Everyone came to the Greenbelt Project for different reasons, they said. Some, like Ava, came from a sense of desperate hope. Here you could see trees, miles and miles of them. Here the forests were making their stand, were turning the tide. Here they would rally and return.
Ava remembered the last oak cut in the park when she was a child, the sense of desperation and the impotent anger she felt. It had been autumn, parched and dry. The storms had thrown the last of the older oaks down the spring before. Only this one remained, but her neighbors thought it was too dangerous. There were historic homes, several of which had been damaged in the storms. Yes, trees were important, yes carbon sinks were needed, everyone understood that—but not these trees.
She had stood on the stump and watched the river, staring across it to where a tiny strip of forest—brush more than anything—hung on the other side, and tried not to cry. It would be too obvious, too trite, to cry for a dead tree.
Here, now, at the Greenbelt, trees were being planted—tens of thousands of them, ultimately millions of them. Ava wanted to be here, to see the new hybrids that would tie up carbon in their tangled branches and root systems. The Greenbelt was a garden, was a dream of tipping the planet back toward balance, a system of managed forests spreading across western North America from Canada to Mexico, and Ava would be a part of it.
As soon as she finished high school, she registered for one of the forest stations.
Odem had grown up in the forests, or what was left of them. His parents were both loggers, and he had lived in the shadows of trees cut for the insatiable demand for paper, boxes, packaging to ship things back and forth across the planet. He remembered his parents talking about the need for better management, of being frustrated when things weren’t done correctly, when corners were cut, when over-logging in one place meant they had to pack up again and head somewhere else. He remembered them shaking their heads and telling him there were better ways, ways that would make it work. Trees were a resource that could grow again, a crop like anything else.
What drew him to the Greenbelt was the idea of managing, of doing things correctly. Companies in competition with each other, with themselves, would always grasp too much; it was their nature. And government was ineffective and often misinformed. The way to fix things was clear eyes and clear thought. Healthy forests meant healthy jobs meant there would never be another family that would suffer because someone up the food chain had screwed up or been too greedy.
When the Greenbelt Project came online and El began its work, Odem put his name in for a forest station immediately.
The Greenbelt, at least the portion of it visible from Odem’s station—which was now, Ava reminded herself, her station too—stretched like a green wall across the hillside. She knew it stretched hundreds of miles farther, to the foothills of the Rockies and then over toward the coast on the other side. Here though, on the eastern edge, she could see it like a green serpent, the edge of a wide river cutting across the continent, swallowing cities and farmland in a rising wave.
The line of trees stretched north and south as far as she could see. Those at the edge were the newest, fastest-growing hybrids: some like pines, some like broad-leaved maples, others bending like young birches. All of them were newly built species, constructed from native stock but with their genetic code put together in new ways to grow faster, denser, to pull more carbon from the atmosphere per cubic inch of wood or square meter of crown-spread.
It didn’t look like the world’s largest science experiment.
It looked like a forest. It looked like what Ava had been searching for.
The station was surrounded by a grassy meadow on all sides. Odem said that when the station was first constructed, the forest had barely been in sight. Now it had crept within a few hundred meters, and the line of trees curved around to the north and south so that soon the station would be within a wide ring of trees. Drones worked ceaselessly, planting trees that sprouted in days, that were knee-high in weeks. They rose and fell from the soil like metallic beetles, kissing the earth, dropping their seeds, smoothing the soil.
Ava had hoped they would do the planting by hand. She had envisioned walking through prairies digging and planting, touching the soil, but of course that had already been tried: corporations had employed people to replant cut forests, most often just replacing the virgin forest with nothing more than a monoculture. It wasn’t enough; it wasn’t diverse enough or fast enough.
The drones didn’t plant in geometric grids; they planted their mix of hybrids according to a complex pattern that only El fully understood, based on soil mixture, topography, and even microclimate—the perfect planned forest.
“Every seed is a prayer,” Ava muttered under her breath. Odem glanced over with a question, and she repeated it, more loudly. “Something my dad used to say,” she added. “Usually standing at the counter with potting soil and a jar of acorns. He also used to say the only harvest he ever wanted was a forest.”
“He would be proud of this.”
She nodded absently.
They stood at the station’s edge, looking at a prairie filled with a new grass. The stalks wore flowers like jagged red crowns. Pollinators were already at work among them. This particular type, which had sprung up almost overnight, was supposed to sequester carbon and fix nitrogen at higher rates than what had previously filled the wide lawn between station and forest wall, but the botanists couldn’t explain exactly how. They just knew it worked.
Like everything El did.
The whine of malfunctioning drone signaled an incoming job. Odem watched it arch from the forest toward the station’s landing pad.
“I’ve got this one.”
He touched her arm as he passed.
Ava had not yet been at the station a full month. Some of the other stations scattered along the length of the Greenbelt held botanists, biologists, and other scientists, but this one was purely mechanical support, mainly drone repair, and Odem and Ava were the only two personnel.
She watched him go and turned back to the grass, which seemed markedly thicker than it had been the day before. Of course the field wasn’t a monoculture; El was too smart for that. Looking closer, she decided there were probably five or six species in this mix alone. Carpets of new grasses came in waves now, one mix of ground cover giving rise to the next as though evolution had been accelerated by a factor of millions.
It wasn’t just the forests and grasses that were evolving. El was evolving too.
“Eventually,” Odem had told her soon after her arrival, as they both stood working beside the open shell of a drone, their arms greased to elbows with oil, “El won’t even talk to us anymore. We’ll be like . . . ” He paused, wiping at his nose and leaving a streak of black. “We’ll be like whale songs to it. Too slow to pay attention to.”
The drones had come to the station almost ceaselessly then, and the two of them always had a queue for repairs.
“Take this,” he said, tapping a narrow module that hung along the drone’s side. “It’s a new kind of cutter. I’ve seen some of the drones using it on deadwood. El designed it. I asked some of the engineers how it worked, and they didn’t know. They’re still trying to reverse engineer it. Said it was the most efficient plasma blade they’d ever seen.”
Drones trimmed the trees. When the Greenbelt Project began, no one had been sure how El would tackle the problem of reducing atmospheric carbon within its given parameters. It quickly became apparent that whatever the solution was, it was fractal in scale, extending from the growth patterns of entire forests to the shape of individual trees. El’s remote drones planted, mapped, and tended the forests on a large scale, but they also carved, trimmed, and pruned on a plant-by-plant basis. The fast-growing hybrids in the forest around the station had bizarre-yet-ordered shapes for maximum efficiency that reminded Ava of something from a Dali painting or the Dr. Seuss books her grandparents had read to her from.
Sometimes El’s decisions didn’t make sense. Odem had told her about a time, only a few weeks after the station had come online and he had arrived to run it, that El had completely clear-cut a hillside within sight of the next ridge.
“There was some old growth there,” Odem told her, shaking his head. He had looked half-wild when Ava was first stationed here, long hair and a wiry beard that covered half his face. That was gone now. “I couldn’t understand why that would happen. I thought it was something we were trying to protect. But it was part of the larger pattern.” His shrug seemed glacial, his face resigned. “It’s working though. Can’t deny that. El sees patterns we can’t.”
The grasses were another new pattern, a woven carpet of species.
She wondered if they would look the same tomorrow.
Ava saved seeds from her walks. The drones came to the station less frequently than they had when she first arrived, though they still passed silently through the trees. There were new models now, printed somewhere farther south, on the scale of birds rather than vehicles. The older models hummed, but she couldn’t hear the new models at all, only the sounds they made snapping twigs or slicing leaves that fluttered down behind them, shaping trees and even the underbrush to grow as efficiently as possible within the parameters of programming and time.
Parsing the pattern finer and finer.
She printed containers from downloaded templates and potted the seeds she gathered on the station’s narrow windowsills, knowing they would not grow as orderly or efficiently without El’s guiding hands.
Odem thought the drones were coming to the station less because they had become more efficient at navigating. It used to be they would get caught in the trees and need to be fetched down for repairs, as though El was a child learning to keep a million kites in the air at once. But Ava’s own suspicion was that there were fewer because they had begun repairing themselves. A week ago, she had come across one sitting in a clearing in the forest, its solar fins spread like petals. It was working with manipulators at the innards of another, half-disassembled before it.
Broken drones still floated to them on occasion though, and she unscrewed their silvered carapaces and followed El’s instructions to repair components she no longer understood. She recorded each new variation she saw, just as she recorded the grasses in the surrounding prairie and new hybrids in the forest, sending her reports back to the Project scientists or sitting in virtual meetings where experts wore continually bemused expressions.
“It’s the space program all over again,” one of them told her during a debriefing. “Those spin-offs NASA was always touting. Who knew saving the planet would have so many technological payoffs?”
For Ava the payoff was watching the Greenbelt expand—watching El slowly but inexorably tip the planet back toward life.
One morning the two of them woke to the sound of drone-hum, heavier than they had heard before. Four drones the size of busses settled at the corners of the field around the station. Each carried a printer in its belly, and as the sound of repulsors faded, Ava heard the high-pitched whine of printers kicking into gear.
Her phone blinked with a message from headquarters.
“We’re installing new turbines,” one of their managers said with a slightly harried look. “El’s begun disassembling the Rain River Windfarm. But there’s a new, more efficient design with less footprint—”
“They’re already here,” Odem told them, peering over Ava’s shoulder.
Within half an hour the construction drones lifted off, leaving four phallic-like towers about twice Ava’s height.
“Blade-less turbines,” she said as the two of them ate breakfast from the station’s small organic printer. Odem fished the stream El had rerouted near the station, but a good portion of their food was still printed from materials delivered by drone. “I’ve read about the design. Supposed to simply vibrate in the wind to generate energy.”
Later that morning, he shifted against her as they napped in his bunk. “Do you ever wonder how El interprets its programming?”
“Only all the time.”
“I saw drones the size of my thumb yesterday taking soil samples. The forests are healthier than they’ve ever been.”
“It’s working.” Ava leaned into his arm. “Reverse climate change for human flourishing.”
“Right. But I’m a human, right?”
“So.” Odem paused. “El’s shaping the forest on a leaf-by-leaf basis at this point.”
He was quiet for a few moments. “How long was it after you arrived before we started sleeping together?”
The sudden shift confused her. “What?”
“Like, two days? Three?”
She pushed up on an elbow and stared him down. “What are you talking about?”
“The station needed another technician. It got one. But I also got the person I’d been waiting for my entire life.”
She rolled her eyes and lay back down. “Human flourishing?”
It was his turn for monosyllables. “Yeah.”
“There were hundreds of qualified applicants in for this posting,” she mused. “Does it change anything if El weeded those profiles for compatibility with the mechanic already posted here? Does it change anything about us?”
“It does,” he said, running a hand through her hair.
“What?” She glared at him. “What does it change?”
“I need to know who to thank.”
The turbine-less generators lasted a little more than a month. Something like trumpet vines started growing up around them, then there was a hard rain, and the structures began dissolving into a kind of gray sludge.
“Biodegradable,” Ava said, wrinkling her nose at the smell.
“Makes sense. I doubt El’s making anything out of plastic anymore.”
“But where’s our power coming from now?”
Odem was going to spend the day in the forest, and there were no drones in for repairs, so Ava set about answering her own question. The lines that had connected the station to the electric grid were long gone, but everything that drew power, from their printers to their screens, was still active. She spent the morning tracing the station’s electrical systems—updated several times since the latest schematic was sent from headquarters—with no luck. No new or unfamiliar devices had been added that might be generating energy. No solar panels had been installed on the roof by industrious drones when they weren’t paying attention.
Ava printed a small shovel and followed the cable running from the station’s main electrical panel to where it disappeared down the wall and into the soil of the surrounding prairie. Scraping away the dirt from its surface, she found it covered in a network of filaments grafted on like roots and disappearing into the soil in all directions.
Odem wanted to climb. There was no need for it, but once he was out among the trees and their haunting geometry, he found he wanted to be in the canopy. When he had first arrived, he and Lily—his first partner, and had El arranged that transfer as well when it became clear they weren’t compatible?—often had to venture into the canopy to fetch down snared drones. They would let out a high-pitched whine when they were caught, and he and Lily would hook each other into their harnesses and climb up to help. Or rather, one of them would climb and the other would stay below and spot. He missed her sometimes, but he had to admit her transfer had been for the best.
He had no harness now, and it was foolhardy to be climbing alone, but the trees here seemed made for it, their branches wide and parting from the trunk at regular intervals that were the perfect spacing to climb like a ladder. The tree he chose was near the top of the ridge, and from its height he could see the forest spread below him, rising behind to the hills and spilling in front of him to the gap he knew was their station.
What were they still doing here? It was clear El no longer needed them. The drones, Ava felt confident, could repair themselves. Were they here now simply as a witness? To continue to measure and record the changes El was making to the landscape? Odem knew that if El requested (ordered?), they would be withdrawn from the station. That they weren’t removed meant either El wanted them to stay close or that whether they were there or not simply didn’t factor into its plans.
Odem knew the dangers of anthropomorphizing AI. There was no way to know whether El “cared” at all; El simply followed El’s programmed mandates.
Odem turned back toward the mountains. He could stay in the tree all day if he wanted, watching the work of the drones, the slow and steady breathing of the forest around him. He was beginning to see the drones as part of the natural landscape, beginning to look past them at what they were creating. Was it beautiful? It no longer had the rough, organic patterns of the forests he remembered as a child. But neither was it the rows of timber the companies had planted once they had clear-cut. This was something else, more like a garden or a huge, living sculpture.
The wind shifted, and Odem reached for another branch, which snapped in his grasp.
The ground came too soon. He was stunned but not hurt, and it took him several moments to realize he had not hit the ground but rather had been caught by something he couldn’t see. He felt the cool, curved surface of a drone beneath him—easily as large as those that had printed the turbines—and manipulators holding him against that surface like he was a child. But he could see nothing; he seemed suspended in air.
The invisible drone set him carefully on the ground. He reached for it, but it was already gone.
For a long time, he sat at the bottom of the tree, his back against its trunk, shaking. He was unsure whether he was terrified by the fall or by the realization El had been with him, watching him, the entire time.
Odem came back in the late afternoon as the forest began to darken.
“I fell,” he explained. “I wanted to climb. Like I used to. When we had to fetch down stuck drones.”
They had harnesses for that, but he hadn’t taken one when he left that morning. He interpreted Ava’s disapproving look correctly.
“It was spur of the moment. Must have been fifty feet up before I stopped.” He paused. “Things are happening up there, in the canopy. The branches . . . It’s like some kind of architecture.”
He paused for so long that she had to prod. “But you fell?”
“A branch broke. I fell maybe halfway.” His voice dropped. “Something caught me.”
“What do you mean?”
He shook his head. “I didn’t see anything. But it was a drone. I felt the curve of its hull. It saved me. Caught me and set me on the ground.”
She sat back in the seat opposite him. “An invisible drone?”
“The forest could be filled with them. Guarding us. Protecting us. It had to be trailing me in order to have been so close when I slipped.”
Ava glanced over her shoulder, suddenly uneasy. “Or guarding the forest from us. We’re still the wild cards in El’s equations. I need to show you something.” She led him to where she had scraped the soil away from the power supply cable. “I think the station is getting power from the forest.”
He stared down at it. “Energy from trees?”
“The vibrators generated energy from wind. I think that was El’s trial run. Trees could be a way to scale that up, millions of leaves vibrating in the breeze, not to mention the solar energy they’re capturing.” She shrugged. “At least, that’s my guess.”
“Makes sense,” he said slowly. “As much as anything makes sense anymore.”
The Greenbelt hummed around them.
Plants could only grow so quickly, Ava realized, but technology could move much faster, and El’s oversight began to stretch farther afield. Farms beyond the forest were repatterned according to its instructions. Crop yields increased, even as food production became more varied, localized, and integrated into cities. Ava’s mother sent videos of her rooftop garden, tended by drones that looked like smaller versions of what Ava saw in the forest.
The summer heat had grown oppressive. It hadn’t rained for weeks, but nothing in the weather was beyond normal parameters according to El’s models. Rain fell other places, where needed. Ava sat with Odem at the small table in the station’s kitchen. Beyond the open door, bees moved among the flowers, accompanied by tiny drones that winked like fireflies.
The fire started as a glow in the sky to the west. There had been a cracking, a sound like claps of thunder, though the sky was cloudless. By the time they realized what was happening and checked the satellite feed, much of the Greenbelt near the station was ablaze. Drones filled the smoky sky, racing eastward.
Ava argued with faces on her terminal.
“El won’t clear any vehicle departures for withdrawal operations,” they told her.
“Why the hell is the forest burning?”
“It’s a controlled burn, we think. Clearing space for new growth.”
“You think? It’s coming closer.”
They couldn’t tell her anything else. Trust El, they almost said, but didn’t. They didn’t have to. It was written on their faces.
Odem stood at the station’s perimeter, staring at the sky.
“They don’t know what’s going on,” she shouted at him as she began loading supplies into the larger of the station ATVs. It had been parked on the edge of the prairie, and a vine with thorns as long as her thumb had grown up around one of its tires. She pulled the vine away to find the tire pierced in several places.
“Ava.” Odem was standing behind her. “They might not know what’s going on, but El does.”
She pushed past him into the repair shed that housed their industrial printer and punched in commands for a new ATV tire, then swore in frustration when it wouldn’t accept instructions.
“El can predict the path of the fire. We can’t.” He had followed her but did nothing to help. “If we leave, we might just put ourselves in danger. The safest thing is to stay here.”
“The wind is bringing it closer.”
“The wind will change.”
The fire made a kind of wailing in the distance. Light grew in the trees so that it looked like the sun was setting just beyond them.
“We don’t know that,” Ava insisted, hauling an older, un-networked printer from storage and inputting instructions for the ATV tire. “We stopped understanding the choices El made a long time ago.”
Odem had turned back toward the forest. “It caught me when I fell. It brought you here. Why would all that happen if it was just going to let us burn?”
Ava grimaced and pulled the fresh tire from the printer’s tray. Heat hit her as she stepped back outside. “Odem, I’m not going to stay here.”
“Listen.” He touched her arm, but she pulled away. “Think about it. El has a plan, and you’ll just be putting yourself in more danger by leaving. The safest thing to do is stay here. Please.” She realized with a start that he was more frightened of her leaving than he was of the approaching fire. “Trust El.”
She stepped backward. “I’m not going to trust a mind I can’t understand.”
Odem did nothing else to stop her, but he looked heartbroken. “We’ll trust it with a world we can’t understand. We have to trust something.”
She said his name one more time, pleadingly, but he turned away.
The last sight she had was of him standing at the station gate, the trees blooming into red and orange across the prairie behind him.
Ava returned to the station three days later. It was burned to ashes, as was the forest as far as she could see. The stream where Odem had fished ran black and gummy with soot. Shoots were pushing up through the landscape like spears, and Ava thought of seeds that could only germinate after they had burst by heat.
She rebuilt the station, or at least the portion they had lived in. It took several trips to the construction-grade printers in the nearest town and all her savings, but she printed walls and a ceiling and bonded them together. Then she hauled in a new printer for organics, keeping everything un-networked. All the driving and hauling strained the ATV’s solar cell to its limit. But though there were plans for newer, more efficient batteries online, she made do with what she had. She wasn’t sure at this point what technologies El had created and what costs might come with them.
Once the shelter was built, it wasn’t long before the same filaments that had powered the original station grew into her power supply. The forest was sharing its power again.
Ava didn’t care. She would only stay for a couple weeks, she told herself, just long enough to figure things out, decide how she felt about this new green world and its new god, one that was apparently willing to sacrifice Odem without warning or explanation to suit its inscrutable purposes. Then she’d go home, or maybe somewhere else entirely.
No one from the Project came to check on her. No one asked about Odem’s fate. There were no other casualties from the fire, which had destroyed hectares of the Greenbelt before it burned out. Apparently, El wasn’t providing instructions anymore. Or if it was, no one understood them. There were reports of people having visions, experiencing bursts of light, compressed impressions from their screens, but being unable to recall what was communicated beyond a sense of peace and purpose. It happened to Ava one evening, and that night she dreamed of oak trees and of Odem.
The next day she stayed off her screen.
The drones were gone, though atmospheric carbon continued to fall. The forest kept spreading, and there continued to be more than enough food, water, and energy, though none of the experts who were supposed to understand how could explain it. Whatever algorithm El had finally fixed upon for the planet’s renewal, it had apparently become self-sustaining.
Weeks turned to months. Ava would need to decide what to do soon. She couldn’t simply stay here, watching a forest regrow, though she wasn’t sure what else to do.
Trees clawed their way upward day by day. They were something entirely new now, spires with geometric branchings both beautiful and terrifying. Ava could almost see them growing, rising like towers from the soil. Some branches spread, others folded down like arms, arrays, or even antennae. Between them, their leaves, if they could be called that, were gossamer, almost iridescent. Between those, like afterimages, the ghosts of drones flickered too quickly for the eye to follow.
Politicians on the networks said the Project was completed, that the goal had been accomplished. The world was green again, greener than it had ever been. Atmospheric carbon was still trending downward. New forest and old were spreading together, integrated with cities and farmlands into a unified whole. For humans it had taken a generation. On El’s timescale, the Project’s origins in gene-splicing and forest management were entire evolutionary ages ago.
It happened on Ava’s final night at the station. The ATV was charged and ready to go. She would leave in the morning, find her way home across a country transformed. The moon hung low over the new forest like an overripe fruit. She stood at the doorway of the station and thought of Odem, who had trusted his god.
The ground rumbled. It was soft at first, like a sleeper turning in the night. Then steadier, a purr. She had seen a rocket launch once and recalled that sense of straining upward and the steady tremble of the ground. This was nothing like that. The strange trees quivered and then, without a sound, began sliding upward. As they rose, they exposed roots that divided and subdivided, silver against the moonlight. Luminescence swirled around their bases and along whorls of bark that seemed etched in gold.
El didn’t explain.
Ava understood though. A single planet wasn’t enough; El was interpreting its parameters ever further. What would it take to green the solar system, to green the galaxy? To spread life throughout the universe?
“Every seed is a prayer,” she whispered.
She hugged herself and watched a forest fall upward into the night, dwindling until it was only a hint of green between the stars.
Stephen Case is a writer, professor, and historian of science. He has published over forty short stories in places like Asimov’s, Beneath Ceaseless Skies, and Orson Scott Card’s Intergalactic Medicine Show. His essays have appeared in Physics Today, Aeon Magazine, and American Scientist, and he reviews fiction for Strange Horizons. Steve is author of the cosmic horror novel First Fleet (Axiomatic Press) and the non-fiction Making Stars Physical (University of Pittsburgh Press) and coeditor of the forthcoming Cambridge Companion to John Herschel (Cambridge University Press).