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Plants are marching north. Native gardening will never be the same.
Thirteen miles isn’t very far: roughly the length of Manhattan or the distance you run in a half marathon. On a freeway, it takes less than 15 minutes to drive.
Multiply 13 by 10, though, and it becomes 130 miles — more than the width of the state of Connecticut. Move the U.S. border 130 miles north, and Whistler Blackcomb becomes an American ski resort; move it south, and Tijuana is the new Los Angeles. If you started walking, it would take you 35 straight hours to cover the distance; if you called an Uber, you’d be looking at a $450 ride.
The temperature regions that determine the local viability of different plants, called plant hardiness zones, are believed to be slipping north at a rate of about 13.3 miles per decade — not a number that sounds especially alarming, but one that will, over a century, add up to dramatically reshape the regional flora of the United States. In addition to being yet another depressing climate statistic, though, that number is also generating a lot of headaches in the surprisingly combustible world of native gardening.
It’s been 16 years (or approximately 21 northward miles) since Douglas Tallamy’s warning in his book Bringing Nature Home that “unless we restore native plants to our suburban ecosystems, the future of biodiversity in the United States is dim.” Though we may still be far from achieving his long-term goal of a “homegrown national park,” in which Americans convert half their yard space to native gardens, Tallamy’s teachings remain hugely influential in gardening and conservation circles (42 states have their own specialized native plant societies promoting these goals).
Tallamy insists that “all plants are not created equal, particularly in their ability to support wildlife.” If we’re to sustain the remaining biodiversity in the U.S., it is essential to feed insects — and in turn, the birds that eat those insects — the foods they’ve evolved to eat. If a plant isn’t native to these ecosystems, then it isn’t worth planting or sustaining. Often, says Tallamy, doing so is actively detrimental to biodiversity goals.
But what even is a native plant in this obviously shifting world? Already, New York City is considered subtropical, capable even of supporting certain hardy palms; by 2040, Seattle could be in the same hardiness zone that central Florida, New Orleans, and parts of Texas are in today. Researchers have seen plants native to the South slowly pushing their ranges north.
Native plants are frequently the species under the most stress from the new weather patterns in their historic ranges. The state tree of Washington, the Western hemlock, for example, is especially susceptible to drought and is struggling to survive in a drier Pacific Northwest. “We’ve found a lot of mortality of trees that should be in the prime in their life,” explained Raymond Larson, an associate director and curator at the University of Washington Botanic Gardens and a contributor to Great Plant Picks, a viability resource for Pacific Northwest gardeners.
As a result, many horticulturalists with an eye on the next century are actively exploring — and recommending — plants that are explicitly not native. Axios Seattle recently published a list of trees that Pete Smith, a program director at the Arbor Day Foundation, believes will be able to tolerate the next 50 to 100 years in the region, and it notably included the Japanese pagoda tree; the pawpaw, a native of the East Coast; and the ginkgo, which is “incredibly tough, very long-lived, and great at tolerating urban stresses” — but an exotic from China that is particularly reviled by Tallamy.
“What honestly most gardeners — many gardeners, anyway — have kind of lost track of is what the word ‘native’ means,” Smith explained to me when I followed up to ask about the globe-spanning range of his recommendations. “It is presumptuous, even, to talk about native plants as if 1492 was some magic date that talks about what is and was native to this continent.”
“Native” doesn’t have a hard and fast definition. In Bringing Nature Home, Tallamy writes that a true native is a plant that interacts “with the community that historically helped shape it,” but he also warns against using too small a timescale when making these determinations: “[A] history measured in centuries is the tiniest drop in the proverbial bucket of evolutionary time.” Native plant purists, Smith added, will argue that “the only quality tree is a tree that was grown from a seed from right underneath the tree that bore that seed. Isn’t that a wonderful ideal? [But] it’s not practical.”
Some native plant proponents have allowed for species that are retreating north (or up) on their own volition since these changes happen slowly and food-chain communities can relocate with them. A number of Southern species in the United States got there in the first place by being pushed down during the last ice age, and have been reclaiming prehistoric ranges as the cold has receded over the last 10,000 years. But ancient forests don’t appear to have migrated as complete ecosystems during these upheavals; it was a race of every-species-for-itself. “There’s a lot more interchangeability among members of an ecosystem than people had thought,” David Jablonski, a paleontologist, told the Smithsonian.
There is also the problem that the climactic zones are moving faster than trees can follow. “The average forest migrates at a rate of roughly 1,640 feet each year,” Wired has written — that is, about three miles in a decade. In order “to outrun climate change,” trees would need to book it north at a rate of “approximately 9,800 to 16,000 feet” a year, or about 10 times as fast. Plenty of foresters aren’t waiting around for that to happen and are seriously exploring the controversial idea of human-assisted migration.
Larson, at the UW Botanic Gardens, meanwhile, said their horticulturalists are looking off-continent for inspiration for the hard years ahead. “We’re experimenting more with plants in Mediterranean climates,” he said, and “also the southern hemisphere: Australia, Chile, New Zealand." Places that have "somewhat similar climates," to the Pacific Northwest, “but tend to get a little bit hotter." And while some of these experiments haven’t panned out as hoped in the past, “we’re going to try them again, because 5 or 10 degrees can make all the difference.”
The conventional wisdom, that introducing or nurturing exotics results in a decline in biodiversity, is also being challenged — often heatedly so. It can seem at times that for every study that expounds on the evils wrought by alien plants, another concludes the exact opposite. The ongoing debate has produced fiery polemics, such as one signed by 19 ecologists and published in Nature in 2011, which announced “it is time … to ditch this preoccupation with the native-alien dichotomy and embrace more dynamic and pragmatic approaches … better suited to our fast-changing planet.” The scientists also swatted down the frequent synonymizing of “nativeness” with “good,” pointing out that “the insect currently suspected to be killing more trees than any other in North America is the native mountain pine beetle.”
(These sorts of back-and-forths are presumably what led former Arnold Arboretum horticulturist Peter Del Tredici, one of the Nature letter’s signatories, to observe, “the use of exotic versus native species … seems to bring out the worst in people, not unlike the debates over gun control and abortion.” Whoever said gardening was boring?)
Arthur Shapiro, a distinguished professor of evolution and ecology at the University of California at Davis, is also among those who have challenged the uncompromising emphasis on the superiority of native plants. “There are many nonnative plants grown in gardens that are immensely useful to butterflies and other pollinators,” Shapiro told me. “And there are many native plants that are completely useless. They might as well be made with rubber or wood.” If you were to uproot every exotic plant in urban California, for instance, you’d “essentially do away with the butterfly fauna.”
That’s partially due to a principle known as ecological fitting, which is “what happens when species with totally disparate histories, that evolved in different parts of the world, come into contact — perhaps as a result of commerce, perhaps as a result of gardening — and they fit together,” said Shapiro. “It’s a marriage made in heaven.” Additionally, oft-vilified “novel ecosystems”, sometimes disparagingly dismissed as “trash ecosystems," arise when exotic species are naturalized due to human influence and/or certain native species recede. Increasingly, though, scientists like Shapiro are viewing these emerging anthropocenic systems as environmental success stories. An unmanaged invasive pine plantation in Puerto Rico, for example, was found to have far more biodiversity than a nearby native-only forest of the same age, Nature recounts; the observation, made in 1979, ran so counter to the established beliefs about the sanctity of native plants that “it took almost a decade" for the resulting paper to pass peer review.
The native/non-native dichotomy is undoubtedly clumsy, so much so that one idea has been to dispense with the unhelpful language altogether. “Neonative,” a term proposed by University of Vienna conservation biologist Franz Essl, for example, could be adapted to describe species that have moved beyond their native ranges and established new foothold populations “due to human-induced changes of the biophysical environment, but not as a result of direct movement by human agency.”
Another idea is to take a step back, put our preconceived notions in check, and learn from what we’re seeing. “As climate changes, communities are going to change, mixtures are going to change,” Shapiro said. “Trying to stop it — except for managing things of economic or medical importance, pests, or disease vectors — is equivalent to trying to plow the sea. It’s futile. So we should actually be paying close attention to what’s happening, because we can learn a lot from it, about how communities self-assemble.”
This isn’t your permission to go plant a bunch of English ivy and scotch broom, though. Two things can potentially both be true: certain native plants have essential ecological functions and some non-native plants can play an important role in shaping future ecosystems. In fact, they’re going to have to, if the climate keeps warming and the hardiness zones continue their upward march.
“We would always tell someone: choose native first,” Smith, of the Arbor Day Foundation, concurred. But at the same time, “Let’s not let the perfect be the enemy of the good.”
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Paradise, California, is snatching up high-risk properties to create a defensive perimeter and prevent the town from burning again.
The 2018 Camp Fire was the deadliest wildfire in California’s history, wiping out 90% of the structures in the mountain town of Paradise and killing at least 85 people in a matter of hours. Investigations afterward found that Paradise’s town planners had ignored warnings of the fire risk to its residents and forgone common-sense preparations that would have saved lives. In the years since, the Camp Fire has consequently become a cautionary tale for similar communities in high-risk wildfire areas — places like Chinese Camp, a small historic landmark in the Sierra Nevada foothills that dramatically burned to the ground last week as part of the nearly 14,000-acre TCU September Lightning Complex.
More recently, Paradise has also become a model for how a town can rebuild wisely after a wildfire. At least some of that is due to the work of Dan Efseaff, the director of the Paradise Recreation and Park District, who has launched a program to identify and acquire some of the highest-risk, hardest-to-access properties in the Camp Fire burn scar. Though he has a limited total operating budget of around $5.5 million and relies heavily on the charity of local property owners (he’s currently in the process of applying for a $15 million grant with a $5 million match for the program) Efseaff has nevertheless managed to build the beginning of a defensible buffer of managed parkland around Paradise that could potentially buy the town time in the case of a future wildfire.
In order to better understand how communities can build back smarter after — or, ideally, before — a catastrophic fire, I spoke with Efseaff about his work in Paradise and how other communities might be able to replicate it. Our conversation has been lightly edited and condensed for clarity.
Do you live in Paradise? Were you there during the Camp Fire?
I actually live in Chico. We’ve lived here since the mid-‘90s, but I have a long connection to Paradise; I’ve worked for the district since 2017. I’m also a sea kayak instructor and during the Camp Fire, I was in South Carolina for a training. I was away from the phone until I got back at the end of the day and saw it blowing up with everything.
I have triplet daughters who were attending Butte College at the time, and they needed to be evacuated. There was a lot of uncertainty that day. But it gave me some perspective, because I couldn’t get back for two days. It gave me a chance to think, “Okay, what’s our response going to be?” Looking two days out, it was like: That would have been payroll, let’s get people together, and then let’s figure out what we’re going to do two weeks and two months from now.
It also got my mind thinking about what we would have done going backwards. If you’d had two weeks to prepare, you would have gotten your go-bag together, you’d have come up with your evacuation route — that type of thing. But when you run the movie backwards on what you would have done differently if you had two years or two decades, it would include prepping the landscape, making some safer community defensible space. That’s what got me started.
Was it your idea to buy up the high-risk properties in the burn scar?
I would say I adapted it. Everyone wants to say it was their idea, but I’ll tell you where it came from: Pre-fire, the thinking was that it would make sense for the town to have a perimeter trail from a recreation standpoint. But I was also trying to pitch it as a good idea from a fuel standpoint, so that if there was a wildfire, you could respond to it. Certainly, the idea took on a whole other dimension after the Camp Fire.
I’m a restoration ecologist, so I’ve done a lot of river floodplain work. There are a lot of analogies there. The trend has been to give nature a little bit more room: You’re not going to stop a flood, but you can minimize damage to human infrastructure. Putting levees too close to the river makes them more prone to failing and puts people at risk — but if you can set the levee back a little bit, it gives the flood waters room to go through. That’s why I thought we need a little bit of a buffer in Paradise and some protection around the community. We need a transition between an area that is going to burn, and that we can let burn, but not in a way that is catastrophic.
How hard has it been to find willing sellers? Do most people in the area want to rebuild — or need to because of their mortgages?
Ironically, the biggest challenge for us is finding adequate funding. A lot of the property we have so far has been donated to us. It’s probably upwards of — oh, let’s see, at least half a dozen properties have been donated, probably close to 200 acres at this point.
We are applying for some federal grants right now, and we’ll see how that goes. What’s evolved quite a bit on this in recent years, though, is that — because we’ve done some modeling — instead of thinking of the buffer as areas that are managed uniformly around the community, we’re much more strategic. These fire events are wind-driven, and there are only a couple of directions where the wind blows sufficiently long enough and powerful enough for the other conditions to fall into play. That’s not to say other events couldn’t happen, but we’re going after the most likely events that would cause catastrophic fires, and that would be from the Diablo winds, or north winds, that come through our area. That was what happened in the Camp Fire scenario, and another one our models caught what sure looked a lot like the [2024] Park Fire.
One thing that I want to make clear is that some people think, “Oh, this is a fire break. It’s devoid of vegetation.” No, what we’re talking about is a well-managed habitat. These are shaded fuel breaks. You maintain the big trees, you get rid of the ladder fuels, and you get rid of the dead wood that’s on the ground. We have good examples with our partners, like the Butte Fire Safe Council, on how this works, and it looks like it helped protect the community of Cohasset during the Park Fire. They did some work on some strips there, and the fire essentially dropped to the ground before it came to Paradise Lake. You didn’t have an aerial tanker dropping retardant, you didn’t have a $2-million-per-day fire crew out there doing work. It was modest work done early and in the right place that actually changed the behavior of the fire.
Tell me a little more about the modeling you’ve been doing.
We looked at fire pathways with a group called XyloPlan out of the Bay Area. The concept is that you simulate a series of ignitions with certain wind conditions, terrain, and vegetation. The model looked very much like a Camp Fire scenario; it followed the same pathway, going towards the community in a little gulch that channeled high winds. You need to interrupt that pathway — and that doesn’t necessarily mean creating an area devoid of vegetation, but if you have these areas where the fire behavior changes and drops down to the ground, then it slows the travel. I found this hard to believe, but in the modeling results, in a scenario like the Camp Fire, it could buy you up to eight hours. With modern California firefighting, you could empty out the community in a systematic way in that time. You could have a vigorous fire response. You could have aircraft potentially ready. It’s a game-changing situation, rather than the 30 minutes Paradise had when the Camp Fire started.
How does this work when you’re dealing with private property owners, though? How do you convince them to move or donate their land?
We’re a Park and Recreation District so we don’t have regulatory authority. We are just trying to run with a good idea with the properties that we have so far — those from willing donors mostly, but there have been a couple of sales. If we’re unable to get federal funding or state support, though, I ultimately think this idea will still have to be here — whether it’s five, 10, 15, or 50 years from now. We have to manage this area in a comprehensive way.
Private property rights are very important, and we don’t want to impinge on that. And yet, what a person does on their property has a huge impact on the 30,000 people who may be downwind of them. It’s an unusual situation: In a hurricane, if you have a hurricane-rated roof and your neighbor doesn’t, and theirs blows off, you feel sorry for your neighbor but it’s probably not going to harm your property much. In a wildfire, what your neighbor has done with the wood, or how they treat vegetation, has a significant impact on your home and whether your family is going to survive. It’s a fundamentally different kind of event than some of the other disasters we look at.
Do you have any advice for community leaders who might want to consider creating buffer zones or something similar to what you’re doing in Paradise?
Start today. You have to think about these things with some urgency, but they’re not something people think about until it happens. Paradise, for many decades, did not have a single escaped wildfire make it into the community. Then, overnight, the community is essentially wiped out. But in so many places, these events are foreseeable; we’re just not wired to think about them or prepare for them.
Buffers around communities make a lot of sense, even from a road network standpoint. Even from a trash pickup standpoint. You don’t think about this, but if your community is really strung out, making it a little more thoughtfully laid out also makes it more economically viable to provide services to people. Some things we look for now are long roads that don’t have any connections — that were one-way in and no way out. I don’t think [the traffic jams and deaths in] Paradise would have happened with what we know now, but I kind of think [authorities] did know better beforehand. It just wasn’t economically viable at the time; they didn’t think it was a big deal, but they built the roads anyway. We can be doing a lot of things smarter.
A war of attrition is now turning in opponents’ favor.
A solar developer’s defeat in Massachusetts last week reveals just how much stronger project opponents are on the battlefield after the de facto repeal of the Inflation Reduction Act.
Last week, solar developer PureSky pulled five projects under development around the western Massachusetts town of Shutesbury. PureSky’s facilities had been in the works for years and would together represent what the developer has claimed would be one of the state’s largest solar projects thus far. In a statement, the company laid blame on “broader policy and regulatory headwinds,” including the state’s existing renewables incentives not keeping pace with rising costs and “federal policy updates,” which PureSky said were “making it harder to finance projects like those proposed near Shutesbury.”
But tucked in its press release was an admission from the company’s vice president of development Derek Moretz: this was also about the town, which had enacted a bylaw significantly restricting solar development that the company was until recently fighting vigorously in court.
“There are very few areas in the Commonwealth that are feasible to reach its clean energy goals,” Moretz stated. “We respect the Town’s conservation go als, but it is clear that systemic reforms are needed for Massachusetts to source its own energy.”
This stems from a story that probably sounds familiar: after proposing the projects, PureSky began reckoning with a burgeoning opposition campaign centered around nature conservation. Led by a fresh opposition group, Smart Solar Shutesbury, activists successfully pushed the town to drastically curtail development in 2023, pointing to the amount of forest acreage that would potentially be cleared in order to construct the projects. The town had previously not permitted facilities larger than 15 acres, but the fresh change went further, essentially banning battery storage and solar projects in most areas.
When this first happened, the state Attorney General’s office actually had PureSky’s back, challenging the legality of the bylaw that would block construction. And PureSky filed a lawsuit that was, until recently, ongoing with no signs of stopping. But last week, shortly after the Treasury Department unveiled its rules for implementing Trump’s new tax and spending law, which basically repealed the Inflation Reduction Act, PureSky settled with the town and dropped the lawsuit – and the projects went away along with the court fight.
What does this tell us? Well, things out in the country must be getting quite bleak for solar developers in areas with strident and locked-in opposition that could be costly to fight. Where before project developers might have been able to stomach the struggle, money talks – and the dollars are starting to tell executives to lay down their arms.
The picture gets worse on the macro level: On Monday, the Solar Energy Industries Association released a report declaring that federal policy changes brought about by phasing out federal tax incentives would put the U.S. at risk of losing upwards of 55 gigawatts of solar project development by 2030, representing a loss of more than 20 percent of the project pipeline.
But the trade group said most of that total – 44 gigawatts – was linked specifically to the Trump administration’s decision to halt federal permitting for renewable energy facilities, a decision that may impact generation out west but has little-to-know bearing on most large solar projects because those are almost always on private land.
Heatmap Pro can tell us how much is at stake here. To give you a sense of perspective, across the U.S., over 81 gigawatts worth of renewable energy projects are being contested right now, with non-Western states – the Northeast, South and Midwest – making up almost 60% of that potential capacity.
If historical trends hold, you’d expect a staggering 49% of those projects to be canceled. That would be on top of the totals SEIA suggests could be at risk from new Trump permitting policies.
I suspect the rate of cancellations in the face of project opposition will increase. And if this policy landscape is helping activists kill projects in blue states in desperate need of power, like Massachusetts, then the future may be more difficult to swallow than we can imagine at the moment.
And more on the week’s most important conflicts around renewables.
1. Wells County, Indiana – One of the nation’s most at-risk solar projects may now be prompting a full on moratorium.
2. Clark County, Ohio – Another Ohio county has significantly restricted renewable energy development, this time with big political implications.
3. Daviess County, Kentucky – NextEra’s having some problems getting past this county’s setbacks.
4. Columbia County, Georgia – Sometimes the wealthy will just say no to a solar farm.
5. Ottawa County, Michigan – A proposed battery storage facility in the Mitten State looks like it is about to test the state’s new permitting primacy law.