Tiny Camac Street, between 12th and 13th streets is little wider than an alley in Center City, but one block between Locust and Walnut has the distinction of being the only stretch of city street paved with wooden blocks.

The paving system is historically protected, and much beloved by residents who take a certain pleasure in it’s nearly useless charm.

Somebody dropped a fresh patch of asphalt over some of it. What’s going on?

That somebody was the city’s Streets Department, whose representatives said Tuesday that's the way it’s gonna be for a while.

The city has to find someone to sell them wooden blocks. 

"The current project is an interim repair because of the extensive deterioration of the street,” said Streets Department spokeswoman June Cantor. 

The wood-paved stretch of Camac Street was paved with wood because the little alley was once lined with genteel clubs whose clients were annoyed with the noise of horse hooves on cobblestone.  Miles of Philadelphia — and in other cities — were lined with wood. 

Over time, the blocks tended to absorb the stench of horse urine and fell into disfavor. They deteriorated rapidly with the advent of cars. 

The city, over time, removed them, until Camac street was last. A major reconstruction was done in 1998, and again in 2008. In 2012, the city patched the street, apparently with the last of its 4-inch by 4-inch oak blocks.

"We used wooden blocks that we left in inventory from the last major reconstruction," Cantor said.

Related: Potholes: Prepare to get your asphalt kicked

Though the Streets Department dropped asphalt over a portion of the street, a 30-foot section of newish wooden pavers remained uncovered on Tuesday. Closer to Walnut Street, deteriorated blocks crumbled under foot. 

The Streets Department needs to solve two big problems before repaving Camac with wood — finding appropriate blocks and finding a way to preserve them. 

It took the city more than a year to find blocks dense enough to serve as a paving material back in 1998, according to an article in the Philadelphia Inquirer from that era.

“Due to the "rarity" of wood block streets, there is no known product that is designed for this specific application,” Cantor said.

Related: Nutter: Yes there will be a fence, and we'll be moving cars for papal visit.

Then there’s another issue: the Historical Commission wants to restore the Camac according to the earliest possible data. That means using white oak, rectangular wood pavers that stretch 4-inches by 8-inches. 

Cantor said the Streets Department got 7 years out of the last batch of blocks, and that's consistent with what they've seen in other cities. But because the underbelly of the street is lined with concrete, the crews have drilled holed in hopes of wicking water away fast enough to minimize rot. 

While older blocks installed at the turn of the century were soaked in creosote, a product that is no longer available for use. The Streets Department is experimenting with other wood preservatives.