Constanza Calderón felt the dark cool forest floor beneath her toes. Sunlight dappled the forest floor but even so the TV cameras had to turn on their lights to film the third-grade schoolchildren sitting in concentric circles around the famous television presenter and activist Thomas Naylor.

Naylor was wearing a black T-shirt that set off his makeup and his dark good looks. ‘These glorious trees are the oldest living things on the planet. They are the Guardians of the Earth. They are wise. And they have a message for us. Leave the planet alone. We must listen to them.’

‘The threat of abrupt climate change,’ Naylor said, ‘is so devastating for mankind and for all life on this planet that conferences are being convened around the world to deal with it. There is one in Los Angeles starting tomorrow where scientists will discuss what we can do to mitigate this terrible threat.

But if we do nothing catastrophe looms. And these mighty magnificent trees will be a memory, a postcard from the past, a snapshot of man’s inhumanity to the natural world. We’re responsible for catastrophic climate change. And only we can stop it.’ He finished with a slight turn to favour his good side and a piercing stare from his blue eyes right into the camera lens.

Half an hour later the plane lifted off the runway and rose over the forest. After his talk he had taken a few minutes to sign autographs for the kids. The cameras filmed that as well. He turned to Constanza giving her his best smile. ‘I thought it went extremely well, didn’t you?’ ‘Reasonably well, considering it was all bullshit.’ Calderón said.

Naylor’s smile remained fixed but his eyes narrowed. ‘I’m not sure what you’re referring to,’ he said. ‘I’m referring to the whole speech. Sequoias are sentinels and guardians of the planet? They have a message for us?’ ‘Well they do…’ ‘They’re trees. Big trees. They have as much of a message as an eggplant.’ ‘I think you are missing… ‘And they’ve managed to survive forest fires? Hardly…they’re dependent on fires. That’s how they reproduce. Redwoods have tough seeds that only burst open in the heat of a fire. Fires are essential for the health of the Redwood Forest.’

‘I think,’ Naylor said rather stiffly, ‘that you may have missed my point.’ ‘Really? What did I miss?’ ‘I was trying to convey…perhaps a bit lyrically…’ ‘Timeless? Primeval? Do you know anything about these forests?’ ‘Yes I think I do.’ His voice was tight. He was visibly angry now.

‘Look out of the window. How long do you think your primeval forest has looked the way it does now?’ ‘Obviously for hundreds of thousands of years…’ ‘Not true. Human beings were here for many thousands of years before these forests ever appeared. Did you know that?’ He clenched his jaw.

‘20 000 years ago the Ice Age glaciers receded from California gouging out Yosemite Valley as they left. As the ice walls withdrew they left behind a damp plain with lots of lakes fed by the melting glaciers but no vegetation at all. It was basically wet sand.

After a few thousand years the land dried as the glaciers continued to move further north. This region of California became arctic tundra with tall grasses supporting little animals like mice and squirrels. Human beings arrived here hunting the small animals and setting fires. ‘Okay so far?’ Calderón said. ‘I’m listening,’ Tom growled trying to control his temper.

She continued. ‘At first arctic grasses and shrubs were the only plants that could take hold. When they died they decomposed and over thousands of years a layer of topsoil built up. And that initiated a sequence of plant colonization that was basically the same everywhere in post-glacial North America.’

First Lodgepole Pine comes in…around 14 000 years ago…joined later by hardy trees like Spruce, Hemlock and Alder…the real primary forest and they dominated this landscape for the next 4 000 years. Then the climate changed. It got much warmer and all the glaciers in California melted.

There were no glaciers in California back then. It was warm and dry, there were lots of fires and the primary forest burned. It was replaced by a plains-type vegetation of Oak Trees and Prairie Herbs and a few Douglas Firs…but not many because the climate was too dry for fir trees.’

‘Then around 6 000 years ago the climate changed again. It became wetter and the Douglas Fir, Hemlock and Cedar moved in and took over the land creating the great closed-canopy forests that you see now. But someone might refer to these fir trees as a pest plant…an oversized weed…that invaded the landscape crowding out the native plants that had been there before them…because these big canopy forests made the ground too dark for other trees to survive. And since there were frequent fires the closed-canopy forests were able to spread like mad.

So they’re not timeless. They’re merely the last in line.’ Naylor snorted. ‘They’re still 6 000 years old for God’s sake.’ But Calderón was relentless. ‘Not true,’ she said. ‘Scientists have shown that the forests continuously changed their composition. Each thousand-year period was different from the one before it. The forests changed constantly.

And then there were the Indians. The Indians were expert observers of the natural world. Those forests may look impressive but they’re dead landscapes for game. So the Indians set fires making sure the forests burned down periodically. They made sure there were only islands of old-growth forest in the midst of plains and meadows. The forests the first Europeans saw were not primeval but cultivated. It’s not surprising that 150 years ago there was less old-growth forest than today. The Indians were realists. Today it’s all romantic mythology.’

…extracted from a Tavern Talk on Climate with Bill Shepherd