Portugal, Greece, Spain, Chile, California and now Hawaii have all battled wildfires this year as high temperatures and strong winds have whipped small sparks into violent infernos.  But fire needs fuel, and what these places also have in common is an invasive species — Australia’s eucalyptus tree.  It comes from the oldest continent in the world and it can grow in even the driest of places.   For more than 200 years, seeds of the eucalyptus tree have been planted beyond the bounds of Australia’s coastline.  It has been cultivated around the world, making a new home in southern Europe, South America, parts of Africa, the west coast of the United States, and even parts of South-East Asia.  But there is now a debate over whether this tree has been worth the industry and habitat it provides.  Eucalyptus trees mature fast.  …Because the eucalyptus tree loves fire and fire loves it.