I took a walk in the forest the other day, a national forest. I’m not, customarily, big on walking in the forest unless there’s a Hansel and Gretel Bar & Grill about 300 yards in, but I’m glad I did. It was an uncommonly sultry April afternoon for San Francisco, and windless, rarer still.

At the entrance to the forest was an impressive, handcrafted wrought-iron gate, about 15 feet high, and just inside was a small wattle-and-daub hut with a watchman inside, a good-sized African-American chap who seemed a bit wobbly on his feet but not unvigilant. On the other side of the fence were a group of chaps, also African-American, of varying size and age, busily conducting commerce of some kind. The smell of marijuana around them was strong enough to knock a bullock sideways, but a not unpleasant, or unfamiliar, aroma on a fine spring afternoon in these parts.

I espied many a plant and tree in the forest, most of which, but not all, are commonly seen in northern California: a couple of fine redwood saplings, a baby sequoia, yucca, staghorn, nasturtium, a handsome white pine, Japanese maple, redbud, cactus, herbs. Above the wattle-and-daub hut was a hydroponic vertical garden, and above that a plaque that read: ‘Tell Your Story Here.’

It is a most refreshing forest, and really quite manageable: 25’ x 136’. I appreciate that in a forest. On either side of the narrow rectangle rise the sides of four or five-storey apartment blocks, one room, or resident hotels, with bright murals painted on, and in one patch there’s a group of painted tiles, the work of children from the nearby Vietnamese Cultural Center. It must be a pleasure for the inhabitants of these rooms to look down on this patch of greenery, which goes by the name of the Tenderloin National Forest.

It used to be called Cohen Place, after the Central Pacific Railroad attorney Alfred Andrew Cohen. A couple of do-gooders, Darryl Smith and Laurie Lazer, have succeeded, over 25 years or so, in turning an alley filled with unspeakable filth and rubbish into a tiny oasis in the middle of San Francisco’s Tenderloin district. The Tenderloin is a catch basin for drug dealers, prostitutes, the mentally unstable and homeless, the streets lined with fleabag hotels and residences, bars, billiard parlours, hoochie-coochie joints, cheque cashing and social service storefronts. Hep C and Aids are rampant. The place is depressing in the extreme, if fairly harmless during the day, but it bares its teeth at night. Darryl’s father, a policeman, drove him through the neighbourhood forty or so years ago and told him: ‘You don’t want to be winding up here, son.’ But he has indeed wound up here and set up shop. He describes the Tenderloin as ‘the most diverse and fascinating neighbourhood in San Francisco’. There’s a good novella about the Tenderloin entitled Whores for Gloria, by William Vollmann. If you want to catch a whiff of the neighbourhood while passing a lazy spring afternoon on your sofa in Somerset, you could do worse.

San Francisco is very much a city of neighbourhoods, with a not terribly interesting downtown. I used to travel on the streetcar down to the Tenderloin in the early 1990s when I was working at 44 McAllister, around the corner from the forest, with homeless veterans. The neighbourhood hasn’t changed much in twenty-odd years and there’s absolutely no good reason to come here, by my lights, unless you’re looking for hole-in-the-wall South-East Asian beaneries, the best in San Francisco. There’s been a large Vietnamese presence in the Tenderloin since the 1970s. Had the forest been up and running when I was spending time here I would almost certainly have come here as often as possible for spiritual refreshment, which is surely what Darryl and Laurie, who run a nearby community arts centre, had in mind. Probably not so much for well-educated, middle-class white boys like me, but all are welcome, and have been since May 2009, and before, when Cohen Place was reclaimed as the Tenderloin National Forest, leased from the city for $1 per year.

The thousands of tech workers from offices around the Tenderloin would be welcome here as well, should they be curious enough, or ‘brave’ enough, to venture to this part of the neighbourhood, adjacent to the busy intersections of Leavenworth and Ellis. It would involve walking over the occasional body or two and past gatherings of unhappy, argumentative characters down on their luck. I think these new visitors, as well, would find themselves refreshed.

There’s a fair bit of chitchat about population density and the changes wrought to San Francisco by the influx of tech types and the building frenzy around the mid-Market area of downtown. If you ask me, I think it’s a bit of a red herring. The most densely populated area of the United States begins about a block south of where I grew up in Fort Lee, New Jersey, along the Palisades, directly across the Hudson from Manhattan, including five of the most densely populated municipal townships in the country. The list goes like this: Guttenberg, Union City, West New York, Hoboken, Kaser (NY, on the border of NJ), New York City, and Cliffside, next to Fort Lee. San Francisco comes 20th on the list.

The Tenderloin is roughly the size of Hoboken, fifty square blocks, forty or fifty thousand people. They’re very different sorts of places, always have been. Hoboken has experienced, over the past twenty-five years or so, a wave of high-rise development and affluent new, younger residents. It’s still Hoboken, more restaurants, less crime, arguably less ‘flavour’; but, truth is, I don’t know just how much of a treat that ‘flavour’ was.

Jan Morris once wrote of San Francisco that it could do with a few thousand more people. The notion didn’t strike me as wrong at the time, and still doesn’t. Stir the waters a bit. Complacent, self-regarding San Francisco could do with some serious stirring up. Morris didn’t specify what sort of people were needed. One always hopes for the right sort. But then, you and I, and Jan Morris, might well have different opinions on that particular subject.