It costs $18 to plant a sapling in Israel. So why, on average, does it cost the parks department $1,100 to plant one in New York City?

The trees planted in Israel are a fraction of the size of the saplings planted by the parks department. Still a former parks commissioner says the city is paying more money than it should for each tree.

The high cost can be attributed in large part to an increase in labor costs, which date to a 2003 decision by the city comptroller, William Thompson, to raise the pay of tree planters more than threefold. Today, tree planters make about $55 an hour, up from the $15 hourly wage they were paid before the change. Prior to that decision, the price of planting a tree was about $700.

“That seems like a lot,” the current commissioner for the parks department in Westchester County, Mitchell Tutoni, said when told of the $1,100 price tag in the city.

The increase in labor costs has resulted in a sharp drop in the number of trees the parks department can afford to plant, a former parks commissioner, Henry Stern, said.

“There are enormous adverse consequences from this to the greening of the city of New York,” he said.

During the first three fiscal years of this decade, the parks department planted between 10,000 and 13,000 saplings each year along city streets, according to the parks department. By contrast, during fiscal year 2006, the department planted 7,200 saplings.

In addition to rising wage costs, one contractor, Angelo DeBartoli, said a second change in the contracts contributes to the high price of planting a tree in New York City. A new rule requires contractors to replant trees that are felled by vandalism within two years of their planting, he said in a telephone interview. Mr. DeBartoli, the owner of Robert Bello Landscaping, said it was “insane” that contractors had to guarantee the trees against vandalism once the plantings were finished.

Still, Mr. DeBartoli said the sudden rise in cost was largely caused by the required wage increase for tree planters.

The decision to raise the wages came as the comptroller’s office reclassified the job of planting trees to labor from gardening.

But that classification is in question today, as it was when it was made.

“We got lumped into the laborer category, but we’re landscapers,” Mr. DeBartoli said. “We don’t come out with cranes and all kinds of fancy equipment. We come out and dig a hole and plant a tree and put stones around it.”

The trees, which are about 8 feet tall, often weigh 400 pounds. While heavy labor is a part of the job, it is only a small part of it, he said.

Mr. DeBartoli, whose landscaping firm plants some 2,000 saplings annually for the city, said he and 10 other contractors have formed an association and intend to ask Mr. Thompson to change the wages they must pay their work crews.

A spokesman for the comptroller did not return repeated calls for comment.