One of the hardest things in arboriculture is determining how heavy a section of wood is. It takes years of experience and even then you might not get it right. Finally, there is an app to quickly estimate the weight of a piece of wood.
Log Weight Pro is available in the Apple App Store. In the app, you select the type of tree, the diameter, and length and it will give you the estimated green weight of a log. The application has weights for 156 North American tree species.
You can download the App here; https://itunes.apple.com/us/app/log-weight-pro/id1406080279?mt=8