Temperate and tropical rainforests share one defining trait: they both receive enough rainfall to sustain dense, moisture-dependent ecosystems. Beyond that common thread, they differ in climate, species composition, soil chemistry, canopy architecture, and how they cycle carbon and nutrients. Tropical rainforests cluster near the equator and stay warm year-round, while temperate rainforests occupy cooler, higher-latitude coastlines where seasons shift dramatically. These climatic differences ripple through every layer of each forest, from the tallest emergent trees down to the fungi colonizing dead leaves on the forest floor.
Where They Grow and What the Climate Feels Like
Tropical rainforests sit between roughly 23.5 degrees north and south of the equator, in regions where average temperatures hover between about 25 and 28 °C throughout the year. Seasonal temperature swings are minimal. A January afternoon in the Congo Basin or the Amazon feels much like a July one. Rainfall is heavy and relatively evenly distributed, often exceeding 2,000 mm annually and sometimes surpassing 4,000 mm.
Temperate rainforests exist in a handful of coastal strips at higher latitudes: the Pacific Northwest of North America, southern Chile, Tasmania, New Zealand’s west coast, parts of Norway, and small pockets in the British Isles and East Asia. Temperatures are milder than in the tropics, typically averaging between 4 and 12 °C annually, and winters can be cold enough for frost or occasional snow. Rainfall is comparable in total volume to tropical forests, often 1,500 to 3,000 mm per year, but much of it arrives during long, grey wet seasons rather than in daily tropical downpours. Fog and cloud moisture play a supplementary role in many temperate rainforests, draping the canopy in persistent dampness.
That seasonal temperature swing matters for the organisms living in each system. Research comparing photosynthetic responses in temperate and tropical rainforest trees found that temperate species can maintain peak photosynthesis across a wider range of growth temperatures, consistent with the larger day-to-day and season-to-season temperature variation they experience.1PubMed. Comparison of temperate and tropical rainforest tree species: photosynthetic responses to growth temperature Tropical species, by contrast, are finely tuned to a narrow thermal band. When experimentally grown at temperatures outside their normal range, tropical trees showed less ability to acclimate their photosynthetic machinery than their temperate counterparts.2PubMed. Do temperate rainforest trees have a greater ability to acclimate to changing temperatures than tropical rainforest trees? This has real implications for climate change: tropical rainforest trees may be more vulnerable to warming precisely because they evolved in such a stable thermal environment.
The Biodiversity Gap
The most striking difference a visitor would notice is sheer variety. A single hectare of tropical rainforest in Borneo or the Amazon can contain hundreds of tree species. A hectare of temperate rainforest in the Pacific Northwest or New Zealand’s South Island might hold a dozen or fewer. Tree diversity in the tropics can be seven or more times higher than at comparable sites in temperate zones.
That plant diversity cascades upward through the food web. A study comparing leaf-eating insects on temperate and tropical trees found that individual tree species support similar numbers of folivorous insect species regardless of latitude, roughly 23 to 29 species per 100 square meters of foliage. Host specificity did not differ between the two regions either. The researchers concluded that the enormous insect richness in tropical rainforests is largely a direct function of plant diversity: more tree species means more niches, and each tree species brings its own complement of herbivores.3PubMed. Why are there so many species of herbivorous insects in tropical rainforests? In other words, the tropics are not richer because each species is carved into finer dietary specializations. They are richer because the menu of host plants is vastly longer.
Temperate rainforests compensate in other ways. They often harbor ancient lineages found nowhere else: the mountain ash of Tasmania, the alerce of Patagonia, Sitka spruce and western red cedar in the Pacific Northwest, and southern beeches in New Zealand and Chile. Some temperate rainforest trees rank among the tallest and longest-lived organisms on Earth. The biodiversity is lower in raw species counts, but the ecological and evolutionary distinctness of the species present can be remarkable.
Dominant Trees and Plant Growth Forms
Tropical rainforests are overwhelmingly dominated by broadleaf evergreen angiosperms, flowering trees from families like Dipterocarpaceae in Southeast Asia, Fabaceae across the Neotropics, and Myrtaceae in Australasia. Conifers are rare in the lowland tropics.
Temperate rainforests, on the other hand, frequently feature conifers as canopy dominants or co-dominants. Pacific Northwest forests are built on Douglas fir, western hemlock, and Sitka spruce. New Zealand’s temperate rainforests include podocarp conifers alongside southern beech. Chilean temperate rainforests feature Fitzroya and Araucaria alongside Nothofagus broadleaves. Research on seedlings of temperate rainforest trees has shown that conifers and angiosperms differ in how they display leaf area: angiosperm seedlings self-shade less and tend to have roughly twice the leaf area ratio of conifer seedlings, largely because they produce more individual leaves rather than bigger ones.4PubMed Central. Traits with Ecological Functions: Seedlings of temperate rainforest conifer and angiosperm trees differ in leaf area display This matters for regeneration: in the dim understory of a temperate rainforest, how a seedling arranges its leaves to capture scarce light shapes which species eventually reach the canopy.
The vertical distribution of plant diversity also differs fundamentally. A large-scale comparison of over 3,400 plant species across 18 forests in the Americas found that plant species in temperate forests are strongly “downshifted” compared to tropical forests. In the tropics, an enormous share of species diversity lives up in the canopy as epiphytes, lianas, and canopy-dwelling herbs. In temperate forests, plant diversity is concentrated closer to the ground.5PubMed Central. Seeing beyond the trees: a comparison of tropical and temperate plant growth forms and their vertical distribution The tropical canopy is, in effect, a second ecosystem stacked above the forest floor.
Canopy Structure and Epiphytes
Tropical rainforest canopies are famously layered. The emergent layer consists of scattered giants that poke above the main canopy, sometimes reaching 50 to 70 meters. Below that lies a continuous upper canopy, then a sub-canopy layer, and finally the dim understory. LIDAR measurements comparing lowland dipterocarp forests in Borneo with montane mixed forests in Japan found that both tropical and sub-tropical forests can produce highly undulating canopy surfaces with distinct emergent layers, though the mechanisms generating that structure differ with species composition.6PubMed Central. Canopy structure of tropical and sub-tropical rain forests in relation to conifer dominance analysed with a portable LIDAR system
Temperate rainforests can also be impressively tall, especially old-growth stands of Sitka spruce or Douglas fir that exceed 60 meters. But the layering is generally simpler. There is often a single dominant canopy layer, sometimes with a few emergent individuals, and then a relatively open understory rich in ferns, mosses, and shrubs. The structural complexity of a tropical canopy, with its interlocking layers of foliage, is hard to replicate in forests with far fewer tree species.
Epiphytes, plants that grow on other plants, illustrate this gap vividly. In tropical rainforests, epiphytes contribute enormously to both species diversity and total plant biomass. Bromeliads, orchids, ferns, and mosses carpet the branches of canopy trees, forming their own aerial communities complete with trapped pools of water that support frogs, insects, and microorganisms. In temperate rainforests, epiphytes exist but are far less prominent. A study of a New Zealand lowland temperate rainforest found that epiphyte-lianoid communities were present but did not approach the species diversity or biomass typical of tropical systems.7Journal of Biogeography. Distribution, abundance and biomass of epiphyte-lianoid communities in a New Zealand lowland Nothofagus-podocarp temperate rain forest: tropical comparisons Mosses and lichens draping temperate rainforest branches give these forests their eerie, primeval character, but the sheer number of epiphyte species pales next to tropical equivalents.
Soil and Nutrient Cycling
One of the most counterintuitive differences between these two forest types lies underground. Despite their explosive above-ground productivity, many tropical rainforest soils are surprisingly nutrient-poor. Millions of years of intense rainfall and warm temperatures have leached away minerals and base cations, leaving deeply weathered, acidic soils. Nutrients cycle rapidly from dead organic matter back into living plants, with most of the forest’s mineral wealth locked in the biomass rather than the soil.
Temperate rainforest soils are often richer by comparison. A study of Pacific Coast temperate rainforests in North America found that these soils contain greater weatherable minerals, higher cation-exchange capacities, more soil organic carbon, and more total exchangeable base cations than tropical rainforest soils in the Pacific Basin. Both types of soils do share certain traits: they tend to be deep, acidic, aluminum-saturated, and can hold large nitrogen reserves.8Forest Ecology and Management. The disturbance of forest ecosystems: the ecological basis for conservative management But the temperate soils have not been subjected to the same relentless chemical weathering, so they retain more of the mineral building blocks that plants need.
The way dead leaves break down also diverges by latitude. In temperate forests, litter from trees associated with one type of root fungus decays faster than litter from trees associated with another, and nitrogen content in the leaves best explains those differences. In subtropical and tropical forests, no such difference between fungal groups shows up, and phosphorus rather than nitrogen drives variation in decay rates.9PubMed. Leaf litter decay rates differ between mycorrhizal groups in temperate, but not tropical, forests This aligns with a broader pattern: temperate forests tend to be nitrogen-limited, while tropical forests are often phosphorus-limited. The nutrient that constrains growth shifts as you move from the equator toward the poles, and the fungi partnering with tree roots respond accordingly. A meta-analysis confirmed that root-associated fungi boost decomposition more strongly at lower latitudes and when the decomposing material has a lower carbon-to-nitrogen ratio.10PubMed. Mycorrhizal fungi modify decomposition: a meta-analysis
Carbon Storage
A common assumption is that tropical rainforests are the planet’s supreme carbon warehouses. They are certainly enormous carbon reservoirs in total because they cover such vast areas. But on a per-site basis, the picture is less straightforward. A comparison across dozens of forest sites found that temperate moist forests stored an average of about 377 tons of carbon per hectare in above-ground vegetation, compared to roughly 179 tons in tropical moist forests and about 171 tons in tropical rainforests.11Mongabay Conservation news. Temperate forests store more carbon than tropical forests, finds study Subtropical moist forests fell in between, at around 294 tons.
How is that possible? Old-growth temperate rainforest trees can be enormous, individual Douglas firs or Sitka spruce accumulating massive trunks over centuries. Tropical trees grow faster but tend to be shorter-lived individually, and the wood of many tropical species is less dense than the conifers dominating temperate old-growth stands. The total global carbon contribution of tropical forests is still staggering because of their geographic extent, but a single stand of ancient temperate rainforest can outweigh a comparable patch of tropical forest in stored carbon.
How Disturbance Shapes Each Forest
Both temperate and tropical rainforests are shaped by disturbance, but the character of that disturbance differs. In tropical forests, the primary natural disturbance is individual tree falls, which create canopy gaps that allow light to reach the forest floor and trigger bursts of regeneration. This process has been intensively studied in Central American and Amazonian forests.8Forest Ecology and Management. The disturbance of forest ecosystems: the ecological basis for conservative management Tropical cyclones can also cause large-scale damage in some regions, but much of the lowland tropics sits outside hurricane belts.
Temperate rainforests face a broader disturbance menu. Windstorms are common along exposed coastlines in the Pacific Northwest, Patagonia, and New Zealand. Landslides triggered by heavy rainfall on steep terrain can strip vegetation to bare rock. Some temperate rainforests, particularly in the Pacific Northwest, also contend with fire, though true rainforest stands burn far less often than the drier forests nearby. In many temperate rainforests, the dominant disturbance is still individual tree fall, but the gap dynamics play out differently because the tree species involved and their regeneration strategies differ. A gap opened by a fallen Sitka spruce in coastal Oregon will be colonized by a different succession of species than a gap opened by a fallen dipterocarp in Borneo, even though the physical process is similar.
Logging and Conservation Pressures
Both forest types face serious human threats, but the scale and nature of those threats differ. Tropical deforestation gets more media attention, and for good reason: the rate of tropical forest clearing for agriculture, cattle ranching, and palm oil production has been devastating over the past half century. But temperate rainforests are also heavily exploited and, in some regions, more thoroughly logged than their tropical counterparts. The Pacific Northwest’s old-growth temperate rainforests have been reduced to a fraction of their historical extent. Chile’s Valdivian temperate rainforests have been logged and converted to plantations.
A meta-analysis of studies comparing logged and primary forests found that logging significantly reduces tree species richness in both tropical and temperate forests.12Elsevier / ScienceDirect. Tree species richness and the logging of natural forests: A meta-analysis The damage is not confined to one biome. A review of landscape change research noted that while tropical deforestation dominates the conservation conversation, temperate forest research differs in having more single-species studies, longer time horizons, and work at scales spanning multiple landscapes.13Elsevier / ScienceDirect (Biological Conservation). Landscape change and the science of biodiversity conservation in tropical forests: A view from the temperate world Direct studies of how forest conversion affects biodiversity remain relatively rare in both tropical and temperate ecosystems, which is a significant gap given the pace of ongoing habitat loss.
Temperate rainforests occupy a tiny fraction of Earth’s land surface compared to tropical rainforests. That rarity itself is a conservation concern. Losing a patch of temperate rainforest in Tasmania or southern Chile eliminates habitat for species that may exist nowhere else, even if the absolute number of species affected is smaller than in a comparable tropical clearing.
Where One Becomes the Other
The boundary between tropical and temperate forest is not always sharp. In East Asia, a monsoon climate that brings wet tropical summers extends unusually far north, to about 35 degrees latitude, creating a broad transitional zone. Research on this tropical-subtropical ecotone found that while canopy tree species change completely at the boundary, tropical understory species persist well into subtropical territory, declining gradually over several hundred meters of elevation in the Himalayas and over ten degrees of latitude in South China.14PubMed Central. The tropical-subtropical evergreen forest transition in East Asia: An exploration The transition is uniquely clear in East Asia because the monsoon extends subtropical evergreen forest farther north than anywhere else on the planet.
Other transitional zones exist along elevation gradients. Climb a mountain in the tropics and you move through lowland tropical rainforest, montane cloud forest, and eventually into vegetation that shares structural features with temperate forests: lower canopies, fewer tree species, mosses and ferns dominating the understory. These montane tropical forests are sometimes called “tropical temperate” by ecologists because their cool, cloud-bathed conditions produce forests that look and function more like temperate rainforests despite sitting near the equator. The distinction between temperate and tropical rainforests, in practice, is a gradient rather than a clean dividing line.
Seasonal Rhythms and Animal Life
Daily life for animals in these two systems follows different rhythms. In tropical rainforests, the relative constancy of temperature and day length means that food resources like fruit and flowers are available year-round, though with seasonal peaks. This allows tropical forests to support large communities of obligate frugivores and nectarivores: toucans, hornbills, fruit bats, hummingbirds, and an extraordinary diversity of fruit-eating primates. Decomposers and invertebrates also remain active continuously, keeping nutrient cycling fast.
Temperate rainforests impose seasonal bottlenecks. Winter brings shorter days, cooler temperatures, and a dramatic reduction in insect activity and fruit availability. Many animals cope through migration (salmon returning to Pacific Northwest streams provide a famous pulse of marine-derived nutrients to the forest), hibernation, or dietary shifts. The resident fauna tends to be less specialized: generalist omnivores like bears and raccoons rather than obligate frugivores. Bird diversity drops sharply compared to the tropics, though breeding seasons bring temporary spikes when migratory species arrive.
Amphibians tell an interesting story. Tropical rainforests harbor the vast majority of the world’s amphibian species, many of them arboreal frogs living in canopy epiphytes. Temperate rainforests support far fewer amphibian species, but those they do harbor can be locally abundant and ecologically significant. The Pacific giant salamander, for example, is a top predator in Pacific Northwest headwater streams. Temperate rainforest amphibian communities may lack tropical flash, but they play outsized roles in local food webs.
Fog, Moisture, and Water Cycling
Both forest types are defined by moisture, but the sources and delivery mechanisms differ. Tropical rainforests receive the bulk of their water as convective rainfall, often in intense afternoon thunderstorms driven by solar heating of moist air. The forests themselves recycle enormous amounts of water: transpiration from the canopy feeds moisture back into the atmosphere, which falls again as rain downwind. This self-reinforcing water cycle is one reason large-scale deforestation in the Amazon threatens rainfall patterns across the continent.
Temperate rainforests rely more heavily on frontal weather systems that push moisture-laden air from the ocean onto coastal mountains, where it rises, cools, and drops its water. Fog interception is a critical secondary water source in many temperate rainforests. On the California and Oregon coasts, redwood forests harvest fog droplets on their needles, channeling water to the ground even during the dry summer months. In New Zealand and Chile, persistent low clouds bathe the forest canopy in moisture that supplements rainfall. This fog-dependence makes temperate rainforests sensitive to changes in coastal cloud patterns, a vulnerability that does not affect most tropical rainforests.
The hydrological footprint of each forest type also differs. Tropical rainforests produce enormous river discharges, the Amazon alone accounting for roughly a fifth of the world’s fresh water entering the ocean. Temperate rainforests drain into smaller but ecologically vital watersheds, many of which support salmon and trout populations that in turn feed terrestrial ecosystems. The connection between forest health and stream health is tightly studied in temperate systems because of the economic and cultural importance of salmonid fisheries.