(Portland, OR)  --  Officials say fireworks are to blame for two holiday-weekend fires that heavily damaged homes in the Portland metro area.  The first fire was reported Friday night at a home on Southeast Alder, where an aerial firework had landed on a porch awning.  Another home was destroyed around 2:45 Saturday morning in Hazel Dell, where officials say a bark dust fire that was caused by fireworks spread to the home.  No injuries were reported in either fire.