Q: Eight years ago, when our house was built, the builders left a pile of pine trunks in our backyard. Today, it is a crumbling heap of free organic material. Can it be used for mulch or top-dress?
A: Decomposed tree trunk is no different from decomposed tree leaf. In other words, you have compost and it can be used freely in your landscape. If the material is composed of chunks smaller than 1/4 inch on a side, you can dig it in as soil conditioner. If the particles are larger, use them as mulch. Or you could separate the materials with a rake and have both conditioner and mulch.