Today there are more fires than in the past . Over 100,000 wildfires burn each year in America . Russia has 20,000 to 35,000 wildfires and Australia has about 60,000 each year. These fires destroy huge areas of forests and burn hundreds of homes . Many experts believe there are several reasons for this sudden increase in fires. The first reason is climate change . In 2010, Russia had the hottest and driest summer with strong winds in a century. In just one month, 500 fires destroyed over 2,000 homes. Some people lost their lives . Traditional fire-fighting practices are another reason for the increase in fires. In America, firefighters used to quickly put out every fire as quickly as they could. They didn't allow the grass and trees to burn. As a result , today many forests have thicker vegetation which provides more fuel for fires . So surprisingly, America has many more fires today partly because of its past fire-fighting practices. Scientists now understand that a fire can be a natural part of a healthy forest. As a result, countries like Australia allow some fires to burn naturally. The fire makes old trees thinner. This allows sunlight to reach the ground. As a result, fires help new trees to grow. Therefore , if a fire is not a serious threat to people , firefighters may let it burn naturally . Russia had so many fires in one month in 2010 because   _   .
lightening spread the fire there was much fuel for fires there were not enough firefighters it was very hot , dry and windy