Hi Di, 

They send these questions to the closest county extension, thus you get me. Just like yourself, I'm not aware of anyone taking tree limbs for mulching purposes. Unfortunately, our area hasn't yet grown into yard waste recycling like some of the communities up north so generally folks just have the options of burning, composting, or trashing their yard waste. I don't think it would hurt though to reach out to tree trimming companies and see if they'd be interested since I do think they offer the mulch they create to customers.