Is the 'monster vegetable' thriving?

Scientists study the giant sequoias in the UK

Volume 2, Number 38 - Thursday, April 18, 2024
Published Mondays and Thursdays

Wellingtonia Avenue is a road in Crowthorne, Berkshire, UK. It is lined with over 100 giant sequoia trees, known at the time of planting as Wellingtonia. — Photo by Anthony Eden, via Wikimedia.

Perspective

A LOT OF ARTICLES were in the news recently about giant sequoias growing in the UK, with at least one (HERE) suggesting that the trees are thriving in Britain and threatened in the Sierra Nevada.

Here’s an excerpt from the article referenced above, published by the Yale School of the Environment:

First introduced to country estates in the 19th century, half a million sequoias now grow in Britain, compared to just 80,000 along the western flank of the Sierra Nevada in California, where they are increasingly imperiled by warming. Up to a fifth of all large giant sequoias in California died in wildfires in 2020 and 2021.

And an excerpt from an article (HERE) published by the UK’s National Trust, about how William Lobb, a plant collector for the Veitch Nurseries, started a craze for giant sequoias — first named Wellingtonia gigantea — during the California Gold Rush:

In 1852, Lobb visited San Francisco, where he first heard of mammoth conifers in the foothills of California’s Sierra Nevada range. Lobb knew this ‘vegetable monster’ would trigger an enormous craze in British horticultural circles and hurried to the Sierra foothills to see the remarkable tree in its native habitat.

He found about 90 towering trees and reported that a felled tree had measured 300 feet with a diameter of over 29 feet near its base. A section of this 3,000-year-old tree was displayed in San Francisco, where its hollowed (and carpeted) slice of trunk could comfortably accommodate a piano with an audience of 40.

Lobb collected seeds, shoots, and seedlings. In fewer than two years’ time, these would give rise to thousands of saplings snatched up by wealthy Victorians to adorn great British estates.

The larger-than-life conifer, so symbolic of the vast American wilderness, suddenly became a status symbol in Britain.

Fast-forward about 170 years, and yes, the remarkable trees are still growing in Britain. They are beautiful ornamental trees, and people are planting more of them.

But are they thriving?

I suspect that’s a matter of opinion. Some of the oldest of them reportedly produce seeds, but conditions aren’t currently right for those seeds to germinate. Will the trees continue to grow, and might the climate change over time to allow natural regeneration? I don’t know.

The recent articles about giant sequoia in the UK are based on research reported in a report published by The Royal Society on March 13. You can read it HERE.

According to the report, the study provides the first estimate of the growth and carbon sequestration of UK open-grown giant sequoias and will provide a baseline for estimating the trees' longer-term carbon sequestration capacity.

I don’t like to use terms (such as “carbon sequestration”) without understanding them. With a little googling, I came up with this definition from the U.S. Department of Energy (HERE):

Carbon sequestration refers to the storage of carbon dioxide (CO2) after it is captured from industrial facilities and power plants or removed directly from the atmosphere. Those captured CO2 emissions are then safely transported and permanently stored in geologic formations.

Storing CO2 is increasingly important because these emissions are warming the Earth’s climate in ways not seen in millions of years. These emissions are causing wildfires, floods, and storms. They are also threatening sea life due to increased acidity in the oceans. 

Scientists are working on two broad types of carbon sequestration: biologic and geologic.

There is a lot more information at the link I included above. In the simplest terms, as regards giant sequoias, it seems that scientists (and others) are thinking that since these massive trees can live for thousands of years and are storing CO2, it’s a good idea to plant more of them.

Where giant sequoias have been planted and grown successfully, not just in the UK but around the world, some people think that planting more of them is a way to offset one’s “carbon footprint” and do good for the environment.

The study referenced above was focused in part on establishing ways to measure the trees and estimating the AGB, which means aboveground biomass, and annual biomass accumulation rates and noted:

Given that carbon sequestration is already being used as a justification for planting S. giganteum in the UK, our estimates can help inform that process. However, like many others, we note that focusing on trees primarily as carbon sinks, particularly when planted individually or in urban areas, risks overlooking their many other potentially more important benefits.

This excerpt points to one of the other values of the research —to provide information as people in the UK consider planting more giant sequoias:

The apparent success of S. giganteum in the UK has also raised interest in their utility as commercial and amenity trees that may be resilient to the changing climate and environment, particularly rainfall, soil moisture and fire, as they are in their natural range. The research arm of the UK’s Forestry Commission, Forest Research, has investigated the viability of S. giganteum as a climate- and disease-resilient species for diversifying UK commercial forestry. Forestry England estimates that there are already over half a million S. giganteum and S. sempervirens in the UK (and more are being planted). 

Just how resilient these trees are in the UK is an open question. Quantifying their carbon sequestration will help in making informed decisions about where (or even whether) to plant S. giganteum and how to manage them successfully.

Hamerly sequoia grove

The UK is not the only place where people are planting large numbers of giant sequoias outside their natural range.

As reported HERE, nearly a year ago, Jim Hamerly added to giant sequoias he found growing on Palomar Mountain in San Diego County. He’s also identified naturally occurring seedlings on CalTech’s Palomar Mountain Observatory grounds. You can read more about that HERE.

Hamerly and others formed a nonprofit organization called Sequoia Sentinels, which is dedicated to the planting, conservation, and restoration of sequoia groves. More than 25 area residents have signed up to plant approximately 150 more giant sequoia trees this weekend.

"Sequoia trees are truly awe-inspiring giants,” Hamerly said in a news release. "Planting these majestic trees not only helps restore our local ecosystem but also provides a legacy for future generations to enjoy. We're thrilled to see such a strong interest from the community and can't wait to get our hands dirty together."

For more information, send an email to: info@sequoiasentinels.com.

Wildfire, water & weather update

Thunderstorms are forecast for the southern Sierra Nevada tomorrow, and rain is possible by midweek, with snow at higher elevations. 

What does the weather have to do with giant sequoias? Quite a lot. The National Park Service offers more information about giant sequoias and climate HERE.

Drought, atmospheric rivers, temperature and the amount of precipitation that falls as snow are among the factors that impact giant sequoias, everything else that lives in the forests where they grow and people who depend upon Sierra Nevada watersheds.

I’ve just discovered another resource — The Center for Western Weather and Water Extremes at the Scripps Institution of Oceanography at UC San Diego. According to THIS REPORT, 51 atmospheric rivers made landfall in California during water year 2024. Atmospheric rivers can cause flooding, landslides, serious road damage and other impacts in the Sierra Nevada, where giant sequoias grow. The referenced report provides more information.

The best Sierra Nevada weather forecasts are at NWS Hanford, HERE, and NWS Sacramento, HERE. 

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