Fossil Carbon Load in Urban Vegetation for Debrecen, Hungary

Abstract

Deciduous tree leaf and grass samples were collected in Debrecen, the second largest city in Hungary. The aim of the study was to determine the rate of fossil fuel-derived carbon in urban vegetation. At the locations sampled, C3 and C4 plants close to roads were collected in September 2017. In total, 82 tree and grass leaf samples were gathered at 36 different sampling points all over the city of Debrecen. The radiocarbon (14C) results of the samples were compared to the local urban background atmospheric 14CO2 data to determine the percentage of the fossil fuel-derived carbon in the plants. Based on our results, the average fossil carbon content in the tree and grass leaf samples were 0.9 ± 1.2% and 2.5 ± 2.5%, respectively. The highest fossil carbon content was 9.6 ± 0.6% in a grass and 4.7 ± 0.7% in a tree leaf sample. It appears that the negative fossil carbon content results obtained at urban sampling areas reflect modern carbon emission, where radiocarbon content is higher than the corresponding local background, presumably due burning of recent wood containing bomb 14C in the suburbs as well as other possible sources such as litter decomposition or soil CO2 emission.

Spatial Distribution of 14C in Tree Leaves from Bali, Indonesia

“…In Quarta et al (2007), the highest fossil carbon fraction is only 2.6% while our highest value is 6.3%. In our former study (Varga et al 2019) the highest measured fossil carbon content was little higher, 9.6%, in a frequent urban area, at a busy crossroad in a Hungarian city, Debrecen. Our study shows that the radiocarbon level in vegetation, which reflects the atmospheric 14 CO 2 concentration with a good approximation, is approaching the preindustrial level.…”

Species-level classification of urban trees from worldview-2 imagery in Debrecen, Hungary: an effective tool for planning a comprehensive green network to reduce dust pollution

“…The other sources of dust pollution are traffic, usually with increased heavy metal content (Ram et al, 2014;Jandacka et al, 2017;Budai and Clement, 2018), and as in all European countries, the Saharan dust (Borbély-Kiss et al, 1999, 2004Varga et al, 2013;Varga and Roettig, 2018). Based on dust adsorption of tree leaves, it was found that trees also act as sediment traps for urban dust (Braun et al, 2007;Molnár et al, 2018;Varga et al, 2019) and are good indicators of dust pollution level due to physiological responses . As tree species adsorb dust in their leaves differently, according to the different number of leaves and the roughness of their surface (Simon et al, 2014), mapping the tree species composition can help in the selection of appropriate species in the planning of urban green infrastructure.…”

WHEAT SEED (TRITICUM AESTIVUM L.) RADIOCARBON CONCENTRATION OVER THE LAST 75 YEARS

“…Using the JFJ radiocarbon record (and calculated April-July mean values) as a reference for a clean-air site (Levin and Kromer 2004), less influenced by anthropogenic fossil fuel emissions, we estimated the fossil carbon contribution within the wheat tissue by Fossil C% 1 F 14 C seed F 14 C JFJ 100 (Quarta et al 2007;Varga et al 2019). Between 1987-2016, fossil C contribution in the wheat tissue is mostly lower than 1%, slightly above 1% in 1990 and 1992, and with stronger excursions in 2010 and 2011 by 1-1.5% fossil C (Fossil_C(%) mean :0.7 ± 0.3; see Figure 3).…”