In winter, sycamore can be recognised by its green buds in pairs. Wild Service Tree is the only other native tree with green buds and they are positioned alternately along the stem, not in opposite pairs like sycamore.
Sycamore seedlings produce two seed leaves at first, and it's not until the third pair of leaves that they begin to look like proper sycamores.
You can see why sycamore is such a successful coloniser. It produces so much viable seed.
These seedlings have germinated under a big mother tree in the hedge at Filnore, but they won't all survive.
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The above pictures were taken in March, but in mid-April those seedlings had developed their second pair of leaves. You can see they only have one point.
Whereas in their second year they develop their true leaves with five points.
We have rather an infestation of sycamore in the new plantation near post 2. We shall have to pull them out or they will take over, shading out other species.
Ash regeneration is also strong but ash is easier to control and doesn't produce the heavy shade of sycamore.