202 1 Arbor Day Blackboard Materials Tree Planting Blackboard

Introduction: With the coming of the annual Arbor Day, in addition to some enterprises and institutions in the society taking advantage of the good season of tree planting and greening in spring, all classes in the school are also busy making blackboard newspapers with the theme of Arbor Day. So, what are the unique materials of the 202 1 Arbor Day blackboard newspaper you have seen? Let's take a look at how to draw a blackboard newspaper about planting trees.

1. First, write the slogan "Arbor Day" in the upper right corner.

2. Then draw a big tree on the left.

3. Then draw a pencil case of a tree in the middle.

Next, draw two rectangular writing boxes up and down on the right.

5. Finally, color the painted elements with corresponding colors.

Origin of arbor day

The origin of Arbor Day is related to a historical figure, that is, Dr. Sun Yat-sen, who has made many great achievements in history, and advocating Arbor Day is one of them. Dr. Sun Yat-sen first proposed a large-scale afforestation plan after the Revolution of 1911. At his initiative, the Arbor Day in China was first set on July 30th, 19 15, and the date of Arbor Day was set as Tomb-Sweeping Day every year. Later, March 1925 and 12 were Arbor Day to commemorate Dr. Sun Yat-sen's contribution in advocating afforestation. Until the founding of New China, it was March 1979, the first Arbor Day in China.

Five Benefits of Arbor Day

First of all, forests can balance the carbon dioxide of the earth.

Forests are the main consumers of carbon dioxide. Every hectare of forest produces 10 tons of dry matter, which will absorb 16 tons of carbon dioxide and release 12 tons of oxygen, making the forest a huge oxygen storage. So afforestation has become the main way to slow down the greenhouse effect.

Second, forests can prevent wind and fix sand.

Forests can reduce wind erosion intensity by reducing wind speed and changing wind direction; The strong roots of trees, especially shrubs, can fix soil particles. Practice has proved that building windbreaks, combined with agricultural and water conservancy measures, can achieve good windbreak and sand fixation effects.

Third, forests can keep water and soil.

Forests can regulate runoff and water quantity in dry season, maintain soil and water, reduce river sediment content and alleviate flood disasters. The observation shows that the litter layer with the thickness of 1 cm can reduce the surface runoff to 1/4 of the bare land, and the sediment amount can be reduced by 94%. The amount of soil loss in bare land caused by rainfall is more than 1000 times that in forested land, but the soil consolidation ability of the combination of wild irrigation and grass is more than1000 times that of pure grass. It is estimated that China's forests reduce the total soil erosion by 24.6 billion cubic meters every year, reduce the soil organic matter loss by 384 million tons, and the soil protection value reaches more than 260 billion yuan. In addition, forests have a fundamental mitigation effect on preventing riverbed rise, floods and droughts.

Fourth, forests can conserve water.

Forest is a natural "green reservoir", which can promote the normal circulation of water, surface water and groundwater. When it rains, more than 20% of the rainfall is intercepted by tree crowns and branches and leaves, and 5% ~ 10% is intercepted and absorbed by ground leaves and weeds. Soil with granular structure in forest can quickly convert surface water into groundwater. According to incomplete estimates, the annual water conservation capacity of forests in China is 347.3 billion tons, equivalent to 75% of the total storage capacity, and the annual water conservation value is more than 250 billion yuan.

5. Forests can protect biodiversity.

Forest is the "home of species" and the biggest treasure house of biodiversity and biological gene resources. More than 50% species in the world inhabit and multiply in various forests, mainly natural forests.