Could be poisonous

Does anyone know what this is I think it is a sugar hackberry well with the weather changing leafs are starting to fall. And I see a whole lot of these in my back yard. The dogs have been having the runs for the last two days, some nasty slimy shit at first I thought someone was throwing poison In my yard so I kept an eye on the dogs I have been walking the yard every few hours then I see one of the dogs eating grass and the seed ,and leaf of this tree. Nothing has changed same food. Anyone have any advice on how I can get them to stop eating this shit also seen shit load of grass in their slimy shit any advice thanks in advance

 

By the pic's it does look like a Sugar Hackberry. Or it could be a dogwood. Is this the first time they have eaten the seeds and leaves? There are various reason dogs eat weird things. Have they been checked out by the vet to rule out a medical problem? You can train the leave it command.

http://www.petwave.com/Dogs/Behavior/Modification/Eating-Strange-Things.aspx

 

They are poisonous

 

dam for real i have like 4 trees 2big ones and 2 small ones

 

My mother in law has them in yard

 

Poisonous to dogs? http://www.wildflower.org/expert/show.php?id=8184

 

so its saying its no poisonous?

 

Thats how I'm reading it.

 

They are not poisonous. Humans can even eat them.