Articles
Shading effect from trees reduces soil respiration in urban lawns
Article number
1374_23
Pages
181 – 188
Language
English
Abstract
Soils of urban green spaces (UGSs) can store significant quantities of organic carbon (C), particularly in the case of lawns largely represented in cities.
Lawns are often contrasted in terms of vegetation cover especially since they are associated with trees.
Trees create a local microclimate (shading, rainfall intercept, etc.), modifying soil biogeochemical cycles (input of litters, fauna and microbial communities, etc.) and can therefore have an important influence on greenhouse gas (GHG) emissions and consequently on C storage.
The objective of this study was to assess the effects of trees on microclimatic (temperature and humidity) and the soil physicochemical properties on soil respiration.
We compared these behaviors to open lawns and urban forest.
Soil atmosphere exchanges of CO2 were measured monthly between June and November 2021, with a portable infrared gas analyzer (DX4040, Gasmet, Finland) in 15 UGS composed of 12 both open and treed lawns as well as 3 urban forests in Angers city (France). Surface soil temperature and soil moisture were measured simultaneously with soil respiration.
Soil properties (bulk density, pH, conductivity, C and N content) were also assessed.
During the growing season, open lawns presented both higher temperature (2.2°C) and CO2 fluxes (1607 mg CO2 m‑2 h‑1) than treed lawns (1049 mg CO2 m‑2 h‑1). Soil moisture was not related to soil respiration.
The strong correlation found between CO2 flux and temperature whatever the soil type, clearly indicates that soil respiration was driven by temperature.
These results highlighted that treed lawns presented less C loss as CO2 compared to open lawns and could therefore enhance the C sink capacity of urban soils.
Lawns are often contrasted in terms of vegetation cover especially since they are associated with trees.
Trees create a local microclimate (shading, rainfall intercept, etc.), modifying soil biogeochemical cycles (input of litters, fauna and microbial communities, etc.) and can therefore have an important influence on greenhouse gas (GHG) emissions and consequently on C storage.
The objective of this study was to assess the effects of trees on microclimatic (temperature and humidity) and the soil physicochemical properties on soil respiration.
We compared these behaviors to open lawns and urban forest.
Soil atmosphere exchanges of CO2 were measured monthly between June and November 2021, with a portable infrared gas analyzer (DX4040, Gasmet, Finland) in 15 UGS composed of 12 both open and treed lawns as well as 3 urban forests in Angers city (France). Surface soil temperature and soil moisture were measured simultaneously with soil respiration.
Soil properties (bulk density, pH, conductivity, C and N content) were also assessed.
During the growing season, open lawns presented both higher temperature (2.2°C) and CO2 fluxes (1607 mg CO2 m‑2 h‑1) than treed lawns (1049 mg CO2 m‑2 h‑1). Soil moisture was not related to soil respiration.
The strong correlation found between CO2 flux and temperature whatever the soil type, clearly indicates that soil respiration was driven by temperature.
These results highlighted that treed lawns presented less C loss as CO2 compared to open lawns and could therefore enhance the C sink capacity of urban soils.
Authors
T. Künnemann, V. Guérin, R. Guénon, P. Cannavo
Keywords
urban green spaces, CO2 fluxes, soil, temperature, moisture, carbon, microclimate
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