This year s Arbor Day , Wang Jingtong, a few months and days is Arbor Day, and this year is the fir

For one, forests balance the planet's carbon dioxide. Forests are the main consumers of carbon dioxide, and every 10 tonnes of dry matter produced per hectare of forest absorbs 16 tonnes of CO2 and releases 12 tonnes of oxygen, making forests a huge reservoir of oxygen. Therefore, afforestation has become the main way to mitigate the greenhouse effect.

Second, forests can prevent wind and fix sand. Forests can reduce the intensity of wind erosion by reducing wind speed and changing wind direction; The strong root system of forest trees, especially shrub trees, can hold soil particles in place. Practice has proved that by creating windbreak sand forests and cooperating with agricultural and water conservancy measures, good windbreak and sand fixation effects can be achieved.

Third, forests can maintain soil and water. Forests can regulate the amount of runoff and the amount of water during dry seasons, as well as conserve water and soil, reduce the sediment content of rivers, and reduce flooding. Observations have shown that a 1 cm thick layer of leaf litter can reduce surface runoff to 1 4 of bare ground and reduce sediment by 94 .

Rainfall causes more than 100 times more soil loss in bare land than in woodland, but the soil retention capacity of trees, shrubs and grasses is more than 1,000 times that of pure grass. Some calculations show that China's forests reduce soil erosion by 24.6 billion cubic meters every year, reduce the loss of soil organic matter by 38.4 billion tons, and protect the value of soil by more than 260 billion yuan. In addition, forests also play a fundamental role in mitigating the prevention of riverbed elevation and floods and droughts.

Fourth, forests can conserve water. Forests are natural "green reservoirs" that promote the normal circulation of sky, surface and groundwater. When it rains, more than 20 percent of the rainfall is intercepted by the canopy and foliage, and 5 10 is intercepted and absorbed by ground leaf litter and weeds.

According to incomplete estimates, the annual water conservation capacity of China's forests is 347.3 billion tons, equivalent to 75 of the total number of reservoirs now, and the annual water conservation value is more than 250 billion yuan.

Fifth, forests protect biodiversity. Forests are the "home of species" and are the largest repositories of biodiversity and biological genetic resources. More than 50 of the world's species inhabit and thrive in all types of forests, mainly natural forests. Agree with 0|Comments.

On March 12, China officially designated March 12 as Arbor Day in 79 years. I guess it's 34.

March 12 this year is the 27th Arbor Day in China.

March 12 is Arbor Day, the 27th.

In February 1979, the sixth meeting of the Standing Committee of the Fifth National People's Congress passed a resolution to designate March 12 as China's Arbor Day according to the proposal of the People's Republic of China, so 2008 is the 30th Arbor Day!

On July 31, 1915, China ** stipulated that the annual Qingming Festival of the lunar calendar was the Arbor Day. Count as the 93rd.

If you are born in 1872, the Arbor Day in Nebraska, USA, is 136 years.

The theme of Arbor Day in 2015 is: Beautify the environment and clean the air.

Pay extra for previous years.

The theme of Arbor Day in 2009 is: Let the forest enter the city, let the city embrace the forest.

The theme for Arbor Day 2010 is: Together with the Big Trees.

The theme of Arbor Day in 2011 is: Pursue green fashion and move towards green civilization.

The theme of the 2012 Arbor Day is: Voluntary tree planting to build a green and harmonious home, planting greenery and protecting greenery to create a provincial demonstration civilized city.

The theme of the 2013 Arbor Day is: to carry out in-depth afforestation and greening, and vigorously promote the construction of ecological civilization.

The theme of Arbor Day 2014 is: Embrace Spring, Sow Green.

Tree planting is the standard, tree protection is the foundation, I participate, I am happy!

Arbor Day in the first quarter.

China's Arbor Day was initiated by foresters Han An and Ling Daoyang, and was originally set to be celebrated on April 5, the Qingming Festival, but was changed to March 12 after the death of Dr. Sun Yat-sen.

Arbor Day is in the first quarter of this year, and this year there are 91 days.

Arbor Day is celebrated on March 12 every year, and this year's Arbor Day falls on Thursday.

Our country's Green Arbor Day falls on March 12 every year, and this year's Arbor Day falls on Thursday.

1. If the number of trees planted in class 62 is x, the number of trees in class 61 is 3 2x, and the number of trees planted in class 63 is 4 3x

3 2>4 3>1 The 61st class is the most.

3 2x+x+4 3x=299 gives x=78

Tree planting in class 61 3 2x=117 Tree planting in class 62 x=78 Tree planting in class 63 4 3x=104

2. Let Xiaohua's speed be x, then Xiaoqiang's speed is 9 7x, Xiaohua's time to run 50 meters is 50 x, and Xiaoqiang's time is 50 (9 7x)=350 9x

Xiaohua uses more time than Xiaoqiang for 50 x-350 9x=100 9x

Let Xiao Ming's velocity be y, then Xiao Hui's velocity is 4 5y

It takes Xiao Ming 50 Y to run 50 meters, and Xiao Hui takes 50 (4 5Y) = 250 4Y

Xiao Hui uses more time than Xiao Ming for 250 4y-50 y=50 4y

Since Xiao Hui and Xiao Ming reach the end point at the same time, the time spent on both sides is equal, that is, 100 9x=50 4y

Simplified, the velocity ratio of x y=8 9 Xiaoqiang and Xiaohui is 9 7x:4 5y=10:7

3. Let the total weight be 1 and the excellent weight be x

The income from selling separately is 6x+3(1-x).

Do not sell separately for income.

If the income from selling separately is 3x+> to get x>

That is, when the excellent is exceeded, the income from selling separately is large.

Arbor Day in China is scheduled for March 12. In February 1979, the Sixth Session of the Standing Committee of the Fifth National People's Congress of China decided to designate March 12 as China's Arbor Day. In December 1981, the Fourth Session of the Fifth National People's Congress passed the "Resolution on Carrying out the Nationwide Voluntary Tree Planting Campaign", and promulgated the specific implementation measures of the National Voluntary Tree Planting Campaign in the following year.

Before and after Arbor Day, all parts of our country should concentrate on afforestation activities.