Water conservation refers to the interception, infiltration and accumulation of precipitation by the ecosystem through its unique structure and water interaction, and the regulation of water flow and water cycle through evaporation.Generally, it can be recovered byvegetationConstruction of water conservation area to achieve controlSoil desertification, Lowersoil erosionThe purpose of.
Water conservation, improvement of hydrological conditions, regulation areaWater cycleForests, trees andshrubwood。It is mainly distributed in the water source area in the upper reaches of riversrunoff, prevent water and drought disasters, and reasonably develop and utilizewater resourceIt is of great significance.Water conservation capacity is closely related to vegetation type, coverage, litter composition, soil thickness and soil physical properties.
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Greening is one of the main technical measures for water conservation.Vegetation is known as "green reservoir", which can conserve water and regulate climateeffectIt is one of the effective ways to promote the virtuous cycle of water in nature.
Vegetation can conserve water mainly for the following reasons:
③ Rainfall is stored and infiltrated by forest soil.
In addition, the forest also has the ability to reduce the temperature difference, so that the climate change tends to slow down and increaseair humidityRole of.In planting trees and grass, attention should be paid to adjusting measures to local conditions and strengthening management.Adapting measures to local conditions means selecting suitable plant species and correct planting methods according to local water and soil conditions.In many areas, the effect of planting trees and grass is not obvious, and the key is to ignore the basic condition of plants' selection of ecological environment.In addition, lack of management and lack of effect are also one of the reasons for the low survival rate of tree planting.Water and soil conservation in ChinaworkHas proved that,Small watershed managementIt is an effective way to improve ecological conditions and conserve water resources.
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As far as the relationship between forest and water is concerned, the first thing that bothers forest related people in the world is that people's understanding of forest and water is inconsistent.Although forest protection in the upstream water source area is indispensable to the protection of water resources, the relationship between forest and water among downstream water users has not been correctly recognized and popularized, so the upstream can not get full support from downstream beneficiaries.
Secondly, there are troubles in water source forest management.The forest uses a large amount of water and competes with human beings for water.As far as the relationship between forest and water is concerned, there are still many problems that cannot be fully understood.
The summary results of the opinions of the "International Forest Expert Meeting" on forests and water held by these worries.Professor Taitian felt that some people overestimated the role of the "Green Dam" (in fact, the General Assembly also pointed out that "myth" and "fact" should be clearly distinguished), and the situation in Japan was no exception.
Japan is a country with abundant rainfall. Even though the forest consumes a certain amount of water, it is insignificant compared with the role of the forest.At the same time, compared with the forest recession, the surface runoff is greatly reduced and the phreatic water is increased, so the forest has the function of preventing dry water.The water demand in Japan is equivalent to 20% of the total river flow. Compared with the reduction of annual outflow, it is more important to ensure the flow in dry season.
However, in most countries with little rain, the problem of forest water consumption does exist.For example, greening desertified land is due to the photosynthesis of plants/EvaporationAnd absorb the water in the soil to lower the groundwater level.But the purpose of greening is to prevent flying sand and floods (floods also occur in dry areas), not to use water.According to theCEOThe report issued by the committee's Prince Paper Co., Ltd., the company's project to prevent salinization in Western AustraliaPlantationOfEvapotranspirationThe underground water from slope to lowland is consumed to prevent lowlandgroundwater levelThe rise of.
Therefore, it must be clearly recognized that forests consume water.If not, the topic of forest and water cannot be started.In Japan, too, forests consume water, and their water conservation function is limited.If these "facts" are not clear, we cannot properly discuss the issue of forests and water, and we cannot have a real dialogue with water users.But in this case, it should also be explained that the water conservation function of forests is beneficial and very important.
