In the Trees: Jungle Warfare with the UK Royal Marines
by Maj Eric Todorski
“It is a state of permanent dampness, rain or sweat, of stifling, windless heat, of dirty clothes, of smelly bodies, of heavy loads, of cocked and loaded weapons, of tensed reflexes, of inaccurate maps, of constant vigilance, of tired limbs, of sore shoulders where equipment straps have bitten in, of a chafed crutch. At night it is darkness, with rotting leaves shining eerily. It is a state of mind that has to be stronger than mere physical robustness. It is a challenge. It can never be taken for granted.”
Lieutenant Colonel JP Cross OBE
Looking at the green immensity below, I could only conclude that those manuals had been written by men whose idea of a jungle was the Everglades National Park.
Philip Caputo, A Rumor of War
Greetings from the Connecting File’s foreign correspondent! In this week’s article we look at ‘environmental training’, specifically preparing troops for operations in the jungle. The UK military places a greater degree of emphasis on environmental training than I have seen in my time in the USMC, with specific environmental qualifications that units and individuals need to attain to be ‘safe to operate’ in a specific environment. As we pride ourselves on our ability to fight in ‘ev’ry clime and place where we could take a gun’, I think there is something we can learn from this practice.
I sat down with the former Training Officer of the British Army’s Jungle Warfare Division (JWD) for a conversation about the UK’s approach to jungle warfare and what units can do to succeed in this unique environment. JWD is located in Brunei where the UK maintains an overseas base, and runs two courses: the Jungle Warfare Instructor Course (JWIC) and the Operational Tracking Instructor Course (OTIC).
JWIC is a train the trainer course, and graduates act as SMEs in their units on jungle training and advise their commanders on jungle operations. OTIC is like the old combat hunter instructor course on steroids, and involves using observation techniques, dogs, tracking, and the like to hunt the enemy in the jungle. While we have our own Jungle Warfare Training Center in Okinawa, the UK’s emphasis and approach are a bit different. The JWIC is ~60 training days compared to ~21 for our Jungle Leader’s Course, and the jungle TAs in the deepest parts of Brunei are nearly untouched primary jungle. Across the board, they put much more emphasis on a soldier or Marine’s individual skills training.
This article is intended to prime a commander’s thoughts (and inform their training plan!) prior to deploying to the jungle.
The key takeaways:
A high level of physical fitness and a deliberate acclimatization plan are essential to success.
The environment will ruthlessly expose any deficiency in basic skills and field craft.
There is no secret knowledge, you can prepare to deploy to the jungle from any home station with basic skills training, classes on the environment, and lots of PT.
What makes the jungle a different operating environment?
The jungle is complex, compartmentalized terrain characterized by limited mobility, limited visibility, difficult communications, difficult command and control, and limited firepower. There are a lot of nuances to the different types and subareas of the jungle, which are outside the scope of this article. This article is focused on operating ‘in the trees’, i.e. in primary or secondary jungle. If you would like to know more, the UK and US publications (MCTP 12-10C) are great references and I recommend you crack them open if you want to really get into it.
Limitations
Mobility. The jungle is restricted terrain and moving ‘cross grain’ is extremely difficult. Good route planning, land navigation, and obstacle crossing skills are vital (more below). While infantry Marines will immediately think of the effect this has on patrolling, don’t forget the effect this has on sustainment. It might be a two-day foot patrol for a platoon to resupply! While this is easy for man portable items, commanders need to think about how to get bulk logistics in and out. What can your engineers do to increase your mobility? Is there a river network you can use? Do you have aviation? Can your vehicles get down a logging track? How much signature will these assets create? Can you risk that?
Visibility. When ‘in the trees’ you will be lucky to get 50m of visibility and a patrol can walk right past a company position and miss it. The jungle is one of the few places where modern sensors struggle. The humidity, damp, and vegetation limit the effectiveness of thermals, and most drones can’t penetrate the canopy. Formations above the squad level are difficult to control as your elements can’t see each other, and SBF likely won’t be able to see maneuver.
Communications. Line of sight wave forms struggle in the trees, and even HF can have issues. Communication internal to a patrol is slow - hand and arm signals are the best technique but take time to travel down the line. You need robust PACE plans at all levels, and to drill your contingencies for losing contact.
Command and Control. A combination of the above points, it is difficult to know what is happening with your disaggregate units let alone influence them. Modern situational awareness tools like ATAK are great but, like any electronics, they will be degraded by the environment. You will have to move forward as a commander to maintain control.
Don’t overlook the impact this has on exercise control and safety. There is an extensive ‘wrap’ (support network), that needs to go around a jungle exercise, and that wrap needs to be in place for every person that goes in the trees, including evaluators, OPFOR, admin movers, etc. Per UK safety policy, every independently maneuvering element must be accompanied by a JWIC qualified instructor as a safety backstop, which is around 10 per company! Everyone (even Gunner!) should travel in pairs, which also increases the personnel requirement. US policy is different, but don’t neglect your EXCON C2 when planning an exercise.
Firepower. The visibility and terrain limit your ability to mass direct fire weapons, which can turn a company attack into a series of team and buddy pair engagements. Indirect fire can be more effective as HE creates secondary fragmentation from the trees, but spotting and adjusting is more difficult. More on this later in the article.
Editor’s Note: Quartered Safe Out Here, a memoir of fighting in Burma in WWII, offers excellent examples of the above, especially the chaos of fighting in the jungle.
Hazards
Climate. The effect of the climate on a unit’s combat power due to preventable illness is consistently overlooked. The heat and humidity are brutal and as a commander you must ensure your troops up their salt intake and are getting enough calories – even if the heat suppresses their appetite. Good nutrition is the key here, not salt or electrolyte tablets. The constant damp leads to chafing, open wounds, sores, and infection. Supervision is a must.
Flash flooding. Frequent, torrential rains can swell rivers, fill intermittent water features, and wash out draws in moments. Everything needs to be waterproofed, and the possibility of flooding should be a planning factor for supply routes, jungle camps, and any infrastructure you construct.
Flora/Fauna. Mosquitos, leeches, poisonous plants, tree sap that will blind you if it gets in your eyes, thorns, snakes, etc. will all harm the unwary. Your Marines need to be educated on what they will encounter and told how to deal with it.
Deadfall. A somber and unfortunately true vignette: During the CASEVAC of a heat casualty, a patrol moved to a LZ for extract. The down force of the approaching helo shook a widow maker (a broken treetop that has fallen but been suspended in another tree’s branches) free from the canopy, which fell on a patrol member at the edge of the LZ, fatally injuring him. The jungle is a 360-degree environment, and leaders need to be looking up into the canopy whenever they are assessing the situation.
The JWIC Training Package
The first three weeks of the JWIC are devoted to individual skills so the students have a solid foundation before moving into more complex tactical evolutions. When units conduct environmental training deployments to the UK’s overseas bases in Brunei or Belize, this type of work is typically the bulk of the training. Those DFTs usually look like 10-14 days of acclimatization and RSO&I, 10-14 days of individual skills (which may include a few days of ‘special to arms’ aka MOS specific training), 4 -7 days of live fire, then a 4-10 day FTX at the end. There are no surprises on this list, which should reinforce that there is no substitute for hard skills competency in the infantry.
Individual Skills
Physical Fitness. The jungle is brutal terrain, and your level of physical fitness directly corresponds to your combat effectiveness. It also has a big impact on your acclimatization capacity, which is explored more below.
Swimming. There is a swim test, roughly comparable to our Water Survival – Intermediate, at the beginning of the JWIC. Your Marines will be in and around the water constantly in the jungle, they need to be competent swimmers.
Survival. This is stereotypical jungle skills training in terms of how you make shelter, procure food and water, and make fire if you get stuck out in the bush. The intent here isn’t to make everyone into SERE graduates, you’re looking at instilling the skills and confidence to survive long enough to execute the lost marine plan and be recovered. This article won’t go into the weeds of all the topics, but some highlights are below.
Health and Hygiene. The fight against disease is a constant battle in the jungle. Any open wound can quickly become infected, improperly procured water can give you dysentery, insect bites can give you malaria, etc. This element is consistently underestimated by commanders. The troops need classes on how the environment will affect their health, what they can do to mitigate it, and supervision from every level of leadership to ensure the unit doesn’t have its combat power drained away by sickness.
Water. Water purification is an individual responsibility, and a trooper should have at least 5L of water on hand, with 2L in their fighting load. You will find yourself drinking water procured from the environment at some point, so get used to using ‘puritabs’ and hasty filters. The ultra-light backpacking gravity filters are cool but are too slow to be the primary method for a patrol procuring water in the field.
Land Navigation. Jungle mapping is often created by aerial photography, where the canopy can disguise water features, terrain relief, etc. Even traditional survey mapping will have features on the map that don’t look anything like they do on the ground. Patrol leaders need to pay special attention to the relief when route planning, as 2km across the gradient can take a whole day, but following a contour can be almost as fast as a trail. Solid map and compass skills are essential, as the wet and the canopy can play havoc with more modern tools like GPSes and ATAK EUDs.
Everyman a paceman. A unique thing I have noticed about British forces in the jungle is that everyone has a pace counter taped to the handguard of their rifle (see the above photo by the end of the handguard). Everyone keeps pace except the machine gunner when patrolling. When the patrol stops, the Assistant Patrol Leader gets everyone’s pace count and determines the average, then they use that to figure out where they are. In general, land navigation as taught in the UK is much more ‘macro’, using larger features for catching and collecting along most of the route, before switching to the ‘micro’ navigation that is more like how we are taught in Quantico.
Mobility
Rope skills are synonymous with jungle operations. This encompasses everything from military mountaineering to safety lines for river crossings. As you’ll see in the equipment section below, every Marine should have a length of tubular nylon/‘loop line’ with a load rated carabiner and squads should carry actual rope. These items are useless without the skill to employ them, however, so you will need classroom instruction, rope corral work, and practical application before you can employ them in the bush.
Water obstacle crossings. The jungle has all sorts of water obstacles and crossing them is a key mobility skill. This can range from rope bridges/guidelines to building pack rafts. Nothing makes people panic more than the water, so take the mystery and fear away in the training environment.
Riverine Operations. If they’re big enough those water obstacles are also avenues of approach, and they might be the only way to get logistics in or casualties out. Riverine training needs to start with basic swim competency and emergency procedures (e.g. capsize and man overboard drills), and should include boat formations, react to contact, and inserting/extracting loop patrols.
Vehicle Operations. A lot of our lightweight expeditionary gear is too heavy to carry. You won’t be able to get a vehicle deep into primary jungle without serious engineering support, but you can use them on logging tracks, roads, and other areas. Vehicles like the Toyota Hilux and Land Cruiser reign supreme here, though the underpowered Land Rover WMIK can still perform. Whatever your ground mobility platform, your mobility or logistics section will need to practice vehicle recovery because you will get stuck, a lot. They will also need to conceal the vehicles whenever they are stationary, as the enemy will know that there are only a few places you can use them.
Special Patrol Insert/Extract. Nothing says jungle operations more than getting yanked out of a hole in the canopy by a helo! Helicopters are especially effective in the jungle but there are only a few places you can land them. This is a key planning concern as a commander. The enemy has a map too and knows where you can put in a MV-22. If you are in a reconnaissance unit (looking at you Scout platoon) you should train on some form of special patrol insert/extract so you can get into the objective area ahead of the main body, i.e. rappelling. You don’t need the full range of insert schools our Recondo brothers have, but you should have something to give your commander options.
Hasty LZs and Winch holes. They don’t have the canopy penetrator we have in Okinawa at JWD in Brunei, so there is a deliberate period of instruction during JWIC on identifying winch holes and making hasty LZs. This is a key leader skill and needs to be a deliberate step in planning for both combat and non-tactical contingencies (i.e. heat casualties). Improving temporary LZs should be an engineering concern in support of your scheme of maneuver.
Night Operations. Is the risk worth the reward?
It is absolute blasphemy in the USMC to say don’t move at night, but if you’re deep in the J you’re substantially increasing your risk of injury and enemy compromise to go a few hundred meters an hour. A commander must consider the terrain, environmental conditions, natural illumination, proficiency of their force, assigned mission, and enemy situation to determine if night operations are worth the risk. The terrain really matters here, as does preparation of the environment. If you’re out where it's less restricted, you might have more success than if you’re deep in triple canopy. Moving down a route that your scouts proofed and marked in daylight is a different story from cutting your way cross grain in the dark.
Night Optics and preparation. As discussed elsewhere, many of our modern night vision devices will be degraded, and most troops have minimal experience at night without these aides. Full disclosure, most UK units only have PVS14 equivalents, with PVS31-equivalents only recently coming to specialized units like the Royal Marines. You may have better luck with your gear, but you don’t want to find out that your PVS31s are subject to the same laws of physics as your old -14s when you try to ‘own the night’ deep in bad guy country. If you want to build this capability adopt a deliberate crawl, walk, run approach. Experiment with weapon mounted night sights to mitigate lenses misting over from your body heat, do confidence building patrols in easy terrain, plan for contingencies like non-combat injuries/lost Marine plan, and always ask yourself if the risk is worth the reward.
Patrol Base Operations and the Jungle Camp
Jungle operations revolve around the ‘jungle camp’, and they feature prominently in JWD’s instruction. A jungle camp is a patrol base, but they usually have some temporary improvements like a raised platform with overhead protection for temporarily storing excess ammunition, a slit trench latrine, or some form of C2 structure (a hasty shelter or even a dugout), etc. A company will occupy a jungle camp for a few days at a time while pushing platoons for specific missions.
Bivouac. You need to make the most of your time in a semi-permissive environment like a jungle camp (or a platoon PB!) by getting quality sleep. JWIC teaches the use of hammocks in the field. It doesn’t take long to set up your hammock, get out of your wet clothes, clean yourself, and get your head down for some shuteye if you’ve practiced. Drill setting the hammock up and breaking it down until you can do it in the dark by feel.
Hard routine. Sometimes you need to get some rest out in the ulu when the enemy threat is high. You can be smarter than just closing your eyes and trying to go to your happy place. Reduce as much exposed skin as possible to prevent insect bites; put your gloves on, make sure your sleeves are down and buttoned, button the top button of your blouse then put a bug net on over your boonie or Kevlar and cinch it under your lapel to keep the insects off your face and neck.
Small Unit Tactics
The fight in the jungle is a team and squad fight. The close range eliminates decision space and rewards those who have rehearsed their drills to a fine edge. There is a discussion on live fire training further in the article.
Battle drills. React to contact, hasty ambush, break contact, etc. the vegetation is going to force you closer together than you would be in the open and will cause visual breaks in your formation even at the squad level. Rehearsals are the only way to build the implicit communication and trust required to operate safely, especially during live fire training.
Patrolling. In addition to the enemy oriented drills above, work all the mundane but essential patrolling tasks: short and long halts, formation changes, etc. Put special emphasis on RV/Link up procedures as the limited visibility and the communication challenges will force you to physically regain contact with your own units, even at the platoon level.
Close Target Reconnaissance. You likely won’t be able to get on an OP with binos to scope your objective during your leader’s recon. How do you reconnoiter the enemy’s jungle camp without standoff or UAS support? Crawl forward as a pair and do a clover leaf of the position to look at the camp from all angles. Leave the ghillie suit at home or you’ll overheat.
How Can My Unit Best Prepare?
Train the above skills! You can do everything outlined above at any base. A patrol FEX, rope practical application, and solid PT plan is a great foundation prior to deploying. If pressed for time you don’t even need to go to the field, you can do the patrol/small unit tactics prep in the backyard, rope corral at the pullup bars behind the CP, practice water crossings in the pool, etc. Don’t forget all the vital but mundane skills, like gear prep/waterproofing classes, reps setting up your hammock, and TEWTs/rehearsals. A lot of these skills are the foundation of good fieldcraft which will make you money in the trees.
Units consistently underestimate the requirement to acclimatize, the fitness required prior to deployment, the time to train troops in basic drills/skills, the impact the environment will have on the medical readiness of the force, the complexity of the logistics to sustain troops on the ground, the communications planning, and the time required to move through the jungle. “They think it can’t be that bad, but it is.” Get ahead of this in your prep time and arrive to the jungle with a plan.
How should I set up my equipment for operations in the jungle?
There is a reason the guys who can wear whatever gear they want, wear Alice gear style belt kit in the jungle - you need to have a lot of equipment on your person for contingencies. The big battle belt with suspenders is standard issue in the UK, but our issued subload belt with suspenders works as well. Chest rigs trap more heat than belt kit, but the issued TAPS chest rig has enough real estate for your combat load and safety gear (i.e. 2L of water, emergency rations, survival kit, survival knife, etc). The micro chest rigs and two-piece gun belts that are popular these days aren’t the best as they can't hold it all. Don't accept a Hydroflask or Nalgene swinging around on a carabiner as a water source, ensure your troops are set up to operates.
Some other tips:
You will wear your body armor and helmet during actions on, but not for the approach march. Strip your flak down so it’s slick, then ‘top flap’ it in your pack until you get to the ORP.
Secure your Kevlar to the outside of your pack (ensuring it doesn’t flop around and won't get pulled off), making it easier to access and freeing up space inside the pack for other gear. Standard SOP back in the UK is to use bungee cords for this, but don’t go overboard as they’re a snag hazard in the jungle.
Ditch the artificial helmet scrim from your Kevlar for this environment as it will get caught up in thick vegetation but leave elastic loops (boot bands or otherwise) so you can add natural vegetation for concealment. You want the veg to pull free and not yank your head over if it gets caught in thorns or vines.
On that note, veg does not give you the edge during movements. Bushes don’t get up and walk around, but a guy patrolling wearing a Ghillie blanket does get caught on things. When moving you want to be streamlined and snag free to prevent excess auditory or visual signature. Additionally, the jungle is hot enough, adding a ghillie blanket is reducing your combat effectiveness - not increasing it.
Waterproof your map, put it in a waterproof map case, then dummy cord it to your person.
Double waterproof your pack using the main pack liner with smaller dry bags inside. This gives you extra buoyancy for river crossings or if you’re suddenly submerged.
Don’t wrap your tarp around your ISOMAT, stow it in a pouch. Wrapping it around your ISOMAT looks good on the parade ground, but you can’t stow it quickly when bugging out and the guidelines are a snag hazard.
Do I need any special equipment?
Consider the following:
Hammock for sleeping (with integrated bug net , otherwise sweating it out in your bivy bag is better than being eaten alive!).
Tie 550 cord guidelines with ‘jungle knots’ to the bungees on your tarp and to your hammock. These are double overhand knots on a bight every fist or so along a ~1m length of doubled 550 cord. You find a tree, wrap the guideline around it, then feed a looped section of guideline through the appropriate fist sized opening so two of the overhand knots are holding tension against the standing end. Pull the running end and it comes free.
Head net style bug net.
Machete or parang.
2 x Folding saws per squad for position improvement when static, such has harvesting concealment or clearing fields of fire.
Loop line/Tublar nylon (8-10m per person) with load bearing carabiner. This is for obstacles crossings, securing kit to trees in case of flash flooding, etc.
Large water bladders (25L). This is for water collection at a source, not to fill up and carry with you on patrol. You empty canteens for extra buoyancy when crossing a water obstacle, and fill the bladders as the unit crosses. When you consolidate at the side far rally point, you distribute water from the bladders to refill everyone’s canteens (add steritabs!), then continue the patrol.
Length of climbing rope per squad.
Other equipment tips
‘Stag Bag’. A prepacked bag for the PB’s sentries. It has range cards, 550 cord for tuglines, pad and pen for the watch roster, a claymore, sector stakes, and two black gear radios with batteries in it.
Black gear? In the UK, all riflemen are issued a PRR, a shortrange radio for intrateam communications. They don’t use them during patrol in the jungle for noise discipline/awareness (the PRR has a headset) but will use them for LP/OPs and sentries in the PB at night.
Tailored uniform. Reinforced crotch and seams, lengthen the blouse so it stays tucked in.
Short brim boonie cover with a piece of signal panel sown on the inside, dummy corded to your lapel.
Mesh scarf around neck as a sweat rag or hasty concealment aide (up over head covering face/optic as a cobra hood).
Medical gloves for writing orders/reports without smearing sweat all over your rite in the rain.
Live Fire Training
There is a large live fire package during the JWIC with individual, team, squad, and platoon level live fire events in the jungle. During the squad package, for example, each squad does a hasty ambush, contact Front/Rear/Left/Right, break contact, man down/casualty recovery, and stoppage drills, all live fire. The culminating event is a platoon reinforced deliberate attack on a jungle camp.
Train combat marksmanship at 50m or less against limited exposure targets, on a shot timer. The Predator-style mag dump into the bush at the slightest sound will burn through your ammo, and resupply could be a two day patrol away. While you will need a high volume of fire to win the initial contact and establish fire superiority, you still need to be killing the people you’re shooting at. Talk with a Vietnam combat vet and they will tell you that you need both volume and accuracy.
Drill individual marksmanship on the flat range first to maximize the training benefit of the work in the trees. If they can’t shoot on the range in ideal conditions, they need remediation before they go into the jungle.
‘Instinctive shooting’ can have a place in the initial moments of contact when gaining fire superiority and is a technique of fire that you can drill, but soldiers/Marines need to be taking well aimed shots. You won’t see the whole target at first (if at all) and they will probably see you at about the same time you see them. You need to be fast AND accurate.
Iron Sights. You will see a lot of UK units using iron sights in the trees, and not just because the rotational gearset is barebones! Optics steam up, get covered in mud/sand, and break. Most of the shooting is close range, so your irons will get the job done. The iron sights on the SA80 have two sized apertures like on a M16A2 sight, one with a small aperture for daytime and a larger one for nighttime. Don’t ditch your SCO just because you read this article, if you’re going to do this you need to zero your irons (hopefully an obvious statement…) and train with them in advance.
Auxiliary weapons. Grenadiers and rocket gunners need to be mindful of their minimum engagement distances as well as branches and vegetation that can impact the flight of their munitions (remember to factor in the stabilizing fins for rockets!). Each platoon will set out multiple claymores every long halt, so get some practice using them for real. Meeting engagements will be within hand grenade range, so practice the frag battle drill in the clutter of the jungle.
Machine Guns. Your M240 gunners need reps on the bipods and from nonstandard positions. Consider putting a gun with your maneuver element during an assault, as your SBF will be cut quickly (if you can even get one setup). Channel John Basilone with a MG react to contact lane.
Demolitions. In addition to the claymores mentioned above, demolitions are useful for mobility/counter-mobility engineering in the jungle. Blasting hasty LZs or winch holes, dropping bridges, cratering roads, and similar tasks are all good demolition skills that will keep the spirit of the 0351 alive in your unit.
Pre-Training Acclimatization
Once you arrive in country you must focus on acclimatization. It will take most people at least 15 days to fully acclimate but you can speed it along with around ten days of gradually increasing PT. The UK and the US Army have done a lot of studies on heat acclimatization, and a key finding is to exert yourself just enough for just long enough to force your body to adapt to the stress of the heat, without going over into heat injury or slacking off too soon. You won’t be running core temps on everyone in your unit to check and everyone’s body responds differently, but this corresponds to getting up to about ~1C/1.8F above normal for a slowly increasing amount of time. Annex E to Joint Service Publication 375 has a basic program as an example.
The hour and a half or so of acclimatization PT that you do daily is the main effort! Afterwards, fill the rest of the training day with classes related to the jungle skills above. You will ruin your acclimatization program if the Marines do their acclimatization PT in the morning then get thrashed doing gun drills in the sun that afternoon. You will also ruin it if you do your PT then go sit in the AC for the rest of the day. Focus on TEWTs, ROC walks, gear prep, and similar low impact activity during this time. Once everyone is adjusted to the environment, then you can increase the activity level. The better shape you are in when you arrive, the easier time you will have acclimating.
In Conclusion
There is no secret to success in the jungle, just ruthless application of the basics. While none of our CONUS duty stations have jungle training areas (though parts of Lejeune and Quantico get close!), any unit can prepare for a jungle deployment from any location. Remember that the jungle isn’t just affecting you, it’s affecting the enemy as well. While they might live in that part of the world, very few people live in the no kidding jungle. Build your edge now, so you prevail when the time comes.
Major Eric Todorski is currently serving in the Personnel Exchange Program with the United Kingdom Commando Force. He can be reached at etodorski@gmail.com. The Connecting File would like to thank Captain Matt Lawes RM who supported writing this article.
Outstanding level of detailed applicable knowledge here. Delighted that I never had to deal with this and by the summer of 1972 US Army Basic Training had already pivoted completely away from any reference to jungle fighting.