The smoke here was so thick that it resembled a heavy fog. Its acrid smell spread to villages more than 1,000 miles away.
To escape the forest inferno, many animals headed into the city. Startled residents in one apartment building found a brown bear in their lobby.
The Siberian taiga is a pristine woodland of conifers, stretching 1.3 million square miles to Russia's Far East Pacific coast. Comprising nearly a quarter of the planet's timber reserves, the taiga is twice the size of the Amazon rain forest. It is one of the earth's great lungs, generating oxygen and extracting pollutants, while providing a refuge for endangered tigers, bears, and birds.
But huge fires have been raging unchecked in the Siberian Far East for three months, devastating vast tracts of primeval forest. United Nations experts who visited Sakhalin island and Khabarovsk, near the Chinese border, this week called it a global catastrophe.
"Forest fires of such a scale fall in the category of worldwide ecological disasters," the UN experts said.
"They bear consequences not only for the ecosystem of frontier countries with Russia but also for a large part of the Northern Hemisphere," the UN statement added.
These 2.2 billion acres of woodland serve as "sinks" that soak up carbon gases that add to global warming. The forests host diverse plant and animal life and make up the traditional homelands of nearly 200,000 indigenous people.
Now the fires, as well as illegal logging, are devastating these woods. Environmentalists say this poses a bigger threat to the world's environment than the destruction of forests in Brazil, Madagascar, or Thailand.
Dry year fuels huge blazes
Forest fires in the Far East are an annual summer event, touched off by both nature and careless humans. But this year was particularly dry, and the autumn rains are late. In Khabarovsk, about 990,000 acres are still blazing and 2.9 million acres have been destroyed. As much as two-thirds of the forest on Sakhalin, an island just miles off Japan, have burned.
"If there is no serious rain, Sakhalin's forest will disappear soon," says Yevgeny Usov, a spokesman for Greenpeace Russia. "The consequences are serious."
Forest fires are difficult to control in this part of the world because there are few roads or towns, little equipment, and scarce funds. The fires began just as Russia's economy collapsed and the central government is too distracted - and bankrupt - to worry about trees.
Foreigners are filling the void. Japan pledged $40,000 in humanitarian aid to the town of Gorky, which was ruined by fire, while foreign oil firms working on Sakhalin have promised $50,000. But Greenpeace estimates that total material losses in the region could top $31.5 billion.
That doesn't even take into account the ecological havoc: As much as 50 million tons of toxic carbon gasses may be emitted this year from the forest fires. And ashes falling into Sakhalin rivers will make it difficult for salmon to spawn. This could affect the red caviar industry on which the impoverished region depends.
Environmentalists fighting to save endangered Siberian tigers are glum. Protection efforts had made progress in stabilizing the wild population at more than 400, but the fires are destroying traditional habitats. "This means they will move closer to towns where they inevitably will be killed by poachers," Greenpeace's Mr. Usov says.
The attention on the forest fires is obscuring another serious problem - the smuggling of valuable cedar, elm, and ash trees to China, Korea, and Japan.
Illegal logging has soared over the past decade, especially since borders opened after the Soviet Union's collapse in 1991. Russia's pervasive corruption means that truckloads of rare wood regularly cross the border unchecked. It can be catastrophic when the trees are cut down in areas of permafrost, where soil remains frozen year round. Swamps are created on which new trees cannot be planted.
Illegal logging adds to losses
Illegal logging is practically equal to forest fires in terms of its threat to the taiga, says Vladimir Shetinin, deputy chairman of the Primorsky region's State Committee on Environmental Protection, based in Vladivostok.
"The real smuggling is only beginning now. Over the past three to four years smugglers got a taste of the money they could make," he says.
Ash is one of the most valuable woods in the world, fetching up to $800 for a small piece, says Vladimir Stegni, director of the Primorsky regional government's Department of International Economic Relations in Vladivostok. Cedar is banned from export because it is so endangered. But it gets to China anyway.
Mr. Shetinin blames the economic crisis, which he says is driving desperate men to smuggle. "Middlemen meet laid-off factory workers and take advantage of their professional skills. This is first-class work."