Afforestation has always been regarded as a long-term pros and cons. But this view has recently been challenged. The "Forest Research Project" funded by the Department of International Development of the British Government came to the conclusion that unscientific tree planting will not be supplemented with water, but will cause the groundwater level to drop, rivers dry up, and aggravate desertification. This report is like a heresy to many people who love trees and environmentalists, but it has the support of many forest and hydrological experts. This was reported in a signed article recently published on the British "New Scientist" website.

 

Planting trees in some areas leads to desertification

 

The article believes that although, in some cases, the use of tree planting can indeed obtain water from the atmosphere, play a role in preventing soil erosion and nourishing the environment. However, it should also be noted that the forest itself also needs to absorb water in the soil and evaporate the water through the leaves, which leads to a decrease in the water level of rivers, reservoirs and groundwater and accelerates the trend of land desertification.

In the environmental protection works in some places around the world, trees can absorb moisture in the air and strengthen water and soil, and can prevent floods and store rainwater. But in other places, such as some dry areas where water is scarce, it is not suitable for large-scale planting. Trees absorb water from the soil and consume water from the leaves, lowering water levels, draining rivers and even creating deserts. John Palmer, the lead author of the Institute of Natural Resources at the University of Greenwich in the United Kingdom, said that the report believes that tens of millions of pounds (1 pound equal to 14 yuan) are wasted every year due to common sense errors in water management. .

 

Experts have different opinions

 

The article pointed out that many projects used to improve water conditions in developing countries may be a huge waste of money. Panama is seeking hundreds of millions of dollars in tree planting funds from the World Bank to increase the water storage capacity of the upper reaches of the Panama Canal and ensure a stable water level in the canal. Palmer said there is no scientific justification for this plan.

But Robert Stollard, a hydrologist at the Smithsonian Tropical Research Institute, disagrees with this view. He said that although the water supply of the forest water system is small, the water supply is stable.

One of the authors of the report, Ian Calder of the University of Newcastle in the United Kingdom, said: "We are not saying that forests have never been beneficial to the protection of water and soil or that their role in the ecosystem is not important, but we must manage water resources effectively. It is wrong to simply think that the more trees the better."

 

 Plant trees to reduce moisture

 

The report is based on the fact that in Himachal Pradesh and Madhya Pradesh, India, in order to increase water storage, large tracts of farmland were converted into large tracts of forest, but in fact, the water content in the land of these two states has been reduced by 16% and 16% respectively. 26%.

In South Africa, exotic pine and eucalyptus trees are planted across the country, which has reduced river water volume by about 3%. South Africa now arranges about 40,000 people to uproot these exotic trees.

Sampno Brookings of the Vrije Universiteit Amsterdam said in a report that in the high mountains of Costa Rica, researchers have discovered that forests are not as capable of absorbing moisture in clouds as people think. After cutting down the forest, the local rainfall hardly changed