Translation:There are more than one hundred cars in the middle of the forest.
I find the verb "standing" to be generally awkward in English in reference to a car that is not in motion. What I mean is that it is usually understood and left out with the understanding that "there are" covers their (inert) existence at a given place. Standing is redundant in my opinion.
It is called the expletive construction. It is a rule of the English language, not Czech. At least as I have been thaught them at school and as I learned English from reading and listening to English speakers.
As I am not a native English speaker I can be easily wrong. But I believe it is necessary here.
An expletive by definition is without meaning, so why would it be necessary?
Universities are encouraging their students not to use them in their texts actually, for example see: https://writing.wisc.edu/Handbook/CCS_expletive.html