The extreme heat that has been in the Columbia Gorge over the last few days has been rough for cherry orchardists in the region.  Oregon State University Extension Agent Ashley Thompson says the cherry harvest was very good early on, but the high, sustained heat is stressful on the fruit and the trees.  She says later varieties can be significantly impacted.  Thompson says the heat causes the cherries to lose firmness, and stem retention goes down.  Thompson adds good irrigation management is key to helping protect the fruit during the heat.  She also says Mid-Columbia Agricultural Research and Extension Center is studying other heat protection methods, including using shade cloth and using a clay based product to surround and protect the fruit.