Robyn - I know some folks are very cautious about even putting tomato plants or fruit into compost piles for fear of transferring disease. Other folks - not so much. Same with potatoes. As for your wood mulch, maybe just a thin, refreshing layer on top of the old? I wouldn't go more than 2" deep in total.
Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize that we can't eat money. Cree proverb