Additionally, many sections of the Wall and fortresses are located in sparsely populated mountainous areas, where villages are generally poor.
After the Great Wall lost its military defense function, the impoverished villagers living nearby used its materials to build houses, causing significant damage, he observed.
"Worse still, the hard access to those off-beaten tracks made it more difficult to detect and address the damages to the Wall," he says.
In 2000, Yang spotted a modern concrete road being built within the ancient section and became very anxious.
"It was a big compromise to the cultural relics and historical appearance," Yang says.
He took immediate action by reporting the problem to a local news outlet, which grabbed the attention of the local authorities.
It didn't take long before modern construction was called to a halt and gave way to a gravel path matching the surroundings.
In 2009, Yang founded the Xinzhou Great Wall Society, which is under management by the local cultural heritage administration.
The society has since played a positive role in Great Wall surveys, studies, promotion and protection, delivering many publications that provide crucial decision-making references for local preservation and development efforts of the Great Wall.
