Biomes are a feature in Rise of Nations that allow you to inflict more attritional damage on your enemy based on the climate in the region.[1]
Terrain vs Biome
Despite popular belief, terrain and biome are not 2 different words that explain the same thing.
Terrain is the physical features of the land, hilly or mountainous for examples, while Biomes are the climatic features of the area, Arctic for example.
Currently there are 6 types of biomes. Each has their own attritional damage hits and speed penalty against units. Here is the list of biomes, from most damaging to least damaging:
- Arctic
- Severe Winter
- Mild Winter
- Arid
- Jungle
- Normal
Every year on November 1 and December 1, the northern hemisphere transitions into winter, and on February 1 and March 1, the northern hemisphere transitions out of winter.
It is possible for the climate to change over time (seasons), making biomes like Severe Winter disappear over time and then reappear again, usually from December to March.
Normal Biome
This is your normal type of biome. No attritional damage, entrenchment bonus, and unit speed reduction.
Countries that have a normal biome
Jungle
Jungle is one of the non-changing biomes. It reduces unit speed by 50%, has a good amount of attritional loss, and provides a 3.25x boost to Entrenchment for all ground units.
Countries that have Jungle biome:
Strategy
A lot of tropical/Jungle biomes are on the coast, which means it is fairly easier to invade when navally invading said nation, unless they have submarines. You should also be warned that the defender receives a bonus.
Artillery
Artillery is desirable to help against troops in Jungle biomes due to the higher defensive bonus that they have whilst in said biome.
Arid
Arid is another non-changing biome. It reduces unit speed by 33% and causes heavy attritional losses.
Countries that have the Arid biome:
| North America | South America | Africa | Asia | Oceania |
|---|---|---|---|---|
| United States | Bolivia | Morocco | Yemen | Australia |
| Tunisia | Oman | |||
| Libya | United Arab Emirates | |||
| Egypt | Qatar | |||
| Algeria | Bahrain | |||
| Mauritania | Saudi Arabia | |||
| Mali | Jordan | |||
| Chile | Niger | Iraq | ||
| Chad | Kuwait | |||
| Mexico | Sudan | Israel | ||
| Eritrea | Lebanon | |||
| Somalia | Syria | |||
| Ethiopia | Iran | |||
| Kenya | Afghanistan | |||
| Peru | Namibia | India | ||
| Botswana | Turkmenistan | |||
| South Africa | Uzbekistan | |||
| Madagascar | Kazakhstan | |||
| China | ||||
| Western Sahara | Mongolia |
Strategy
Deathstacks
Using deathstacks can be extremely helpful here due to the high amount of attrition, and because most Arid cities are scattered.
Tech
Researching Mobility tech for all units can be useful here.
Criticism
Yet at a smaller scale compared to the notorious Arctic biome, certain players do not like certain mountainous countries having arid biomes, due to extremely slow conquering speeds (ex. Chile and Iran). Both take extreme amounts of time to conquer and have spread out cities to ensure your troops will maximize attrition.
Mild Winter
Mild Winter is a seasonal variant of the Severe Winter biome. Both of these appear during Winter, most commonly in countries in the North (Russia, Canada, United States, etc.). Winter slows down units by 75% and causes very high losses due to attrition, unless your troops have winter specialization.
Countries who have Mild Winter at all:
Strategy
It is advised you wait for the end of winter before attacking areas with Mild Winter. You can take good amounts of attrition if the country you are attacking knows what is happening.
Severe Winter
Severe winter was one of the many factors that caused Napoleon to exile and lose the Napoleonic Wars, and Operation Barbarossa to fail. Deals significant amounts of attritional damage, reduces unit speed greatly, and provides a good entrenchment bonus.
The countries with severe winter are:
| Europe | North America | Asia |
|---|---|---|
| Russia | United States | China |
| Belarus | ||
| Estonia | ||
| Latvia | ||
| Lithuania | ||
| Finland | ||
| Sweden | Canada | |
| Norway | ||
| United Kingdom | ||
| Denmark | ||
| Poland | ||
| Ukraine |
Strategy
It is advised you wait for when winter ends before invading into areas with Severe Winter.
Arctic
It deals the most attritional damage, and a 75% unit speed reduction. It is non-changing.
It is advised you don't troop spam in Arctic biomes as you will suffer from heavy attrition.
Countries with Arctic biome:
| Europe | North America | Antarctica |
|---|---|---|
| Russia | United States | Antarctica |
| Finland | ||
| Sweden | ||
| Norway | Canada | |
| Greenland | ||
| Iceland |
Strategy
As it seems that most tend to struggle against Arctic Biomes, the strategies for invading areas with these biomes will be provided.
Roads
You may find these useless, but when invading nations with an Arctic Biome, roads can be extremely useful as roads double the mobility of all troops, meaning you will not have to suffer from moving extremely slow, and not take more casualties from attrition as a result.
To do this, own any surrounding areas to Arctic biomes to be able to then build roads into it. In the case of Iceland, quickly navally invade their coastal cities, build roads and allow your troops to reinforce. However, beware, as the defending nation may destroy roads on purpose in order to slow down your troops.
Roads have been replaced with infrastructure in the 01/26/2024 minor update.
Tech
Infantry and Tank Mobility are also highly recommended to have from the tech tree, for it increases the mobility of both, allowing you to move faster in Arctic regions. This reduces the time spent in attrition.
Bombing
If, however, they have chosen to fortify their cities in the Arctic, it is highly advised you bomb said cities to destroy the fortifications, therefore allowing you to take it faster with less casualties.
If the cities are located near water, say in Iceland, you can grab a few ships such as aircraft carriers or battleships to inflict heavy damage on the garrisoned troops, allowing a similar strategy to bombing.
Transport Aircraft
Using Transport Aircraft is a good idea to invade Arctic nations, although they can put Anti Aircraft. So it is recommended with this strategy to also use your Navy or artillery to destroy the anti-aircraft.
Tank Stacking
By stacking tanks without merging them (turning off auto merge), then the tanks will still suffer from attrition, but the attrition limit is higher and at a reasonable number (like 200). Although they move slower in mountainous arctic areas, they have the huge advantage of capturing cities with less units. This is very useful for cities such as Fairbanks, Yellowknife and Vostok, where they are far from seas, and when the player controlling it has anti aircraft. However, be aware of artillery.
Criticism
A large portion of the community despises the Arctic biome due to immense attrition, slow speeds and an insane defense bonus. Cities in Canada in the north such as Yellowknife and, notoriously, Vostok in Antarctica, are extremely difficult to take, due to not being near the ocean and far away from other cities. Due to Canada's Arctic biome being literal hell for any country that invades it, North American Union has been declared as a rare formable, as it's now barely seen in games. Canada and other similar countries can also fortify artillery units to deal damage to your troops, making it even harder to capture their cities. With countries such as Norway or Iran, the mountainous terrain incurs the even slower capturing of cities, making it almost impossible to capture one's cities if they defend it well.
Tutorial by Zack on How to take less attrition:
