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"Poisonous" does not mean deadly. Some manifestations of toxicity are subtle. The dose, as always, determines if a plant is safe source of nutrients or a toxic hazard.

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BRIEF: Does black locust wood affect horses?

I was wondering if Black Locust fence posts would be a problem when fencing in horses? The bark is removed and all posts are "oiled". If the horses chew the wood would it be toxic? Another quick question...we have some black walnut trees on this new property and am aware of the sawdust being toxic to horses standing on it but not ingesting the bark, leaves etc...IF my horses eat the bark, leaves etc...would this be toxic? I am located in central Wisc.


The posts should be OK, but what kind of oil? Horses bedded in black walnut sawdust sometimes have problems, but I am not aware of much trouble otherwise.