Watering, weeding, checking the stakes and formative pruning are all important. Following these tips should help you get your new tree established.
The importance of watering just can't be over emphasised. Moving a tree disturbs and damages its root system - the system it uses to extract moisture from the earth. With many of the tree's essential fine roots gone it's vital to ensure that those that are left are able to find adequate moisture.
Water your tree regularly, but be careful not to overwater. Most trees do not like to be in waterlogged soils. It is particularly important to water trees during warm, dry weather. A typical newly planted tree uses the equivalent of about two watering cans of water each week.
It is not necessary to use clean, fresh water. In times of low rainfall it is more sustainable to reuse 'grey' water. Try collecting the water from your washing up, for example. It also helps if you installed some sort of irrigation pipe when you planted the tree. This ensures that water goes down to the roots, rather than running off or evaporating from the surface.
Weeds will compete for water very effectively. Try to keep an area at least 1m in radius free from weeds. And that includes grass. A good layer of bark mulch or a mulch mat are the best way to achieve this. Cutting grass encourages more vigorous growth so is not an effective way of reducing its water consumption. Furthermore, it is very easy to damage your new tree with a mower or a strimmer. Similarly, using weed killers is not recommended and should be left to professionals. It is easy to poison to your tree as well as the weeds if your are not careful.
In its early years the tree may need some formative pruning to encourage it to develop a good shape. Removing some of the lower branches is the most common operation. Remember that a branch only 0.5m above ground in a young tree will still be only 0.5m above ground when the tree is mature. You should avoid pruning until the tree has been in the ground for at least a year. Immediately after being planted the tree is quite stressed enough without further damage.