(1) Forest ecosystem is the most complex ecosystem on land. The biological components in forest ecosystem are mainly tall trees, and forests play an important role in water conservation and soil and water conservation. For example, forests can alleviate the water crisis, promote the water cycle, affect the atmospheric circulation and increase precipitation, so they are called "green reservoirs". Because green plants can release a lot of oxygen under photosynthesis, they are also a building.

(2) Forest transpiration loses a lot of water, which can reduce the temperature. So in summer, the temperature in Mengshan is lower than that in the county.

(3) The main organ for plants to absorb water is the root, and the main part for roots to absorb water is the mature area of the root tip. There are a lot of root hairs in the mature area, which can absorb water. Water in soil →→→→→ root hair cells → cell layer in epidermis →→→ ducts in roots →→ ducts in stems → ducts in veins →→→ ducts in leaves → mesophyll cells → stomata → atmosphere (water vapor). Therefore, trees are sensitive to water.

(4) "Arbor Day" is a festival stipulated by some national laws to publicize forest benefits and mobilize people to participate in afforestation. According to the length of time, it can be divided into Arbor Day, Tree Planting Week or Tree Planting Month, collectively known as Arbor Day. Through this activity, we can arouse people's love for afforestation, improve people's understanding of forest functions, promote the greening of the whole people, and achieve the purpose of loving forests, expanding forest resources and improving the ecological environment. In order to increase China's

So the answer is:

(1) Forests can conserve water and increase precipitation, which is called "green reservoir". The photosynthesis of forests releases a lot of oxygen, which is also called "natural oxygen bar".

(2) Transpiration can reduce the temperature;

(3) root hair; Catheter;

(4) Arbor Day.