Wildfires dynamic in the larch dominance zone

Abstract

A fire return intervals (FRI) for zone of larch dominance and “larch‐mixed taiga” ecotone was studied. Extreme fire events were connected with summer air temperature deviations. Average FRI determined from stem fire scar dating was 82 ± 7 years for the zone of larch dominance, and 77 ± 20 for the “larch‐mixed taiga” ecotone. For the zone of larch dominance FRI on north‐east facing slopes was 86 ± 11 years, for south‐west facing slopes at 61 ± 8 years, for flat terrain at 68 ± 14 years, and for bogs 139 ± 17 years. FRI decreased from 101 years in the 19th century to 65 years in the 20th century, for the zone of larch dominance, and from 97 years to 50 years for the “larch‐mixed taiga” ecotone. A climate and anthropogenic impact on this phenomenon was analyzed. The decrease of FRI may interfere with climate‐driven migration of competitor species into zone of larch dominance, affecting biodiversity at high latitudes.

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

“…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. Mean annual fire density has been estimated to be 2.0 fires per 10 4 km 2 for Siberian mountain-tundra open forests (Valendik, 1996;Furyaev et al, 2001), though in our study area annual fire density between 2000-2007 averaged 0.3 ± 0.3 fires per 10 4 km 2 along the forest-tundra ecotone and 1.0 ± 1.0 fires per 10 4 km 2 in the Kolyma Mountains.…”

“…Eurasia experienced a record-breaking heat wave in (IPCC, 2007 that was associated with an extreme fire season across Siberia (Soja et al, 2007). Extreme fire events in the larch-dominated forests of central Siberia have previously been linked with summer air temperature deviations (Kharuk et al, 2008). During the positive phase of the AO, high pressures at northern mid-latitudes enhance the drying of phytomass and lead to a positive association between annual burned area and summer temperatures in central Siberia (Balzter et al, 2005).…”

Wildfires Dynamics in Siberian Larch Forests

“…For example, the date of the first fire varied by up to 30 days. The fire return interval (we obtained earlier [6,20,21]) increased along the latitudinal gradient (Figure 6b). It varied from 80 years at 64° N to about 200 years at the latitude of the Arctic Circle.…”

“…Trees were sampled until at least 12 samples were collected. In this study we used earlier obtained data on FRI in northern larch forests [6,20,21] which were analyzed against insolation along the meridian. Test sites where FRI data were obtained are shown on Figure 1.…”

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.…”