Ground Squirrels : Tree Squirrels :: Dwarves : ???

Dwarf digs hole. He also lives in the hole. Some squirrel is like that. 

But some squirrel lives in the tree and digs to bury his treasure. 

 

Another important thing about Tree Squirrels is that they forget about a lot of the nuts they bury. Those nuts grow into the trees in a form of forgetful symbiosis.

 If a dungeon is the acorn, then what is the tree? 

Please, my soul yearns for the answers to these mysteries.

Some Quick Hexcrawl Horizon Visibility Calculations

How far away can an object be before it dips below the horizon and is no longer visible?

For simplicity, treat the planet like a smooth perfect sphere, and ignore the atmosphere and any other obstacles.

Table of Examples

Assume that your eyes are 1.8 meters above the surface of an earth-sized sphere. From how far away can you see the tops of various objects?

Object	Object Height (m)	Visable Distance (m)	Vis. Dist. (miles)
The Ground Itself	0	4,800	3.0
Garden Gnome	0.5	7,300	4.5
Another Person	1.8	9600	6.0
A Male Giraffe	5.2	13,000	8.0
An Aspen Tree	16	19,000	12
Statue of Liberty (with base)	93	39,000	24
Great Pyramid of Giza	140	47,000	29
Statue of Unity (with base)	240	60,000	37
Burj Khalifa	830	110,000	67
Mount Everest	8800	340,000	210
Severe Thunderstorm	18000	480,000	300

The practical takeaways for hexcrawling are that if you're standing in the middle of a flat twelve-mile hex, then: 

• You can just barely see the top of someone's head if they're standing at the edge of the hex. (But there's probably a shrubbery in the way.)
• You can see the top of a mature tree standing in the middle of the neighboring hex. (If you use a telescope and there are no other trees in the way.)
• You can see the top of a giant robot from two hexes away. (Very important to know.)
• You can see storms and mountains from quite some distance. (Haze will be more important than horizon by that point. I don't know whether you'd actually be able to recognize a storm at 300 miles (25 hexes), but here are a couple anecdotes of people noticing thunderstorms from more than 120 miles (10 hexes) away under the right conditions.)

I've seen similar numbers before, but wanted to recalculate everything in a tidy little list for my own use. 

Calculator widget below