I’ve heard that deer will browse maples so if you’re trying to start some saplings, it might be good to protect them.
I did that with some maple saplings I started around our property, which is replete with deer.
My maple is a Japanese dwarf, and when I planted it as a baby a littile over one ft tall, I made a small hoop fence out of white PVC 1/2” pipe to protect it, mainly from dogs! Now it is around 6 feet tall.