What could kill all vegetation in an area and then stop it from growing back?

Question

So I need a barren wasteland with some dead vegetation (mainly dead trees). There should be pretty much no living plants left but it should be apparent that it was a lush place for flora and fauna about 20-25 years ago.

What could have killed all the vegetation while leaving some dead trees still standing? What could be the reason for plants not growing back?

The thing that comes to mind is a volcanic eruption. But that usually brings nutrition to the area affected and that's why the place would probably be blossoming again after 20-25 years.

Could there be something in the ground like toxic soil or just low levels of nutrition that would make it inhabitable? What could the toxic soil be? How did it get there? Why would the ground suddenly lack in nutrition?

Any other reasons why this could happen?

There is no specific location for this wasteland, but I would rather not have it placed very far north or have it be a typical sand desert. It would take at least several days to walk through it. Assume Earth-like conditions and medieval tech.

Answer 1

There's a reason why "salting the earth" is an expression.

Excessive salt will suck out the water in plants and kill them, leaving the skeletons behind. you will need to ensure the salt can't have washed away since.

This salt could be suddenly supplied by a volcano by having the volcanic ash containing a large amount of salt. Otherwise some evil conquerers could have done it.

Answer 2

One option is to have the area's water needs originally met by only a single river. Rivers naturally meander, which will occasionally cause them to jump their banks and take a new route. For example, the Mississippi River has been on the verge of re-routing itself down the Atchafalaya River's path for many years. If your single source of water meandered enough to find a different path that bypassed the area in question, you'd see the plants gradually die off as groundwater was depleted and never regenerated. Since there was no destructive force like a fire, volcano, or windstorm, trees would generally die in place and many would remain standing.

This type of scenario could be triggered by a number of different causes, both natural (meandering, landslides, sinkholes, earthquakes) or artificial but low-tech (dams, canals, excavation). This type of scenario could also be reversible, in case you need it to be.

Answer 3

If you want a more exotic reason than excess salt, a very very rare natural phenomenon could cause radio activity that would kill the vegetation and everything else in an area. As far as we know it has only happened in one geographical area here on earth at 16 sites in Oklo, Gabon Africa.

In simple layman's terms, there existed in the area very rich uranium deposits that as some point in ancient earth history, ground water entered the deposits, and caused natural nuclear fission to take place. This of course released great amounts of energy, and thus heat, which boiled away the water until the the reaction would stop, and the deposits would cool. But then the groundwater would flow back in and the reaction would start slowly once again. (This could happen in cycles from days to weeks or even months.)

Anyway, the heat and radiation would easily create the conditions you are looking for, and would cause the rise of many local legends about it being a magical and deadly place. There would also be steam vents and it would likely cause heavy fog in the area on cool days. The radiation could also have a preservative affect preventing the natural decay process of the trees and other plants in the area, because bacteria and molds would be killed as well. The whole area would be mysteriously dead but also have the appearance of being frozen in time for centuries.

There would be times when the reaction would die down enough, and the amount of radiation to subside to allow the area to be entered without lethal doses of radiation. But imagine what stories would arise from people entering the "cursed" area when the Gods or whatever are "angry" and then mysteriously die days later with their hair falling out suddenly in large chunks, sever pain, and a host of other mysterious symptoms.

Also had another thought about how this could have been influenced by humans. If they were trying to irrigate an area and diverted a river to do so, it could have caused an abundance of ground water to enter an area where there once was very little causing the conditions to be just right for the process to begin.

Answer 4

Just to offer a few non-chemical options as well:

• The region used to be fed by a river, somehow the river got diverted and turned the region into a desert. Depending on the strength of the desert, they may be no plant life left. This does set some limits on the weather.

• Rapid climate change. Suppose the climate changed a lot due to some previous event (say large volcano eruption or meteorite impact, this can happen thousands of miles away). Most plants would not adapt and die. Plants that would thrive in the new climate may not exist close enough to colonize the land within 20-25 years. Depending on the severity of the climate change and the variety and adaptability of the native plants, some plant and even animal life may still exist. If you go into nuclear winter type scenario (also works with volcano ash cloud) effectively everything would be dead.

• Radiation. One of the nastier ways to kill all life. You'd probably still see some plants life with lots of mutation and cancer. A drawback would be that the land would still be radioactive.

Answer 5

Areas around volcanoes have dead zones all the time. when the activity changes locations all of a sudden you have a bunch of dead trees standing around.

Look at Yellowstone National Park. Especially around the hot springs for easy pictures. Dead trees standing all over. The hot springs can change the ph of the soil. gas vents can also do this, but that is more dangerous (it would kill people too), and would likely be more localized.

Answer 6

Severe forest fires can do what you describe. Fire can have a wide range of effects on soil, but one of them is that in clayey soils it can destroy the soil's ability to hold water - kind of like putting a clay pot in a kiln. It changes the structure permanently.

So if you had an area that was once densely wooded, with lots of fuel on the ground, and a fire came roaring through, it would kill all vegetation, likely leave large, charred, dead trees standing, and prevent new plants from being able to grow.

Answer 7

This answer builds on several of the others and offers a purely natural way to achieve the desired result.

If you have a low-lying basin near the sea then an exceptionally high tide/storm/tsunami would flood the area with sea water.

Over the next few decades that sea-water would gradually evaporate, naturally concentrating the salt into a smaller and smaller area.

In the end once all the water has vanished you would see an area that had normal vegetation at the edges, dead trees in the center, and slowly decreasing levels of vegetation until you reach a completely dead area in the center.

Answer 8

Consider looking at the Salton Sea in Southern California. I think it was in 1910 that the Colorado River flooded, and due to some bad design it breached trough some irrigation gates and flooded the Salton Sea. Move this event to some tree covered basin and you have an event that would kill the tress and leave them standing. A rather shallow lake would do this, say something around ten to fifteen feet deep. Have the flood go through a salt deposit and you have the chemical to keep the basin quite barren of vegetation for a few centuries.

Draining the lake might be a problem, it may take a decade or so to evaporate. You could invent some device in your story line where most of the water soaks into the ground over the course of some time that fits your needs, the ground retaining the salt so your landscape remains sterile.

The flood alone would drown the trees, the salt would be the reason the vegetation does not grow back.

Answer 9

You have severe limits by rejecting desert, and having medieval tech. Humans had way too weak influence to do anything too destructive back then, and life is adaptable.

But I do have something for you, even if it might take few centuries instead of few decades:

Start with a landlocked sea, like Black Sea. Earthquake sealed connection to other seas, and changed course of few important incoming rivers. Evaporation is bigger than water inflow. For first few decades, life can continue, even as fishing is worse, but not too bad.

Only after few decades, when sea evaporated, you have winds spreading salt all over, destroying the countryside. Even if remains of sea are somewhere (see Dead Sea), life cannot continue.

If you want to go full speed, you can close Gibraltar, and dry out Mediterranean sea. Much deeper, much hotter, climate in whole area was much worse. As link says, it really happened 5.6MYA, and might happen again (but then we would drill channel to flood it back).

But of course such events are much slower. It would take 1000 years for Mediterranean sea to almost completely evaporate. Even then, life would be possible in river deltas.

Answer 10

Oil. A natural oil leakage from underground, tar pits and similar water contamination will lay an area barren. An earthquake could be the release mechanism. If it was once lush, it could become boggy too, with oil-soaked dead vegetation decayed in the mess, making some areas impossible to traverse, and deceptive until caught in it. Natural gas would also produce will-o-wisps, and eerie sounds as it escaped from the ground. You can make it very dramatic by having small flames burn spontaneously if you want. Spontaneous combustion is very believable in such an area. In some places the air itself could be so poisonous as to kill any animals that wander in, even if they could get a firm footing and not get caught in the bog.

Of course if magic is involved you could add any number of additional intriguing aspects.

Answer 11

I would suggest a build up of some chemicals in the soil, perhaps salts as suggested by Ratchet Freak.

The build up could be caused by adding a fertilizer that had an adverse reaction with minerals in the local soil. Sulfur has been used as a fertilizer for a very long time, but I have not found a good substance for it to react with, others might be better at chemistry 101 than me.

And when the local plants don't grow well, what do you do? Add more and more fertilizer until you have an environmental catastrophe.

The end result is soil saturated with the chemicals.

Answer 12

Some few grams of antihydrogen (antimatter) annihilates over the area with massive (let say 10 times of the bomb dropped on Hiroshima) energy release (without radioactive spill of "unburnt fuel") cause soil to turn into a glass or a ceramic, rendering essantial minarals insoluble in the water.

In this "glass desert" and without essantial minerals plant life cannot recover for a long time (hundred years may be).

A few trees might still stand in the center of explosion (like the trees in the center of the tunguska explosion).

Answer 13

Radioactive fallout

We have pretty much this situation in the "Red Forest" near Chernobyl. Fallout tends to stay very localized because it binds easily to soil. So unless you have massive rainfalls that wash away the soil, a dumping-ground for Cs-137 or Sr-90 could make a localized and rather well defined area practically sterile for at least a century.