If you've chosen to use an Oak tree (regular tree) for the Challenge, you may be in for a little surprise the next time you log on. Unfortunately, with the upgrade to CraftBukkit 1.0.1 on the server, a new bug was introduced that causes some Oak saplings to disappear rather than grow when placed close to each other or other trees. Placing a sapling near another tree and either using bone meal or letting the sapling grow naturally may cause it to vanish, rather than actually grow.

Mailleweaver and Syhd found this bug while working on their own tree farms, and through thorough testing we have determined that this is a bug in CraftBukkit that we will need to wait for them to fix.

In the meantime, you can still use the other trees to do the challenge, and can also use Oak trees (though you should be careful about placing your saplings further apart, or risk losing them permanently). If you are an oak, place your saplings at least 5 blocks away to ensure that you do not lose any saplings, though you may certainly lose some progress.

We will keep you updated on the status of this bug through this comment thread attached to this blog.