Problem: Choose the best answer. Why are natural brush and forest fires important to some ecosystems? Need Assignment Help? Many atmospheric ecosystems benefit from the chemicals released by brush and forest fires. Many forest ecosystems depend on fire to remove small brush and dead branches to keep a devastating fire from occurring. Some plants require the heat of the fire for the seeds to germinate. Some ecosystems become so destructive that they need a fresh start. 11) Select four ways that humans cause change in ecosystems. reducing carbon emissions carbon in the atmosphere channelizing rivers destroying entire habitats preserving natural habitats introducing new species