Forests and ozone: productivity, carbon storage and feedbacks

Abstract

Tropospheric ozone is a serious air-pollutant, with large impacts on plant function. This study demonstrates that tropospheric ozone, although it damages plant metabolism, does not necessarily reduce ecosystem processes such as productivity or carbon sequestration because of diversity change and compensatory processes at the community scale ameliorate negative impacts at the individual level. This study assesses the impact of ozone on forest composition and ecosystem dynamics with an individual-based gap model that includes basic physiology as well as species-specific metabolic properties. Elevated tropospheric ozone leads to no reduction of forest productivity and carbon stock and to increased isoprene emissions, which result from enhanced dominance by isoprene-emitting species (which tolerate ozone stress better than non-emitters). This study suggests that tropospheric ozone may not diminish forest carbon sequestration capacity. This study also suggests that, because of the often positive relationship between isoprene emission and ozone formation, there is a positive feedback loop between forest communities and ozone, which further aggravates ozone pollution.

Ozone effects on European forest growth—Towards an integrative approach

“…As most PBMs use arbitrary DRRs, or the ones that derived from chamber experiments, ozone effects on forest ecosystems may be overestimated a second time (e.g. Franz et al., ; Wang et al., ; Table ).…”

Deciphering the ozone-induced changes in cellular processes: a prerequisite for ozone risk assessment at the tree and forest levels

“…Recently, Fares et al (2013a), Hoshika et al (2011) and Nunn et al (2010) applied Jarvis's model parameterized with environmental observations with field data, and they were able to predict well stomatal conductance. The recent study of Wang et al (2016), which simulated the O 3 impact on forest composition and ecosystem dynamics over 500 years, indicated that elevated O 3 could even lead to an increase in forest productivity due to diversity change and compensatory processes at the community scale.…”

“…1). In addition, this pollutant is thought to impact negatively forest productivity (Ainsworth et al 2012), although species composition can modulate this effect (Wang et al 2016). Since a large part of global forest areas is predicted to be exposed to O 3 in the future (Fowler et al 1999), carbon sequestration by forests may be reduced (Sitch et al 2007;Subramanian et al 2015).…”

Biodiversity matters in feedbacks between climate change and air quality: a study using an individual‐based model

“…This model has demonstrated satisfactory simulation of forest compositional and structural dynamics and ecosystem level isoprene emissions in this region (Wang et al. , ). For example, with its prominent “individual‐based” feature this model has been successfully applied to test the hypothesis that extinction of the American Chestnut ( Castanea dentata ) in the forests of the eastern United States in the late 19th and early 20th centuries enhanced isoprene emissions by favoring oak species ( Quercus spp.…”