We now know after the latest trailers for C5 that Bridlewood is not the Everfree from G4, which may have possibly existed as the home of the Breeziers back when the Mane 6 were alive.
The case of troggle ghosts in C4 and the many mysterious crystals that could store magic is a solid indication that Bridlewood may have been a magical disaster area as a result of war. This may have made the ecology of the forests vulnerable with endangered animals and plants entering into a dependent relationship maintained by the latent magic. Bridlewood may have been a magical nature conservation park during Twilight’s reign, and became an attractive tourist destination with a resort for travelers, especially from Canterlot.
The Troggles were a warrior people loyal to Grogar in G1, and it is possible that these had fought against Gusty the Great and her army of unicorn warriors who may have eventually exterminated the entire tribe and razed their home - which may have been Bridlewood. This may explain the crystals, they may have been conjured up as weapons against troggles, and frequent use of war magic may have destabilized the area so much that it acquired its own special magical character.
Gusty and Grogar were likely in a merciless war back then, and what we know about Gusty from G1 means that such ruthlessness is not unlikely - she was not only known for her bravery and fighting spirit, she was described as being stubborn and impatient, who can be translated into decisiveness in her choice of action. When Grogar was the emperor of all he sees, it wasn’t just monsters he used to hold onto power, he had an empire of loyal warrior hordes at his disposal, and the troggles were possibly infamous and feared.
Bridlewood several thousand years ago - likely long before modern Equestria arose, as it is possible that after defeating Grogar, the ponies left middle Equestria to become depopulated - may have been razed to the ground with unstable magic, which eventually produced a unique area with its own fauna such as the Breeziers, who were possibly a nomadic people as seen in G3, made their home in later times. It may also have produced the magical trees with crystal in them, which may have been known in G4.
The unicorns who fled to Bridlewood, a magical forest, learned how to live in harmony with their surroundings because even though the magic was gone - it was only the ACTIVE magic, not the INTERNAL magic of animals, nature and the celestial bodies. The magic of Bridlewood was not gone. And perhaps the unicorns’ antipathy to magic came from this. Izzy knows this, which was why she had warned Pipp against picking too many flowers, which are definitely magical and therefore part of the internal magic of the forest.
