Despite your photograph, it is very difficult to ascertain what the white spots really are. We see that these are concentrated on the veining of the leaves (which may be the lowest point of  the leaf which when wet, picks up  fluid.) From the second photo, we learn there is no damage to the back side of the leaves. We're unable to enlarge specific portions of the leaf to see if the line of dots on the upper leaf is more white spots or perhaps  sucking insects, such as mites. Beyond these facts, we really don't know the answers to the following questions. Has there been any spraying of herbicides or pesticides in the neighborhood of the tree recently? Is the entire tree affected, or just leaves in one general area of the tree? Is the damage low on the tree, scattered throughout, or high in the tree? Do the leaves fall when affected? We could make a guess that an insect is scraping the leaves, but the back side doesn't show damage that is visible in the photograph.  It's possible the ash and smoky atmosphere have something to do with this, but we don't know how long this leaf condition has existed.  It's unlikely your lack of watering the tree is responsible, but sometimes droughty conditions can cause abiotic  damage. We strongly urge you to take the samples of the actual leaves that are damaged to the Master Gardener Plant Clinic, located at the OSU Extension Office at 569 Hanley Road, Central Point. (It is located on the portion of Hanley Road that is route 238). The clinic operates Monday through Friday from 10 to 2. The telephone is<personal data hidden>. The clinic techs can examine the leaves under a microscope if necessary and offer you a diagnosis and suggestions for care. And yes, you probably should rake and dispose of all leaves this fall: it's good practice for all fallen leaves. If they are not diseased or insect damaged, you can compost them or use them as mulch.