Woods (sometimes called forests) are a widespread terrain feature in Civilization VI. Woods appear on flat and hilled Grassland, Plains, and Tundra tiles. They do not appear next to Lake tiles, unless they are part of a Natural Wonder.
- Yields: +1
Production. - Movement needed: 2 Movement MPs (3 if on Hills)
- Defense provided: +3 (+6 if on Hills)
- Additional traits:
- Can receive a special Tile Improvement, the Lumber Mill, which may only be constructed on Forest tiles.
- Raises the Appeal of surrounding tiles by +1
- Provides +0.5 Faith to adjacent Holy Site districts (rounded down).
There are actually two variants of Woods, which become distinguished after the Conservation civic has been unlocked:
- Old-grown woods are the ones that already existed in the world (i.e. they have never been removed). After they get included in your Territory they gain a bonus +1 Appeal on their own tile (as well as still providing +1 Appeal to all nearby tiles)
- Newly-grown woods are the ones Builders have planted, as per their newly-gained ability 'Plant Woods'. They provide the usual +1 Appeal bonus to nearby tiles, but not on their own, even if they are inside your borders. New - grown woods may be Planted everywhere they appear naturally.
Other than the Appeal bonus, both types work exactly the same.
Strategy
Woods have many uses throughout the game. Forests ensure productivity and protection for civilizations living within them, and provide adjacency bonuses to Holy Sites. Once Machinery is researched, Lumber Mills can be built to increase their 
Production (especially along rivers).
Woods can become especially useful in flatlands (regions without Hills) - they are the only Production booster there, barring the odd Resource where you could construct a Mine or Quarry. They are also a major saving grace in the Tundra.
In contrast to Rainforests, Woods will increase the Appeal of nearby tiles, making them ideal for Neighborhoods or tourist attractions. The Conservation civic also allows workers to plant New-growth Woods; while they don't have as much appeal as Old-growth Woods, they can be used to dress up cities and improve tiles in tundra environments. This civic also gives a +1 Appeal on the Forest tile itself for Old-grown woods; this usually is not very useful (because most stuff that depends on Appeal will remove the Forest), except in one case: when you are attempting to designate a National Park. Because in this case the individual Appeal of each and every tile counts, you may find it possible to use Forest tiles which before didn't have enough Appeal to be included in the Park! You can even Plant Woods in a diamond-shaped area to gain a combined +4 Appeal - this all but ensures the minimum Appeal of 2 needed to designate a Park!
Also, each additional Appeal point increases the 
Tourism produced by the park.
Woods can be Harvested (after researching Mining) to provide a progressive amount of Production (adjusted by game speed, difficulty and Era) to the city owning the tile. New-growth Woods will not yield any Production when Harvested, so it might be a good idea to harvest a Woods tile for the Production boost, then re-plant it after researching Conservation.
Civilopedia entry
The bounty of woods has been crucial in the survival of more than one tribe, providing timber, animals, and plants in such variety as to stagger the imagination. Sadly, civilization has too often chopped them down to make room for farms, roads, and suburbs … and then there are those greedy corporations, looking to grow rich from pelts, logs, and metals.
Gallery
.png "Forest on grassland tile in-game (Civ6).png (880 KB)")
.png "Forest on plains tile in-game (Civ6).png (720 KB)")
.png "Forest on tundra tile in-game (Civ6).png (891 KB)")