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The Forest Map of Spain 1:200,000. Methodology and analysis of general results - page 8 / 16

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The Forest Map of Spain 1:200,000

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with an unique layer represent the highest maturity in many Halohydrophill sites.

Not all vegetation patches within a type domain can reach the maximum EL, as there are natural factors which do not allow that (slope inclination, soil charac- teristics and depth etc.). This is one of the reasons why many pine forests outside Taiga-like and Hyperxerophile domains may represent the highest maturity possible despite they do not reach the maximum value (9) in their general area. Similar cases could also be found in highly degraded areas.

most general categories have been rejoined in the par- ticular cases of the structure and the plant community due to the long list of units used on the map. The values are expressed in percentages of the total surveyed area or of the area of each Type.

The objective of the analysis to be presented is not to carry out a brief description of the Spanish vege- tation, but to show its general state from the point of view of each studied characteristic (CST, height, EL, and community).

Results

The floristic component

This fourth component uses the concept of plant community (Ruiz de la Torre, 1977, 1981, 1990) as of a sample of vegetation patch with homogeneous com- position and structure. This sense is similar to the meaning given by other authors such as Guinochet (1973) and Küchler (1988) for phytocenose.

Communities are mainly described by their dominant species (Ruiz de la Torre, 1977), either trees, scrubs of different heights or less often herbaceous species. The concept is the most appropriate to refer to non abstract groups and when the study addresses a wide range of technicians and scientists, large areas are studied and there is a limited amount of time to develop the work.

In order to express in the MFE2C the vast existing diversity of plant covers, more than 900 different codes have been adopted for dominant species or mixed commu- nities, often combined among themselves giving therefore a very large number of expressions of floristic composi- tion.The specification of the most abundant communities exceed the aims of this paper; many descriptions, though, can be found in Ruiz de la Torre (1981, 1990). Communities can be qualified as monospecific, oligo- specific and multispecific. Monospecific ones are repre- sented by a dominant species (for example, the community of Cistus ladanifer). Oligospecific, by 2 or 3 species (i.e., pine forests of Pinus pinaster and Pinus pinea). Multispecific ones are often expressed by general terms: fraga (mixed broadleaf deciduous forests in Galicia, mixed thorn scrub, mancha and garriga (mediterranean termphile shrublands), mixed heathlands etc.

Material and Methods

Data shown below have been obtained from a group of queries and refinement of the MF2C database. The

The surveyed area in the MF2C with non agricultu- ral plant communities in peninsular Spain plus the Balearic Islands is 26,552,231.46 ha (53.3%) and 559,207 ha (72.1%) in the Canary Islands. The number of forest patches studied is 108,427 and 3,458, respec- tively; so far, the agricultural lands undergoing any type of forest inclusions are not considered in this analysis.

The spatial percentages related to the surveyed area of each CST in peninsular Spain and the Balearic Islands are shown in Figure 8. It can be deduced that the total area supporting forest zonal types is almost 92% of its whole. Sclerophyll (34.98%), followed by Subsclerophyll

ype (32.95%), occupies the largest area; the third ype represented is Deciduous with 16.97%; High Mountain, Taiga-like and Hyperxerophile Types mean 1.13, 4.06 and 3.11%, respectively. The Intrazonal vegetations altogether represent 6.80%, which includes those which occur on gypsum (chalky) soil, salty wetlands, river bank forests, estuaries, lakes, rocky areas, karst, etc.

In the Canary Islands, percentages occupied by the CST are shown in Figure 9. The zonal forested types represent 28.39%, with 11.69% of Alize tradewinds forests Type and 16.70% of Extra Alize tradewinds fo- rests Type. The largest type within these islands is Below potential forest belt Type, with almost 33%; the intrazonal types, in this case generally non arboreous, cover a conspicuous area (29.9%), mostly located in Lanzarote and Fuerteventura islands.

Dealing with the main vertical structural categories (see Fig. 6), it can be derived that, in zonal peninsular Spain, the arboreous types reach almost 40% of the considered area, while the non arboreous ones make up the remaining 60% (Table 1). An important part is occupied by subarboreous plant covers (21.59%). In non forested lands, prevailing communities are those

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