Fireflies in a forest at night can be quite magical, especially when they just hatch and there are thousands upon thousands of them all emerging and flowing between the trees.
However, fireflies (all those little white specs) in your rendered images in Blender 3D can be quite frustrating. They are usually a result of lighting in your scene.
But there are some different options to try to reduce and/or remove those fireflies. One good source I found is on BlenderGuru.com.