I have done the following:
When ever I stumble upon information about potential bow wood (on the internet or in books) I find the tree species in my handbook. If the species is relevant to my area, either native, introduced or grown in gardens I give it a bow wood grade (1-4 stars). Yew, Laburnum and elm has 4 stars, ash, plum, cherry, rowan, hazle, black locust 2-3 stars, willow and fir 0 stars…you get the point;-). The grade is highly subjective and based on my own preferences and experiences as well as other bowyers experiences.
I also add notes about how likely the species is to check while drying (VERY important), if its good for back/belly only or both and if it is poisonous or not!
I keep the book and a folding blade pull saw in my car:-)