What does it take to change the environment (without magic)?

[Alzrius]

So I'm thinking of running an E6 campaign with no full-progression casters (or, alternately, having them use Spheres of Power). It's supposed to be somewhat gritty, and being in a frontier area I'm going to be playing up interaction with the local environment. However, I'm having quite the hard time figuring out how to adjudicate how much time and what sort of rolls (if any) are necessary for some of these things:

1) Digging a pit - a 10-foot deep pit that's 5-feet wide and long (your basic pit trap, in other words) probably shouldn't require any rolls, but I'm not sure how long it takes to dig (without getting into all sorts of cumbersome equations...let alone issues of Strength scores, how many people can participate, adamantine shovels, etc.). This also goes for trenches.

2) Making a berm - roughly the same problem here, insofar as time adjudication goes. This is made with the displaced earth from digging a pit. I'm mostly confident no rolls are needed here either.

3) Chopping down trees - This one seems a lot simpler. Wood has hardness 5, and 10 hp per inch of thickness. The issue is that there's a question as to whether or not that's too much for "just" chopping a tree down, since usually that's enough to open up a 5-foot square in a wall.

4) Damming a river - I have no idea how to adjudicate this. Presumably there's some sort of skill check involved, and the dam would have hardness and hit points?

5) Salting the earth - Alkalizing a patch of earth so it won't ever grow anything again (at least for a while). For a 5-foot by 5-foot patch of earth, how much salt does this take, how much would that salt cost, and how long would it take to do this? Would any rolls be involved?

6) Erasing a scent - Obviously a stronger scent can cover up a weaker one. But besides a powerful chemical, or a skunk, what can do this? Is there a scent equivalent to covering yourself in mud to hide your body heat? There's presumably some intersection of Perception and the scent ability here, but the specifics seem vague.

7) Insects as irritants, not threats - Presuming that things like mosquitoes don't become deadly swarms, what's a good way to treat them as irritants that have some sort of mechanical effect don't rise to immediately life-threatening dangers?

8) Sleeping in trees - This isn't really an issue of altering the environment, but I'm not sure if I should hand-wave this or not. Would this require a Reflex save not to fall out of the tree during the night? Can you get sufficient rest while tucked in branches?

9) Camouflage - I really don't like the idea of this being limited to rogue talents and racial traits. Are there any rules that generalize this?

10) Smoke signals - I'm tempted to have this just be a language, taken with a single rank in Linguistics. Presumably there wouldn't need to be much of a Perception check within a few miles, at least during the daytime.

[Claxon]

Pathfinder just isn't the sort of game designed for this.

You're creating a survival type game, and Pathfinder just isn't that kind of game. It's a heroic quest game, not tame the wilderness and try to survive.

As you're noticing you really just have to make up a lot of stuff that no one ever really thought about because that's not the focus of the game.

I would personally recommend you look for other game systems that are designed to support this type of game.

[Alzrius]

That's not really an option for me. Even leaving aside that I'm not sure what game that would be, trying to get my group to learn a new system is like trying to make cats walk in a parade.

I can conceivably persuade them to play a low-level Pathfinder campaign with a wilderness focus. I'm not nearly as confident of getting them all to learn a new system.

[Grovestrider]

Alzrius wrote:

3) Chopping down trees - This one seems a lot simpler. Wood has hardness 5, and 10 hp per inch of thickness. The issue is that there's a question as to whether or not that's too much for "just" chopping a tree down, since usually that's enough to open up a 5-foot square in a wall.

If you are indeed using Spheres of Power, the Geomancer's Handbook has basic stats for different sized trees (which may be useful), you can see the table here (if you scroll down a little).

[Vatras]

I was going to say you need shovels...and water. But mostly shovels.

1) It does not really matter what your shovel is made of, once it is good enough to do the job. Your basic pit has roughly 8m³ earth and let's say it takes 4-6 hours to dig. Then what happens with the earth? Just digging it up is usually not the idea, you have to transport it somewhere else, too. Afterwards you may want to fortify your earthworks or it won't last. From this it would take about 10 man hours for the job.
All you need to do is to assign a skill for the work, which already includes the attribute bonus, and can - if you really like - be bolstered by magical adamant shovels. If the PC succeeds at the check, he progresses normally, if he fails he needs double time, and if he succeeds critically, he gets it done in half. DC is determined by terrain, say 15 for earth, 10 for sandy ground and 20 for rocks strewn in.
There would be just enough space to split the work, so you can divide the hours between two. For larger earthworks you simply calculate the total hours and divide by the number of workers.
This is a very rough attempt, but you don't really need mathematical precision here.

2) Building a structure that will withstand something - like 100 man passing across - take way longer than moving earth, and also some construction material, typically timber when we think of the roman legions. Maybe take a look at the construction time/costs in various D&D books for examples.

4) That takes an engineer to work out how, and the workers to do it. The check would be against the craft skill I suppose, since he will supervise the work, too.

5) As a wild stab in the dark lets say 1 lbs per 10' square. It cannot have been too much, since that was also a valuable commodity back then.

6) Vinegar. That will cover most stuff.

7) Maybe use a new condition (pestered?) with some sort of penalty associated with it. Might also carry a risk of disease like malaria.

8) I have never seen someone do it, so I am skeptical.

9) Yes, use a skill for it.

You can find stuff in some older books, if you go looking (AD&D 1E and 2E), and also in the Basic D&D books dealing with building player dominions. But as Claxon says, this is a sideshow in the books at best.