Making sure that your fruit tree stays healthy is very important, but not as hard as some might think. There are several vital things you need to do: don't harvest all of the fruit on the tree at the same time; make sure the soil is healthy; watch out for pests; plant it correctly; be sure it is protected when it is young. I will expand on all of these things.
One way to ensure that your fruit tree will remain healthy is to never harvest all of the fruit at the same time. If all of the fruit is left on the tree, it will grow to an unbearable weight. The combined weight of all of the fruit can get very heavy and snap the branches. So once the fruit starts to grow, you should always pick some of them before they are completely ready. Even if you don't want to pick the fruit before it is ready, it will be beneficial to your tree. While you should do this to prevent it from becoming too heavy, you should also never over-harvest. This can be equally damaging.
Another part of making sure that your fruit tree stays healthy is planting it in fertile soil. If you plant anything in soil that doesn't have the proper amount of nutrients in it, it will not grow and flourish as I am sure you would like it to. You also have to be sure that you plant the right tree in the right kind of soil, because some types of fruit trees do better in drier soil while some kinds or trees do better in damp soil. Just look up what kinds of nutrients your desired tree requires and you'll know for sure whether to plant it or modify your soil in any way.
Another way to ensure your fruit tree's health is to watch out for pests. To help keep the pests away from your tree, try to eliminate places by your tree that pests might be living. Always look for old piles of brush, weeds, old leaves, or any other decaying matter where pests could be hiding. Another way to keep pests away is by using bug sprays and repellents. Also, regularly turn over a little bit of soil around your tree and look for pests that could be hiding underground. Sometimes the ones that are hidden out of sight can be the most harmful.
If you don't plant your fruit tree correctly, it could end up being very unhealthy. So to avoid this, always look for instructions before you plant trees. When you are planting a tree, make sure that your tree is perfectly vertical, so it won't grow to be pointing off in an abnormal direction. When you are planting a tree you should also spread out the roots so that the tree will always be stable. This will help it live longer since the maximum water intake will be optimized.
The final thing to do in keeping your fruit tree healthy is to keep it protected when it is young and fragile. When you have a young tree you should tie it to a stake to help it to survive strong winds. Don't tie it too hard, you should always allow room for the tree trunk to grow. Another thing to do when it is young is to put a small fence around it. This can help keep it safe from animals that will eat its bark if given the chance. A fence will also help to guard the base against strong wind and other weather.
If you follow all of this advice during the early years of your tree, you should have an experience that is nothing but joyful. Hopefully you'll learn from the mistakes of others, and take great care of your tree. Just remember to always look up information on the type of tree you have, so that you can find out what exactly it requires.