Winter Tree Finder:
A Manual for Identifying Deciduous Trees in Winter
May Theilgaard Watts & Tom Watts
A pictorial key to winter identification of deciduous trees of the eastern United States and Canada.
Nature Study Guild Publishers.
To select from a dropdown list of genera, type only the first 2-3 letters.
If "briar" doesn't deliver the results you want, try an alternate spelling such as "brier", etc.