Birch Gall Questions

I am undertaking a big landscape job here on Puget Sound, and there are a lot of young paper-birches with birch gall on each side of the property, mostly twelve to eighteen foot little trees, each with at least a few "knots" in the higher branches, some with a great many of these knots. I have to make the decision whether or not to remove all these birches, & am leaning toward replacing them with fruiting trees. But before I start getting rid of two dozen young trees, I would welcome opinions from anyone with experience with birch gall, since this is my first encounter that I personally had to do anything about, & I'm not at all certain what's best. Some questions:
Can the birch gall mites infect any other shrubs & trees other than birches?
The gall isn't apt to damage the longevity or general health of the tree, but I gather it can make the leaves look pretty crappy. If some or all the birches are left where they're at, will foliage look pretty decent even with gall?
I also gather that miticides don't work very well even for the non-organic gardeners who don't mind using them. I don't want to use such chemicals, but wonder if there are any risks to just ignoring the presence of birch gall mites?
Is the standard advice to remove & replace these trees to be taken seriously?
If I do remove these trees I want to do it now while the mites are dormant & I have a better chance of burning every one of the little bastards. I'm hoping they're not apt to attack the ornamental maples or fruit trees since usually each gall is species-specific & no future birches will be planted. If they are by & large harmless, though, I could view the two- & three-inch knots in the branches as being themselves rather ornamental.
-paghat the ratgirl
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Are you sure the galls are being caused by mites? It sounds alot like crown gall, which is caused by a bacteria that lives in the soil, and can absolutley be spread to other succeptible plants. Typically mites do not make galls as big as you are describing, though there are some parasitic wasps that do. If it is an insect, just cut them off and be done with it. If it is crown gall, you could remove them, along with another 6-8 inches of healthty branch below it and see what happens, or you could remove the trees. 2 dozen trees is alot to remove if it isnt necessary.
Toad
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I would second the opinion to confirm your diagnosis. If they are birch budgall mites, unless the infestation is severe there is no need to do anything. Otherwise, some judicious pruning is in order. And no, that specific mite is unlikely to bother anything other than birches. Leaf gall aphids do no damage to anything other than foliage - you would not detect any noticeable woody or knobby galls on stems or branches and they too are not inclined towards other species. OTOH, European white birches develop what are referred to as "galls" of dormant buds, which paper birch do not - are you certain of your ID? EWB's, while not native to this area, are somewhat naturalized and do spring up spontaneously.
Either way, unless they are aesthetically displeasing or it is crown gall as Toad suggests (uncommon in the upper branches of a birch), removal is not necessary and no control other than pruning out of obvious stem galls is recommended.
pam - gardengal

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Thanks to you & Toad. There is one Young's white birch on the property & it's the only birch unaffected. All the paper birches have the woody knobs, all higher than arm's reach. So I'll regard them as no real threat & just try to trim off what I can.
-paggers
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