Acute injury event.
Rain is the dew that nourishes everything. How can it become a "killer" who destroys forests? Recently, by China Forestry Science.
On the occasion of the 40th anniversary of the founding of Chinese Academy of Forestry, the author interviewed the Academy at the International Symposium on Integrated Forest Control in Acid Rain Hazard Areas.
Dr. Shang He, a researcher at Wang Yanhui Institute of Forest Ecological Environment Protection, and Dr. Peter, a forestry expert at the University of G? ttingen.
Nature is punishing us.
Experts pointed out that acid rain is the punishment of nature for human's uncontrolled consumption of mineral energy. With the rapid development of economy,
A large amount of sulfur dioxide and nitrogen oxides produced by burning coal and fuel oil combine with water in the air to produce sulfuric acid and nitric acid; When it rains
When the pH value of the medium is lower than 5.6, it is called acid rain.
Experiments show that if the PH value of river water is 6.0, it is not suitable for fish to survive. At 5.0, there are no fish. The soil in Chongqing is
The acid value is serious, and the PH value of some mountain streams is close to 4.0. It is no wonder that masson pine will suddenly die in a large area. It is also caused by the same reason
Abies emeishan died in a large area.
Acid deposition is one of the main environmental problems today, including dry deposition and wet deposition. There are acid rain and acid fog in dry settlements.
In the early 1990s, the area of acid rain in China reached 2.8 million square kilometers, which has increased to 40% of the national territory in recent years, making it the second largest in Europe.
The third largest acid deposition area in the world after North America.
To calculate the economic account, we should also calculate the ecological account.
From 1996 to 1996, it is roughly estimated that there are 1 1 in the southern areas with serious acid rain pollution in Jiangsu, Zhejiang and Anhui.
The direct economic losses caused by the reduction of forest volume in various provinces and regions reached 4 billion yuan. Among them, Sichuan is threatened by acid rain.
The forest area is the most serious, accounting for nearly 32% of the woodland area and 5.7% of the forest death area; Wood loss in Sichuan and Guizhou provinces is calculated as 15 years.
About 6.3 million cubic meters, with a direct economic loss of 3 billion yuan. It is also common that forests in Guangdong and Guangxi are polluted by acid rain and sulfur dioxide.
All over.
It is worth noting that in recent years, Houma, Shanxi, Beijing and Tianjin, Dandong, Liaoning and Tumen, Jilin have also appeared in North China.
There is acid rain.
The loss of timber is only an economic account. According to the calculation of Japan and the United States, the economic value of forest ecological function accounts for the total economic value.
90%, while the similar calculation value of Yunnan Forestry Investigation Team for the whole province's forests is 94%. Experts say this is caused by forest destruction.
The loss caused by soil erosion and greenhouse effect is far greater than the economic value of wood, which is the most serious loss.
Experts also remind people that due to the accumulation effect of acid deposition in soil, in addition to acute injury, the initial stage often
Can't see the destruction of the forest; On the contrary, in the alkaline soil in northern China, if acid is properly supplemented, trees will flourish for a while.
However, if it is not prevented early, acid deposition will lead to the decline of soil fertility and the process of root damage can be slowed down, but it is irreversible.
When trees are seriously damaged by yellowing and crown shedding, it is too late to prevent them.
It is urgent to control the "acid source"
For a long time, coal accounts for 70% of China's energy consumption; The sulfur content of coal in southwest China is as high as 5%-8%. Coal platoon
Acid precipitation caused by the massive release of sulfur dioxide in China is characterized by sulfuric acid rainfall.
Coal desulfurization is expensive, and the more important reason is backward technology. According to statistics, if China's energy utilization rate reaches that of developed countries,
If the home is as beautiful as Japan, it will save a lot of raw coal every year and the emission of air pollutants will be greatly reduced.
Experts at home and abroad agree that it is urgent and a long way to go to control acid deposition: first, strengthen research and clarify the pollution mechanism;
The second step is to control pollution sources and reduce emissions; The third step is to fertilize and nourish and restore soil fertility.
Dr Peter also introduced the experience of Godin University in studying and controlling acid rain since 1974. At present, Germany has
There are more than 800 acid rain observation points and more than 30,000 sampling points. The Foundation has funded afforestation of Miyun Reservoir in Beijing and soil and water conservation in Chongqing.
More than a dozen projects. He particularly emphasized that it is more important to improve forest stability and effectively protect planted trees; According to the country's experience,
It is much more effective to put limited funds into this research as soon as possible than to treat it after causing pollution.