[Aeneas]

I planted a grove of silver birch (15 trees) four years ago using bare rooted plants. In general the trees have developed well and now vary in height from about nine to twelve feet. This year the trees were late to get into leaf and when the leaves did develop some of the branches did not leaf along their entire length. As of now about three-quarters of the branches are in leaf, the remainder are bare and brittle with numerous twiggy bits that are easy to snap off. Is this normal or could there be a cultural problem? The trees are planted on clay soil that gets quite wet in winter, and being near the sea are subject to strong winds.

[cooler]

This dieback is probably caused by a combination of the two factors you mentioned.

"clay soil that gets quite wet in winter" A possible lack of oxygen in the soil from the wet soil which may also be compacted.

"being near the sea are subject to strong winds" This can cause leaf loss and damage to new growths. The trees may have reached a height where they have begun to recieve a full blast of sea breeze.

[GPI]

Aeneas, is your soil quite alkaline (limey) in places, as silver birch would not enjoy this.

A lot of arborists or tree surgeons will tell you that the true cause of this dieback is still unknown.
No matter, branches without sap that have been killed by birch dieback would be better if removed and disposed of offsite.

[Aeneas]

Thanks for the advice. I will take off the dead, brittle branches and twigs. I suppose it would be best to cut back from the tip until I reach sappy wood. From what you say it appears that "dieback" is a common enough condition on silver birches. Does it progress until the tree dies or can they live and develop satisfactorily with it?

[cooler]

It can progress until the tree dies if left unpruned. When you prune out the damaged wood, you will promote new healthy shoots.