Cajander larch (<i>Larix cajanderi</i>) biomass distribution, fire regime and post-fire recovery in northeastern Siberia

Abstract

Abstract. Climate change and land-use activities are increasing fire activity across much of the Siberian boreal forest, yet the climate feedbacks from forest disturbances remain difficult to quantify due to limited information on forest biomass distribution, disturbance regimes and post-disturbance ecosystem recovery. Our primary objective here was to analyse post-fire accumulation of Cajander larch (Larix cajanderi Mayr.) aboveground biomass for a 100 000 km 2 area of open forest in far northeastern Siberia. In addition to examining effects of fire size and topography on post-fire larch aboveground biomass, we assessed regional fire rotation and density, as well as performance of burned area maps generated from MODIS satellite imagery. Using Landsat imagery, we mapped 116 fire scar perimeters that dated c. 1966-2007. We then mapped larch aboveground biomass by linking field biomass measurements to tree shadows mapped synergistically from WorldView-1 and Landsat 5 satellite imagery. Larch aboveground biomass tended to be low during early succession (≤ 25 yr, 271 ± 26 g m −2 , n = 66 [mean ± SE]) and decreased with increasing elevation and northwardly aspect. Larch aboveground biomass tended to be higher during mid-succession (33-38 yr, 746 ± 100 g m −2 , n = 32), though was highly variable. The high variability was not associated with topography and potentially reflected differences in post-fire density of tree regrowth. Neither fire size nor latitude were significant predictors of post-fire larch aboveground biomass. Fire activity was considerably higher in the Kolyma Mountains (fire rotation = 110 yr, fire density = 1.0 ± 1.0 fires yr −1 × 10 4 km −2 ) than along the forest-tundra border (fire rotation = 792 yr, fire density = 0.3 ± 0.3 fires yr −1 × 10 4 km −2 ). The MODIS burned area maps underestimated the total area burned in this region from 2000-2007 by 40 %. Tree shadows mapped jointly using high and medium resolution satellite imagery were strongly associated (r 2 ≈ 0.9) with field measurements of forest structure, which permitted spatial extrapolation of aboveground biomass to a regional extent. Better understanding of forest biomass distribution, disturbances and postdisturbance recovery is needed to improve predictions of the net climatic feedbacks associated with landscape-scale forest disturbances in northern Eurasia.

Siberian tundra ecosystem vegetation and carbon stocks four decades after wildfire

“…The study was conducted in northeastern Siberia, in the Sakha Republic of the Russian Federation. The study site was located in a previously identified fire scar (Figure 1) [Berner et al, 2012] on the eastern bank of the Kolyma River in close proximity to Ambarchik Bay on the Arctic Ocean (69.47°N, 162.18°E). The area is characterized by a cold, dry climate.…”

“…Recent observations of increased fire frequency and unusually large fires [Jones et al, 2009[Jones et al, , 2013 in arctic tundra indicate that fire is becoming an increasingly important component of these ecosystems. Fire is widely recognized as an integral component of boreal forests, where it exerts strong influence on ecosystem structure [Goetz et al, 2007;Alexander et al, 2012;Berner et al, 2012] and function [Mack et al, 2008;Johnstone et al, 2010]. Changing boreal fire regimes [Kasischke and Turetsky, 2006;Kelly et al, 2013] are resulting in ecosystem changes that are likely to act as climate feedbacks [Randerson et al, 2006;Beck et al, 2011;Jin et al, 2012].…”

Disturbance-effects on treeline larch-stands in the lower Kolyma River area (NE Siberia)

“…Scorch marks on remaining logged stumps indicate that the sites must have been burnt after this logging event, but no other burned wood was found, thus we cannot make assumptions on the pre-fire stand structure or fire frequency. Berner et al (2012), however, showed evidence for fires in the 1970s in the larger area. At the RB site, new land became available for forest colonisation ~60 years ago.…”

“…Alexander et al 2012;Berner et al 2012Berner et al , 2013. Our analyses were conducted along a latitudinal gradient in the lower Kolyma river area, where Larix cajanderi Mayr is the only tree taxon.…”

Water availability limits tree productivity, carbon stocks, and carbon residence time in mature forests across the western US

“…Advances in satellite remote sensing, such as NASA's new Global Ecosystem Dynamics Investigation Lidar (GEDI) instrument, are anticipated to help overcome some of these challenges (Goetz and Dubayah, 2011). Nevertheless, current BIO maps (e.g., Kellndorfer et al, 2012;Wilson et al, 2013) proved to be valuable tools for ecologic and natural resource assessments (Berner et al, 2012;Goetz et al, 2014;Krankina et al, 2014).…”