biodiversityThe number and mix of species found in one place. Rainforests are home to about half of all the plant and animal species on Earth.
buttress rootA broad fin of root that braces a trunk at its base. Buttress roots grow on trees with shallow roots in thin, poor tropical soil. They may keep the tree from falling over.
canopyThe nearly unbroken roof of a forest, high overhead. It holds most of the largest trees, typically 30 to 45 meters tall, and the densest life in the forest.
drip tipThe pointed end of a leaf that lets rain run off. Water that runs off quickly does not damage or break the leaf.
emergent layerThe few giant trees that stand above all the rest. Emergent trees reach 45 to 55 meters, and a few species 70 to 80.
epiphyteA plant that perches on a tree without harming it. It uses the tree for support only and takes its moisture from the air and the rain. Many orchids, ferns and bromeliads are epiphytes.
Show all 36 terms (30 more)
Layers of the rainforest, continued
forest floorThe lowest layer of a forest, dim and still. Only 2 percent of the sunlight reaches it, so only plants suited to low light grow here. Dead matter disappears quickly in the warm, humid air.
humidityMoisture in the air that you feel but cannot see. Warm, humid air is what makes dead leaves decay so quickly in a rainforest. Epiphytes take moisture straight from it.
lianaA thick, woody vine that loops from tree to tree. It is rooted in the ground and uses trees for support as it climbs to the sunlight. Lianas make bridges that sloths and monkeys use as paths.
rainforestA dense forest of tall trees in a very rainy place. Rainforests are tropical or temperate.
stratificationThe arrangement of a forest in layers by height. Most rainforests are described as having four layers, from the forest floor up to the emergent trees.
understoryThe dim layer of small trees under the treetops. Only about 5 percent of the sunlight that falls on the canopy gets this far. Birds, snakes and lizards live here, and so do jaguars and boa constrictors.
Climate, soil and cycles 12
broadleafHaving wide, flat leaves and not needles. Tropical rainforest trees are mostly broadleaf, with large dark green leaves. Temperate rainforests may be broadleaf or coniferous: Sitka spruce and western hemlock fill the northern Pacific ones.
carbon dioxideThe gas, written CO2, that trees absorb from the air. Photosynthesis uses it up and gives off oxygen as a by-product. With fewer trees, less of it is taken out of the air.
decomposerA mold, mushroom or microbe that makes things rot. Many kinds of fungi grow on the forest floor of a rainforest and help decay plant and animal waste. Bacteria do the same work.
evergreenNever leafless; green in winter and summer alike. An evergreen loses its leaves little by little and not all at once. Most plants of a tropical rainforest are evergreen.
leachingThe washing of nutrients out of soil by water. Soil under a tropical rainforest is subject to heavy leaching.
leaf litterWhat trees shed: leaves, bark and twigs on the soil. As it is decomposed it releases nutrients into the soil. It also holds moisture in and hides small animals.
nutrient cycleThe path of minerals from soil to plant and back. Calcium, potassium and magnesium are among the nutrients. When a rainforest is cleared the cycle stops, because no trees are left to shed leaves and feed the soil.
runoffWater that the soil cannot soak up, moving downhill. It happens when rain falls faster than the ground can take it in. Clearing a rainforest leads to soil erosion and flooding.
temperate rainforestA cool, wet forest of the middle latitudes. One of the largest stretches lies along North America's Pacific coast. The rain forest valleys of Olympic National Park in Washington State get 12 to 14 feet of precipitation a year.
topsoilSoil at the surface, the part richest in microbes. Rainforest trees have shallow roots that take their nutrients from this layer. The soil is red since it holds a lot of iron.
transpirationA plant's release of moisture through its leaf pores. Rainforest trees give off so much water that about half of the rain that falls on the Amazon is produced by the forest itself.
tropical rainforestA hot, wet forest found near the equator. It is typically found within 10 degrees of the equator. The Amazon is the largest.
Animals, people and the forest 12
arborealSpending its life in the trees. Sloths and many monkeys are arboreal. Some animals climb trees only now and then, and others live nowhere else.
carbon sinkA reservoir, such as a forest, that soaks up carbon. Soils and forests are the main natural carbon sinks on land.
conservationThe care and protection of wild places and species. National parks have played a large part in it, and some of the first were set up in the United States.
deforestationForest loss: trees give way to fields and towns. Farming is the main cause: forest is cleared for crops and for pasture. Forest covers about 31 percent of the land on Earth today.
endangered speciesA species likely to become extinct before long. Species become endangered mainly through the loss of their habitat.
habitatThe surroundings a plant or animal is suited to. Each layer of a rainforest gets a different share of water, sunlight and moving air, so each is a habitat for different species.
loggingCutting down trees and hauling the timber away. Clearcutting removes nearly every tree from a site. Selective logging takes only mature trees and leaves the canopy standing.
nocturnalAwake and feeding in the dark hours. Some kinds of bat are able to function only at night. Nocturnal animals generally have highly developed hearing and smell.
prehensile tailA tail that can grip a branch like an extra hand. Howler monkeys and spider monkeys have one, and so does the kinkajou.
reforestationBringing woods back to land that had lost them. A forest that grows back by itself after clearing is called secondary forest.
seed dispersalThe travel of seeds to new ground, by wind or animal. Gravity and water carry seeds too. Wings on a seed and flesh on a fruit are signs of how it travels.
slash-and-burnA way of farming that opens plots with ax and fire. The ash feeds the soil for a time. Within three to five years the harvests shrink, and the farmer leaves the plot and moves to a new one.
How this list was compiled: Term list chosen for this site on 2026-10-12. Each meaning is written in our own words and was checked that day against the article on the term in the English Wikipedia (https://en.wikipedia.org/), whose text is under the Creative Commons Attribution-ShareAlike license: Rainforest, Tropical rainforest, Temperate rainforest, Pacific temperate rainforests, Hoh Rainforest, Canopy (botany), Understory, Stratification (vegetation), Forest floor, Humidity, Biodiversity, Epiphyte, Liana, Buttress root, Surface runoff, Transpiration, Amazon rainforest, Evergreen, Broad-leaved tree, Leaching (pedology), Plant litter, Nutrient cycle, Topsoil, Arboreal locomotion, Prehensile tail, Seed dispersal, Nocturnal animal, Habitat, Endangered species, Deforestation, Reforestation, Secondary forest, Slash-and-burn agriculture, Logging, Nature conservation and Carbon sink. The four layers, drip tips, buttress roots, the soil, leaching, the nutrient cycle, carbon dioxide and the effects of clearing were checked a second time against BBC Bitesize (https://www.bbc.co.uk/bitesize/guides/zx8n39q/revision/1, Tropical rainforests, three pages, and https://www.bbc.co.uk/bitesize/articles/zppthcw, Tropical rainforests); the layers also against National Geographic Education (https://education.nationalgeographic.org/resource/rain-forest/, Rainforest); rainfall and where rainforests lie against the Earth Observatory of the National Aeronautics and Space Administration (https://earthobservatory.nasa.gov/biome/biorainforest.php, Rainforest); soil, leaching and tree form against the University of California Museum of Paleontology (https://ucmp.berkeley.edu/exhibits/biomes/forests.php, The forest biome); the temperate rainforest against the National Park Service (https://www.nps.gov/olym/learn/nature/temperate-rain-forests.htm, Temperate Rain Forests, Olympic National Park). The fact after each meaning is from the same pages. Licence: own work
How it works
This rainforest vocabulary worksheet lists canopy, understory, emergent layer, forest floor, humidity, biodiversity, epiphyte, liana and four more terms down the left, with their meanings in another order down the right and an answer key on the last page.
Read the full guide
Climate, soil and cycles
Set opens on Layers of the rainforest. The second set has tropical rainforest, temperate rainforest, runoff, transpiration, evergreen, broadleaf, leaching, leaf litter, decomposer, nutrient cycle, carbon dioxide and topsoil.
Animals, people and the forest
The third set has arboreal, prehensile tail, seed dispersal, nocturnal, habitat, endangered species, deforestation, reforestation, slash-and-burn, logging, conservation and carbon sink.
The animals and plants by name, from jaguar to bromeliad, are words on the rainforest word search.
Questions and answers
Where are rainforests found?
Tropical rainforests lie between the Tropic of Cancer and the Tropic of Capricorn, in tropical America, Africa, Southeast Asia, Madagascar and New Guinea. Temperate rainforests grow in rainy regions farther from the equator, such as the Pacific Northwest, southwestern South America and New Zealand.
How much rain does a rainforest get?
More than any other biome: a typical year brings a rainforest 2,000 to 10,000 millimeters of rain, which is 79 to 394 inches.
Why is rainforest soil poor?
Its nutrients do not stay in it. Dead leaves decompose fast and shallow roots take the nutrients up again at once, and heavy rain washes much of the rest away. What is left is nutrient-poor and acidic.