Is this tree sick?

[McNutty]

I should probably just find a tree doctor to check it out, but just in case this is something obvious... Here are some photos of a tree in our front yard. Every year, some of the branches have green leaves and some have leaves that are partially green and partially pale brownish green. I never paid a ton of attention and always assumed that they were just in different stages of development. However, it seems like that might not be the case, as it's always the same branches in one state or the other. Also, I can't be sure, but I think that over the years, there has been less and less of the tree that's the nice healthy-looking green.

So my questions are: First, can anyone tell me what kind of tree that is? Some distinguishing features are that there's a stage where the leaves have a bunch of ... stuff hanging from them which I assume is related to flowering or something, but it never really gets anything I'd call "flowers" (zoom in on photo 4), and the branches and trunk are covered with a nasty yellowish-green powdery gunk that gets all over you (see photo 6). If you ignore the one wild branch that's reaching for the sky, I'd say it's about 15 feet tall. I'm in Seattle in case that's important.

Second, is there something wrong with it?

[CherryBomb]

No idea what type of tree it is, but it definitely looks ill, some kind of blight or possible infection. My ex was an arborist that owned his own business, so I've seen my share of sick trees. I just had to cut down the last of my aspens, they were all sick with the tree version of AIDS. Made me sad...

[WhyNot]

It does not look like a well tree. More than that, I can't say, but I'd call a tree doc if that tree were in my yard.

[Harmonious Discord]

I would say it's a Box Elder tree, which is a tall soft wood nuisance tree banned in many cities because of the Box Elder bugs it attracts. It's sick regardless and should be cut down. Being a tall growing tree under a power line also is a reason to get rid of it. Plant a short growth habit tree that will stay lower than you power lines.

[McNutty]

That's not a power line, it's cable TV. And aside from that one branch, it's got a long way to go before it even reaches that. I am disinclined to cut the tree down if it can be helped.

[Harmonious Discord]

That's not a power line, it's cable TV. And aside from that one branch, it's got a long way to go before it even reaches that. I am disinclined to cut the tree down if it can be helped.

I figured that or you would have just cut i down. It will probably linger a few years for you.

[featherlou]

Yup, that looks like a sick tree to me. The green stuff looks like a kind of fungus. Box elders (Acer negundo, aka Manitoba Maples) are huge trees, too, if that's what that is.