Most people's mental image of a family tree is the same: a leafy branching structure with photographs, themselves at the bottom, parents above, grandparents above that. It's attractive, legible and comforting. As a research tool, however, it is imprecise and can be actively misleading.
Professional genealogy uses several fundamentally different types of chart, each with its own purpose. Understanding the differences changes both how you build your tree and what you actually search for.
The ascending tree — also called an ancestor chart — is the most commonly used type in genealogical research. It is built from one person (the proband) upward: to their parents, their parents' parents, and so on. Each person in the chart has ancestors, but no siblings, aunts, uncles or cousins.
The Ahnentafel numbering system: proband = 1, father = 2, mother = 3, paternal grandfather = 4, paternal grandmother = 5, maternal grandfather = 6, maternal grandmother = 7, and so on. The rules: any person's father = that person's number × 2; mother = number × 2 + 1. All men have even numbers, all women have odd numbers (except the proband). This allows records to be kept as a numbered list, without any diagram at all.
The descending tree starts from one ancestor and works downward — to their children, grandchildren, great-grandchildren. It shows all the descendants of one person. This type is used when researching the history of a particular family from a known founder, or when trying to connect oneself with other living relatives.
A family group sheet is not a tree but a table for one nuclear family: husband, wife and their children. For each person: date and place of birth, marriage and death, and — crucially — the source for each item of information. It is a researcher's working document, not a presentation chart. The family group sheet is the foundation of any serious genealogical work, because it forces the recording of not just names but sources.
The most common mistake in amateur genealogy is building a tree without citing sources for each fact. Names, dates, places — every piece of information must have a reference: an archive citation, a book, a website, a specific record. Without this, a tree is a collection of assumptions that no future researcher — including yourself in ten years' time — can verify or challenge. A practical rule: if you cannot name the source for a fact, it is a hypothesis, not a fact. Hypotheses belong in a tree, but they must be marked as hypotheses — with a question mark, special formatting or a note.
A classic pitfall: a researcher finds a birth record for Peter Johnson in 1850 in the right village and links it to their great-grandfather Peter Johnson. But there may have been more than one Peter Johnson in that village. Without additional identifiers — age, parents' names, other corroborating documents — this connection is unreliable. The Genealogical Proof Standard requires that connections be supported by reasonably exhaustive research, with each conclusion based on a preponderance of credible, well-cited evidence.
Traditional genealogy historically focused on male lines — because surnames were passed patrilineally. But you have exactly as many ancestors on your maternal line as on your paternal line. Ignoring female lines means researching half your history. Practically: for every woman in the tree, record her maiden name if known. That name — not her married name — is the key to finding her family.
A paper tree is attractive but impractical for research: adding a generation means redrawing the whole chart. For research purposes, software is the better choice. Free options: Gramps (open source, powerful citation system) is the best choice for serious research. MacFamilyTree (Mac) and Family Tree Builder (MyHeritage) are more beginner-friendly. Online platforms — Ancestry, MyHeritage, Geneanet — store the tree in the cloud and allow comparison with other researchers. FamilySearch.org is free and integrated with an enormous database. GEDCOM is the standard format for transferring genealogical data between different programmes: if you start in one application, GEDCOM allows you to move everything to another without loss.
A family tree is not the goal of genealogical research — it is a tool. The goal is to understand real people who lived real lives. The chart helps structure what has been found and shows what is still missing. The more rigorous the approach to sources and identification, the more reliable and valuable the result. And: a tree is never 'finished'. It is a living document that grows with the research.
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