Growing trees in Minecraft Pocket Edition is as simple as plopping down a few seedlings and coming back after a few night/day cycles (or tossing some bonemeal about, of course) to harvest all the lovely wood for the endless number of bloody sticks you will need.
In Survival Craft, apart from the constant need for sticks, things are a little different. Saplings don’t automatically root & grow where you place them, oh no. For them the temperature & moisture content of the surrounding air & soil have to be just right, the picky little bastards. If either are even a fraction out then the saplings wilt to a dry twig and die and I can’t tell you how many times I’ve laid out a full stack of 40 only to find kindling littering the ground the next day, even when I’ve used the in-game thermometer & hydrometer! I’ve even followed the designers own advice and planted saplings in the same place I harvested the trees I got the saplings from in the first place and still every ruddy one karked it!
So imagine my surprise when, after planting 40 pine firs on a whim outside my latest deep mine, I came back to find a veritable bloody forest on my doorstep! God knows why it worked this time over all the others, but if it works again here I rather think I’ve just found the location for my first lumber farm :-D