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Sakhalin spruce and fir taiga and forest fires
Spruce and fir forests in general, particularly those on Sakhalin, have some distinctive features relating to forest fires. The predominant species for these forests of Sakhalin are spruce (Picea ajanensis) and fir (Abies Sachalinensis and Abies Mayriana). For thousands of years, before the area was developed by humans, the natural regeneration of spruce and fir stands was uninterrupted and constant due to a lack of stress in the forest ecosystem. Ancient giant stands died naturally (uprooting, diseases, fungus accelerated this process with no damage to the forest stands), whereas the number of young trees increased under the humid and shaded forest canopy, so the young trees were able to grow higher into the gaps. Coniferous taiga has perfectly adapted itself to the humid climate of the Sakhalin Island, which has frequent and strong winds, so fires didn't significantly affect the natural dynamics of spruce-fir forests. Unlike pine and larch forests covering most of Eurasia, Sakhalin forests hadn't really suffered fires until the 20th century. However since this time, the primary forest stopped to regenerate over major burnt areas. Young growth of spruce and fir which felt at ease in a shaded, wet, thick forest, can't survive in the open, without the protection of a forest canopy. In over cut and burnt-out areas, the direct sunlight burns the young growth, dries the soil and air. In the summer, topsoil can reach temperatures in the 70's Celsius in the open areas. Even if seeds cover burnt-out areas, young spruce can not grow in these conditions, because it requires humid cool shelter. As a result, it dies out - and has no chance to adapt to new conditions. On Sakhalin the fireweed, small reed, raspberry, willow, bamboo - in the South Sakhalin, at best - birch were spread over burnt areas within fir-spruce forests (as well as within vast sites of clear cuttings). Meadow communities and barren lands replaced forest communities in the open. It is these kinds of secondary landscapes, resulting from fires and cuttings in recent decades, that we see over huge expanses of Dolinsky, Makarovsky, Uglegorsky, Tomarinsky, Tymovsky Regions, in the southern part of Smirnykhovsky Region, which abounded in forest just several decades ago. Spruce and fir are absolutely unprotected against fire, so even a ground fire of medium and low intensity can dry them over considerable areas. The sensitive bark of spruce and fir in the lower part of the trunk (unlike larch) can not withstand even a running fire - the growth and metabolism are disrupted and the tree dies.
Thus, fires appear to be extremely detrimental first of all to spruce and fir stands in the Sakhalin taiga, where in most cases, spruce and fir forests are transformed into larch and deciduous cover for many decades if not centuries.
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