Effects of Seasonality, Tree Species and Urban Green Space on Deciduous Leaf Litter Decomposition in Lithuania

Understanding ecological processes and environmental change in different urban green spaces is an important challenge to secure human well-being. The variety of urban green spaces provides a platform to generate knowledge on how urban environments affect tree leaf decomposition and quality. We measured the leaf litter decomposition of four dominant native deciduous tree species from five different urban green spaces over three time periods in Kaunas, Lithuania. Using the modified litter bag technique, we calculated the decomposition of 60 leaf litter samples for 4, 8, and 12 months respectively. For each leaf litter sample, we determined total N, total P, and organic C. Results indicated that the decomposition of leaf litter amongst tree species, urban green spaces and seasonality (time) were significantly different. The leaf litter of Betula pendula and Acer platanoides from street green spaces decomposed fastest during the spring-summer period. Quercus robur showed small but significant leaf litter loss differences between the green spaces, with the leaf litter from peri-urban forest decomposing the fastest. A decreased C:N ratio for Q. robur leaf litter showed accelerated leaf litter decay. In conclusion, our results show that the ecological processes of leaf litter decomposition, differs between tree species, type of urban green spaces and seasonality and thus must be considered in urban town planning to help maintain urban environments. Keywords: city trees; deciduous trees; green infrastructure; leaf litter quality; nutrient cycle; parks; peri-urban forest; street trees; urban environmental processes.