Caring For The Trees, China

Chinese astronomers were among the first to record observations of a supernova. The work of the astronomer Shen Kuo (1031–95) alone was most impressive, as he theorized that the sun and moon were spherical, corrected the position of the polestar with his improved sighting tube, discovered the concept of true north, wrote of planetary motions such as retrogradation, and compared the orbital paths of the planets to points on the shape of a rotating willow leaf. With evidence for them, he also postulated geological theories for the processes of land formation in geomorphology and climate change in paleoclimatology.
Other important astronomers included Gan De, Shi Shen, Zhang Heng, Yi Xing, Zhang Sixun, Su Song and Guo Shoujing. Chinese mathematics evolved independently of Greek mathematics and is therefore of great interest in the history of mathematics. The Chinese were also keen on documenting all of their technological achievements, such as in the Tiangong Kaiwu encyclopedia written by Song Yingxing (1587–1666).
China's science and technology had fallen behind that of Europe by the 17th century. Political, social and cultural reasons have been given for this, although recent historians focus more on economic causes, such as the high level equilibrium trap. Since the PRC's market reforms, China has become better connected to the global economy and is placing greater emphasis on science and technology.