TTrifoliate orange Tree in Sagi-ri and Gapgot-ri
Trifoliate orange trees planted in the Sagiri and Gapgotni (natural monument No. 78 and 79 respectively) zone are an environmental evidence that Ganghwado might be a northern boundary where trifoliate orange trees can not grow in the north beyond this geographical point.
Plantation of these trees were considered able to hold back the enemies' penetration underneath the castle wall. These are one of defensive relics that imply our ancestors' concern for the means of national defence.