How is fire bad?

Answer 1

Fire is bad if it goes up in the wrong place at the wrong time where it threatens lives and homes.

However, fire is not bad in the natural ecosystem. Depending on the plant community or biome, fires have, can (and still should) occur every 5 to 10 years (grasslands) to every 10 to 40 years (some forests like the boreal) all to reduce litter content and put nutrients down for more plants to grow and to encourage plant growth.

What is bad about wildfires, though, is the infrequencyin which they occur due to human efforts to prevent any means of starting a fire. For example, the tall-grass prairie naturally and normally had a fire frequency interval of around 3 to 5 years. With human involvement and efforts to prevent fires from occuring in such grasslands, we end up with a plant community that hasn't seen a fire in 20, 30, even 50 years. When that happens, we get a huge build up of litter over time, less biomass production from live grasses, and when someone throws a cigarrette out of a vehicle or lightning hits, the fires that do occur there occur with a rabid intensity that is truly frightening, far more frightening than if that native grassland was allowed to burn more frequently. It's no different with forest fires: The longer fires are withheld from a forested area and the more litter is built up, the more intense and ferocious the fires.

Answer 2

Fire isn't bad if it's not threatening peoples', pets' or livestocks' lives and property: Fire is the second worst damage that can take place in a building (flooding is topped as the worst), and a scary thing because it can kill or leave someone scarred for life.

When in a natural ecosystem like a forest or grassland, it's a natural disturbance that is needed by these plant communities to sustain life, a natural balance and biodiversity. It is a means to "cleanse" a rangeland (which encapsulates not just grasslands but forests [and tundra] as well) of dead organic matter in order to encourage more life to spring forth. For example, you might think that a forest fire of the boreal forest or of the montane regions destroys everything, but not long after you find an abundance of new life coming in to replenish what was once lost. Grasslands are no different: everything is black and desolate at first, but a week or so later new grasses begin to emerge, and pretty soon the land is green again.