How to classify a region that could qualify as more than one terrain?
 

The terrain types (for things like Survival) are pretty good broad classifications, but I'm not clear where to put regions that fit into multiple categories. A few examples:

Taiga (Arctic and Woodlands)
Montane forest (Mountains and Woodlands). These can also be cold enough to qualify as Arctic.
Something like the Aleutian islands (Island/Beach and Arctic)

Re: How to classify a region that could qualify as more than one terrain?
 

Allow either Survival skill.

Re: How to classify a region that could qualify as more than one terrain?
 

It depends more on the situation. I would use the most appropriate for the situation and in some cases either skill.


Taiga in the winter would be Arctic as the main challenges are likely coldness and similar issues, in the summer more like woodlands.

Montane forest, things that have to do with not falling into crevices and similar would be mountains, but foraging more like forests.

Aleutian islands, are more like Arctic for the cold, but Island/Beach for foraging..

Re: How to classify a region that could qualify as more than one terrain?
 

Some options:

• Only one: Decide if it's more one or the other and pick that one.
• More like one than the other: Pick a favored terrain but allow rolls against the other at a small penalty (say, -2 rather than going with a default).
• Both are good: Allow rolls against either terrain type
• Both are necessary: Roll against the average of specialties.

Which one to pick? Depends on how complicated you want it to be, I suppose.

Re: How to classify a region that could qualify as more than one terrain?
 

I would require the lower of the applicable Survival skills.

Re: How to classify a region that could qualify as more than one terrain?
 

I treat the types as exclusive. So, for example, I take Arctic to be tundra, because that is clearly not Woodland. I take taiga, temperature forest, Pacific rain forest, and Mediterranean to be Woodland. I don't take tropical rain forest to be Woodland, because it's clearly Jungle, and the same for monsoon forest. I don't consider Mountain to be also Arctic; rather, I take Mountain to refer primarily to the parts of the terrain that are above the tree line, and consider it to be comparable to Arctic but not the same category.

In my current setting, Tela, I have dwarves living underground; elves in Woodland and Jungle; ghouls in Desert; men in Plains; nixies in Swampland and Rivers/Lakes; selkies in Island/Beach and Lagoons; and trolls in Arctic and Mountains.

Re: How to classify a region that could qualify as more than one terrain?
 

In games where I've been the GM, I've usually ruled that the -3 default penalty between specialties is "conserved" and gets distributed. So in pure X, it's Survival (X) or Survival (Y)-3; in mostly X but a bit like Y, it's Survival (X)-1 or Survival (Y)-2; in mostly Y but a bit like X, it's Survival (X)-2 or Survival (Y)-1; and in pure Y, it's Survival (X)-3 or Survival (Y).

There are two exceptions:

1. Really harsh environments with all the worst aspects of both X and Y (e.g., a mountain in the middle of the Arctic): Use the lower of Survival (X) and Survival (Y).
   
   
2. Really bounteous environments with all the best aspects of both X and Y (e.g., sparsely wooded plains with both lots of grasses and herd animals, and lots of trees and woodland creatures), or environments where one can move between the two terrain types quickly and at will (e.g., a beach on the edge of a jungle): Use the higher of Survival (X) and Survival (Y).

Re: How to classify a region that could qualify as more than one terrain?
 

I would just gauge it individually in the different situations.

Type of terrain and vegetation is important, as is climate and season. Also, the activities might affect the skill used. As a GM I'mn open for player-negotiations, if there are valid arguments.

In our apparantly never ending Cliffhangers campaign, on wilderness advantures I often ask for HT based survival rolls to avoid fatigue from travel, weather etc.
If they trek across the African savannah under a blazing sun, Desert might be as good to avoid Fatigue loss, while Plains is used to deal with animals, plants etc.
Same with snow covered, forested mountains. Arctic might be used to avoid frostbite etc. but Mountains is used to avoid falling into cracks etc. and Woodlands perhaps to forage.