GRE Reading Comprehension: JiJing 352-GRE阅读机经352篇 - 5RR5VL5HCPHG25TYK

Seeding a forest with nonnative species after a fire can impede native plant regeneration and spread invasive species in vulnerable fire-affected soils. Moreover, native seed sources are almost always sufficient for early nature reestablishment of native species, so planting should be considered only when natural regeneration is unlikely. Replanting dense stands of fast-growing conifers – a common postfire management practice – truncates the biologically rich early stage of ecological succession and can increase the severity of future fires. Other treatments should be carefully scrutinized for their potential to spread noxious weeds. For instance, straw mulch applied extensively to reduce erosion after the 2002 Hayman Fire in Colorado was contaminated with cheatgrass, an invasive grass difficult to control or eradicate once established.