40d:Tree

Trees can be found on almost any playable map. Depending whether trees are scarce or dense, they can be a great renewable source of wood. The density of growth is determined by the biome, and those are visible on the pre-embark screen by hitting F1, F2 etc. Density does not change - there are no climate shifts during game play.

There are many different varieties that grow in various different types of biomes. Tower-caps are trees (giant mushrooms, actually) that grow only underground, and are the only ones that do, and then only under special circumstances. The only difference between different types of trees is the (usually very minor) difference in the weight of the log or item produced - otherwise all trees are identical, equal in usefulness and value.*

(* Note that preferences can alter a dwarf's perception of the value of items made from a type of wood that they prefer.)

Viewed on their same z-level, many different sub-types of trees have their own symbol, such as ♣, ♠, ¶, ╞ or ⌠. Some share the same symbol, but since the only difference is for preferences, this is not a significant problem. (See table, below, for tree/symbol pairs.) For most purposes, a tree is a tree.

Trees viewed from one z-level higher look like coloured rectangles ( █ ), appearing identical to coloured blocks floating in the air. Deciduous trees will change colour to red or yellow in autumn ( ♣, ♠ ), and lose their leaves in winter ( ╞ ). This does not affect their usefulness - they may be cut down in any season, and produce the same end result.

Trees are currently^{v0.28.181.40d} not a source of food or other material, so it is not possible to harvest mangos, maple syrup, nuts, rubber, etc.

Harvesting / Removing the barrier

Trees are a type of map tile that form a solid barrier, like stone or ore. Trees (but not saplings) will block movement, and prevent designation of channeling, walls and other constructions. Caravans are especially vulnerable to being blocked by trees, since they require a path 3-tiles wide. Trees do not form a floor on the level above them - creatures cannot walk "on top of" trees.

They must be designated for removal from the designations menu chop trees, which will instruct dwarves with the woodcutting labour enabled to grab an axe and begin chopping down the tree. Once cut down, they become one wood log, which is movable and can be hauled by enabling the the Haul Wood labour on any dwarf and designating a wood stockpile.

Trees will not as of yet be destroyed by magma or fire (nor will water damage them in any way). Saplings can 'drown' in water and magma, though. Ballista arrows can destroy trees, but catapult stones will not.

Under certain circumstances arrows can wind up "on top" of trees (1 z-level above the tree). This occurs when an arrow reaches its maximum range above a tree, and then falls onto it, or an item is otherwise dropped directly above the tree. As dwarves cannot walk on trees, the only way to recover these items is to cut down the tree.

Trees and ramps

Digging a ramp underneath a tree will cause a cave-in - but the tree will be removed. This is not true of saplings.

Tree growth

Trees grow from saplings, which start growing randomly on tiles of a suitable biome. Saplings can be killed by heavy traffic, and also flooding. Dead saplings will remain for some seasons, and then disappear - or heavy traffic will trample them away. To grow from a sapling to a tree takes about a year and a half or more, though this seems randomized to some degree. Trees do not need to be (and can't be) "planted" - even if a map is stripped of all trees, new saplings will regrow, randomly and in their own time.

Saplings will not grow on a tile with items on it (such as stone, food, etc). Saplings will not grow where a road has been laid down. Saplings will appear but not grow into trees if there is a layer of stone under the top-layer of soil under them, or if the soil has been dug out from beneath that top layer.*

(*Tower caps operate differently, and are not fully understood. See that article for a more complete discussion on their growth requirements.)

A given area block has a limit of "things that can grow on it" - and trees and shrubs compete for this when that maximum is reached.* Removing shrubs will allow more trees (and shrubs) to be able to grow. A downside to removing these shrubberies is that most of the saplings in the area will be trampled in the process unless they are marked as low-traffic or restricted areas first, a slightly time-consuming process.

(*Tower caps (and underground shrubs?), on levels below the first "above ground" level, do not seem to count toward this limit.)

Elven Diplomats

Elven diplomats eventually come to talk about the "tree situation" in your fort. Sometimes the diplomat will arrive and merely complain but most often the diplomat will want to set a limit to the number of trees butchered harvested to feed fuel your earth blighting death machines industry. This quota is based on all the logs you have in your stocks, no matter what the source. It doesn't matter if you have a Tower-cap farm or if you import all your wood; if you have any wood in your stocks, the treehuggers elves will complain.

Trees also gain names near elven settlements. It is unclear what effect this has on gameplay, if any at all.

List of Trees

Tree Name	Tile	Biome / Habitat	Alignment	Deciduous	Density (g/cm3)	"Likes them for their..."
Acacia	♣	Tropical Dry Broadleaf Forest (Dry) Tropical Grassland Tropical Savanna Tropical Shrubland	All	No	500
Alder	♣	Any Temperate Broadleaf Forest (Dry)	All	Yes	410
Ash	♠	Any Temperate Broadleaf Forest (Dry)	All		620
Birch	♣	Any Temperate Broadleaf Forest (Dry)	All	Yes	670
Cacao tree	Γ	Tropical Moist Broadleaf Forest (Dry)	All	No	500
Candlenut	Γ	Any Tropical Forest (Dry)	All	No	500
Cedar	↨	Temperate Conifer Forest (Dry) Tropical Conifer Forest	All	No	380
Chestnut	♠	Any Temperate Broadleaf Forest (Dry)	All	Yes	500
Feather tree	♣	Not Freezing (Dry)	Good	No	100
Glumprong	┤	Not Freezing (Dry)	Evil	No	1200
Highwood	¶	Not Freezing (Dry)	Savage	No	500
Larch	↑	Taiga Forest (Dry) Temperate Conifer Forest	All	Yes	590
Mango	Γ	Any Tropical Forest (Dry)	All	No	500
Kapok	Γ	Tropical Moist Broadleaf Forest (Dry)	All	No	500
Mahogany	♠	Any Tropical Forest (Dry)	All	No	600
Maple	♣	Temperate Broadleaf Forest (Dry) Temperate Grassland Temperate Savanna Temperate Shrubland	All	Yes	755
Oak	♠	Any Temperate Broadleaf Forest (Dry)	All	Yes	700
Palm	Γ	Any Tropical (Dry)	All	No	500
Pine	↑	Taiga Forest (Dry) Temperate Conifer Forest Tropical Conifer Forest	No		560
Rubber tree	Γ	Tropical Moist Broadleaf Forest (Dry)	All	No	500
Saguaro	╞	Any Desert (Dry)	All	No	500
Mangrove	♣	Mangrove Swamp (wet)	All	No	500
Tower-cap	♣	*Subterranean SPECIAL*	All	No	600
Willow	⌠	Any Temperate (Wet) Any Tropical Forest Tropical Grassland Tropical Savanna Tropical Shrubland Tropical Freshwater Swamp Tropical Saltwater Swamp Tropical Freshwater Marsh Tropical Saltwater Marsh	All	No	420