Dwarf Fortress Bug Tracker - Dwarf Fortress
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0011157Dwarf FortressDwarf Mode -- Environmentpublic2019-10-03 12:292019-10-06 09:29
Urist McuristUrist 
normalminorhave not tried
Personal ComputerWindows 10 PC10.0.18362
0011157: Maximum number of trees seems absolutely unrelated to the initial amount of trees on the map.
Basically I embarked on a Savage Temperate Sand Desert biome with Scarce trees and within three years it became more forested than most Heavily Forested regions are on embark. I don't think that's the intended behavior.
1. Embark on a Sand Desert (or, most likely, any desert with soil)
2. Wait unthil trees start to appear
3. Trees will cover everything
Might be just the lack of a feature and not a "true" bug.

Embark biome is a pure unmixed Savage Temperate Sand Desert, no river or ocean.

Caverns have been breached before I noticed this.

http://dffd.bay12games.com/file.php?id=14551 [^]
No tags attached.
duplicate of 0009581acknowledged Loci Sparsely forested/vegetated biomes will get lush in some years 
Issue History
2019-10-03 12:29Urist McuristUristNew Issue
2019-10-04 02:17PatrikLundellNote Added: 0039523
2019-10-06 09:29LociRelationship addedduplicate of 0009581
2019-10-06 09:29LociStatusnew => resolved
2019-10-06 09:29LociResolutionopen => duplicate
2019-10-06 09:29LociAssigned To => Loci

2019-10-04 02:17   
It's a lack of features. As far as I've been able to determine (a thread a number of years ago), the criterion for whether a sapling can mature to a tree is that there is nothing blocking its access to the sky (above ground trees only, naturally), and that there is nothing blocking access to the tile above (i.e. a 2Z headroom [and bridges don't count: trees readily grow through those on maturation]).
The biome (or possibly the Vegetation parameter) determines the rate at which saplings are spawned, and so the rate at which the junglification happens. I don't know if there is any variation in sapling withering rates between biomes.
Stockpiles block maturation for as long as they cover a sapling, with withering/maturation determination happening shortly after the stockpile is removed.