I smoke with alder 90% of the time and love it. I smoke pork sausage, kielbasa, salmon, salami etc. If you are using chips, great. I have a full size smoke house (4ft by 4ft by 8 ft) and cut down an alder from my property prior to smoking something. If you are using alder from a tree, make sure you remove the bark as it will leave a bitter taste and discolor the meat.
Start will lo temperature and slowly build up the heat. Good luck
Joe Fishin