Climate change, fire return intervals and the growing risk of permanent forest loss in boreal Eurasia.

Climate change has driven an increase in the frequency and severity of fires in Eurasian boreal forests. A growing number of field studies have linked the change in fire regime to post-fire recruitment failure and permanent forest loss. In this study we used four burned area and two forest loss datasets to calculate the landscape-scale fire return interval (FRI) and associated risk of permanent forest loss. We then used machine learning to predict how the FRI will change under a high emissions scenario (SSP3-7.0) by the end of the century. We found that there are currently 133,000 km2 forest at high, or extreme, risk of fire-induced forest loss, with a further 3 M km2 at risk by the end of the century. This has the potential to degrade or destroy some of the largest remaining intact forests in the world, negatively impact the health and economic wellbeing of people living in the region, as well as accelerate global climate change.

Carbon dioxide and methane fluxes: seasonal dynamics from inland riparian ecosystems, northeast China.

Riparian wetland ecosystems have been described as significant hotspots for carbon dioxide (CO2) and methane (CH4) fluxes, but their role in the release and sequestration of these greenhouse gases has been insufficiently assessed within China. The influences of vegetation and soil parameters on daily and seasonal variations in carbon flux in the Nenjiang basin, northeast China, were recorded using a static closed-chamber technique during the non-growing (November and January) and growing (June, July and August) seasons of 2009-2010. Seasonal differences in average CO2 flux were observed (growing season: 6.605g·C·m(-2)h(-1); non-growing season: -0.185g·C·m(-2)h(-1)) and these were significantly correlated with CH4 emission (r=0.532, p=0.011) and soil temperature at 5 cm depth below ground (r=0.852, p=0.000). Average diel gaseous flux showed significant variation between hours for both gases (CO2 flux one-way ANOVA F=3.075, p<0.01; CH4 flux one way ANOVA F=2.622, p<0.05). Various significant correlations were also found between CH4 and CO2 fluxes and multiple vegetation and soil parameters. For example at both sites, growing season-CH4 flux was correlated with vegetation cover (r=0.580, p<0.05) and total vegetation phosphorous (r=0.474, p<0.05). This study allowed key temporal differences in gas release and their potential biotic and abiotic drivers to be identified. Crucially, it also highlighted important areas in need of further research, to enhance our understanding of gaseous flux from inland riparian habitats.