Many great poets in the Tang and Song Dynasties in China, on the one hand, cared about the sufferings of people's livelihood and collected a large number of Zhi Zhu ci and folk songs from all over the country; On the other hand, he loves nature and is good at understanding the hints of birds and flowers, imitating such folk songs and bamboo branches and writing poems. Moon, dew, wind, clouds, flowers and birds are a language of nature. Through this language, we can understand the nature, that is, the laws of nature, and poets can better grasp the meaning of this language, so they can write poems and pass them on to future generations. In the sense of natural rhythm, phenology is a cyclic process of moon, dew, wind, clouds, flowers and birds in a year. Great poets in the Tang and Song Dynasties made great contributions to the singing of phenology.
People living in the tropics and subtropics hope that autumn will follow midsummer. However, what is the indicator of the arrival of autumn? As we all know, the word "autumn" in Chinese characters comes from the word "harmony", and Shuowen regards the word "autumn" as a solution to the maturity of five grains. Mid-Autumn Day in German is the same as harvest, and autumn in English means autumn. In fact, the phenological explanation of autumn can be found in the poems of China poets in the Tang and Song Dynasties. The idiom "quite critical" is an important index to reflect meteorological information with biological information. "Quite critical" comes from the Tang poem "A monk in a mountain can't figure out the number of Jia Zi, and a leaf falls to know the autumn on earth." Evolved. Why do leaves fall in autumn? It turns out that there are many small holes on the leaves of plants, which are called stomata. Some trees have more than 10000 stomata on the leaf surface. These holes are channels for water vapor and other gases to enter and exit. The autumn wind is cool, the temperature drops day by day, and when the air is dry, the water in the trees evaporates and transpires quickly, but the water absorbed by the roots can't keep up with the evaporation and transpiration consumption of the leaves. When water and nutrients are insufficient, the trees themselves no longer adjust themselves and the leaves begin to dry up. In order to survive, trees form an isolation layer at the junction of petiole and leaf stem. Coupled with the low temperature, chlorophyll is destroyed, lutein becomes active, leaves will turn from green to yellow, and fall under the action of autumn wind and their own weight.
When Tang Bai Juyi was a teenager, he wrote a poem praising grass ("ancient grass"): "The vast sea of grass, four seasons come and go, wildfire never quite consumes them, the spring breeze is blowing high. ..... "These four five-character poems point out two important laws in phenology: first, there is an annual cycle of the rise and fall of fragrant grass; The second is that this cycle changes with the climate, and it wakes up as soon as the spring breeze comes to the grass.
People in temperate regions hope that spring will come after a cold winter. But what is the sign of spring? This can also be found in many Tang and Song poems. Li Bai's poem: "The east wind is green with porridge and grass, and the purple palace and the red building feel good in spring." Wang Anshi wrote a poem in his later years: "The spring breeze is green in Jiang Nanan, when will the bright moon shine on me?" Later generations verified that when Wang Anshi wrote this poem, it was originally written as "Spring Breeze Comes to Jiang Nanan Again". After repeated deliberation, he thought that the word "Zhi" was inappropriate and changed it several times before writing the word "Qing". Li Bai and Wang Anshi use green words to symbolize the arrival of spring in their poems. Today, in phenology, the flowering of flowers and trees has become one of the important signs of the arrival of spring. To be sure, the greening of trees is a very important indicator in early spring. However, all kinds of trees paint green at different times. What kind of tree can be regarded as an indicator of early spring? Judging from the chanting of poets in Tang and Song Dynasties, Liu Yang is the most valued. It is no accident that willow was chosen as the representative of early spring. First, because willows bloom early; Secondly, because it is widely distributed, it is everywhere from Wuling in Nanling to Beiguan. It is not afraid of wind and sand, and it is not too low-lying. Tang Yili said in a poem: "The desert in spring reaches the Hutuo River in the south, and the green willows and green Saimaduo." Liu Yuxi wrote "Zhi Zhu Ci" in Sichuan, saying: "The bamboo building on the river is sunny and rainy, the spring scenery in the west, and the willows in the east of the bridge. People come to sing. " It shows that from the desert south to the east of Sichuan, everyone regards green vitamins as a symbol of spring. The quatrain in Wang Zhihuan's "The Great Wall" is: "Why should the Qiangdi complain about the willow? "The spring breeze is just the Yumen Pass", which means that you can only hear the willow tunes from the flute outside the Great Wall.
Poets in Tang and Song Dynasties are also very concerned about migratory birds. They pay attention to swallows in early spring, rhododendrons in southwest, and rhododendrons in north China and east China in late spring and early summer. For example, when Du Fu entered Sichuan in his later years, he wrote clearly about the distribution of cuckoos in his poems: "There are cuckoos in Xichuan, there are no cuckoos in Dongchuan, there are no cuckoos in Fuwan, and there are cuckoos in Yun 'an. ..... "Lu You, a poet in the Southern Song Dynasty, wrote an early winter poem at the age of 76:" Poems drain light all his life, and he loves early winter frost. The better the maple leaf, the more fragrant the plum blossom. ..... "This proves that Lu You knows phenology. He not only pays attention to phenology, but also uses it to predict agricultural time. For example, the poem "Birds Singing" can illustrate this point: "Savages have no calendar days, and birds singing know the four seasons. Listen to the rules in February, and spring ploughing is not too late; Smell orioles in March, and young women pity silkworms for hunger; Rhododendron in April, silkworm on the cluster; In May, Uncle Ya rang, and the young plants were worried. ..... "Therefore, Lu You can be called a poet who knows natural language.