Here's why:
* The "a" in "Ashley" makes the short "a" sound, like in "cat" or "hat".
* Long vowel sounds typically have a single vowel followed by a silent "e" at the end of the word. For example, "ate," "cone," "bike."
* The "e" at the end of "Ashley" is pronounced, not silent.
Therefore, the vowel sound in "Ashley" is considered short.