Climatic conditions are basic factor to induce optimal growing of crops and so is their spatial distribution in the world. The elements of climate are key factors that induce the success or failure of cultivated crops [12] [13] [14] [15].

Basic agroecological information of the state of Chiapas was reviewed in order to determine the potential areas for Cedrela odorata (L) and Swietenia macrophylla King under rainfed conditions. When all agroecological soil and climate variables interacted properly, in a specific area, the zone was classified as a high potential one whilst when variables interacted properly but with some limitations the area was classified as sub-optimal one. When all factors were not properly, at all, the areas were unsuitable for both forest trees.

The agroecological requirements of cedar and mahogany were determined by consulting the bibliography, databases and expert knowledge. In Table 1 are shown all agroecological variables such as: soil type (texture, depth, pH, drainage), average annual temperature, altitudes and slopes, among others which were considered to regionalize the state into different potential production areas.

In order to process and analyze the information, Arc/View version 3.3 software was used. This is a program developed by the American company ESRI from which georeferenced data can be represented and the characteristics and distribution patterns of these data can be analyzed and eventually reported [16].

All activity in Arc/View occurs within the project, as a set of linked documents workable during the sessions. Projects can contain five types of documents such as: views, tables, charts, layouts (or printouts) and scripts. Windows can display names of all documents contained in Arc/View Project, organizing and storing the status of all of them; and the appearance of Windows can be easily modified.

The Project information is stored in a file ASCII format and always with extension *. apr. The Arc/View was used as a mainly vector map generator and the processing was performed in Arc/View 3.3 in order to carry out the intersection process of all variables with the purpose to generate areas of high and medium potential and unsuitable zones.

Vector maps are mainly generated through cartographic intersections between polygons, and potential classes are described and maintained at each intersection process. The final map provides information of all intercepted variables. These maps are more representative than the raster models because of their accuracy since the surface is estimated by polygonal processes (Figure 1).

Once the forest trees requirements were properly identified, the cartographic intersections were carried out to regionalize and locate the optimal and suboptimal areas for of Cedrela odorata (L) and Swietenia macrophylla King cultivation.

The geographical distribution of cedar is scattered from the Atlantic to the Pacific ocean; on the Gulf of Mexico it is located in the south of Tamaulipas, southeast of San Luis Potosí, the region of the Huastecas, Veracruz, Tabasco and the Yucatan Peninsula; in the Pacific it is distributed from Sinaloa to Chiapas [17] [18]. While Mahogany is found in the states of Oaxaca, Veracruz, Tabasco and in the Yucatán Peninsula [19].

Currently, in the state of Chiapas it is reported the existence of more than 16 thousand hectares of Commercial Forest Plantations [20]. According to the results, it was determined that in rainfed areas, opened to cultivation, there are 428 thousand hectares of Medium Potential and 81 thousand hectares of High Potential suitable for cedar cultivation whilst for Mahogany there are 91 thousand hectares of High Potential and 629 thousand hectares of Medium Potential (Figure 2).

This surface far exceeds the current reported surface; and therefore, there is a great possibility to increase commercial plantations of Cedar and Mahogany in high and medium potential areas. This study also confirmed that as for Cedar there are 51 municipalities with high productive potential areas and 82 with medium potential as is shown in Figure 3. The same figure shows that for Mahogany there are 40 and 93 municipalities with high and medium potential areas respectively.

Cedar (Cedrela odorata) is the second highly commercially valuable forest species after mahogany. Although the high and medium productive potential areas were determined to be in 51 and 82 municipalities respectively, the most outstanding ones, because of having the largest areas, are the next to be mentioned.

In Figure 4 the distribution of all high and medium potential areas, through the state, are being shown.

The outstanding municipalities with high potential areas in the North are: Catazajá, Palenque and La Libertad. From west to east, the outstanding ones are: Ocozocoautla de Espinosa, Tecpatán, Jiquipilas, Cintalapa, Hhuitiupan, Simojovel, Pantelhó, Chenalhó, Chalchiuitán and San Andrés Duraznal; whilst in the south part are: Ocosingo, Maravilla Tenejapa, Las Margaritas, Amatenango de la Frontera, La Concordia, Villa Corzo, Angel Albino Corzo, Chicomuselo, Tonalá, Pijijiapan and Mapstepec.

The Medium Potential areas were located in most of the geography of the state, standing out municipalities such as: Jiquipilas, Cintalapa, Las Margaritas, Amatenango de la Frontera, La Concordia, Villa Corzo, Chicomuselo, Villaflores, Motozintla, Mazapa de Madero, La Grendeza, Bejucal de Ocampo, Bella Vista, Frontera Comalapa, La Trinitaria, Chiapilla, San Lucas, Nicolas Ruíz, Totolapa, among others with smaller surface area.

Chiapas has adequate conditions for Cedar forest plantations in most of the State. Its climate is warm-humid with rainfall variations [21]; the annual average pluvial precipitation is 3087 mm. The temperature reaches a lowest 9.5˚C and during the summer it ranges from 34˚C to 36˚C. The land is very rugged, mountainous, and heights ranging from sea level to four thousand five hundred meters above sea level [22].

Mahogany is the most important timber species in the country's forest industry [17] [23] [24] [25] [26] and it is among the group of precious tropical species highly used in Mexico [19]. Regardless of the large number of productive municipalities, as in the case of Cedar, just the most outstanding ones are mentioned. Those with High Potential areas are: Ocozocoautla de Espinosa, Palenque, Huitiupán, Simojovel and Sabanilla; however, the largest areas were classified as Medium Potential ones, all related to the complex relief of the state and scattered as shown in Figure 5.

Chiapas has 71.03% of its topography ranging from 0 to 1000 meters above sea level and confined the largest Medium Potential areas mainly located in the municipalities of Mapstepec, Pijijiapán, Tonalá, Catazaja, Salto de Agua, Palenque, Cintalapa, Jiquipilas, Villaflores, Villa Corzo and La Concordia.