Many types of vegetation are suitable for the role of markers, but those most available and conspicuous in the park area are the pine trees and their allies.
(Many types of vegetation; are; suitable for the role of markers) (those most available and conspicuous in the park area; are; the pine trees and their allies)
Many types of vegetation those most available and conspicuous in the park area
are are
suitable for the role of markers
the pine trees and their allies