There are many more trees in a few years ago in the world.句中的many more我认为many是作为副词,但是字典上却没有many作为副词的用法,而I ate much more meat than you.中much是作为副词修饰吧?
我明白了,much more后跟形容词或副词时,more是比较级,如more beautiful,much是程度副词,而much more加不可数名词时much是形容词,more是比较级much more water即 more much water更多的水,many more加可数名词同理
参考资料:baidu,sina