Considering the influence on the structure and dynamics of the Russian forest fund, forest fires have a dominating role among all the natural and anthropogenic disturbances. According to the forest inventory data of the Russian Forest Fund (state: 1 January 1993) the area of totally fire-damaged (non-regenerated) forest comprised 28.4 million ha. This area of severely burned forests (dead stands) was 3.3 times higher than the area of non-regenerated cuttings.
Regular forest fire observation is carried out only in the zone of active forest protection, corresponding to 2/3rds of the Forest Fund area. This zone includes almost all the European part of Russia, the southern and central regions of Siberia and the Far East. In the northern regions of the Asian part of Russia, covering 1/3rd of the Forest Fund territory, forest fire fighting is not carried out or is carried out only episodically. Thus, regular acquisition of fire data in this zone is almost lacking.
The number of forest fires registered annually in the protected forest zone ranges between 10,000 to 30,000, affecting between 0.5 to 2.1 million ha. Taking into account the correlation between the area of burned out forests and dead stands in actively protected, non-protected and episodically protected territory, the area of the Russian Forest Fund annually affected by fire is estimated to range between 0.9 and 3.7 million ha. Taking into account the lack of instrumental methods to sufficiently monitor burned areas and the earlier practice to reduce the number of reported damages, we must consider these estimations as being at the lower limits of its possible ranges.
About 20,287 forest fires affecting a total area of 723,100 ha were registered in 1994 on actively protected forest lands. The number of fires in the 1994 season was near its average annual value for the previous five-year period (20,355), and the area burned was only a half of the average area burned annually (1,437,200 ha). A peculiarity of this forest fire season is that almost a half of all forest fires (9,875) arose on the territory of the European part of Russia with well developed infrastructure and relatively high levels of forest protection. These forest fires were promptly controlled, and the area burned was only 26,700 hectares, corresponding to less than 5.0% of the whole burned area of the Forest Fund. The other 1,412 fires occurred in the regions of Siberia and the Far East, covering 510,100 ha of forests. The average area of a single fire in these regions was 18 times higher than that in the European part of Russia.
Detailed information about forest fires is available for the Forest Fund area that is under aerial protection and is included in a Geographic Information System. Aerial forest fire protection is carried out on an area of 731.3 million ha and includes almost the whole protected territory of the Forest Fund of Siberia and the Far East and also the relatively forest-rich regions of the European part of Russia (Fig.1). In 1994 active aerial fire fighting was carried out on an area of 551 million ha; this area includes 122.5 million ha of deer pasture lands. A total of 14,796 forest fires burned 644,700 ha of the protected Forest Fund territory. About 147 fires burned a total area of 172,600 ha of deer pastures.
Fig.1. Map of Russia showing boundaries of Avialesookhrana divisions. The unprotected zone is in the northern regions of the Asian part of Russia, covering 1/3rd of the Forest Fund territory.
More than 75.5% of the number of fires, and 90% of the area burned in the lands protected by aerial means were in taiga forest (Fig.2). In the zone of mixed and deciduous forests and in the forest steppe 20% of the number of fires burned 6% of the area. The low number of fires reported in the tundra and tundra-taiga transition zone can be explained by the fact that there is no or only episodic systematic fire observation and control. Only 5.0% of the area of deer pastures affected by fire was in the category of forest lands.
Fig.2. Fire distribution in Russia (1994) by forest vegetation zones
The majority of forest fires arose in light coniferous species (pine, larch) and softwood forests (birch, aspen) in which surface fuels consist of highly inflammable materials (grass, shrubs, lichen, green moss [Fig.3]).
Fig.3. Fire distribution in Russia (1994) by forest-forming species and types of ground cover.
Fig.4. Causes of Forest Fires in Russia (1994)
Fig.5. Means of detection of forest fires in Russia (1994)
Fig.6. Duration of forest fires in Russia (1994)
Fig.7. Size distribution of forest fires in Russia (1994)
The distribution of forest fire causes show the dominating role of anthropogenic sources (ca. 90% of all forest fires registered in Russia). On the Forest Fund territory covered by aerial forest fire protection the share of anthropogenic sources of fire was 70.0%, natural factors (lightning) 12.7%, and unknown causes 12.3% (Fig.4). Although the number of lightning-caused fires was relatively small, these fires burned 37% of the total area burned. This can be explained by the group character of these fires and the long distance from transport roads and populated points.
About half of all forest fires (9,725) were detected by aerial reconnaissance. On the territory covered with aerial forest fire protection the share of fires detected by aerial observation was 70% (Fig.5), 25% of the forest fires were detected by ground services, and 5.0% were detected by the local population, expeditions, loggers, etc.
About 5,034 forest fires (ca. 1/4th of all fires in the Forest Fund) which burned 526,900 ha (3/4 of the total area burned) were controlled by aerial means (including 132 fires which finally affected 163,800 ha of deer pastures). On the total territory covered by aerial protection the share of forest fires put out with aerial means was 34,0%. The role of aviation forest fire protection in forest fire detection and fighting was lower than in the previous fire seasons. This was due to the fact that because of insufficient finances the frequency of aerial forest patrolling and the number of aviation forest protection staff were reduced.
The majority of forest fires were put out in the day following its detection. On the territory covered with aerial fire protection 45.0% of the forest fires were suppressed on the day of detection, and 35.5% forest fires were put out the day after detection (Fig.6). The share of these fires in the total area burned of the Forest Fund did not exceeded 5,0%. At the same time more than a half of this area was burned due to lightning fires, which were put out 10 and more days after starting; the number of these fires did not exceed 2.0% of the total number.
As in previous years, the main part of the Forest Fund area affected by fire is concentrated in several regions of highest wildfire risk within Russia and represent the limited number of large forest fires which went out of control. The hotspots were in Irkutsk region, Krasnoyarsk territory and Republic Sakha (Yakutya). The total area burned in these three regions was 464,700 ha, or 72.1% of the burned surface on the area covered by aerial forest fire protection.
No less than 3/4ths of the all forest fires, that occurred on the Forest Fund territory protected by aerial means, were put out while still small in area, not exceeding 5 ha (Fig.7). The number of large forest fires burning more than 200 ha was only 3.5% of the total.
Because of the high variability of periods of high fire danger and fire occurrence, the analysis of forest fire risk must be based on long-term datasets and specific mathematical processing methods. Sufficiently full understanding of the influence of fire on forest ecosystems can be formulated only when we can organize regular fire monitoring on episodically protected and unprotected Forest Fund territory. Under conditions of inadequate ground-based and aerial infrastructures, fire monitoring in these regions can be provided only by spaceborne remote sensing methods. As a first step in this direction we are considering the installation of the NOAA AVHRR receiving stations in Krasnoyarsk, Yakutsk and Khabarovsk.
From: Georgy N. Korovin and Edgar N. Romanovich Address:
International Forest Institute
Novocheriomushkinskaya st., 69
RUS – Moscow 117418
Centre of Ecology and
Forest Productivity Problems
Novocheriomushkinskaya st., 69
RUS – Moscow 117418