As the title suggests you can have a set of records which does in fact closely resemble a tree, with the main trunk, the main branches and all the little twigs and leaves.
You are the main trunk, then come your parents the main branches, then your grandparents and Gt.
grandparents and so forth.
There are different ways of building your tree.
You can just research your Father's line, your paternal surname, or include your Mother's line, your maternal surname, or even go as far as your four Grandparents lines.
Of course you will already be doing two of those lines - your Father and Mother's names, plus two others who married into those families.
Personally, I add every branch, twig and leaf to mine.
I started out just doing my four main ones, but of course there are marriages in every generation which give you more names added to your list.
Some people are not interested in anyone other than those belonging to their four main lines - personally I cannot understand why not.
After all they are all on your family tree so why would you not be interested.
Granted it is just more work - but you should find it an honour and a pleasure to research your tree and it should not seem like work.
You may say that a lot of these people had no impact on you because you did not descend directly from them, and I will agree with that point, but they still belong on your tree.
It all depends on why you are doing your History.
If you are trying to prove descent because of some inheritance, regarding land, or social standing, or whatever, then you would obviously just stick to your main lines.
However, if you are doing it for the sheer enjoyment of seeing just how many people and families were joined into your family over the centuries then you will go for all the lines, never mind how many.
This is all part of the fun and excitement of Family History research.
I have found some very interesting marriage connections on my tree, and I am perfectly sure that there are many more just waiting to be discovered.
One of the easiest ways to expand your tree is if you are lucky enough to be able to tap into an already established pedigree.
This is great when it happens, you have so much information there already provided that you are really on a roll!! Of course, not having done the research yourself you may want to check it out, although pedigrees are usually the work of generations of genealogists and I would think in general, can be relied upon to be as accurate as possible.
The internet being so full of information gives you the opportunity, if you really want to, to check it all before you add the extra information to your tree.
You should be able to confirm the details easily, especially if the people concerned are historical figures.
Lucky for me, the pedigree I was able to tap into, contains historical figures so it is easy to check their details, for my own peace of mind.
Another point regarding following only your main lines is if you are trying to establish health patterns.
Many people today are trying to tap into their history to find any clues to particular illnesses and conditions, whether they are genetic.
This is one area where you would definitely just stick to your main lines of descent.