Jungle warfare
History: 

Pre-modern: Throughout world history, forests have played significant roles in many of the most historic battles. For example, in the Battle of the Teutoburg Forest between the Romans and the Germanic tribes in 9 CE, the Germans used the forest to ambush the Romans. In ancient China, the Chinese Empire planted forests on its strategic borderland to thwart nomadic attacks. For example, the Northern Song Dynasty (960-1127) constructed and maintained an extensive defensive forest in present-day Hebei.
In the Amazon rainforest, there were fighting and wars between the neighboring tribes of the Jivaro. Several tribes of the Jivaroan group, including the Shuar, practised headhunting for trophies and headshrinking.

Nicaragua guerillas: 

World War II: 

Conventional jungle warfare: At the start of Pacific War in the Far East, the Japanese Imperial Forces were able to advance on all fronts. In the Malayan Campaign, time and again they infiltrated through the jungle to bypass static British positions based on road blocks so that they could cut the British supply line and attack their defences from all sides.
In early 1942, the fighting in Burma at the start of the Burma Campaign took on a similar aspect and resulted in one of the longest retreats in British military history. Most members of the British Indian Army left Burma with the belief that the Japanese were unstoppable in the jungle.

The Chindits were a special force of 3,500 that in February 1942 launched a deep penetration raid, code-named Operation Longcloth, into Japanese occupied Burma. They went in on foot and used mules to carry supplies. The operation was not a military success but was a propaganda boost for the Allies because it showed that Allied forces could successfully move and fight in jungle terrain well away from roads. On the back of the propaganda success, Orde Wingate, the eccentric commander of the Chindits, was given the resources to increase his command to divisional size and the USAAF supplied the 1st Air Commando Group to support his operations. The availability of air transport revolutionized Wingate's operational choices. In February 1944, Operation Thursday was launched, and air transport support supplied 1st Air to allow the Chindits to set up air supplied bases deep behind enemy lines from which aggressive combat patrols could be sent out to interdict Japanese supply lines and disrupt rear echelon forces. That in turn forced the Japanese 18th Division to pull frontline troops from the battle against X Force, which was advancing through Northern Burma, to protect the men building the Ledo Road. When the Japanese closed on a base and got within artillery range, the base could be abandoned and then set up in another remote location. The ability to sustain the bases that relied totally on air power in the coming decades would prove a template for many similar operations.

After the first Chindits expedition, thanks to the training the regular forces were receiving and the example of the Chindits and new divisional tactics, the regular units of the Fourteenth Army started to get the measure of both the jungle and the enemy. When the Japanese launched their late 1943 Arakan offensive they infiltrated Allied lines to attack the 7th Indian Infantry Division from the rear, overrunning the divisional HQ. Unlike previous occasions on which this had happened, the Allied forces stood firm against the attack and supplies were dropped to them by parachute. In the Battle of the Admin Box from 5 February to 23 February, the Japanese were unable to break through the heavily-defended perimeter of the box. The Japanese switched their attack to the central front, but again, the British fell back into defensive box of Imphal and the Kohima redoubt. In falling back to the defensive positions around Imphal, the leading British formations found their retreat cut by Japanese forces, but unlike previously, they took that attitude that the Japanese who were behind them were just as cut off as the British. The situation maps of the fighting along the roads leading to Imphal resembled a slice of marble cake, as both sides used the jungle to outflank each other. Another major change by the British was that use of air support both as an offensive weapon to replace artillery and as a logistical tool to transport men and equipment. For example, the 5th Indian Infantry Division was airlifted straight from the now-quieter Arakan front up to the central front and were in action within days of arriving. By the end of the campaigning season, both Kohima and Imphal had been relieved, and the Japanese were in full retreat.
The lessons learnt in Burma on how to fight in the jungle and how to use air transport to move troops around would lay the foundations of how to conduct large-scale jungle campaigns in future wars.

Unconventional jungle warfare: Immediately after the fall of Malaya and Singapore in 1942, a few British officers, such as Freddie Spencer Chapman, eluded capture and escaped into the central Malaysian jungle, where they helped to organize and train bands of lightly-armed local ethnic Chinese communists into a capable guerrilla force against the Japanese occupiers. What began as desperate initiatives by several determined British officers probably inspired the subsequent formation of the above-mentioned early jungle-warfare forces.
The British and the Australians contributed to the development of jungle warfare as the unconventional, low-intensity, guerrilla-style type of warfare understood today. V Force and Force 136 were composed of small bodies of soldiers and irregulars, equipped with no more than small arms and explosives but were rigorously trained in guerrilla warfare-style tactics, particularly in close-quarters combat, and fought behind enemy lines. They were joined in Burma by American led Kachin guerrillas were armed and coordinated by the American liaison organisation, OSS Detachment 101, which led,  armed, and co-ordinated them.
Another small force operating in the Far East was the Australian-led Z Special Unit, which carried out a total of 81 covert operations in the South West Pacific theatre, some of which involved jungle warfare.

Cold War: 

British experience during Malayan Emergency: After the war, early skills in jungle warfare were further honed in the Malayan Emergency, when in 1948 guerrilla fighters of the Malayan Communist Party (MCP) turned against the Commonwealth. In addition to jungle discipline, field craft, and survival skills, special tactics such as combat tracking (first using native trackers), close-quarter fighting (tactics were developed by troopers who were protected only with fencing masks and stalked and shot each other in the jungle training ground with air rifles), small team operations (which led to the typical four-man special operations teams) and tree jumping (parachuting into the jungle and through the rain forest canopy) were developed from Borneo's native Iban people to actively take the war to the Communist guerrillas, instead of reacting to incidents that were initiated by them.
Of greater importance was the integration of the tactical jungle warfare with the strategic "winning hearts and minds" psychological, economic, and political warfare as a complete counter-insurgency package. The Malayan Emergency was declared over in 1960, as the surviving Communist guerrillas were driven to the jungle near the Thai border, where they remained until they gave up their armed struggle in 1989.

Cuban Revolution: 

Brazilian military government guerrilla: 

Portuguese Colonial War: In the 1960s and early 1970s, Portugal was engaged in jungle warfare operations in Africa against the independentist guerrillas of Angola, Portuguese Guinea and Mozambique. The operations were part of what is collectively known as the "Portuguese Colonial War". In fact, there were three different wars: the Angolan Independence War, the Guinea-Bissau War of Independence and the Mozambican War of Independence. The situation was unique in that small armed forces, those of Portugal, conducted three large-scale counterinsurgency wars at the same time, each in a different theatre of operations and separated by thousands of kilometres from the others. For those operations, Portugal developed its own counterinsurgency and jungle warfare doctrines. In the counterinsurgency operations, the Portuguese organized their forces into two main types, the grid (quadrilha) units and the intervention units. The grid units were each in charge of a given area of responsibility in which they were responsible to protect and keep the local populations from influence from the guerrillas. The intervention forces, mostly composed of special units (paratroopers, marines, commandos etc.) were highly-mobile units that were used to conduct strategic offensive operations against the guerrillas or to temporary reinforcing grid units under heavy attack.

Vietnam War: The British experience in counterinsurgency was passed onto the Americans during their involvement in the Vietnam War, where the battlegrounds were again the jungle. Much British strategic thinking on counterinsurgency tactics in a jungle environment was passed on through BRIAM (British Advisory Mission) to South Vietnam headed by Sir Robert Thompson, a former Chindit and the Permanent Secretary of Defense for Malaya during the Emergency.
The Americans further refined jungle warfare by the creation of such dedicated counterinsurgency special operations troops as the Special Forces (Green Berets), Rangers, Long Range Reconnaissance Patrols (LRRP), and Combat Tracker Teams (CTT).
During the decade of active U.S. combat involvement in the Vietnam War (1962–1972), jungle warfare became closely associated with counter insurgency and special operations troops.
However, although the American forces managed to have mastered jungle warfare at a tactical level in Vietnam, they were unable to install a successful strategic program in winning a jungle-based guerrilla war.