If they think of them at all, most people see plants as domestic accessories, with all the awareness of a Marcel Breuer Wassily chair. Gardeners and other plant lovers tend to see plants as horticultural eye candy, flaunting their pretty flower heads solely for our pleasure. Until very recently, even most scientists assumed that plants are essentially passive—rooted in place, taking whatever moisture, nutrients, and sunlight chance brings their way. It’s not exactly surprising, then, that the word “vegetable” is used to describe people with brain damage so severe they have no discernable awareness.

A trove of new research, however, is demonstrating that plants are far from botanical automatons. To be sure, researchers have found no signs of Socratic logic or Shakespearean poetry in the plant kingdom. But there is so much new data on plant intelligence—including abilities like sensing and, yes, even learning, remembering, and recognizing kin—that the investigation of plant intelligence is suddenly a serious scientific endeavor.

The latest case in point: You know the perennial debate over the role of nature vs. nurture—heredity or the environment—in the development of a human being? Studies have shown that, depending on their distinct personal experiences, identical human twins can have a different chance of getting a disease. Well, it turns out that in this respect plants may not be so different from people.

In a new study, University of Toronto biologists found that genetically identical poplar trees—clones—responded to drought differently, depending on the nursery the plants were obtained from. They took cuttings of the poplar clones from nurseries in two different regions of Canada and regrew them under identical climate-controlled conditions. Half of the trees were then subjected to drought. Since the trees were regrown under identical conditions, the researchers predicted all the specimens would respond to drought in the same manner, regardless of where they had come from. But low and behold, the genetically identical specimens responded differently to the drought treatment, depending on their place of origin.

Malcolm Campbell, one of the study’s authors, called the finding “quite stunning.” “A tree’s previous personal experience influences how it responds to the environment,” he said. In other words, the trees “remember” where they came from.

Discoveries such as this have the potential to transform the public’s view of plants. In fact, they’re helping to transform our understanding of the nature of intelligence itself.

They also have practical implications for gardeners, landscape designers, and foresters: The “memory” of previous experience discovered in this study could help determine how plants from a particular nursery will respond to conditions in a particular landscape. It may also help predict how certain plants will respond to climate change or other environmental stresses.

Sometimes when I’m depressed about The State of the World I cheer myself up by thinking about how radically things have changed in my own lifetime. More and more women are at the top of their professions. Cigarettes are taboo. Same-sex marriage is now legal in my state. The Sustainable Sites Initiative is poised to transform the way we design and maintain landscapes…

Less than two years ago, I was told by a client not to say too much about climate change in a publication we were developing because the issue is a political hot potato. But just last week at its annual meeting, the American Public Gardens Association unveiled a partnership with the National Oceanic and Atmospheric Administration to educate gardeners and plant enthusiasts about the possible effects of climate change on the country’s gardens, landscapes, and green spaces. Yay APGA!

And I’m happy to report that my latest book, The Climate Conscious Gardener, which was published by Brooklyn Botanic Garden last year, has won a 2011 Garden Writers Association award. Kudos to BBG for continuing to raise critical—and potentially controversial—issues in its acclaimed handbook series. And thanks, GWA, for the recognition!

The following was published as part of my regular “Growing Greener” column in Public Garden magazine, Vol. 24 No. 3 (2009). Public Garden is the flagship publication of the American Public Gardens Association. In “Growing Greener” I answer sustainability-related questions from public garden staff.

Q: There are so many different green roof systems. Are they all effective?

A: It’s easy for us plant enthusiasts to be seduced by the idea of verdant rooftops. Aesthetically, living roofs are a major improvement over typical asphalt or tar roofs, which are about as hospitable to humans and most other life forms as Death Valley on a mid-summer day. But before falling head over heels for green roofs it’s worth asking whether they really, as touted, help insulate buildings and thus save energy that would otherwise be consumed for heating or cooling, counteract the urban heat island effect, remove particulates from polluted air, detain and cleanse storm water, and more. (more…)

Oxfam wants us to demand action on climate change until we’re blue in the face—literally. The goal of the global anti-poverty group’s new campaign is to send a strong message to world leaders who will meet this December in Copenhagen to negotiate a new climate deal. To make the point, Oxfam is sponsoring face-painting and picture-taking sessions at festivals across the UK this summer. The photos will be used to create a giant multi-media petition.

When I was a kid, we didn’t eat meat on Fridays. I came from a Catholic family, and like most Catholic families, meatless Fridays were a commemoration of the crucifixion and death of Christ, which according to scriptures occurred on a Friday. Not being all that impressed with the rituals of Catholicism, my brother and I held our noses and ate the standard end-of-the-week fare—fish cakes or fried flounder. But like millions of other kids we survived. In fact, we were probably healthier for having avoided still another evening meal of beef stew, hamburgers, or pot roast.

Now a new movement called Meatless Monday is gaining traction. The goal of the campaign, which is being promoted in association with Johns Hopkins’ Bloomberg School of Public Health, is to reduce meat consumption by 15 percent to improve personal health, reduce our carbon footprint, and conserve resources like fresh water and fossil fuel. Last month Ghent, Belgium became the first city in the western world to go meatless once a week, although they’re doing it on Thursdays instead of Mondays.

On the Meatless Monday website, you can find information on seasonal fruits and vegetables, including recipes, check on who’s going meatless, and take the Meatless Monday pledge yourself.

These days, as part of my semi-nomadic life as a program planning and interpretation consultant for public gardens and nature centers, I’ve been offsetting a lot of travel-related carbon emissions. Like this week. I just got back from one of those places that seem to engender periodic bursts of human creativity. Call it karma or happy coincidence, these places suddenly  become magnets for artists, oddballs, and other rebellious types who, through a critical mass of their collective contrarian consciousness, change the course of history. Like Florence in the 15th century, or Baraboo in the 20th century. Baraboo??

Baraboo is a small city in south central Wisconsin with a population of less than 12,000. The surrounding Baraboo Ranges are all that remain of one of the most ancient rock outcrops in North America, composed of Baraboo Quartzite, a metamorphosed form of sandstone that originated about 1.85 billion years ago in what geologists call the Early Proterozoic Eon. The Baraboo area is also the terminal moraine of the Wisconsinan, the place where this final glacier of the last Ice Age dumped its debris, creating impressive sights like Devil’s Lake Gorge, where quartzite blocks crunched up by the ice sheet cling tenuously to steep slopes.

It was in Baraboo in 1884 that the Ringling Brothers began their circus, a band of oddballs if there ever was one. Over six seasons, the circus expanded from a wagon show to a railroad show with 225 employees, touring cities across the United States each summer. Baraboo remained the circus’s headquarters and wintering grounds until 1918.

A few years later, in 1924, Aldo Leopold arrived in nearby Madison, and in the early 1930s he purchased a dilapidated chicken coop and a few hundred acres of Dust Bowl-ravaged land near Baraboo as a weekend retreat for his family. At the shack, as it was called, Leopold was inspired to write conservation classics like A Sand County Almanac, launching the fields of restoration ecology and land ethics. 

The Baraboo Ranges continue to work their magic. A couple of years ago, about a mile down the road from the shack, the Aldo Leopold Foundation built the Aldo Leopold Legacy Center. The second highest-rated LEED Platinum facility to date, the Legacy Center also meets the 2030 Challenge, which aims to rapidly transform the U.S. and global building sectors from the biggest single contributor of greenhouse gas emissions to a central part of the solution to the climate crisis by changing the way buildings and developments are planned, designed, and constructed. 

The Legacy Center also happens to be the first carbon-neutral building certified by LEED. The initial carbon budget for the facility was based on projected emissions from combustion (including stationary sources such as wood-burning stoves and fireplaces, vehicles driven by employees to and from and at work, and estimated visitor vehicle use); on-site electricity generation from photovoltaic cells; wind-generated electricity purchased at night and on days when the solar array does not meet building demand; and carbon sequestered by the Foundation’s 500 acres of forested land. You can find out more about how the Center reduces and offsets its carbon emissions here.

The beautiful facility is located on the land where Leopold perished in 1948 while fighting a brush fire on what was then a neighbor’s property.

Three cheers for citizen scientists! Twenty years of data compiled by an avid hiker and naturalist and analyzed by researchers at the University of Arizona in Tucson show that plants in the state’s Santa Catalina Mountains are flowering at higher elevations as summer temperatures rise. 

Dave Bertelsen told Science Daily he’s been hiking the Finger Rock trail one to two times a week since 1983 and recording what plants are in flower. His 5-mile hike starts in desert scrub and climbs 4,158 feet, ending in pine forest. He’s completed 1,206 round-trip hikes and recorded data on nearly 600 plant species. The researchers found that during the 20-year study period, summer temperatures in the region increased about 1.8 degree Fahrenheit.

Bertelson hooked up with the scientists at a 2005 meeting about monitoring plant species held by the U.S. Bureau of Land Management in which one of them, UA climatologist Michael Crimmins, discussed his need for data to study the effect of climate change on ecosystems over time. According to Theresa Crimmins, research specialist for the UA’s Arid Lands Information Center and lead author of the resulting paper, the role of citizen scientists is becoming ever more important—biological changes caused by climate change are coming fast, she says, and ”more eyes on the ground” are needed to monitor them.

Scientific American marshals the evidence on how much eating meat, especially beef, contributes to global warming—a lot, more than either transportation or industry.

Pound for pound, beef contributes more than 13 times as much to global warming as chicken, and 57 times as much as potatoes.

In all the coverage of the study published a few days ago suggesting that the effects of climate change will be “irreversible” for 1,000 years, and that several parts of the world will suffer “dust bowl-like” conditions due to decreasing rainfall, I haven’t seen anyone point out that the affected regions include some of the “hottest” of the Earth’s biodiversity hotspots, the so-called mediterranean-climate regions.

The regions mentioned in the paper include southern Europe, South Africa, southwestern North America, and western Australia,  meaning big trouble for at least four of the five mediterranean-climate regions, which cover just one to two percent of the land surface but harbor about 20 percent of the plant species on the planet. The most distinctive plant communities that have evolved in the cool, wet winters, warm to hot, dry summers, and poor soils of these areas are shrublands—the fynbos of South Africa’s Cape Floral Kingdom, maquis and garrigue in the Mediterranean Basin, Australian mallee, and Californian chaparral, as well as Chilean matorral.

Among the unique plants found in these regions are proteas, the signature plants of the Cape Floral Kingdom, whose spectacular, often large blooms, with vase-shaped bracts surrounding cone-like clusters of slender, curving, tube-shaped flowers, are critical to the worldwide floral trade. Proteas are named for the Greek sea god Proteus, who could change his form at will. But many of the plants won’t be able to change fast enough to cope with anticipated climate change. More than half of all protea species are already threatened with extinction. Habitat loss alone is decimating protea populations, and when climate change is factored in, the situation is all the more dire.

Some perspective on the stunning new paper in the Proceedings of the National Academies of Science that concludes

“… the climate change that is taking place because of increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop”

and that among these “irreversible impacts” are reductions in dry-season rainfall in several regions comparable to those of the “dust bowl” era, including southern Europe, northern Africa, southwestern North America, southern Africa. and western Australia:

Joseph Romm at climateprogress.org: “Bottom line: A few decades of prevention is worth 1,000 years of curemisery.”

James Hrynyshyn at scienceblogs.com: “What this means to me is those who are pushing for strong climate change mitigation action are going to have to emphasize that what’s already in the pipeline will pale compared with what will come if we don’t get our act together.” In ”Can geoengineering reverse irreversible climate change?” he also comments on the following qualification in the paper—”we do not consider geo-engineering measures that might be able to remove gases already in the atmosphere or to introduce active cooling to counteract warming.”