Source: Reader`s contribution, original author: Wong Siyuan Vivian Wong
In recent years, forest fires around the world seem to be more serious. Such as in november 2018, a mountain fire in northern california, although the local government to deal with, but driven by the wind, the fire directly swallowed up the entire town, killing 86 people, more than 200 people missing, burning the tragedy of 20,000 houses. Get global attention.
In March 2019, a fire broke out in the forest in Liangshan Muli County, Sichuan Province, burning 20 hectares of forest, sending out about 700 firefighters and local firefighters,27 professional firefighters and four mass cadres to die.
The Brazilian Amazon rainforest, with the title "Lung of the Earth," burned a month-long fire in August 2019 that burned 830,000 hectares of pristine forest. The world`s environmental groups and people are worried, forcing Brazil`s president to send 40,000 troops to put out the fire.
As of the night of January 10,2020, nearly 60,000 square kilometres of land had been burning, causing 27 people to burn dead, burning nearly 2,000 houses, killing an estimated 500 million mammals, birds and reptiles, and about 20,000 of Australia`s iconic koalas, with the entire forest ecosystem devastated.
In late 2019, a forest fire in Valparaiso, Chile, burned more than 100 house ……
Forest fires cause great losses to fire areas or countries, so how to prevent and extinguish forest fires has become an important topic in the world today, but also a difficult world problem.
For man-made forest fires or arson, people can also be strictly prohibited to carry fire and other methods to prevent. At present, many forest areas in China use this method to prevent many man-made forest fires. However, it is understood that there is no good way for forest fires caused by lightning strikes. Therefore, this paper makes a special discussion on this issue, and puts forward a suggestion: using the lightning rod method to prevent the forest fire caused by lightning strike.
Lightning strike fire is an important factor causing forest fire. The devastating forest fire in Muli County, Liangshan Prefecture, Sichuan province, in March and April 2019, was triggered by a lightning strike of a Yunnan pine tree about 18 meters tall and about 250 centimeters tall. According to the network, the countries with the largest number of forest fires caused by lightning strikes mainly include the United States, Canada, Russia, China and Australia. In Canada, lightning strikes account for 76 per cent of the total number of forest fires; in the United States, an average of 10,000 to 15,000 strikes a year; in the western United States, about 68 per cent of forest fires are caused by lightning strikes; in Victoria, Australia, about 26 per cent of forest fires are caused by lightning strikes, almost 50 per cent of the total area; and in Russia,16 per cent of forest fires are struck by lightning every year; and in the Inner Mongolia and Heilongjiang regions, the most frequent lightning strikes occur. Judging from the statistics of the causes and losses of forest fires, the summer lightning strike has become the main cause of fire in Daxing`anling forest area. Wang Shengnan, China Lightning Protection,2018-07-14).
Experts say the response to lightning strikes is now a worldwide problem in the field of forest fire prevention, although many countries are actively exploring and studying, but so far there is no very effective way. The prediction and monitoring of lightning strikes in China is still in its infancy. Forestry departments have been exploring forest lightning fire prevention, lightning fire is a natural source of fire, conventional fire prevention measures cannot reduce the number of lightning fire. In general, we still focus on the passive defense of "finding-fighting" in response to lightning strikes, with simple means, low efficiency, many difficulties and problems that need to be solved, and often cause sacrifices, such as the forest fire caused by lightning strike trees in Muli County, Liangshan Prefecture, Sichuan Province in 2019,30 firefighters died, affecting the hearts of countless people throughout the country. Even in the so-called most developed united states, the california wildfires of the end of 2018, driven by the wind, that big fire of global concern directly engulfed the entire town, killing hundreds of people and burning 20,000 houses.
Some experts believe that on a global scale, in recent years, with the warming of the climate, El Nino, La Nina and other abnormal climate phenomena frequently appear, lightning strike forest fires have entered a new round of multiple periods. The probability of lightning strike in Daxing`anling and Xinjiang northern forests in China may also be greatly increased, which must be highly valued.
However, at present, the forest lightning fire prevention and extinguishing generally have the following major difficulties:
One is the difficulty of monitoring. Most of the lightning strikes in the forest area occurred between 13 and 17 hours, and most of the initial period developed in the covert combustion of humus or tree vegetation, with few open fires and large smoke columns, which were not easy to be found by lookout towers and forest rangers. Found at least a few hours old, missed the opportunity to play early and small.
Second, accurate positioning is difficult. At present, the early observation and positioning of lightning strike mainly depend on observation of watchtower, aerial reconnaissance of aircraft and remote sensing of satellite hotspots. Among them, the observation of the watchtower is greatly influenced by the trees and fog, and there is a big error in the location of the distant target. Aircraft air surveillance depended to a large extent on the level and experience of observers, and was also heavily influenced by meteorological conditions and air control, and could not be dispatched at any time. Satellite hot spot remote sensing is difficult to play a role in the small fire, has a certain lag.
Third, it is difficult to save. Restricted by the terrain, infrastructure, equipment, personnel team, communication support and so on, the lightning strike fire fighting and disposal is often unable to catch. Taking aviation forest protection as an example, a dry thunderstorm often causes multiple lightning strikes at the same time, while large and medium-sized helicopters in forest areas are in short supply. In june 2019, inner mongolia`s daxinganling aviation forest protection bureau faced the dilemma of using eight helicopters to deal with seven fire spots at the same time in one day.
In this regard, some experts suggested that strengthening the forecast of lightning strike, monitoring and verification are still the most important measures for lightning disaster reduction, and it is urgent to improve the emergency handling capacity of lightning strike fire.
However, the authors of this paper have different views on the above measures, we propose that the installation of lightning rods as the main method to prevent forest lightning fire.
The first author of this paper, huang siyuan, has worked as a lightning rod installer and electrician when he was young, and the second author, weiwei huang, is an electric engineer.
Although it was once thought that lightning rods could not be installed in the forest to prevent lightning strikes from catching fire. Because the lightning rod`s protection range is limited, it`s about 45 degrees down from the top. To protect the forest, I do not know how many lightning rods to be installed, in fact, is not feasible.
But we still think that because the lightning rod`s protection range is 45 degrees from the top to the surrounding range. It is better to install lightning rods to prevent forest fires in steep, rugged, inaccessible mountain forests. Because these places are on fire, almost all by lightning, and after the fire, fire engines, firefighters are extremely difficult to go up to the fire, even in the smoke in the helicopter is not easy to approach, landing; and relying on aircraft or artificial rainfall will also be steep, rain loss quickly and the effect is not good.
The first is that the separation zone is too long to be set up, that there are too many trees to be cut down, and that new vegetation will soon grow again; the second is that it is very difficult for people to go up and cut down such a long separation zone; the third is that there are too many trees to be thrown into the distance by manpower; and the fourth is that the mountain fire sweeps through it from top to bottom or from bottom to top, and the separation zone does not know how wide it will work? Like the recent fires in Australia, there are places where the separation zone is 30 meters away from the violent wildfires.
So the best way to prevent these mountain forests is to install a lightning rod. The installation of lightning rods (devices) is still the most effective way to avoid lightning strikes and fires we know so far. For at least 200 years since the invention of the lightning arrester by the American Franklin in 1753, the practice of lightning protection has been carried out for at least 200 years (because it is said that there is a lightning protection device on the roof of the Deqingxue Palace, an ancient building in Zhaoqing, Guangdong province - a lightning protection device that is hundreds of years before the invention of the lightning rod by Franklin). Now that billions of people around the world are building and shipbuilding, this ancient and effective method is widely used, why wouldn`t lightning rods be installed in the forest to prevent lightning from catching fire?
Although the number of lightning rods to be installed in the forest may be very large, a small number of lightning rods can be used to protect large areas of the forest from lightning strikes, because of the mountain height and the depth of the valley.
Because forest fires often cause great damage to affected areas or countries, they are often not only economic losses, but also serious damage to governance and national politics, social impact, people`s lives and property, protection of rare animals and plants, protection of the environment and so on.
However, for the more flat forests are not suitable to install lightning rods. Because every lightning rod in such a forest is too small and expensive to protect, fire engines and firefighters are more likely to go in to fight the fire after a fire, and the effect of air or artificial rainfall is higher.
Of course, for those mountains too high forests are not necessarily suitable, such as the kunlun range, qinghai-tibet plateau, above four or five thousand meters above sea level, their peaks snow-covered, thunderstorm clouds are wrapped around their waists, many lightning also occurs at the foot of the hillside, if the lightning rod on the top of these mountains will be meaningless.
Therefore, the method of installing lightning rods to prevent forest fires is not applicable to all forests, but may only be some of them suitable. Therefore, it is suggested that lightning rods should be installed to prevent lightning strikes in deep forests, but this method should not be adopted uniformly. However, we should not abandon the attempt to install lightning rods to prevent forest lightning strikes because some forests are not suitable, but should continue to sum up lessons and gradually popularize the application by choosing more suitable forests to pilot them.
Specific methods of operation:
1. In the more suitable forests, such as the steep peaks that are generally below three thousand metres above sea level (such a high forest is actually relatively large in our country and the number of the world), lightning rods are installed at every height (not only the top of the mountain) that are measured to direct the lightning current to the earth. Because the lightning rod is protected in the 45 degree umbrella range, so at the edge of this umbrella protection range to find another installation lightning rod tree object, need to install another lightning rod, as far as possible to protect the dead angle.
Choose the tallest and strongest tree at each height. After installing it as a lightning rod, it is necessary to cut the tip of the tree to adapt to the lightning protection fire. If there is a higher position than the tree, but not suitable for the lightning rod to rely on trees, must be chopped off or sawed down. making the tree the tallest object in the region. The lightning rod should be about one meter above the top of the tree. The wire needs to be able to withstand high temperature, the outside should be fitted with a thicker resistance to heat ceramic tile tube, to prevent the hot lightning through the wire underground to ignite the trunk.
Because of the dense foliage of trees, the general lightning rod may be difficult to drop from the helicopter, so it can be used to bend the extension of the lighter and electrically conductive metal cable (easy to put in the helicopter) as the lead wire, the lead every other distance with a convenient nail or bundle to fix the small ring.
Third, if the top of the cliff is not suitable to be a lightning rod to rely on the big tree, then can be placed metal tripod type tower lightning rod, fixed on the top of the cliff.
In short, except for bare rocks that cannot or are not necessary to install a lightning rod, it can only be the tree or tripod type tower that has been installed as the tallest object in a certain area.
Because this is a benefit to future generations. Once and for all, the capital construction project of "forest ". Therefore, better materials should be used. If the lightning rod has good metal quality, it can take decades or even longer.
The installation of forest lightning rods shall be marked to facilitate regular inspection, inspection, testing, repairing and relocation by professionals in the future.
A destination or target tree that is difficult for both people and materials to reach is often carried only by helicopter.
For Australia, which has just been burned with 6 million hectares of mountain forests, and Brazil, which has 830,000 hectares of primeval forest, it may be easier to install lightning rods on bare hilltops, or more likely to be supported by people who have been ravaged, intimidated, and government, and the value of installing lightning rods to avoid forest fires seems to be greater.
Of course, the installation of lightning rods for lightning protection is not a panacea for absolute safety, it is reported that lightning rods have been installed in the building was reported. But this could be just a rare case. According to Xi Xiushu, a researcher and lightning expert at the Institute of Atmospheric Physics of the Chinese Academy of Sciences," The lightning rod cannot be installed to protect the building 100%, and the phenomenon of lightning bypassing the lightning rod on the building will still occur. "Similarly, the installation of lightning rods does not protect the forest 100 per cent, but must significantly reduce the occurrence of forest fires caused by lightning strikes. Therefore, the idea of installing lightning rods in suitable forests is worthy of study and attempt, hoping that this proposal can be valued and supported by government and relevant departments.
(Author Huang Siyuan: Male,67 years old, before retirement is Guangdong Province Zhaoqing senior university executive vice-president, senior title. Vivian Wong: Female,37, Electrical Engineer, Sydney, Australia)
Author contact:
Weiwei Huang (Vivian Wong)
4A Patricia St, Rydalmere , NSW 2116
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