Most of us learned as kids in school that lye is used to make soap. We learned that one must be very cautious handling lye because it acts like an acid and burns your skin. That little bit of knowledge almost made me stop using soap! I remember wondering why soap was safe to use! Thank goodness...
UNDER NO CONDITIONS EVER EVER BURN POISON IVY!!!!
The oil that causes the rash does not dilute or dissipate when cut down, uprooted, or whatever. When burned the oils rise in the air and you and any creature nearby breathe this oil into the lungs producing poison ivy rash inside the lungs...