How many tree species do you have in your yard?

[Denninmi]

And, are you actively trying to increase the diversity of your plantings?

I want to make a list of what I have. I already have a mental list of some of the ones I don't have that I want, which includes Stewartia, Zelkova, Halesia carolina, some type of large-flowered yellow magnolia hybrid, Katsura, and some cultivar of Linden.

I also need to make an effort to add more evergreens -- right now, I only have a couple of white pines and a couple of small spruce. I had a row of mature spruce and arborvitaes, but they got old and sad and ultimately unsafe, so I had to take them out before one of them took out my garage.

When the Emerald Ash Borer swept through SE Michigan (we were the site of the original infestation), it really taught people a lesson in biodiversity. Entire communities had been planted in monocultures of predominantly Marshall Seedless Ash, and entire streets would lose all of their trees at once over the course of one or two season.

Several communities made an effort to replant with a big diversity of species, and the results have been, IMHO, very impressive -- so nice to see all different kinds of trees along the streets.