Tundra is a terrestrial biome at high latitudes and high altitudes defined by permanently frozen subsoil (permafrost), very low precipitation, a short growing season, and sparse, shallow-rooted vegetation with no trees.
Tundra is one of the major terrestrial biomes you'll meet in Unit 1, and it's the coldest one. Think of it as a frozen, treeless landscape near the poles (Arctic tundra) or at the top of high mountains (alpine tundra). The defining feature is permafrost, a layer of soil that stays frozen year-round. Only a thin top layer thaws in summer, so plant roots can't dig deep. That's why tundra vegetation is low and shallow-rooted: mosses, lichens, grasses, and small shrubs instead of trees.
Per EK ERT-1.B.1, every biome's plant and animal communities are shaped by its climate. Tundra's climate is cold and dry, with a short growing season, so the species there are adapted to survive long frozen winters and a quick burst of summer growth. EK ERT-1.B.2 lists tundra among the major terrestrial biomes, and EK ERT-1.B.3 ties its features to a mix of climate, latitude, altitude, and soil. High latitude and high altitude both mean cold, which is why Arctic and alpine tundra look so similar despite being far apart.
Tundra shows up in two very different places in the CED, and that's the whole point of this page. In Unit 1, topic 1.2, it supports learning objective AP Enviro 1.2.A, describing the global distribution and environmental aspects of terrestrial biomes. In Unit 9, topic 9.5, it becomes a case study for learning objective AP Enviro 9.5.A, explaining how climate change impacts ecosystems. Tundra is the biome the exam loves to use as the example of an ecosystem hit earliest and hardest by warming, because warming a frozen, low-diversity system changes it fast.
Keep studying AP® Environmental Science Unit 1
Boreal forest / taiga (Unit 1)
The boreal forest sits just south of the Arctic tundra. As the climate warms, the treeline creeps north, so the taiga can expand into what was tundra. Tundra is the biome getting squeezed out from the top.
Ice and snow albedo feedback (Unit 9)
Bright snow and ice reflect sunlight (high albedo). When tundra warms and that white cover melts, darker ground absorbs more heat, which causes more melting. This feedback loop is why high latitudes warm faster than the global average.
Glacier melt and global change (Unit 9)
Thawing permafrost is tundra's version of glacier melt. Frozen tundra soil locks away huge amounts of carbon, so when it thaws it can release CO2 and methane, adding to the warming that thawed it in the first place.
Elevation zones (Unit 1)
Climbing a mountain mimics traveling toward the poles. Alpine tundra sits above the treeline at high elevation for the same reason Arctic tundra sits at high latitude: it's too cold for trees.
On multiple-choice questions, tundra is the go-to answer for 'which biome is hit first and hardest by warming?' and 'which biome shifts northward as the climate warms?' If a question describes a biome with a short growing season, permafrost, and shallow-rooted plants, that's tundra, and the climate factor responsible is cold temperature driven by high latitude or altitude. It also turns up in low-biodiversity questions, since a small temperature increase can wipe out cold-adapted species that have nowhere colder to go. For FRQs, you won't usually get a whole prompt on tundra by name (the 2023 ecosystem-restoration FRQ used temperate forests, not tundra), but you should be ready to explain albedo feedback, permafrost carbon release, and biome shifts in a free-response answer about climate change.
Both are cold, high-latitude biomes, so they're easy to mix up. The difference is trees. Tundra has permafrost and no trees (just mosses, lichens, and shrubs), while the boreal forest is just south of it and is dominated by cone-bearing evergreen trees. As warming pushes the treeline north, boreal forest tends to advance into former tundra.
Tundra is the cold, treeless biome found at high latitudes and high altitudes, defined by permafrost, low precipitation, and a short growing season.
Permafrost (year-round frozen subsoil) is why tundra plants are low and shallow-rooted, with no trees.
On the exam, tundra is the classic answer for the biome hit earliest and most severely by global warming.
Ice and snow albedo feedback makes tundra warm faster than average, because melting bright snow exposes dark, heat-absorbing ground.
Thawing permafrost releases stored carbon as CO2 and methane, which speeds up further warming.
As the climate warms, tundra shrinks while boreal forest shifts northward into it.
Tundra is a terrestrial biome at high latitudes and high altitudes with permafrost (permanently frozen subsoil), low precipitation, a short growing season, and sparse, shallow-rooted, treeless vegetation. It's listed as a major biome under EK ERT-1.B.2.
Yes. Tundra is the standard exam answer for the ecosystem that experiences the earliest and most severe impacts from warming, because thawing permafrost and ice-albedo feedback amplify warming at high latitudes and its cold-adapted species have nowhere colder to retreat to.
Both are cold and high-latitude, but tundra has permafrost and no trees, while the boreal forest just south of it is dominated by evergreen conifers. As temperatures rise, the boreal forest's treeline tends to shift north into former tundra.
Because temperatures are too cold for the deep soil to thaw. Only a thin surface layer melts in summer, so roots can't penetrate the frozen ground below, which keeps vegetation short and shallow-rooted with a short growing season.
Both conditions produce cold temperatures. Arctic tundra forms near the poles (high latitude) and alpine tundra forms above the treeline on mountains (high altitude), so climbing a mountain mimics traveling toward the poles, as described in EK ERT-1.B.3.
Connect this key term to the AP exam workflow: review the course, practice questions, and check related study tools.
Review units, study guides, and course resources.
Check this vocabulary in multiple-choice context.
Apply key concepts in written AP responses.
Estimate the exam score you are working toward.
Review the highest-yield facts before practice.
Put the full course together before test day.