Soundtracker, a portrait of audio preservationist Gordon Hempton, is a well timed piece of work. For the past few decades, Hempton’s self-appointed quest has been to preserve the acoustic landscapes of nature before the hum of the power line and the blast of the overhead plane eradicate their memory. The nonhuman soundscape – a vanishing communication commons – is a resource many living things depend on. And as a legitimate form of environmental degradation, noise pollution is a topic needing more attention. Beyond the NIMBYists bothered by local road repair, there are people like Hempton, who not only grasp the profundity of our loss of silence, and the severing of our communication with the nonhuman world, but the ecological costs of acoustic fragmentation. Hempton trained as a botanist before finding his calling in digitally capturing those vanishing signals from nature. In Soundtracker we follow him around the breathtaking back country of Washington State, as he locates areas where the rustle of tallgrass and the call of seabirds still sound as they always had.

It's safe to say that the Alberta Oil Sands have achieved a singular level of regard in the national imagination. Images of them proliferate the media. Usually beautifully detailed and taken from great heights, they conjure up anxieties running deep in our culture — of thirst and demolition and bewildered entitlement. They are the largest and perhaps most important industrial energy project in the world. And I wonder, after seeing the provocative and powerful documentary H2Oil, if the Oil Sands aren't simply an icon for our times, but if they are perhaps some great metonymy for them as well. Cruising across their unreal expanse at the beginning of the film, we acquire the sense that what's visible of the Sands can only ever stand for something larger.  The Oil Sands are a flash-point for volatile inter-provincial debate, a bulging knot in the North American petroleum market, the fuel for our cities, and an environmental wager of global proportions. The best thing about H2Oil is perhaps also its admirable weakness — it refuses to define the Oil Sands from any singular vantage. There are many important stories to tell about the Oil Sands, and H2Oil tells of a lot of them. It explores the political economy of oil, taking us into an Oil Sands Buyer Convention in Edmonton. It assesses the ecological devastation caused by the Oil Sands projects, showing us interviews with renowned ecologists David Schindler and Kevin Timoney. Through the stunning animation work of James Braithwaite, it visualises the costly and unusual method by which bituminous oil is separated from the deposits contained deep underground. Throughout, the film maintains a sense of the rich interdependancies that exist between these narratives. Interestingly, the central storyline in H2Oil is perhaps also the hardest one to picture: the story about tiny strains of arsenic and mercury that started traveling through the waters of the Athabasca.  About 200km downstream of the Oil Sands, the residents of Fort Chipewyan began witnessing declining fish populations, and weird ailments in their small game. This, it turns out, is nothing new: we learn from candid interviews with local residents that Oil Sands- related contaminants have been impacting their local ecologies for decades. But as the energy projects have picked up in the last 7 years, so too have basic forms of sustenance become more and more dangerous to consume. Forms of cancer than should only happen to one in one hundred thousand people have begun to hit — and kill — the residents of Fort Chipewyan at truly alarming rates.

Watching Those Who Remain, a doc about the Mexican families who lose loved ones to American immigration, I kept thinking about a Mike Davis book called Magical Urbanism. It's a study of the recent ‘Latinization' of US cities. Not only are Latino immigrants are invigorating such places as never before, Davis argues, but they are finally piercing the glass ceiling of political disenfranchisement that's plagued America's ethnic immigrant communities. “Jose is now the most popular name for baby boys in both California and Texas,” Davis enthuses, “and Southern Californians are more likely to greet each other with ‘Que tal?' than ‘Hey Dude!'” Magical Urbanism is a fundamentally optimistic book (which, if you know Davis' other work, isn't saying much) and Those Who Remain is not. Its subjects aren't broken exactly, but they are hardened, and in many cases quite sad. The reasons their loved ones have emigrated is universally simple: money, opportunity, jobs. Every year, millions of Mexicans “cross over.” Some never return. Some come back, only to leave again. The resignation which accompanies these painfully cyclical lifestyles is hard to fathom. We meet one father, Adriano, as he plans his US departure to fall after the Baptism of his third child. Birthing, his wife tell us, is the only reason he'll stick around for more than a month. Another father only exists on the end of a telephone, and we watch painfully as his baby daughter's wander away from the receiver distractedly.

The street-length rush line awaiting my arrival outside the Royal testified to the amount of buzz Hubert Davis' “Invisible City” has been getting (making it quite possibly the hottest Doc in the festival after Baichwal's "Act of God"). A title-riff on Ralph Ellison's portrait of alienation, “Invisible Man,” Davis' piece follows two high-school kids— Kendell and Mikey — as they grow up in Toronto's Regent Park. This housing project, the oldest of its kind in Canada, is in the process of a huge redevelopment that holds a very uncertain future for the community. These parallels — between the unrelenting evolution of urban form and community — are powerfully explored throughout the film. “Invisible City” reminds me a lot of “Killer of Sheep,” Charles Burnett's masterpiece portrait of Watts, Los Angeles, in the 1970s.  Both explore black communities in urban centres with a special ability to capture their vividness — a sun-dappled tree-shadow across a cracked courtyard — within a city that has half-forgotten they exist. The cinematography throughout “Invisible Cities” is beautiful; Davis is especially deft at capturing the expressiveness of his subjects — the avoiding glances, dismissive smirks and wide grins — as they deal with quiet frustrations and unexpected challenges. Mikey is shy and cerebral; he wants to take an advanced math class but also deals crack and skips curfew. Kendell is handsome and athletic; a natural with little kids who gets in trouble for fighting and skipping basketball practice. Both are supported by single mothers who seem always exhausted and yet are completely dedicated.  â€œI love him bad,” Mikey's mom says. These interactions seem to become more and more compelling as the story grows. Fortunately there is also Ainsworth, a former pro-athlete who has returned to the neighborhood as a school teacher.  Ainsworth understands his role as surrogate father to these kids — one extends far beyond the class room. He lectures them in the parking lot, invites them over for family dinner, jokes with them in the hallway. Three years of high-school life unfold against the rhythm of Regent's wrecking ball deconstruction — a backdrop which mimics the helplessness of change that each boy is confronted with. Mikey dreams of getting out of Regent, of seeing of the world, but the pull of neighbourhood is strong. “It's all right here,” he says, pointing toward the playground where he grew up. “All my memories are right here.”

I caught one of the NFB 70th Anniversary retrospectives Saturday afternoon that featured three short films from the NFB vault — “Streetrailway Switchman,” “Corral,” “Nails” — and one longer piece, “The Back-breaking Leaf.” All explore communities of labour in Canada. Shot in the 50s, 50s, 70s and 50s respectively, they are fundamentally optimistic portraits of busy times, hungry men in a country hungry for hard work. “Street-Railway Switchman,” the first of the batch, introduces us to a Polish immigrant who's job tending the streetcar tracks on Winnipeg's windswept North Main thoroughfare has left him with wistful but happy. He works alone, shoveling almost invisibly in the wintry night while people on the streetcars doze and wait for the car to start up again. The next morning he sits in a diner with a pile of sausages and 6 hard-boiled eggs. “It's not hard,” he tells us of the job, “and I eat a lot of fat.” “Corral” might very well be an Ian Tyson song — one of the happier ones. Again, the worker is singular, solitary, and satisfied. This unnamed cowboy — no words at all in this one — trots around a pen guiding wayward horses with grace and calm. A guitar strums some Western ballad and the tall-grasses blow. Unapologetically romantic, but it works. The Alberta setting is beautiful. The sky looms vast over-head. The cowboy opens the gate and the horses burst free. End picture. “The Backbreaking Leaf” is the main event — an award winning work directed by Terence Macartney-Filgate in 1959. Here, we witness the perennial transformation of tiny Delhi (pronounced: “Del-Hi”) ONT as it is flooded by summer laborers to work the Tobacco fields. Men lurch through the field in the dewy morning heat, gathering leaves. “You break your back to get the leaves,” the narrator explains, "because a machine hasn't been invented to harvest the [crop].” And this isn't a bad thing. Again the theme is of perseverance: work is tough but so are people. One guy from North Carolina says Canadians are a pretty nice bunch too. As long as the evening meals are satisfactory, people are content. Hungarian Immigrants set up their beer gardens and mud-speckled farm women gossip about doing nails on their day off.