"I think half of that shade tree shit is, 'If it cranks up and runs...'"
Back in the last century, when men were men and Pluto was a planet, cars used to come devoid of any computers or microprocessors. What you did to your engine was between you, your distributor and your head bolts. It was a great time for car tinkering. Fortunately for a lot of wallets, it was also a great time for fixing your own car when it broke down. This potential for this low tech servicing gave rise to the shade tree mechanic.
It should comes as no surprise that working on a car is taxing, both emotionally and physically. Alcoholically, too. So on those hot summer days, it was best to work under the cover of a large shade tree. Otherwise you may sweat so much that the beer slips out of your hand. Driving or pushing a car under a large oak would therefore produce ideal tinkering conditions.
Alright, that's one mystery down. No gold stars for figuring that one out ahead of time. But what I would like to know is where this term came from exactly.
Even farther back in that manly-man, Pluto-planet century, there was a group of unexpected hotrodders: shine runners. While the east coast ran shine, the west coast ran like hell. All manner of speed records were set on the salt flats. A number of great names started their dynasties out there, but last time I checked, Bonneville didn't have a lot of trees. I tend to think that the title of "shade tree mechanic" probably got started in the back woods of the east coast, due to the amount of sly mechanicking and trees. I say "back woods" because even if your home has a tree with which to shade, there's no way in hell you're going to kill the manicured grass overnight with car fluids. But when you have 20 acres and at least one tree that has been growing for 60 years, there's no grass left under it anyway and nobody cares.
Regardless of the origins, shade tree mechanics sometimes get a bad rap due to an inherent lack of formal training. Some of these guys are more "parts changers" than "mechanics," I'm sure. Still, I personally don't think the title is derogatory in any way. I know several people who qualify as shade tree mechanics, and believe in them wholeheartedly. If you don't mind waiting a little while longer to get your car back, Shade Tree Inc is a great place to have your car fixed. Especially when you leave civilization and get out into the country, all the mechanics you'll encounter earned their stripes at Shade Tree U.
Unfortunately, the rise (to ubiquity) of onboard car computers has thinned the ranks of shade tree mechanics. The scary voodoo electronics scare off most people from working on their car anymore. I think anyone who is intimidated by OBD computers is overreacting, but that's just me. A large part, if not all, of the old shade treers got into it because they could make their car go faster. Nowadays, some of the adjustments that could previously be made by hand are exclusively in the realm of car computers so I can understand the old guard becoming disinterested. But I promise it's not as bad as anyone thinks, just go out there and turn some wrenches. Best to bring a drink too.