Generally patterns in firefighting aircraft are flown at the same traffic pattern altitude as everyone else. CDF has their own internal policies, but USFS and BLM both require adherence to local traffic pattern altitudes and procedures. Horsing around in the pattern isn't a good idea. A mid-air collision between a USFS Baron and a DC-4 at Ramona years ago was in part the result of at least one of the two aircraft (the Baron) still talking to the fire and not keeping his head in the game when it came to flying the traffic pattern.
Whereas much of the flight operation for firefighting aircraft is well below 200 when in the fireground, operating close to the surface isn't a big deal; it's done all the time. Just not usually at the airport. Departures when loaded, of course, often don't allow much excess performance, and one may remain low for a long time, struggling for altitude all the way to the fire.
I only did it with recip Droms in Aus, but I can tell being in the plane in that moment isn't exactly a calming situation either lol. Low and in the smoke surrounded by fire in a Polish POS isn't exactly a Sunday stroll.
I flew Dromaders for seven years doing SEAT work on fires, mostly with Garret and Pratt conversions. I had one engine failure in the Garrett conversion while working a fire and ended up making a forced landing during the fire. It made for a really long day, but didn't work out too badly.
I flew air attack for several years in various platforms, and flew several different heavy tankers, too. I did six years of ground firefighting, as well. I also flew Air Tractor 802's on fires, as well as 502's.
I liked the Dromaders; I got really comfortable in them, but the 802 was a much better machine for firefighting. Much more power, more capable, although not as forgiving a wing, and a lot less forgiving to land.
Cal Fire planes operate from their Air Attack bases, all of which have long paved runways. It's really cool to see how quickly they can refill and head back out.
Some bases have long runways. Hemet doesn't. Neither did Ramona. We often used all the runway, plus some.
When we get air tankers here for fires they only come out of Jacksonville which is approx 80 miles away. It is actually neat to watch as there is a spotter plane then the tanker follows and wherever the lead flies, the tanker is comes in about a minute later.
When operating in Florida, I dropped at NAS Jax, but operated out of Talahassee, Brooksville, Punta Gorda, Ocala, and Lake City. In the late 90's we had a lot of activity down there in Brevard and Voluisia counties.
Sometimes in the tanker we work off the lead, and sometimes the lead follows, depending on what's desired. Usually the tanker stays close to the lead, unless the lead is doing a show-me run to illustrate the line or the start and stop points. Sometimes it's more beneficial to have the lead above and behind, to call the drop. The P3's (such as T-22, in your picture) are gone. AeroUnion shut her doors.
Just a guess here but I'd assume that CDF planes often land at unimproved strips or perhaps just fields and dirt roads.
While I've done that many times in ag aircraft and SEATs, the CDF does not. There's no need.
You know what makes Ag flying dangerous? Boredom!
There's a certain amount of truth to that. Ag flying isn't dangerous until someone makes it so; the most dangerous part of ag flying is the pilot.
I was working one morning behind someone who went through a quad set of powerlines. We always flew with enough up-trim in that we had to hold the stick forward; a moment of inattention and the airplane would climb. The man ahead of me, a 15,000 hour ag pilot, dozed off, and was awakened by the sound of hitting those power lines. It tore off his wingtips, smashed his leading edges, shattered his canopy, cut through his propeller, pulled the spray booms off the wings, and messed the airplane up a little. When I asked him later what happened, he simply said "I fell asleep." Going back and forth in a field in the calm early morning hours, little breeze, atrazine and 2,4-D covering the windscreen until one can just rub a small spot on the lower left corner, enough to see forward, the rhythmic back-and forth with 30 seconds of straight and level each direction is like rocking a baby to sleep. It's all work, but those 30 seconds of relaxation, the straight and level between the turns, were enough.
It requires not one iota more skill than flying around at altitude.
Having done both a LOT, I'd tend to disagree with you. What it does require are specialized skills and attention to detail. An instrument approach requires thinking a long way ahead, where ag work is very much living in the moment. You concentrate on that next powerline until you're past it and then you throw it away; divorce the thought and concentrate on the ground right past the powerline. You pull and level and then push, hold 5', and now the ground isn't important but the standpipe or circle irrigation ahead is. It's the most important thing in the world, more important than family, church, or taxes, because if you gauge wrong, you won't go to church, see your family, or dodge taxes ever again. Get past that standpipe, and now it's the powerlines ahead; everything else is forgotten. It's that living in the moment, abandoning everything that just went behind and focusing on what's right in front, that makes it different.
Another aspect is fully using the performance envelope of the aircraft. With turns at the end of a field done at 75' to 150', the turn is often tight enough to feel the airplane buffet, and it's got to be done by feel. I used to do a lot of formation work in fields when I was a teenager; we did formation spraying largely to save on flags (dropped by an "automatic flagman" on the wing). In the turns, one worked the airplane tight in the turn, and had to deal with the wingtip vortices of the airplane ahead. The airplane would shudder and buffet, and we'd work it in and out of the buffet, with it trying to roll this way or that. It's very much a feel and true seat-of-the-pants kind of flying...until one gets into the smoke on a fire, and then it's a combination of all that, and instrument work, plus the particulars of working the terrain and escapes in the terrain, as well as doing precision application on the fire.
I've got lots of dead friends who would disagree that it doesn't require a special skillset to be doing that kind of work. It does. Even with that, and with regular practice, and a lot of experience, the job and the operation can still bite, and it often does.