Wildfires in northern Siberian larch dominated communities

Abstract

The fire history of the northern larch forests within the permafrost zone in a portion of northern Siberia (∼66 • N, 100 • E) was studied. Since there is little to no human activity in this area, fires within the study area were mostly caused by lightning. Fire return intervals (FRI) were estimated on the basis of burn marks on tree stems and dates of tree natality. FRI values varied from 130 to 350 yr with a 200 ± 50 yr mean. For southerly larch dominated communities, FRI was found to be shorter (77 ± 20 yr at ∼61 • N, and 82 ± 7 at 64 • N), and it was longer at the northern boundary (∼71 • ) of larch stands (320 ± 50 yr). During the Little Ice Age period in the 16th-18th centuries, FRI was approximately twice as long those as recorded in this study. Fire caused changes in the soil including increases in soil drainage and permafrost thawing depth, and a radial growth increase to about twice the background value (with more than six times observed in extreme cases). This effect may simulate the predicted warming impact on the larch growth in the permafrost zone.

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

“…Our ecotone-level estimates of fire rotation are similar to the mean fire return interval calculated for Siberia's northern sparse forests (227-556 yr, mean = 357 yr) from AVHRR satellite data (Soja et al, 2006). Furthermore, they are similar to dendrochronological estimates of fire return interval along the forest-tundra ecotone in central Siberia (130-350 yr, mean = 200 ± 50 yr) (Kharuk et al, 2011). Our fire rotation estimate for the mountain larch forests (64.5-67 • N) was slightly greater than the fire return interval determined for larch-dominated communities (∼ 64 • N) in central Siberia (Kharuk et al, 2008(Kharuk et al, , 2011, potentially due to slightly cooler temperatures and less human disturbance of the landscape.…”

“…Subdividing the ecotone into southern mountain larch forests and northern lowland forest-tundra revealed that fire rotation differed sevenfold between these two zones (110 vs. 792 yr). This spatial pattern of fire activity is similar to that observed across Siberia, with fire return interval generally increasing from south to north (Furyaev et al, 2001;Soja et al, 2004;Kharuk et al, 2011) and correlated with both summer temperatures and AGB (Furyaev et al, 2001). Our ecotone-level estimates of fire rotation are similar to the mean fire return interval calculated for Siberia's northern sparse forests (227-556 yr, mean = 357 yr) from AVHRR satellite data (Soja et al, 2006).…”

“…Larch reestablishment and biomass accumulation depends on nonlinear interactions among fire periodicity and severity (Furyaev et al, 2001;Schulze et al, 2012), climate conditions (James, 2011;Lloyd et al, 2011), site micro-topography and permafrost (Koike et al, 2010;Zyryanova et al, 2010) and availability of seeds Sofronov and Volokitina, 2010). Fire frequency (e.g., fire rotation or fire return interval), which is the interval of time between successive disturbances, averages around 80 yr in northern larch forests, though exhibits considerable topographic and regional variability (Furyaev et al, 2001;Kharuk et al, 2011). If successive larch cohorts are destroyed by fire prior to reaching maturity and outside seed sources are not available, then forests can convert to nonarboreal vegetation (Sofronov and Volokitina, 2010).…”

Quantifying ecological drivers of ecosystem productivity of the early‐successional boreal Larix gmelinii forest

“…In Siberian larch forest, the fire regimes can be highly localized, contingent on soil moisture, permafrost status, and understory vegetation characteristics. For example, both satellite and dendrochronological data have shown that fire return interval is generally longer in northern regions (Kharuk et al 2011) and northeast-facing slopes (Kharuk et al 2008). Therefore, higher solar radiation and more frequent fire could promote the permafrost thaw and drainage on southwest-facing slopes.…”

Climatogenic Dynamics of Solifluction in the Permafrost Zone of Central Siberia

“…Пространственная структура оползней неоднородна относительно азимута: все оползни локализованы на склонах южной и юго-западной экспозиции; ни один оползень не обнаружен стом напочвенного покрова в виде мхов и лишайников, действующих в качестве теплоизолято-ра [32]. В аномально тёплые годы наблюдается оттаивание почвогрунтов выше среднегодовых показателей, что приводит к потере сцепления корней с глубьлежащими слоями почвогрунтов.…”