ALJUN The marvels of nature and the genius of medieval Arab military architecture have given northern Jordan two of the most important ecological and historical attractions in the Middle East: the sprawling pine forests of the Ajlun-Dibbine area, and the towering Ayyubid castle at Ajlun, which helped defeat the Crusaders eight centuries ago. Ajlun Castle (Qal’at Ar-Rabad) was built by…