Landscape Fires in Transbaikalia

Аннотация

This paper presents results of wildfire studies conducted Transbaikalia over the last five decades. Station-based experimental investigations into fire hazards of vegetation accomplished at the regional forest fire stations during those years covered all altitudinal vegetation zones, representative landscape localities and forest types. Route investigations were made in different natural areas. Arial monitoring of landscape fires was used during two fire seasons. Long-term effects of fires in the Baikal Natural Area and in Central Transbaikalia were investigated. Fire regimes in vegetation complexes were analyzed and for each of them the duration of the fire hazard was determined both as the total duration for the entire season and as a continuous duration for the period of the fire maximum. Characteristics of the regimes for the altitudinal belts are provided in three versions according to precipitation amounts for a season (normal, dry and wet). It is found that forest fires occur in intensive and extreme fire regimes where most of the vegetation complexes of the region become exceptionally hazardous as compared to adjacent areas. In such a situation, there are almost no barriers to fire, except for broad rivers, lakes and mountain crests. The forest fire frequency index is high due to a predominance of light coniferous stands. A rapid spread of fires is also promoted by dry grass stands and fire-hazardous shrubs where the fire is spreading nearly as fast as the speed of wind. It was established that unmown meadows, and abandoned pastures and croplands in the outskirts of villages present the threat of devastating fires not only in forests but also in settlements. In a situation, such as the one that arose in 2015, landscape fires turn to a natural disaster with severe forest-ecological consequences. Surviving forest stands decrease in productivity and increase in self-thinning, followed by an increasing degradation caused by subsequently recurring fires. Burns undergo local deforestation or a long-lasting replacement of coniferous stands by deciduous forests. The future runoff from the burned-over areas is able to enhance pollution of Lake Baikal. It is concluded that the EMERCOM resources used to fight the latest fires in Transbaikalia showed very little promise because of being delayed. A reasonable alternative to EMERCOM would involve advanced forecasting of high risks of fire occurrence in order to rapidly fight fires with moderate expenses without letting them turning to a natural disaster.