(“Los Recursos Forestales de la America Latina”, 1981- FAO UN 32/6.1301-78-04 Informe tecnico 1)
"Closed broadleaved formations"
Rainforest ("hoog drooglandbos", "high dryland forest"): in its most abundant form it shows three or four storeys, with emergents up to 45 m. The lower storey attains between 25 and 30 m. Underneath appears an undergrowth consisting of small trees and poles. In the northwestern part of Surinam the emergents are not so conspicuous, the forest is less dense and generally the number of storeys is limited to two or three. Palms are common: paramaka (Astrocaryum paramacca) and boegroemaka (A. sciophyllum), Attalea spp. in the undergrowth and up in the conopy koeboe (Oenocarpus bacaba). Lianes are fairly uncommon. The total number of species over 25 cm diameter is around 140 and about 50 different ones per ha. The forest is evergreen. Very often a few species only are dominant but to a high degree. Among these are Qualea spp., Protium spp., manbarklak (Eschweilera spp.), wallaba (Eperua falcata), Micropholis spp., foengae (Licania spp.), Pouteria surinamensis, Piptadenia suaveolens, Vouacapoua americana, Tetragastris spp, Inga spp. Dicorynia guianensis. Underneath occur Vochysia spp., Lecythis spp. and Couratari spp. among others. Goupia glabra, Cecropia spp. and Jacaranda copaia occupy natural clearings.
A somewhat poorer form of rainforest called "ritsbos" consists of two storeys up to 30 m. The undergrowth is formed by palms. In the upper storey occur Hymenea courbaril, Cedrela odorata, Simaruba amara and Licania spp.: the latter are becoming dominant in the east of the country.
On shallow soils patches of "climber forest", without storeys may appear. Trees are widely spaced and openings are filled with lianes and climbers.
"Closed broadleaved formations"
Dry evergreen forest ("Hoog savannebos", "high savanna forest") is two-storeyed, with a closed upper canopy reaching 25 to 30 m in height. Big trees are scarce. Palms are few and small. Dominant species are the same as in the rainforest. It occurs on deep white sands. When one (or more) species is particularly dominant the following types are distinguished:
- the wallaba forest with Eperua falcata occurring in all sizes:
- the dakama forest with Dimorphandra conjugata. In this forest a very thick organic layer is formed on the mineral soil causing fire hazard. Herbs are absent;
- the dakama-wallaba forest;
- the dakama-savanneyzerhartbos with Swartzia bannia.
In the other mixed types of dry evergreen forest the following genera are mentioned: Protium, Bombax, Ocotea, Nectandra, Licaria, Eschweilera and Licania.
"Closed broadleaved formations"
Xeromorphic woodlands ("laag savannebos", low savanna forest) do not show any storeying. Height varies from 10 to 20 m. This type of forest is very dense and closed, and more homogeneous than the previous ones. Important species are Clusia fockaena, Licania incana, Bombax flaviflorum, Swartzia bannia, Ocotea spp. and Protium spp
"Closed broadleaved formations"
The "bergsavannebos" or "mountain savanna forest", corresponds to the xeromorphic rainforest in Guyana, and occurs on bauxite hills with laterisation or in the mountains of the interior where soils are thin and shallow. Predominant families are Myrtaceae and Bromeliaceae. It has no pronounced storeying and is rather low. Floristic composition is different from the previous type.
"Closed broadleaved formations"
Marsh forests are characterized by insufficient drainage, causing seasonal fluctuations in the moisture conditions, from very wet to very dry. The upper canopy is somewhat irregular, with a height between 15 and 20 m, with a very dense understorey 5 to 15 m high. Generally this forest is quite rich in species. Among the most important ones are: krapa (Carapa guianensis), nekoehoedoe (Clathrotropis brachypetala), hoepelhout (Copaifera guianensis), manbarklak, nickerie basralocus (Lonchocarpus hedyosmus), possum (Hura crepitans), kankantri (Ceiba pentandra), soemaroeba (Simaruba amaro), goebaja (Psidium spp.), groenhart (Tabebuia serratifolia), foengoe, mora (Mora excelsa) and morototo (Schefflera paraensis). In the lower storey occur Rinorea sp., Gustavia sp., and Jacaranda rhombifolia. There is a well developed herb layer. Epiphytes are very common, palms well represented: maripa (Maximiliana maripa), pina (Euterpe oleracea), koemba, maurisie (Mauritia flexuosa) in the upper storey, and in the under storey kiskismaka (Bactris spp.) tas (Geonoma spp.), paramaka and boegroemaka. In the western part concentrations of troeli (Manicaria saccifera) can be found.
Marsh forests show a considerable diversity according to local conditions. Three types are mentioned:
- riparian forest (oeverbos) along the rivers, with typical species as kroebara (Pentaclethra macroloba), moeserki (Zygia spp.), rode locus (Hymenaea courbaril) and oeverwallaba (Eperua spp.). Locally palms are very dominant;
- the mora forest is considered as a special case of riparian forest, in which Mora excelsa is dominant in all layers. It occurs in the western part of Surinam along river plains seasonally inundated. Its eastern limit lies more or less along the Saramaca river. The canopy reaches a height of 35-40 m;
- creek forest occurs in the hill country, and is strongly influenced by the surrounding rain forest.Wallaba is well represented in most cases;
- the possum forest occurs locally in the coastal area, where possum (Hura crepitans) becomes dominant. It is one of the trees attaining the largest diameters in Surinam (up to 250 cm);
- the krapa forest in which Carapa guianensis is dominant, especially in Western Surinam along the Corentyne river.
"Closed broadleaved formations"
Swamp forests (zwampbos) are marked by very wet conditions all year round. However, the shorter the time of inundation, the more it resembles the rain forest.
-High swamp forest is at least 20 m high, with two or more storeys. The canopy is fairly closed and consists of small crowns, between 18 and 30 m high. Characteristic species are baboen (Virola surinamensis), mataki (Symphonia globulifera), mierenhout (Triplaris surinamensis), watrabébé (Pterocarpus officinalis), zwamppanta (Tabebuia insignis) and kanamboelie (Simaba multiflora). In the understorey typical species are Diospyros sp. and Bactris sp. Many trees have spreading horizontal branches. The herb layer is present but its characteristics vary. The palm pina (Euterpe oleracea) occurs abundantly. The following types are distinguished according to location:
* high swamp forest on the recent formations of the young coastal plain and along the rivers: it is characterised by an abundancy of mierenhout and consists of a few species only;
* high swamp forest on the other formations of the young coastal plain: characterised by baboen and mataki. There is accumulation of peat (pegasse), sometimes various metres deep;
* high swamp forest on the lower parts of the old coastal plains, the low sites behind the riverbanks and on creek grounds, This is a richer forest and no species are very dominant. Peat is present only intermittently.
- low swamp forest varies in physionomy from an open scrub to a low closed forest with one storey from 10 to 15 m high. Palms and epiphytes are rare. The water is brackish or fresh. Soils are heavy clay. The forest has no large trees and is not rich in species: watrabébé, zwamppanta, mierenhout, zwampzuurzak (Annona glabra), taproepa (Genipa americana), kanamboeli, pruim (Chrysobalanus icaco) and Ficus sp.
This category includes also a forest type with a totally different physionomy, where the palm Mauritia flexuosa forms a 20 m high canopy with smaller trees of pruim and Clusia nemorosa.
- Mangrove forests cover 115 000 ha. They are one storeyed and closed, 10-25 m high. The undergrowth is restricted to ferns (Acrostichum sp.). Two types are distinguished:
* the parwa forest, along the coast with Avicennia nitida, and
* the mangro forest, along the major rivers with Rhizorphora mangle and patches of low trees of Laguncularia racemosa.
In the major river mouths a mixed type of mangrove occur with species such as Carapa guianensis and Pterocarpus officinalis.
"Scrub formations"
Towards the open savanna the xeromorphic woodlands change into a scrub (called "struiksavanne"), with the same floristic composition. Only Bombax flaviflorum appears as a small tree.
Vegetation types
(“Mapa de la Vegetación Actual de Venezuela”, 1983 Ministerio del ambiente y de los Recursos Naturales Renovables)
Es un tipo de bosque que se encuentra formando una associaciòn edáfica, siempre verde, monoestradificado, que crece a orillas de los cursos de agua (márgenes y áreas de influencia freática), con sus raices en la zona de saturación de humedad o cerca de ellas. Situado en las tierras bajas, planas y collinas, tanto en zonas de vegetación baja (sabanas), como dentro de los macizos boscosos.
Formación arbórea de 3 a 30 m de altura que occurreen los litorales con suelos planos y fangosos, influenciada por las mareas e inundata constantemente, o solo con la marea alta. Constituida por comunidades casi puras (pertenencies a las familias Avicenniaceae, Combretaceae, Rhizophoraceae, etc.), que soportan condiciones de relativa alta salinidad o salobre, con raíces aéreas respiratorias, algunas zanconas, otras con neumatóforos, lo que le imprime una fisionomía particular a la formación.
Formación vegetal arbustiva xerófila de fisionomía achaparrada, compuesta por especies frecuentemente armadas, de hojas pequeñas, de 3 a 8 m de altura, asociada con cactáceas suculentas, algunas de ellas columnares, las cuales pueden hacerse dominantes.
Formación vegetal arbustiva de menos de 5 metros de altura, monoestratificada, de fisionomía variable de acuerdo a las condiciones climáticas. Las especies componentes en general poseen abundantes ramificación desde la base, lo que la hace, en ciertos casos difícil de penetrar.
Para efectos del Mapa de Vegetación, el término matorral viene dado tanto por el de origen natural, con su dinámica ecológica propria, como el resultante de la intervención umana, que se manifiesta en comunidades fuertemente intervenidas y en proceso de recuperación, conocidas con el nombre de rastrojo.
Formación vegetal de fisionomía semejante a la sabana abierta de llanura, diferenciándose de ésta en que la vegetación, principalmente compuesta por herbáceas no se dispone en macollas, sino que forma un estrato continuo de hierbas altas. Predomina hacia las colinas y faldas de las altas montañas; su origen puede estar asociado a influencias antrópicas.
Formación natural climax, predominantemente herbácea, donde el suelo está tapizado por formas de vida en rosetas y de cojín, musgos y líquenes. Más diseminado aparecen los frailejones (de la familia Compositae), típicos de esta formación y pueden presentarse árboles pequeños (de la familia de las Rosaceae) formando bosquetes.
Esta formación característica de las altas montañas (2.500-4.000 m.s.n.m.), ocurre entre el límite superior del bosque y límite inferior de las nieves perpetuas.
Formación vegetal monoestratificada donde predominan gramíneas perennes y dispuestas en macollas, exenta casi totalmente de elementos arbóreos o arbustivos, o presentándose en forma muy dispersa. La continuidad de las sabanas puede interrumpirse por la presencia de morichales y bosque de galería.
En general, las sabanas están sujetas a condiciones de clima alternantes y rigurosas: época de extrema sequía seguida por una de alta pluviosidad y temperaturas elevadas durante todo el año. La occurrencia de fuegos periódicos aunado a las características edáficas limitantes y a las continuas intervenciones humanas con fine agropecuarios, condicionan notablemente su fisionomía.
Formación natural de apariencia herbácea, florísticamente autóctona, con predominancia de especies endémicas de gran especialización y escasa presencia de gramíneas, localizada en las cimas planas de los tepuyes, en ciertas áreas de la altiplanicie de la Gran Sabana y en alguna planicies con suelos de arenas blancas del Territorio Federal Amazonas.
En las cumbres de tepuyes, sobre roca de arsenica, se asocian especies pertenecientes a las familias de las Cyperaceae, Rapateaceae, Bromeliaceae, Poligalaceae, etc.
En las planicies prevalecen las mismas especies, pero entremezcladas con elementos arbustivos enanos de las familias Apocynaceae, Euphorbiaceae, Malpighiaceae y Melanostomataceae. En esto caso Huber (1982), ha denominado a esta formación Sabana Amazonica.
Asociación de la formación sabana con un componente arbóreo de pequeña altura, carácter pirófilo, de densidad variable y de fisionomía característica achaparrada, que se conoce comúnmente con el nombre de chaparro y al que corresponden diversas especies resistentes a condiciones adversas, tales como: suelos degradados y fuegos periódicos. Entre las familias representativas pueden reconocerse las siguientes: Dilleniaceae, Malpighiaceae, Papilionaceae y Proteaceae.
Formación vegetal constituida por la asociación sabana con chaparros y grupo de árboles y arbustos formando matas, en donde la sabana con chaparro ocupa la mayor proporción.
Formación vegetal que debe su origen a la combinación en proporciones similares de sabana con chaparros y bosques de galería, situados sobre paisajes accidentados y asociados de tal forma que no es posible cartografiarlos por separado a la escala 1:250.000.
Combinación de la formación sabana con individuos arbóreos que pueden estar dispersos y/o concentrados formando grupos aislados, con apariencia de pequeños bosquetes conocidos con el nombre de matas.
Estas matas presentan una forma casi circular, se establecen en sitios localizados con condiciones favorables de suelos, disponibilidad de humedad y protección a los fuegos periódicos.
Formación vegetal predominantemente herbácea con individuos arbóreos dispersos y con relativa abundancia de palmas, que se presentan en forma aislada o concentradas en sitios húmedos y cursos de agua.
Son formaciones vegetales establecidas por el hombre a través de técnicas silviculturales, bien sea con fines protectores o productores. Para los efectos del Mapa de Vegetación, son áreas reforestadas indistintamente de la especie y cuya superficie sea superior a la unidad mínima mapeable en la escala 1:250.000.
Son áreas casi o totalmente desprovistas de vegetación, presentes sobre afloramientos rocosos, nieves perpetuas, campos de dunas y playas, pendientes muy escarpadas y salinas.
Formación vegetal natural, generalmente pluriestradificada, en la cual predominan formas de vida arboreas, de por lo menos cinco metros de altura y cuyo dosel presenta una cobertura de cierto grado de densidad
Comparison and attribution of the FRA classes have been possible through an accurate analysis of the vegetation descriptions given by the sources.
Methodologies of classification used by the countries are very different. Some of them have produced very detailed description based on several parameters as: altitude level, annual average of temperatures and rainfalls, etc. Others have produced slight descriptions not enough significant for the attribution to the belonging class.
The problem has been solved with the help of photographic material. In fact, in some cases it has been possible to individualize a vegetation type from a comparison between the photos and the description.
Looking at the results of the attribution of the FRA classes in Annex, is possible to see that “Broadleaved closed forests” contains about the 50% of the vegetation types found. This means that that the class is quite big and could be interesting to create a further distinction following different parameters.
The parameters to be considered could be:
altitude level : The 8 countries show in fact, a great variability, since 0 to over 4000 meters over the sea level. An idea could be to create a subdivision following natural changing in vegetation with the altitude. Or fix different belts of,for example, 1000 meters in thickness.
annual average of temperatures and rainfalls: the same subdivision can be made looking at this two parameters and the change in vegetation because of one, or both of them.
topography: the state of the ground (plan, ondulated,…) can have influence in the dynamics of colonization of the vegetation and can allow the growth of some species instead of others.
climax formations: typical formation of different countries can be aggregated: an example is the “paramo”. It is present in different countries with similar names and the vegetation seems to be same.
density: number of trees per ha.
The same could be said for the “Broadleaved open forests” which contain a considerable number of vegetation types.
A particular mention has to be made on the “mosaics” of vegetation. In fact, into the “open forest”, we can find different types of “tree savannah”: in some cases they are not only gramineous layer with scattered trees, but patches of gramineous layer and gallery wood (which belongs to the “closed forest” class!). This mosaics are characteristics of the fluvial lowlands along the big rivers. They are typical only because they exist together in this structure. It seems that they are not well represented by the FRA classification. The vegetation types made of a mixture of two different FRA classes, forming a typical landscape, should have a special class of belonging.
An other example of mosaic is the “Agroecosistema basal fragmentado” (Colombia): it has been classified as a “Broadleaved closed forest”, although it is a patches of both dense wood and increasing agricultural land!
Our job could not go ahead due to the lack of detailed reports that did not allow us to follow the scheme provided by FRA Terms and Definitions. It would be necessary to have more time to search and collect information about the parameters that we have mentioned, using others reliable sources.
The collection and the analysis of vegetation types have been possible through the creation of a database that has the primary objective to briefly resume all the information. The fields considered for our interests were:
a) country
b) vegetation type (only the name)
c) FAO codes (both, old and new code)
d) FRA class code.
The main idea was to have a scheme to easily compare different description and to combine a new code for a further subdivision of the FRA classes, following the proposals seen above. Having more time to complete the collection of data (photos or descriptions), an other goal was to create an archives which links each vegetation type description with its photo, previously collected from books or web sites.
