《管子·地员》
五种沃土，无论在丘在山，在陵在冈，无论在边角之地，或在丘陵阳面，左右两侧，都适宜于下列树木：桐、柞、扶栘和椿树，此外还有白梓。
五沃之土，若在丘在山，在陵在冈，若在陬，陵之阳，其左其右，宜彼群木，桐、柞、枎、櫄，及彼白梓。
The five fertile soils are suitable for the following trees regardless of whether they are on hills or mountains, on ridges or slopes, or at the corners, or on the sunny side of hills and slopes: paulownia, oak, Zelkova schneideriana, and Evodia, as well as white Zelkova.