Complex sentence: The woodland has suffered bigger alterations, since most autochthonous species (like the fig tree or the rebollo) are now reduced to symbolic representation, since the reforestation of nearly one fourth of the surface with pine trees and eucalyptus.
Split into simpler sentences: The woodland has suffered bigger alterations, since most autochthonous species (like the fig tree or the "rebollo") are now reduced to symbolic representation. The reforestation of nearly one fourth of the surface with pine trees and eucalyptus.