Domestic / escaped apple (Malus × domestica)
Domestic apples usually have larger fruit and can show woollier leaf undersides, but wild, escaped and hybrid trees blur the boundary. Do not claim pure crab apple from one feature.
The field guide: what to look for, what can confuse you, and the features to confirm together.
Genuine reference photographs show the overall pattern. They help you orient yourself; they are not enough on their own for safe identification.
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Recognising an apple tree is approachable, but distinguishing true native crab apple from escaped or hybrid apples takes more care. Use several tree features together rather than relying on fruit size.
Do not pick from fruit alone. Confirm an apple-type tree, attached fruit, leaves and twig features together. If the tree itself is uncertain, leave it.
Domestic apples usually have larger fruit and can show woollier leaf undersides, but wild, escaped and hybrid trees blur the boundary. Do not claim pure crab apple from one feature.
Without the apple-like fruit, related flowering trees can be harder to separate. Wait for stronger seasonal features or use a proper tree key.