Tree spawning on sand in "Swampland" biome

Please provide the seed and the coordinates.

Seed: 4389209112284902216
Coordinates:
x: -195
y: 64
z: 199

You have to set large biomes on.

There is no swamp...

-Retried with 1.4.7 - still no swamp.-

Have you tried to set the world type to large biomes?

World Type: Large Biomes, I spawn in a snow biome when I go to those coords.

edit: tried again, now I'm in a swamp

edit2: attached screenshot

Finally confirmed.

Very likely the same backing reason as for MC-610.

The trees are spawned on "right spot", the problem is that spot gets changed afterwards. In this case, the lake comes later, after which dirt-to-sand conversion is done (to create beaches near waters). In this example case, there is indeed a lake right next to the location. There are also other similar spots in the same world and same swamp - tree on top of sand near a lake. Not very common, though.

The sand generator code is indeed so simple that it only scans a defined radius around the randomly chosen water block for dirt or grass and converts it to sand. It ignores the existence of anything else there might be, like trees.

However, depending on how MC-610 gets fixed (if it gets), this issue may or may not go away at the same. (Edited: ) Lakes and these sand spots are created alike, as part of the "decoration process" which is supposed to happen after the chunk base generation, but have some inter-order issues with that ordering. The particular order of generating chunks can affect the outcomes, too.

Going to resolve this as a dupe of MC-610