Wei Xiaokuan (508-580 AD) was a famous soldier in the Western Wei and Northern Zhou Dynasties. He was born in Jingzhao Ling Du (now southeast of Xi 'an). According to the fifty-second record of li yanshou's Biography of Northern History in the Tang Dynasty, in the second year of the Western Wei Dynasty (AD 552), Wei Xiaokuan was awarded the secretariat of Yongzhou for his exploits.
Since ancient times, an earthen platform has been erected on the roadside every other mile on the official road as a mark for calculating the road mileage, which is now a milestone. After Wei Xiaokuan took office, he found that the soil platform had many shortcomings. After weathering by wind and sun, especially by rain, it is easy to collapse and needs frequent maintenance, which not only increases the state expenditure, but also makes the people suffer from hard work, which is time-consuming, laborious and inconvenient.
After investigation and understanding, Wei Xiaokuan resolutely ordered all the places where earthen platforms were set on Yongzhou Road to replant a locust tree instead of earthen platforms. In this way, it not only does not lose its marking and sliding functions, but also provides shelter for pedestrians and does not need maintenance. Wei Xiaokuan's practice is undoubtedly an important measure to benefit Mulberry, reduce the burden on the people in his hometown and benefit the country and the people.
Shaanxi, as the earliest place to plant trees on official roads in history, was once a model of road greening in China. Wei Xiaokuan's earliest Sophora japonica has been loved by people for thousands of years, especially Shaanxi people have a special liking for this Sophora japonica, which is widely planted. Now this locust tree has been identified as the symbol tree of Xi city.