Every trunk is really an open book. The growth rings in a cross-section of wood reveal the age of the tree, the weather in individual years and even dramatic events – fires, droughts or insect attacks. Learn to read growth rings and you will see wood in a completely new light. The guide below covers everything essential, and you can try it out straight away in the quiz.
🎮 Game: the growth ring and wood quiz
Can you tell what a narrow growth ring reveals? Do you know where the heartwood grows and where the sapwood is? Test yourself at three levels – easy, medium and hard. Each game has 10 questions, drawn from a pool of 36.
🌳 Looking for a gift made of natural wood? At AMADEA you will find handmade kitchen and serving boards made of wood from Czech forests, where the growth rings are the main decoration – every piece is an original.
Visit AMADEAGuide: how to read growth rings and everything they reveal
Growth rings are yearly increments of wood produced by a thin layer of cells under the bark – the cambium. The cambium divides and produces new wood inwards and bast outwards. In the temperate zone, which includes the whole of the Czech Republic, the cambium stops working in winter and starts again in spring – and it is this pause that creates a clear boundary between the years.
Earlywood (spring wood)
Earlywood is the paler, softer part of a growth ring, formed in spring when the tree has plenty of water and needs to supply its buds and leaves quickly. The cells are large and thin-walled with a wide lumen – the wood works like a "water motorway". In a cross-section, you can recognise earlywood by its pale shade and low density.
In ring-porous woods such as oak and ash, the earlywood contains prominent large vessels arranged in a single row – which is why these woods have such a beautiful, distinct figure that adorns sawn boards, for example.
💡 How to recognise it: on a freshly cut stump, earlywood is the paler band in each growth ring. Under a magnifying glass you will see larger "porous" cells – especially clearly in oak and ash.
Latewood (summer wood)
Latewood is the dark, dense part of a growth ring. Trees form it from late spring until the end of summer, as growth gradually slows. The cells are smaller with thick walls and provide the trunk's mechanical strength. The greater the proportion of latewood, the harder, denser and more durable the resulting wood.
It is the contrast between pale earlywood and dark latewood that creates the visible growth ring – the boundary of one year. Without this seasonal pause, growth rings would not form, which is why many tropical trees lack distinct rings.
💡 Did you know? In high-quality spruce tonewood for violins and guitars, latewood typically makes up around 15–30 %, and the rings must be regular and very narrow (1–2 mm). Such wood comes from slow-growing mountain spruces from altitudes above 1,000 m.
Heartwood (duramen)
Heartwood is the inner, darker part of the trunk. It forms when the tree deposits resins, tannins and other substances in its older growth rings, which preserve the wood and protect it from fungi. Heartwood no longer conducts water; it serves the tree only as mechanical support.
In oak, larch and black locust (robinia), the heartwood is much darker than the sapwood – which is why these woods have a beautiful two-tone figure that craftspeople like to use in wooden boards and bowls. Some trees (beech, spruce, fir), on the other hand, do not form distinct heartwood.
⚠️ Watch out for confusion: beech often shows a so-called red heart (false heartwood). It is not true heartwood as in oak, but the tree's reaction to stress, injury or infection. It does not automatically mean poorer wood – just a different colour and sometimes a greater tendency to crack.
Sapwood (alburnum)
Sapwood is the outer, paler layer of the trunk, which the tree actively uses. Every year, the newest growth rings conduct water and store starch. Sapwood is usually more susceptible to fungi and insects, so it is often removed from timber or has to be treated.
The width of the sapwood varies by species: in oak it is typically 5–15 rings wide, in black locust only 2–5 rings. In pine it can take up almost a third of the cross-section. When making kitchen utensils, sapwood is handled with care – in some pieces its contrast with the heartwood is a deliberate decorative feature.
Medullary rays (radii medullares)
Medullary rays are fine lines that cross the growth rings at right angles – they run from the centre of the trunk to its edge. They store reserve substances and provide transport across the trunk. In a cut they create a beautiful "mirror" figure, known especially in oak as silver grain (oak rays can be several millimetres wide).
These rays give oak wood its characteristic effect in a radial cut – which is why the most beautiful oak boards are cut by so-called quarter-sawing, which brings out the rays. This figure adorns quality parquet floors and some oak serving boards.
💡 How to recognise them: oak, beech and plane have distinct medullary rays. In conifers the rays are very narrow and almost invisible to the naked eye – which is why coniferous wood has a "cleaner", more uniform figure without prominent cross lines.
False and missing rings
Sometimes a tree forms two growth rings in one year (a false ring) or, on the contrary, none (a missing ring). This complicates age estimation and dendrochronological dating. False rings typically form when a tree loses its leaves to caterpillars or hail and then comes back into leaf. Missing rings are typical of old trees on extremely dry sites – part of the trunk simply does not grow in a given year.
⚠️ Note: in a 100-year-old oak on a dry south-facing slope, a ring may be completely missing in some years of its life. That is why dendrochronologists never rely on a single sample – they always compare several trees and check the pattern of ring widths against a so-called master chronology.
🌿 The most common mistakes when reading growth rings
Mistake 1: Thick branches = thick trunk = same age. The number of growth rings increases from the centre of the trunk outwards. A side branch that started growing when the tree was, say, 30 years old has only as many rings as its own years – not as many as the whole tree.
Mistake 2: A wide growth ring = quality wood. On the contrary – wide rings usually mean softer, less stable wood, especially in conifers. For instruments, furniture and carving, narrow, regular rings are prized. Some hardwoods (walnut, cherry) are an exception, where slightly wider rings do not matter.
Mistake 3: Every growth ring = exactly one year. Usually yes in the temperate zone, but trees in the tropics can form rings according to rainy and dry seasons – even two a year. And in trees from regions without distinct seasons (mangroves, some eucalypts), growth rings practically do not exist.
Comparison table: Czech trees and their growth rings
| Tree | Ring type | Heartwood/sapwood distinction | Typical age in Czech forests | Common uses |
|---|---|---|---|---|
| Pedunculate oak (Quercus robur) | Ring-porous, very distinct | Distinct (dark heartwood, pale sapwood) | 150–300 years | Boards, furniture, roof trusses, parquet |
| European beech (Fagus sylvatica) | Diffuse-porous, not very distinct | No true heartwood (sometimes red heart) | 120–250 years | Boards, furniture, pencils, toys |
| Norway spruce (Picea abies) | Coniferous, clear earlywood/latewood contrast | No distinct heartwood | 80–200 years | Musical instruments, construction timber |
| Scots pine (Pinus sylvestris) | Coniferous, with resin canals | Distinct (pinkish heartwood) | 80–180 years | Furniture, windows, lanterns |
| Common ash (Fraxinus excelsior) | Ring-porous, very distinct | Slight distinction | 100–250 years | Tool handles, sports equipment, veneers |
| Wild cherry (Prunus avium) | Semi-ring-porous | Distinct (golden-brown heartwood) | 60–120 years | Furniture, decorations, veneers |
| European larch (Larix decidua) | Coniferous, contrasting | Distinct (reddish-brown heartwood) | 150–400 years | Outdoor structures, planters |
As you can see, each Czech tree has its own completely different "handwriting" in its growth rings. A craftsperson or carver therefore chooses wood for a particular product by the figure of its rings – something different suits kitchen accessories than outdoor lanterns.
Frequently asked questions
How many growth rings does a tree add each year?
In the temperate zone, usually one growth ring a year – made up of pale earlywood and dark latewood. Occasionally double rings form (when a tree loses its leaves, for example to caterpillars, and comes back into leaf) or missing rings in extreme drought, frost or shade.
How can I find out a tree's age without felling it?
Growth rings can be counted without harming the tree using an increment borer (Pressler borer), which removes a thin cylindrical core 4–5 mm in diameter. As a rough guide, age can also be estimated from the trunk's circumference – for most broadleaved trees, about 2.5 cm of circumference growth per year, measured at breast height (130 cm above the ground).
Why are some growth rings wider and others narrower?
The width of a growth ring reflects the growing conditions in that year. A wide ring means a warm, wet year with plenty of nutrients. A narrow ring signals drought, cold, shading, pest attack or damage to the crown. This is why trees work as natural weather stations.
What is dendrochronology and what is it used for?
Dendrochronology is the science of dating wood by its growth rings. By comparing ring-width patterns with a reference chronology, it can determine the exact year a tree was felled. Long oak chronologies in Europe stretch back thousands of years and help date the roof trusses of Gothic churches, archaeological finds and old tools.
What is the oldest tree in the world according to its growth rings?
The oldest known individual tree is a Great Basin bristlecone pine (Pinus longaeva) in the White Mountains of California, with more than 4,850 counted growth rings. In Europe, the spruce Old Tjikko in Sweden is famous – its visible trunk is young, but its root system is estimated to be around 9,500 years old. In the Czech Republic, the oldest trees are oaks, limes and yews several hundred years old.
Can I find products at AMADEA where the growth rings are the main decoration?
Yes. In our ranges of kitchen and serving boards, bowls and plates and trays, the growth rings and figure of the wood are the main aesthetic feature. Every piece is an original – no two ever look exactly alike. We make them from Czech oak, beech and other native woods. For the garden, wooden planters and flower pots are also a good choice, where the figure of the wood is part of their natural look.
🪵 Every product is an original! With AMADEA's handmade boards and decorations, the pattern of the growth rings is unique – no two pieces are ever the same. Choose your own original made of Czech wood.
Browse the AMADEA rangeAuthor: Martin Portych – specialist in wooden products, gift advice and shop content
Editorial policy: Our content is based on the day-to-day practice of the AMADEA shop, the real needs of our customers and a commitment to clear, useful and trustworthy information.