Trees fall down after 18 months? Is he talking about Christmas trees at Trump Tower they forgot to remove?
They don't explode because they're dry, they explode because of their sap. Same is known to happen to trees when they are struck by lightning.
The cones of Pinyon pines REQUIRE heat from fire to open and scatter their seeds. And they're not the only plants in the area that need fire to sprout. It's called a Fire Dependent Ecosystem for a reason.
He wasn't "L" word-ing (I got 48 last July for using that word in regards to him, so I can't post it), he was just, as usual, making things up.