This world has these massive tunnels in which large quantities of heat and air travel from one point to another, being permanently pushed by magic.

Their exits are basically massive updrafts coming out of pits in the planet. They can occur just about any where but in particular, I wanna know how it would affect a rainforest over time.

My question is, If a permanent massive updraft like this were placed in the middle of a rainforest, how would it be affected?

Additional details:

  • The exit has a diameter of about 10 km
  • Air as it exits the hole has a windspeed of about 60km/hr
  • The Humidity of the air exiting the vent is about 65%
  • $\begingroup$ Welcome to the forum, interesting question. It is actually quite a few questions wrapped together, could you please reduce it to just one issue, such as “if my tunnel began in the jungle, what would happen to the temperature there?” As your question stands it can’t be answered. But don’t worry, you can ask several questions. Thank you. People may close this until it gets edited. You can open it up again later tho. $\endgroup$
    – Vogon Poet
    Commented Mar 11, 2022 at 23:12
  • $\begingroup$ alright, I've edited it a bit to be simpler, thanks for the advice! I'm not really quite sure how to frame or phrase my questions a bit on these forums. I've read posts, but I haven't posted before. $\endgroup$ Commented Mar 11, 2022 at 23:19
  • $\begingroup$ The HELP link at top right should make it simple. But here is a quick list of things to a avoid in a good question. As I said, feel free to ask several focussed questions related to problems in your world. $\endgroup$
    – Vogon Poet
    Commented Mar 11, 2022 at 23:21
  • $\begingroup$ alright, I'll have a look at it next time I ask a question here, thanks for the help! $\endgroup$ Commented Mar 11, 2022 at 23:24
  • $\begingroup$ You could add things like the relative temperature of the updraft, the humidity content, and some indication of the speed. $\endgroup$ Commented Mar 12, 2022 at 1:07

2 Answers 2


Effect depends on moisture.

Hot air can hold a lot of water. Your 10 km hole will be kicking out a lot of hot air.

If the air coming from the hole is saturated with water, then as the air cools on mixing with outside air that water will come out of the air. There will be clouds and rain around the hole.

If the air coming from the hole is dry, it will then trap a lot of moisture and carry it away. It will be dry around the hole. There may be thunderstorms some distance downwind from the tunnel mouth as the hot air and the moisture it has taken with it does eventually meet colder air.


I'm not confident enough to speculate on the science of what the draft would do in terms of humidity etc, but solely on an airflow level it would definitely have an impact on the growth shapes of the plant life around it.


Prevailing wind direction in exposed places is enough to be considered a reliable marker for natural navigation, for example in the UK its south westerly, and you often see exposed trees growing at strange angles where prevailing wind has put pressure on them over time, so a constant draft would definitely cause your trees to grow at angles leaning away from the draft, probably creating a hole in the canopy. That in turn would affect the ecology just around the edge of the hole, favouring light loving species, and the kinds of plant and animal life life that tend to colonise the edges of rainforests and natural clearings.

It would also affect (effect? I can never remember) the heights of forest growth, you'd have shorter, sturdier trees nearest the hole, with deep roots to hold them firm against the drafts, rising in height as you move away from the updraft.


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