Energy crops in urban parks as a promising alternative to traditional lawns - Perceptions and a cost-benefit analysis

In this study, we investigated the possibility of replacing existing lawns located in urban parks with patches of energy crop plantations as a way to reduce maintenance costs. We selected six sites located on the edges of urban parks in Warsaw (Poland), characterized by low aesthetical value, high noise levels, and low vegetation diversity. For these sites, we evaluated replacing existing vegetation with selected energy plant species from a social and economic perspective. We conducted face-to-face interviews with park visitors to assess the public's perception of the aesthetic value of the energy crops using a series of computerized visual simulations. Also, we analyzed the costs and benefits of energy crops cultivation over a 20-year cycle and compared them with the maintenance costs of the current management of lawns in parks. The results from the survey showed that after introducing energy crops in all the cases, the attractiveness of the parks' interiors would increase compared to existing conditions. Replacing existing lawns would have a minor effect on vegetation diversity, and this would only concern species typical for turf lawns common in urban landscapes. We found that over 20 years, the production of biomass from 9 of the 13 species is related to lower costs than those related to maintaining existing lawns in Warsaw. Only for H. salicifolius, L. thuringiaca, S. pectinata, B. napus is the production of biomass non-profitable in comparison to maintaining existing vegetation. For all other species, we found losses in the production of biomass over 20 years. However, these losses are still lower than the costs of lawn maintenance, suggesting that planting ECs is more profitable than the existing green infrastructure.