What has caused the widespread decline of the american chestnut tree ?

Chestnut curse. Ulcers brought about by the contagious disease cause the bark to part.  It is the primary driver of chestnut scourge, an overwhelming illness of the American chestnut tree that in the mid 1900s caused a quick, across the board cease to exist of the once copious tree from its noteworthy range, in the Eastern United States.  

The airborne bark growth spread 50 mi (80 km) a year and in a couple of decades supported and murdered up to three billion American chestnut trees. Rescue logging amid the early long stretches of the scourge may have accidentally crushed trees which had large amounts of protection from this malady and consequently irritated the disaster.

Chestnut curse. Ulcers brought about by the contagious disease cause the bark to part. It is the primary driver of chestnut scourge, an overwhelming illness of the American chestnut tree that in the mid 1900s caused a quick, across the board cease to exist of the once copious tree from its noteworthy range, in the Eastern United States.

The airborne bark growth spread 50 mi (80 km) a year and in a couple of decades supported and murdered up to three billion American chestnut trees. Rescue logging amid the early long stretches of the scourge may have accidentally crushed trees which had large amounts of protection from this malady and consequently irritated the disaster.

Explanation: