What Your Tree Drawing Says, According to Koch's Method (and What the Real Evidence Says)

Draw a tree: the trunk, the canopy and, if you like, the roots. In 1949 that instruction gave rise to one of the most widely used drawing tests of the 20th century.

From a vocational counselor to a clinical manual

Before Koch there was Emil Jucker, a Swiss vocational counselor who in the 1920s was already asking people to draw trees to explore personality traits, in a career-guidance context rather than a clinical one.

Karl Koch systematized that idea and published Der Baumtest in 1949; the English edition arrived in 1952. His method applied principles from handwriting analysis to the elements of the tree, so that trunk, canopy, branches, and roots became variables to interpret.

Why a tree, and not a person

For Koch, the tree was an especially stable symbol of the inner self-image of the person drawing. By not being a person, it would allow content to be projected with less conscious censorship than a self-portrait, and every decision, from size to trunk shape or the presence of fruit, would reflect something about the subject without them realizing it.

The classic symbolic catalogue

Some of the most cited readings within this tradition:

• Visible roots: a solid connection to one’s own past. Missing roots: insecurity, although they’re often simply due to the edge of the paper or the ground line.
• Large, leafy canopy: an active imaginative and social life. Small canopy: introversion.
• Straight trunk: rigidity. Curved trunk: sensitivity, adaptability.
• Fruit present: need for achievement.
• Tree atop a hill: grandiosity or isolation. Tree in a dip in the terrain: feelings of inadequacy.

It’s an extensive catalogue in which almost no element of the drawing escapes interpretation.

The problem: almost none of this has been tested

To prepare this article we looked for controlled studies on each of these signs (roots, canopy, branches, fruit, trunk shape) and found none confirming them by comparing groups with data.

It isn’t that they were studied and failed, as happens with other drawing techniques. For the most part, they were never rigorously tested: they’re clinical inferences repeated for decades, not replicated findings.

Where something does show up: objective measures

What’s interesting about this test is that when the tree is measured objectively instead of interpreting symbols, differences do appear. Two recent studies show it.

2015: tree size and cognitive decline

Stanzani Maserati and colleagues studied 405 people in Italy: 118 patients with Alzheimer’s disease, 19 with frontotemporal dementia, 46 with vascular dementia, 132 with mild cognitive impairment, and 90 healthy controls.

Among other measures, they calculated what proportion of the page the tree’s bounding rectangle took up (height times width, divided by the size of the sheet). In Alzheimer’s patients, the tree took up on average 3% of the page; in controls, 23%, a highly significant difference. The trees of people with mild cognitive impairment fell somewhere in between, and tree height and the trunk-to-canopy ratio independently predicted impairment.

2025: a scoring scale for screening suicidal ideation

Zhang and colleagues tested, in adolescents, a fixed scale of items derived from the tree drawing, scored with the help of image recognition. They compared 46 adolescents with depressive disorders and suicidal ideation with 58 healthy adolescents.

With a cutoff of 9, the scale reached a sensitivity of 0.935, a specificity of 0.966, and an area under the ROC curve of 0.971. Those are high numbers for a first study.

Three caveats carry weight. The authors themselves acknowledge that the sample is small and that the scale hasn’t been tested in other cultures. The comparison group wasn’t adolescents with depression but without suicidal ideation, but healthy adolescents, so part of the difference may be due to depression rather than to ideation itself. And the article isn’t entirely consistent: the abstract speaks of 36 cases and the main text, of 46.

That scale is applied by professionals within a clinical process. If you’re worried that you or someone close to you may be at risk, in the US you can call or text 988 (the Suicide & Crisis Lifeline, free, confidential, and available 24/7); wherever you are, please reach out to your local crisis line or emergency number.

Why this doesn’t validate the test you know

These two studies do not validate Koch’s symbolic interpretation. They don’t say that roots mean security or that a large canopy means sociability. What they show is much narrower:

• A numerical measure, not a free interpretation.
• A fixed scoring scale, applied by professionals.
• Groups defined in advance (with or without dementia, with or without suicidal ideation), not isolated personality traits.
• The goal of screening for a specific problem within a broader assessment, never as the sole basis for a decision.

That’s the difference between “the tree says something about your personality” and “this specific measurement of the tree helps a professional decide whether a clinical concern is worth investigating.” They’re claims of a very different nature, and the most solid future for these techniques seems to lie in the second: one more measure, among several, within a serious assessment.

How our test works

Our Tree Drawing Test collects 9 indicators from this tradition:

• 4 are measured directly from your stroke: size, placement, pencil thickness, and shading.
• 5 depend on you telling us what you drew: roots, canopy, branches, fruit, and trunk shape.

Size is the only indicator with any backing, and we explain that clearly: the backing comes from a clinical context of cognitive decline and doesn’t show that a small tree reveals anything about personality. The rest, the classic symbolic interpretation, appears alongside the statement that we haven’t found studies confirming it. A stroke made with a mouse doesn’t reproduce the pressure of a pencil on paper; what gets recorded are magnitudes.

The tree shares a tradition with the Draw-an-Animal Test by Levy, which follows a similar projection logic and has a different kind of evidence behind it.

Sources

• Koch, K. (1949). Der Baumtest: Der Baumzeichenversuch als psychodiagnostisches Hilfsmittel. Verlag Hans Huber.
• Stanzani Maserati, M., Matacena, C., Sambati, L., Oppi, F., Poda, R., De Matteis, M., & Gallassi, R. (2015). The Tree-Drawing Test (Koch’s Baum Test): A useful aid to diagnose cognitive impairment. Behavioural Neurology, 2015, 534681.
• Zhang, Y., Liu, Y., Liu, W., Sun, L., Leng, F., Li, Z., & Liu, G. (2025). Validity of the Tree Drawing Test Suicide Ideation Assessment Scale in adolescents. Frontiers in Psychiatry, 16, 1701452.