Urban Grassland Afforestation as a Public Land Management Tool for Environmental Improvement: The Example of Krakow (Poland)

Abstract

Afforestation can play a significant role in greenhouse gas emission reduction through increased carbon (C) sequestration in the biomass and soil. However, its environmental effects, especially through changes in soil characteristics as a result of afforestation, are still poorly understood. In this work, we studied the response of grassland soils derived from two different parent materials to afforestation. We measured the basic soil properties, including pH, C accumulation, nutrient contents and enzyme activity, in soils from grasslands and mature forests. We focused on the parameters associated with organic matter and the changes resulting from afforestation. We established that in the humus layers, habitat played a more important role in creating the soil properties, including organic-C accumulation, than land use (forest vs. grassland). We created models to explain the C storage in the soils, which indicated the substantial role of certain conditions in promoting the stabilisation of the organic matter, such as pH, and the amount of clay, humines and residue. We determined negative changes in the soil properties when compared with grassland and forest soils, but we found increased C storage, which counteracts the increased emission of carbon dioxide into the atmosphere. The results of our work may be of use for afforestation planners and urban managers.

Methodological Approaches and Literature Analysis in the Study of Soil Carbon in Urban Green Spaces: A Systematic Review

“…The included studies examined soil carbon using both direct and indirect approaches. Direct studies explicitly focused on carbon stock analysis in urban green areas [4,17,18,21,25,28,[48][49][50][51][52][53][54][55][56][57][58][59][60][61]. The indirect studies deviated from a specific focus on soil carbon as a central theme.…”

“…As mentioned in the introduction, a predominant focus on soil carbon has been studied in the form of SOC [1,2,4,[16][17][18][19]21,22,[26][27][28][29]43,45,[48][49][50][51][52][54][55][56][57][58][59][60][61][62]65,67,[69][70][71][72]74,76,[80][81][82][83] and in the form of Total Carbon [25,50,51,63,65,66,68,73,75,[77]…”

“…In terms of the methodology, there majority of the articles reported in situ sampling in soils of urban green areas. Many of these studies were based solely on in situ measurements [1,2,16,18,21,22,29,43,49,[52][53][54]56,[58][59][60][61][62][63][64][65][66][67][68][70][71][72][73][74][75][76]78,80,81,83,85]. Some researchers complement this approach with other methods such as remote sensing imagery [4,26,27,57], open data [26,28,45,79,84], logarithmic modelling [17,31,48,50,…”

“…In the analyses carried out using in situ measurements, a discrepancy was found in the criteria used for soil sampling depth. While the prevailing trend was to focus on the upper 0-20 or 0-30 cm soil depth [1,4,18,27,28,31,49,54,[56][57][58][59]62,63,65,69,71,72,75,82,83], there were also studies that consider the superficial soil layers, specifically 0-5 cm [21,76], or 0-10 cm [22,29,43,53,64,68,70,85]. Furthermore, some studies even considered in situ sampling at soil depths greater than 50 cm [2,16,17,25,26,45,48,50,52,60,67,74,[78][79][80]84].…”

“…Other studies found focused on urban horticultural spaces, community gardens, and allotment gardens [16,17,27,28,31,71,82], cultivated farmland [31,48,77], residential gardens [21,43,63,69,74], urban grasslands [1,4,49,59,70,76], green roofs [84], shrublands [4], roadsides and road greenbelt [75; 69; 85; 43; 76; 28], educational areas, university campuses or experimental centers [2,28,31,43,50,69,76], infiltration and vegetated swales [83], car parks [84], construction sites [77], bare land [77], and even cemeteries [31]. Wetlands [48,52,63,77] and mangroves [79] were also considered.…”