowledge about ragweed ecology, its distribution and phenological characters of flowering and its environmental health risk. The authors demonstrated that invasive ragweed is an environmental health threat both in its native range and in the regions in which it has been introduced.
Ragweed was first recorded in Hungary in 1908 (Jávorka, 1910). Regular weed surveys since the 1950s have revealed an extension of the species’ distribution in Hungary. However, in the 1950s, ragweed was not a problematic weed; therefore, no attention was paid to its control. By 1997, under favourable environmental conditions and due to the excellent adaptation ability of this species, ragweed had become the dominant weed species, covering 4.7% of the arable crop area (Béres, 2004). In the most recent weed survey in 2007–2008, ragweed maintained its dominant position, covering 5.33% of Hungary\’s arable crop area (Novák et al., 2009).