I have been told in the past silvers were poisonous and was relieved, as my entire horse pasture is surrounded by sugars. For seven years, not one issue with this and 3 horses. I planted a bunch of ashes, known to be safe, in as added shade which one horse has taken to eating the bark off and killing the big ones. I almost bought Autumn Blazes as replacements, but did a little research only to find Ontario scientists and Cornell U researchers say all Reds are toxic but Cornell says silvers and norways are okay. Ontario says silvers are bad too. I don't know what to believe. As Autumn Blazes are hybrid, are those known to be more or less toxic than reds? I don't like the "better safe than sorry" approach much...I like to know, can I plant silvers or norways, and would the Blaze be okay?