Impacts of prescribed burning on soil greenhouse gas fluxes in a suburban native forest of south-eastern Queensland, Australia

Abstract

Abstract. Prescribed burning is a forest management practice that is widely used in Australia to reduce the risk of damaging wildfires. Prescribed burning can affect both carbon (C) and nitrogen (N) cycling in the forest and thereby influence the soil-atmosphere exchange of major greenhouse gases, i.e. carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O). To quantify the impact of a prescribed burning (conducted on 27 May 2014) on greenhouse gas exchange and the potential controlling mechanisms, we carried out a series of field measurements before (August 2013) and after (August 2014 and November 2014) the fire. Gas exchange rates were determined in four replicate plots which were burned during the combustion and in another four adjacent unburned plots located in green islands, using a set of static chambers. Surface soil properties including temperature, pH, moisture, soil C and N pools were also determined either by in situ measurement or by analysing surface 10 cm soil samples. All of the chamber measurements indicated a net sink of atmospheric CH 4 , with mean CH 4 uptake ranging from 1.15 to 1.99 mg m −2 d −1 . Prescribed burning significantly enhanced CH 4 uptake as indicated by the significant higher CH 4 uptake rates in the burned plots measured in August 2014. In the following 3 months, the CH 4 uptake rate was recovered to the pre-burning level. Mean CO 2 emission from the forest soils ranged from 2721.76 to 7113.49 mg m −2 d −1 . The effect of prescribed burning on CO 2 emission was limited within the first 3 months, as no significant difference was observed between the burned and the adjacent unburned plots in both August and November 2014. The CO 2 emissions showed more seasonal variations, rather than the effects of prescribed burning. The N 2 O emission in the plots was quite low, and no significant impact of prescribed burning was observed. The changes in understory plants and litter layers, surface soil temperature, C and N substrate availability and microbial activities, following the prescribed burning, were the factors that controlled the greenhouse gas exchanges. Our results suggested that the low-intensity prescribed burning would decrease soil CO 2 emission and increase CH 4 uptake, but this effect would be present within a relatively short period. Only slight changes in the surface soil properties during the combustion and very limited impacts of prescribed burning on the mineral soils supported the rapid recovery of the greenhouse gas exchange rates.

Short-term changes in soil properties after prescribed fire and mulching with fern in Mediterranean forests

“…Some authors report unaltered pH values and ephemeral variations in electrical conductivity (Badía et al 2017;Alcañiz et al 2020), while, one year after the prescribed fire, other research shows marked decreases in nitrogen (Blankenship and Arthur 1999;Muqaddas et al 2015) as well as the recovery to pre-fire contents of magnesium and calcium (Alcañiz et al 2020). It has been found that the recovery of pre-fire soil properties may take place over short (Zhao et al 2015) or long (Alcañiz et al 2016) time spans, depending on fire temperature and residence time, topography of the burned area, rainfall, and degree of vegetation regeneration (Úbeda et al 2018;Girona-García et al 2019). Therefore, further research is needed to better understand the effects of prescribed fires in environments with contrasting characteristics (Hubbert et al 2006;Hueso-González et al 2018).…”

Fire alters the availability of soil nutrients and accelerates growth of Eucalyptus grandis in Zambia

“…Although fire may have a positive influence on the soil, divergent conclusions have been reported (Neff et al 2005;Verma and Jayakumar 2012;Heydari et al 2015), suggesting that the question of how fire affects soils and plant growth has not been answered. Fire has decreased soil nutrients through volatilization (Zhao et al 2015). Inbar et al (2014) reported a significant decrease of organic matter in the soil following a severe fire, which adversely affected chemical, physical and microbiological properties (Antoine et al 2013;Zhao et al 2015).…”

“…Fire has decreased soil nutrients through volatilization (Zhao et al 2015). Inbar et al (2014) reported a significant decrease of organic matter in the soil following a severe fire, which adversely affected chemical, physical and microbiological properties (Antoine et al 2013;Zhao et al 2015). Decreases in soil organic N and C have also been observed after fire (Murphy et al 2006).…”

Greenhouse Gases in Soils of the Coconino National Forest that have been Burned by Wildfires

“…Secondarily, the destruction of forest trees, shrubs and grasses will also have an effect of the food sources for the soil microbes. These effects will alter respiration from the soils for potentially years or decades after a wildfire [10][11][12].…”