As nature priests, druids will frequent places where they are most needed to focus on maintaining an existing balance, or restoring balance in nature.
I have this image of druids being in forests and encouraging the spread of the forest, seeking to make the old growth forest spread. I can see in the right circumstances, a druid working with woodcutters to cut the specified trees at the right intervals to enhance the growth of the forest or enable a certain section of the forest to better fulfill a certain need.
I briefly researched mistletoe since our Wednesday night game set in a subtropical island archipelago had a druid in the party for a short time. Mistletoe grows in almost all climates around the world. In reality, a quick perusal indicates that nearly every continent and clime have mistletoe. There is a desert variety in Arizona.
This means that for a druid to function, there have to be some sort of plant life to support the material component needs for spells of the druid.
This would make an arctic or sub-arctic druid very rare, unless your world have a type of mistletoe, holly, or oak that grew in sub-arctic regions. There are a few ways around this limitation.
- The simplest is that druids living or operating in these regions would have a large supply of leaves before going to such an extreme location. Regular means of re-supply would be needed.
- There is a thermal vent from hot springs, geysers, or some moderately active to very active volcanic processes.
- There is a cave or region with some form of light to support photosynthesis. Light from lichens, mosses, insects, or types of rocks could generate this light.
- Some form of druidic sanctuary that through the power of the druids has enabled an oasis hidden in the ice to survive. This could lead to a hidden group of druids, or a lonely hermit druid sent to maintain this far off location.
In the typical desert of sand and/or rock and heat, a druid or group of druids would tend to encourage the growth and enlargement of oases. This would tend to have one druid in each oases, other than large oases in hidden valleys or canyons off the trade routes. Smaller oases would tend to have a single druid regularly checking the oases in his care.
Mountainous regions would tend to not have druids above the tree line. At least, they would not live above the tree line, and would only go their as a patrol or to get to another region under their care, and only with the appropriate supply of mistletoe, holly, or oak leaves.
Beaches or islands without trees or shrubs of the appropriate family of plants would be another source of limitation for druids.
What this leads us to conclude, is that druids will not be found very far from shrubs or trees, since the right kind of leaves are needed for their magic. This means that any druid found more than 100 miles or so from a known forest/source of leaves is either an NPC on a special mission, or a PC or NPC adventurer, or there is a secret or little known druidical area or nature sanctuary nearby. Other reasons could be the druid was teleported far away, or is under a geas or quest, etc.
Of course, one can get around some of these limitations by developing an ice oak that grows in the frozen areas and supports ice mistletoe. There could be sea oaks that grow under the ocean with sea mistletoe. Druids could live in undersea caves and encourage the growth of kelp forests. Sea elves could have their own form of druid. A half-elf with one parent a sea elf could be such a druid.
How do druids fit into your campaign word?