Here is another picture of a pear bonsai. I am pretty sure its a wild Callery pear. This type of tree is particularly tough and vigorous. It can outcompete many native plants and trees here in the Ohio River Valley and is a widely invasive species. I often set out on foot in search of good material to extract. The one in this picture is from an area near some railroad tracks. Railroad tracks are often a great place to tree hunt. Check your local laws regarding this activity, if you don't own the land that is, or risk being fined or imprisoned. There are a lot of great wild pear trees out there along with elm, mulberry, hawthorn, and even some catalpa and eastern red cedar. I honestly feel that the pear trees develop much quicker that the others. They have a higher threshold for abuse, including root trauma, which makes them easy to collect if you know what you're doing.