外来植物的引进和竞争的加强,会降低森林的经济价值并导致森林生物多样化。例如,具有生长迅速、生命周期短等特点的原产于东亚中国的乌桕(Sapiumsp)就是这类引进植物。自18世纪后期,乌桕做为观赏植物、油料植物或潜在的燃料多次被引入北美。随着不断地移植,该树种目前已分布于 The introduction of exotic plants and the intensification of competition will reduce the economic value of forests and lead to the diversification of forests. For example, Sapiumsp originating from East Asia, China, with its rapid growth and short life cycle, is the type of plant introduced. Since the late 18th century, black jackals have been introduced into North America many times as ornamental plants, oil plants or potential fuels. With continuous transplant, the species is currently distributed