Soften yeast in lukewarm water. (Use warm water for dry yeast.) Pour scalded milk over sugar, salt and butter. Cool to lukewarm. Stir in 1 cup flour and eggs. Add softened yeast and oats. Combine 1/4 cup flour and candied fruits; stir to coat fruits evenly with flour. Add to dough; mix well. Stir in enough more flour to make a soft dough.
Turn out on lightly floured board or canvas; knead until smooth and satiny, about 10 minutes. Round dough into ball; place in greased bowl; brush lightly wtih melted shortening. Cover and let rise in warm place until double in size, about 1 hour.
Punch dough down; cover; let rest 10 minutes. Divide dough in half. From one half, pinch off 17 pieces of dough; shape to form balls. Arrange balls in the shape of a Christmas tree on greased cooky sheet. Brush lightly with melted butter. Repeat with other half of dough. Cover; let rise in warm place until nearly double in size, about 1 hour.
Bake in preheated moderate oven (375 F.) about 20 minutes. Decorate with confectioners' sugar frosting and candied citron.