• is the largest tropical forest in the world and extends on approximately 5 500 000 km²;
  • represents more than half of the world’s remaining rainforests;
  • it is estimated that it contains up to 390 billion individual trees divided into 16,000 species [zotpressInText item=”{ENWDC4S7}” format=”(%num%)”];

The Amazon rainforest is a plant – tree community divided into several storeys. The highest one, the emergent layer, belongs to small number of tall trees – the emergents. Most of the tallest trees create the middle tree storeythe canopy. This thick layer allows only a very small part of sunlight to reach the understorey, the shrub storey and the forest floor. The underground area is further divided into the top, the middle and the bottom root layer [zotpressInText item=”{8VP8Q3TZ},{G7EUJ2VQ}” format=”(%num%)”]. Light gaps or crown gaps (Figure 1) are created by fall of one or more emergent trees or trees from the canopy (sometimes even large branches). When a large tree falls, two gaps are created (one in the original stand of the tree and one where the crown falls down). These gaps are colonized by pioneer species, that are resistant to direct sunlight. Thanks to this property, they are able to quickly provide a primary vegetation cover and create conditions for the growth of other plants (Figures 2 and 3) [zotpressInText item=”{G7EUJ2VQ}” format=”(%num%)”] [zotpressInText item=”{QI2USAXV}” format=”(%num%)”].

Figure 1. Chablis – from medieval French, means fallen tree, its rests and caused light gap; vertical and horizontal projection (Oldeman, 1978, source [zotpressInText item=”{CVF5CP9K}” format=”(%num%)”]).

Figure 2. Dynamics of the forest and stages of silvigenesis; A Destruction: the infrastructure is disrupted; B Regrowth starts; C Fierce competition: the forest is without structure, consists of competing pioneer species and the infrastuctural set is growing vertically; D Homeostatic phase: pioneer trees are maximally distributed “trees of the present”; E Death of the pioneers: competition among shade tolerant trees – “trees of the future”; F Homeostatic phase: newly established structure maintained by the second group of trees and meristematic tissues of pioneer species. Source [zotpressInText item=”{QI2USAXV}” format=”(%num%)”].

Development and changes in the composition in the forest communities is called succession (Figure 3), its final stage is so called climax. Silvigenesis is the development of the forest formation or ecosystem from previous stages of succession and regeneration cycles (dying and rejuvenation of trees). Based on the structural changes of the tree storey, changes in the soil and microclimate take place and consequently the alternation of animal populations.

Figure 3. Primary succession on newly deposited alluvium, biological station Cocha Chashu on the river Manu, Peruvian Amazon. Adapted from [zotpressInText item=”{8G9DD3KG}” format=”(%num%)”]. 

In the Amazon we recognize following basic types of forest  [zotpressInText item=”{343VB68F}” format=”(%num%)”]:

  • Floodplain forest (várzea and igapó, Figure 4), are the lowest-lying areas along the rivers (80 to 250 m.a.s.l.), which are periodically almost completely flooded for several months during the rainy season. Floodable forests represent 3-4% of the Amazon basin. The trees reach here the average height of 25 m.

Figure 4. Schematic cross-section of the Amazonian floodplain showing how the height of the water and composition of the substrate influence the composition of the floodable forest. Adapted from [zotpressInText item=”{MAGA9XWV}” format=”(%num%)”].

  • Fig 2Lowland forest (Figure 5) occurs in altitudes until 800 – 1000 m.a.s.l. (in Peru including regions Loreto, Ucayali, Madre de Dios, and part of Cusco). The largest trees reach the diameter over 3 m and height over 50 m.

Figure 5. Profile of a lowland forest plot of 20 x 30 m in Trois Sauts, French Guiana. Current canopy trees: in contours; future canopy trees: densely dotted; emergent and undergrowth smaller than 8 m are not shown. Adapted from zotpressInText item=”{QI2USAXV}” format=”(%num%)”].

  • Fig 3 Montane (fog) forest (Figure 6) grows in Peru in regions between 1000 and 3500 m.a.s.l. and can be found in regions Amazonas, Loreto, San Martín, Ucayali, Huánuco, Pasco and Junín. The largest trees here commonly reach over 40 m and many endemic species are found here. It is one of the most endangered types of forest.

Figure 6. Schematic profile of montane fog forest, Rancho Grande, Venezuela, 950 m.a.s.l. Adapted from [zotpressInText item=”{A2WTNXVX}” format=”(%num%)”].


Different plant species use different strategies to reach sunlight, water and nutrients. The dominating feature of the Amazon forest are treesphanerophytes, which form support for many other life forms such as herbaceous and woody vineslianas (Figures 7 and 8), air plants epiphytes, aerophytes, decomposing plants saprophytes and parasitic plants. Still waterbodies and their surroundings are colonized by aquatic plants hydrophytes, hygrophytes and helophytes.

Terrestrial herbs cryptophytes, hemicryptophytes and therophytes grow scattered in the shade of the forest or on the edges of the light gaps, on riverbanks and along paths. Ferns, mosses, lichens, algae, cyanobacteria and fungi are very common here. There are also specific growth forms such as tree ferns, liana palms and hemiepiphytes [zotpressInText item=”{Z2JUXDCQ},{G7EUJ2VQ},{8VP8Q3TZ}” format=”(%num%)”].


Figure 7. Growth forms of vines. The stem of lianas is often longer than 100 m, very firm and flexible. They use trees for support to reach sunlight in the upper storeys of the forest.


Figure 8. The family or genus of the lianas can be determined from the cross-section of the stem. (A – Odontadenia, B – Aristolochia, C – Parabignonia, D – Callichlamys, E – Clytostoma, F – Mendoncia, G – Combretum, H – Maripa, I – Hippocratea, J – Gurania, K – Doliocarpus, L – Plukenetia, M – Machaerium, N – Salacia, O – Bauhinia, P – Apelozizyphus, Q – Strychnos, R – Stigmaphyllon, S – Mascagnia, T – Menispermaceae, U – Menispermaceae, V – Dilkea, W – Passiflora, X – Seguiera, Y – Moutabea, Z – Coccoloba, AA – Paullinia, BB – Paullinia, CC – Cissus). Adapted from  [zotpressInText item=”{WB5DDNN5}”]

Hemiepiphytic plants (Figure 9) have an unusual growth habit and in some cases can act as stranglers – e.g. Clusia spp., Clusiaceae, or fig – Ficus spp., Moraceae. Their development starts by germination of the seed on the surface of the trunk or branches of another tree, from where their roots grow towards the soil. As soon as the roots reach the soil nutrients they grow thicker, start connecting to each other and forming an ever tighter net around the trunk of the host tree thus stopping its growth. The strangler competes with its host for sunlight and nutrients and it usually wins and occupies the living space. The host consequently dies, decomposes and returns nutrients into the soil and the hemiepiphyte grows individually as a normal tree but with a hollow net of woody roots for a trunk [zotpressInText item=”{G7EUJ2VQ}” format=”(%num%)”], [zotpressInText item=”{8VP8Q3TZ}” format=”(%num%)”].


Figure 9. Strangler fig (Ficus sp.) and three stages of its development. Adapted from [zotpressInText item=”{M6I3IDIR}” format=”(%num%)”].

PLANT ADAPTATIONS (some examples)

  • Pillar roots and stilt roots of the palms (Figure 10) are developed to anchor tall unstable trees in shallow waterlogged soils.
  • Thin smooth barkhelps the woody plants to evaporate water in humid environment and prevents other plants from growing on the surface of the trunk. Many tree or shrub species from thorns or spines.
  • Cauliflory and ramiflory is the ability of some species to form inflorescences and fruits directly on the trunk or main branches which facilitates pollination and spreading of the seeds [zotpressInText item=”{8VP8Q3TZ}” format=”(%num%)”], [zotpressInText item=”{G7EUJ2VQ}” format=”(%num%)”].
  • Drip tips of the leaves accelerate drainage of water from the leaves and contribute to faster dying in humid environment. This decreases the risk of infestation and collonization of the leaves by pests [zotpressInText item=”{3R36I844}” format=”(%num%)”].
  • Extrafloral nectaria on the leaves – produce nectar, which is an attractive source of nutrition for ants who protect young leaves from being eaten by herbivores – phytophagous insects [zotpressInText item=”{SE2KWE3U}” format=”(%num%)”]. Plants living in mutualistic association with ants are called myrmecophytes.



Figure 10. Stages of palm “walk”: A. falls down at the age of 12 years; B. two years later; C. five years later. Adapted from [zotpressInText item=”{6E2GG7XJ}” format=”(%num%)”]


Mapa Ecosistemas Amazonicos

Figure 11. Ecological systems of Peruvian and Bolivian Amazon. Source:  IIAP, NatureServe, CDC-Unalm,


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Recommended reading

Burley, J., Youngquist, J. Evans, J., 2004, Encyclopedia of forest sciences. Elsevier, Netherlands.

authors of the text: Jiří Lipenský, Ludvík Bortl, Marie Kalousová, Alexandr Rollo a  Hana Vebrová
authors of the pictures: Ludvík Bortl (LB), Jiří Lipenský (JL), Lukáš Huml (LH), Alexandr Rollo (AR), Hana Vebrová (HV),  David Honys (DH), and Hana Doležalová (HD)

 ⇐ Amazon basin || Biodiversity

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