If you use nothing but the information and tables in any of the core D&D rulebooks, I’m pretty sure the only thing that really differentiates jungle regions from other types of terrain is the wandering encounter tables. There might be something about how long it takes to travel through the area, or how easy it is to get lost there like in Barbarian Prince/Road of Kings, but that doesn't seem like enough. It seems to me that the jungle itself should be just as much of a challenge as the stuff you encounter there, or you’re missing an opportunity.
You could (and probably should) treat the jungle as a dungeon in and of itself. I probably wouldn’t go so far as stocking a complete subhex breakdown, but creating a point crawl for each hex (not as detailed as that one though) really isn’t that bad as far as prep goes.
|A tile from an old board game called magic realm.|
Old-school versions of the DM Guide always made it a point to tell DMs what ratio of rooms with monsters to rooms with treasure (for example) they should be going for. This table is the same thing as that, but for nodes instead of rooms:
1d6 JUNGLE NODE CONTENTS
1 Nothing Unusual
3 Encounter & Treasure
4 Terrain Feature
5 Terrain Feature & Encounter
6 Terrain Feature, Encounter & Treasure
I tried to keep most of the following rules and information as general-purpose as possible, which is my excuse for not including encounter tables in this post. That said, I’m writing this so I can use it in the Yucatan Peninsula, and a few details are going to be specific to that region. You can always change them if you want.
This table lists a few of the major terrain features that your players could come across. There should be fairly obvious ways to interact with all of them.
D12 JUNGLE TERRAIN FEATURES
1 Quicksand - Starting at the beginning of the party's marching order, everyone saves until someone fails and falls waist deep into the pit. Every 10 second round, that person sinks another 1d10 inches (shit I may have to put a blank spot for height on my character sheet). People wearing heavy armor sink 2d10 inches per round. Pulling the character out with rope requires a strength check, more than one person pulling grants advantage on the check.
2 Banana Grove - If you can climb a tree, you can get as much food as you can carry. It goes bad in 1d8 days. 1/6 chance of an anaconda lying in wait. Otherwise, there are 3d12 howler monkeys hanging out that will probably attract attention.
3 Running Water - Secretly check for piranhas (1/6) and also roll 1d4 on this table.
1 Stream - Only a couple feet deep and 1d10+20’ wide.
2 River - 1d10+10’ deep, 1d20+30’ wide, swimming check or end up downstream.
3 Rapids - Large (and slippery) rocks sticking out of the water all the way across, skill checks/saving throws to cross without falling in and ending up downstream (no swim check).
4 Waterfall - Same as Rapids, plus Cliff.
4 Blasted Clearing - No trees here, just blackened stumps, but that means the undergrowth is getting crazy amounts of sunlight. Any attempts to find useful (or dangerous) herbs in this area get advantage.
5 Cliff - If this node has more than one approach, decide whether someone traveling from each direction would be at the top or bottom of the cliff and mark it on the map. Any combatants at the top of the cliff would have an obvious tactical advantage. Moving up or down the cliff requires a successful climb check.
6 Cave - Oh come on. If you can’t think of something fun to do with a cave then you need to let someone else DM.
7 Ancient Trees - A thousand years old and a hundred feet tall and a dozen feet in diameter. Climbing these trees requires specialized equipment and takes time, but allows you to see major features four hexes away. Wildlife encounters are common at the top.
8 Ridgeline - Can see major features two hexes away from the highest point.
9 Ravine - Double random encounter chance in this area, probably an ambush.
10 Cenote - Deep and wide natural limestone pits with freshwater pools at the bottom. There’s a 1/3 chance that a village has formed around the cenote.
|View from inside Ik Kil, a cenote near Chichen Itza|
11 Recent Battleground - Broken and rusted weapons and armor half-buried in the bloodstained mud. At least two separate mass graves, the occupants of which may or may not A) be buried with valuable trinkets and B) be undead.
12 Overgrown Ruins - Site of an ancient city. Roll 1d4, 1d3 times, to see what’s left of it (and accessible). Only one palace should be here but there could be multiple temples and tombs.
Roll on the appropriate weather table for the season at the start of each day. Rainfall typically occurs in the late afternoon and lasts 1d12*30 minutes. The only two seasons are wet and dry.
Temperature is in the 70s - 80s (fahrenheit) range year round, with a crazy amount of humidity during the wet season.
D6 WET SEASON (June—October) JUNGLE WEATHER
1 Dry Today - +1 chance of random encounters for 24 hours starting at dusk.
2 Light Misty Refreshing Rain - Heal 1d4 hit points during rainfall, even if traveling. This type of rainfall doesn’t heal you during combat, but will afterwards if the rain doesn’t stop first.
3 Big Ol’ Fat Rain - Non-natives suffer a -15’ movement penalty during rainfall and a -5’ penalty for the next 24 hours.
4 Torrential Downpour - Non-natives suffer a -30’ penalty and a -10’ penalty for the next 24 hours. Natives treat this like non-natives treat Big Ol’ Fat Rain.
5 Lightning Storm - 1d12 chance that the storm is focused on your current hex, in which case trees near the party keep getting struck by lightning and exploding, sending grenade-like shrapnel off in every direction. Save or take 1d6 damage. This happens right next to you every 1d10 minutes until you get out of the hex.
6 Hurricane - Torrential Downpour for 24 hours before the hurricane, which lasts 1d4+2 hours with a 1d6*10 minute period of complete calm in the middle, and again for 24 hours after the hurricane.
During the main storm, anyone without shelter must make two saves every hour; one reflex save to avoid flying debris, and a fortitude save against exposure to the elements. Failing either save means that a character is incapacitated, and will suffer 1d4-2 (minimum 1) points of damage for the remainder of the storm (including the Torrential Downpour) unless rescued (which might be even worse, depending on who finds you).
Even if you do find shelter, it should take damage during the storm, though you’d get a chance to make some quick repairs during the calm. I’m comfortable waiting until it comes up in play to figure out exactly how that works.
D20 DRY SEASON (November-April) JUNGLE WEATHER
1-16 Dry Today
17 Light Misty Refreshing Rain
18 Big Ol’ Fat Rain
19 Torrential Downpour
20 Lightning Storm
JUNGLE SURVIVAL RULES
-Natives get to ignore this whole section.
-You need to drink twice as much water as usual. Three times as much during the wet season.
-Roll a navigation check to make it from one node to the next. If you fail, you find yourself walking in circles and basically spend another turn in your current node. (This is straight out of Barbarian Prince).
-Even if you don't get lost, it takes twice as long as usual to travel.
-Every day, each character has a 1% chance to have to roll a successful saving throw or come down with malaria.
-Symptoms appear for 1d4+2 hours at a time every 24 hours, and basically make you bed-ridden, shitting and vomiting out everything in your system.
-You can’t survive a malaria flare-up without either A) some sort of medical attention or B) very very careful preparation (shitload of water, safe space, a few buckets, etc. Think about the detox prep scene in Trainspotting).
-Save every day, or your condition worsens, now affecting you 24/7. If you fail your daily save while your symptoms are already active all day every day, your condition doesn’t immediately worsen further, but if you fail three days in a row in that condition, you fucking die and need to roll up a new character.
-If you make your daily save three times in a row, you beat the infection. All symptoms disappear and you are now immune to malaria, for the duration of the campaign at least. Thank fuck.
-A cure disease spell would work but wouldn't give you a future immunity.