1. What is a forest fire? What are the "three elements" of forest fire? How to classify disasters?
Forest fire refers to a kind of free burning phenomenon that loses human control and destroys the forest during the forest burning process. The "three elements" of forest fire are: forest combustible, meteorological articles and fire source. The above three factors are simultaneously available. Then there will be a forest fire. If one of the factors does not meet the conditions, there will be no forest fire. China's "Regulations on Forest Fire Prevention" stipulates that forest fires are divided into four levels. 1. Forest fire: the affected forest area is less than 1 hectare. 2. General forest fire: the affected forest area is more than 1 hectare and less than 100 hectare. 3. Major forest fire: the affected forest area is more than 1000 hectares and less than1000 hectares. 4. Extraordinary forest fire: the affected forest area exceeds 1000 hectares.
Second, is the Tawei forest flammable? How are they classified?
The organic matter contained in the forest can be burned, which is generally called forest combustible. Generally can be divided into:
Underground combustible-refers to humus, peat and tree roots that are semi-decomposed or decomposed below the litter layer. The fire formed by the burning of underground combustible materials is called "underground fire". "Underground fire" is characterized by slow burning speed, long burning time and high temperature, which is difficult to put out and causes great losses to trees.
Surface combustible-refers to all combustible materials above litter layer to 1.5 meters. Including litter, weeds, shrubs, young trees, fallen trees, root cutting, etc. The fire formed by combustible materials burning on the surface is called "surface fire". Surface fire burns faster and is easier to put out than underground fire.
Combustible in the forest-refers to the combustible above the ground 1.5 meters. Including branches and dead wood. The fire formed by combustibles burning in the forest is called "crown fire". The "crown fire" is not easy to put out. Under the strong wind, it is easy to form a raging fire or produce "Fei Huo", "fire whirlwind" and "fire storm".
3. What are the fire sources that cause forest fires?
There are two kinds of fire sources that cause forest fires:
1. Natural fire source: refers to forest fires ignited by some natural phenomena. Such as lightning fire (landing lightning), volcanic eruption, rolling stone sparks, peat spontaneous combustion and so on.
2. Man-made fire source: refers to the forest fire caused by fire in human life and production. Such as burning wasteland, charcoal, bricks, fire lines, locomotive fires, tiles, high-voltage lines falling off, throwing cigarette butts, having a picnic to keep warm, burning paper on graves, children playing with fire, fools lighting fires, and bad people setting fires. Both natural and man-made fire sources have regional and seasonal characteristics. The local forest fire prevention headquarters should take corresponding countermeasures to strengthen the management of fire sources and control the occurrence of forest fires according to the changing laws of fire sources within their respective jurisdictions.
4. What are the main meteorological factors affecting forest fires?
The main meteorological factors that have obvious influence on forest fires are:
Precipitation-the amount of precipitation directly affects the water content of combustible materials in forest areas. The higher the water content of combustible materials, the lower the ignition rate; The lower the water content of combustible materials, the higher the ignition rate. If the annual precipitation in an area exceeds 1500mm, or the monthly precipitation and water volume exceed 100mm, forest fires generally do not occur or rarely occur.
Temperature-daily maximum temperature is often the main indicator of whether this place is on fire. The most frequent occurrence of forest fires is at the highest temperature in a day. Because the temperature rise accelerates the temperature rise of combustible materials, the water content becomes smaller and it is easy to approach the ignition point. Therefore, high temperature weather is an important factor of forest fires, so we should be especially vigilant. Forest fires generally occur in the temperature range of-10-25℃. If the temperature is above 25℃, the combustible will turn green and the water content in the body will increase, then the probability of forest fire will also decrease.
Wind speed-wind plays two roles in the occurrence and development of forest fires. First, the unburned combustible materials are evaporated and dried to make them flammable; Second, after combustibles are burned, the wind brings fresh oxygen, which makes the fire burn more fiercely. So there are many windy days and many fires. Wind is also an important factor in the spread of forest fires. The greater the wind speed, the larger the burning area. As the saying goes, "Fire borrows wind, and wind helps fire" is the truth. It can be seen that "wind" is an obvious sign of fire danger.
Relative humidity-The greater the relative humidity, the higher the water content of combustible materials. Usually, when the relative humidity is above 75%, forest fires are not easy to occur; 75-55% may have a fire; Less than 55% is easy to catch fire; Below 30%, a serious fire will occur. In addition, even the number of dry days and cloud cover will affect the occurrence of forest fires.
5. What is the range and changing law of forest fires?
There are about 200,000 forest fires in the world every year, and millions of hectares of forest land are burned, which is about 0. 1% of the existing forest area in the world. There are an average of 10,000 forest fires in China every year, and about 1 million hectares of forest land are burned. The forest fire area in China accounts for 1/3 of the afforestation area. Forest fires change regularly. Judging from the annual change, it mostly appears in years with less precipitation and longer continuous drought days. Judging from the seasonal changes, Northeast China and North China mostly appear in spring and autumn, with sunny weather, less precipitation, dry vegetation and windy. That is, April, May, June and September of each year 10, 165438+ 10. In winter, due to the low temperature and snow cover, fires are not easy to occur. There is a lot of precipitation in summer. Combustible grows vigorously and has high water content, so it is not easy to cause fire. The fire season in East China, South China and Southwest China mostly occurs in winter and early spring. At this time, it is dry season, with more sunny days, less precipitation, and timely temperature. Other months are rainy season, which is not easy to cause fire. The forest fire prevention period in Xinjiang in the west of China lies between the north and the south, mainly in July, August and September. In particular, lightning fires are concentrated in July and August; According to the daily change, forest fires mostly occur between 10 in the morning and 16 in the afternoon, which is a period of high temperature, low humidity and high wind speed in a day. At this time, a fire broke out, which developed strongly and spread rapidly, making it difficult to put out.
6. What is the spread of forest fires? What are the influencing factors?
After the forest vegetation burns, the fire will continue to spread around. Through thermal convection, thermal radiation and heat conduction, the burning area is continuously extended and expanded, which is called forest fire spread. The main factors affecting the spread of forest fires are: 1. Type and water content of combustible materials: shape, structure and size of combustible materials; Different water content leads to different propagation speeds, such as weeds and shrubs are short and dry, with low ignition point and fast propagation. Wet, thick dead branches and fallen wood are not flammable and spread slowly. 2. Wind is the main factor that determines the spreading direction and speed of forest fire. Wind promotes air circulation and accelerates combustion reaction, with high wind speed and fast spreading speed. Downwind fire spreads faster than upwind fire, and crosswind fire is in between. 3. Terrain: The uneven terrain causes microclimate change, water and heat difference, and affects the spread of forest fires. Such as sunny slopes and ridges, spread rapidly; Shaded slopes and valleys spread slowly; Mountain fires spread faster than mountain fires; Steep slopes spread faster than gentle slopes. 4. Day and night changes: there is sunshine during the day, high temperature, low humidity, high wind speed, dry combustible materials and fast forest fire spread; Night is the opposite of day, and forest fires spread slowly. Therefore, firefighters take advantage of the weak and slow spread of the fire at night and seize the time to put it out in one fell swoop.
7. What are the basic principles and methods of extinguishing forest fires?
When putting out forest fires, as long as any factor of the fire is controlled, the fire can be put out. 1. Reduce the temperature of combustible materials below the ignition point. 2. Blocking combustible materials and destroying the conditions of continuous combustion. 3. Isolate combustible materials from air (oxygen). The basic methods used are: cooling the sweater and sprinkling water on the burning combustible. Use chemicals or wet soil to reduce the heat, so that the temperature of combustible substances can be reduced below the ignition point, thus putting out the fire. The first method of isolation is to separate fire from combustible materials, and to separate burnt materials from unburned materials. Generally, fire lines (belts) are set up by spraying chemicals on combustible materials, or manually beating, turning over the soil by machines, using high-speed wind to burn ahead of time, and moderately blasting to separate the fire from combustible materials, burned combustible materials and unburned combustible materials. At the same time, spray water or chemicals on the burning combustible materials; It can also increase the fire resistance and flame retardancy of combustible materials. The first suffocation method reduces the oxygen content in the air to below 14- 18% by isolating the air, thus suffocating the fire. Generally, machines and tools are used to put out fires, covered with soil, sprayed with chemicals and blasted.
8. What does aviation forest protection include?
Aviation forest protection includes patrol, alarm, fire report transmission, skydiving fire extinguishing, air fire extinguishing (aircraft spraying chemical fire extinguishing agent from the air) and so on. Because of the advantages of fast speed, large observation area and strong maneuverability, aircraft patrol is often used in remote primitive forest areas with inconvenient transportation and sparse population. After the forest fire is discovered, it shall transmit the fire report to the forest fire prevention headquarters within its jurisdiction. Point out the fire location, fire type, fire area, forest fire spread direction, spread speed, and the route of hitting people on the ground. If the plane finds the fire early and the burning area of the fire site is small, the firemen on board can directly drop the fire or use helicopters to send the firemen to the fire site, and implement "fighting early, fighting small and fighting big" to eliminate the forest fire in the early stage. If the fire area is large and the forest fire spreads quickly, chemical fire extinguishing agents and flame retardants should be sprayed by aircraft to limit the expansion of the fire area and reduce the fire, and cooperate with ground firefighters to put out the forest fire. In addition, the plane is also used to transport beating tools, daily necessities and transport the wounded to the fire.
9. How to avoid burning and burning in forest fires?
Putting out forest fires is an urgent task. Firefighters face high temperature, smoke suffocation and exhaustion. Combustible materials in fire can sometimes produce ground temperature above 200℃ and air temperature of 1000℃, while human body loses its function in the environment above 120℃. Therefore, high temperature, heavy smoke and excessive physical exertion are the dangerous triangles of firefighters' casualties. Therefore, the personnel involved in fire fighting must pay attention to: 1. Wear safety protection equipment, including helmet, clothes, gloves, boots, safety cover, glasses and gas filter mask, to avoid dizziness and suffocation caused by fire caused by high temperature and smoke. 2. Obey the command of personnel with experience in fighting forest fires, and pay attention to the surrounding fire environment and the development characteristics of forest fires. (1) Don't move in the fire area line when extinguishing the fire, but move along the peripheral edge line of the fire area. (2) When putting out grassland fires, we should not be reckless; Prevent sudden change of wind direction and wind speed and flame burn; Don't climb the mountain in case of mountain fire, follow the fire head to prevent being surrounded by fire; When playing underground fire, be careful not to fall into the sapropelic layer and be burned by the fire; Be careful not to be injured by fallen trees when fighting forest fires; When a fire breaks out, you should choose a place with weak fire as a breakthrough, and don't storm in a place with strong fire; For the fire that can't be attacked for a while, we should avoid the fire head and wait for annihilation. When the wind is strong and the fire is strong, you should return along the extinguished fire line to avoid the downwind fire and prevent it from being swallowed up by the fire. During the break, fire lines should be laid around the camp to prevent being surrounded by fire.
Ten, surrounded by forest fires, how to save yourself?
Due to the sudden change of wind direction or terrain characteristics, people involved in fire fighting are sometimes surrounded by fire, and the way to escape is:
1. In the vicinity, first set fire to remove an open space as a safe area, and then enter the fire.
2. If it is too late to ignite, immediately choose a nearby pit, river beach or river ditch. Soak clothes with water, cover your head and lie in the fire.
3. Wrap your head in clothes, choose a place where weeds are short or easy to walk, and rush out to meet the fire in one breath, so you can escape safely. (Wu Shiying)
XI。 What is the task and scope of forest fire prevention in China?
Forest fire prevention is an important part of forest resources protection, and it is also a social, mass and professional work. According to the Regulations on Forest Fire Prevention, people's governments at all levels are responsible for forest fire prevention, organize relevant departments to establish forest fire prevention organizations, build forest fire prevention facilities in large-scale forest areas, publicize and organize the masses, delimit forest fire prevention responsibility areas, establish forest fire prevention systems, and do a good job in forest fire prevention. The main task of forest fire prevention is to implement the principle of "prevention first, active elimination", implement the principles, policies and rules and regulations of forest fire prevention, do a good job in forest fire prevention and fighting, and protect the safety of forest resources. Its scope of work includes forests and trees owned by the state, collectives and individuals.
Twelve. What new technologies are used in forest fire prevention and extinguishing in China?
1. Artificial precipitation enhancement: In the forest fire season, choose weather conditions suitable for rainfall, and use artificial catalytic rainfall to prevent and extinguish fires. At present, the catalysts used to promote artificial rainfall in China are dry ice and silver iodide. Aircraft, rain rockets, anti-aircraft guns, etc. It is used as a seeding and evacuation tool to bring catalyst into high-altitude clouds to promote artificial rainfall.
2. Forest chemical fire extinguishing: a fire extinguishing method that uses chemical agents to block the occurrence and spread of forest fires. Chemical fire extinguishing agent is made of ammonium phosphate, urea, etc. Chemical extinguishing agent is directly sprayed on the fire head or fire line by plane or backpack fire extinguisher to extinguish the fire. In addition, chemical herbicides are used to open the fire line.
3. Use infrared fire detectors and infrared photography to detect forest fires. Based on the principle of infrared thermal radiation, we can find the initial forest fire and underground fire, and can shoot the fire line and fire area through smoke, monitor the residual fire and calculate the fire area.
4. Using artificial earth satellites to detect forest fires: accurately determine the location and fire area of forest fires through meteorological satellite ground receiving stations. Through the color photos of fire occurrence and development, the fire analysis is carried out to provide reliable information and basis for the forest fire prevention command department.
5. According to a large number of meteorological factor data provided by the meteorological department, the computer is used to predict and calculate, and the most suitable fire prevention scheme is determined.
Thirteen. When and where did the biggest forest fire in China occur since the founding of the People's Republic of China? What lessons should be learned?
The biggest forest fire in China since the founding of the People's Republic of China occurred in the northern forest area of Daxinganling, Heilongjiang Province1from May 6 to June 2, 987. This is a huge forest fire that shocked China and foreign countries, and brought huge losses to the national forest resources and people's lives and property. The total area of burned forest land is 1 140000 hectares, including 870000 hectares of deforestation. The lesson to be learned is that
1. The leadership bureaucracy responsible for forest fire prevention is manifested in "the fire was busy for a while, and then no one asked".
2. The forest fire prevention policy of "prevention first, active elimination" has not been really implemented. It is manifested in "it is better to spend more money to treat diseases than to spend less money to prevent diseases".
3. Management confusion and lax discipline. It is manifested in lax system and unclear responsibility. Fire prevention personnel are mobilized at will and are not on duty during fire prevention.
4. Lack of appropriate technical facilities and weak fire fighting ability.
5. The quality of the fire fighting team is low, and it does not pay attention to the propaganda of fire fighting science and legal education.
6. Disrespect for talents and reality. Forest fire management has not been brought into the scientific track. 1987 After the catastrophic forest fire broke out in August, Comrade Tian Jiyun, the commander-in-chief of the National Forest Fire Prevention Command, personally wrote the instructions of "Strengthening the forest fire prevention ability by using modern scientific and technological achievements and protecting China's green treasure house" in Xilinji, Daxing 'anling. It points out the direction for forest fire management in China in the future. As every citizen of our country, it is everyone's responsibility to strengthen the awareness of forest fire prevention.