Air vents for the Morlocks.

They are air vent pipes to allow carbon dioxide releases caused by the City of Portland's downspout disconnect program. It causes excess ground water in concentrated form that encourages more soil microorganism oxygenination that releases excess, disruptive dioxides.

global warming pipes?

They are air vent pipes to allow carbon dioxide releases caused by the City of Portland's downspout disconnect program. It causes excess ground water in concentrated form that encourages more soil microorganism oxygenination that releases excess, disruptive dioxides.

Seriously?

It's where people are stowed when they testify one too many times at the City Council. I think they're called Broussard Beacons.

They look like the extra long version of those barbecue chimneys--you know, the things where you stuff newspaper in the bottom and charcoal in the top and thus don't have to use lighter fluid?

Where are they? My barbecue chimney rusted out over the summer.

I'd like to know, too. I used one for the first time at a friend's place this summer, and it worked great.

Where are they? My barbecue chimney rusted out over the summer.

I have seen them at BiMart, Walmart, GiJoes, Fred Meyer. But this time of year it might be hard to find one.
Walmart is probably the best bet, actually.

Home depot

Just based on how they're positioned around the tree and the fact that they don't seem hollow, I would guess that they're to keep people from accidentally driving over that tiny curb and running into the tree.

This may be a sewer vent shaft: A structure provided to limit pressure fluctuation within the sewerage system, or for air to enter and escape from the system. Sewer vents are an essential part of sewerage systems. Their purpose is to introduce a flow of fresh air through the sewers in order to reduce the production of noxious and corrosive gases by enabling their release.

Often times they are incorporated into lamp posts to make them blend in to the streetscape, and in some cities they can be quite ornamental:

http://www.askaboutireland.ie/show_narrative_page.do?page_id=613

http://www.sydneywater.com.au/Publications/Factsheets/TheObelisk.pdf

I'm pretty sure that's a sewer vent, as Nick said. Not as pretty as the images he attached, but still functional, I guess. I haven't seen them around here often, but they are all over the place in Southern California.

Weber make the best bbq chimney, lasted me 3 years so far. I got mine at the Home Depot

Here here, Travis. I've used a Weber chimney vent for at least 3 years. It still is in great shape. The knock-off brand I had before that fell apart after 10 barbecues.

Moreover, I've had my Weber kettle grill for 8 or 9 years now and it still looks choice. Just keep 'em out of the rain and they'll last forever. Good stuff that Weber.....

Yep.

Now, back to those things sticking up out of the ground...

This sounds likely,

Anonymous said at 8:30 AM...
It's an air release valve, probably installed by the Portland Water Bureau. It's designed to automatically release small pockets of accumulated air from a pipeline while the system operates under pressure.
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However, it doesn't explain why they are only in Sellwood. I would think they would be scattered all over the inner east side.

So my money is with the Morlocks - it's the simplest answer.