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Revista mexicana de ciencias agrícolas

versão impressa ISSN 2007-0934

Rev. Mex. Cienc. Agríc vol.7 spe 16 Texcoco Mai./Jun. 2016

 

Articles

Native trees with dendroenergy potential for the design of agroforestry technologies in Tepalcingo, Morelos

César Augusto Yescas Albarrán1 

Artemio Cruz León2  * 

Miguel Uribe Gómez2 

Alejandro Lara Bueno2 

Ranferi Maldonado Torres2 

1Posgrado en Ciencias Agroforestería para el Desarrollo Sostenible-Universidad Autónoma Chapingo. Carretera. México-Texcoco, km 38.5, Chapingo, Texcoco. C. P.56230, Estado de México. Tel: 595 952 540. (camilo303@hotmail.com).

2Universidad Autónoma Chapingo. Carretera. México-Texcoco, km 38.5, Chapingo, Texcoco. C. P. 56230, Estado de México. Tel: 595 952 1540. (etnoagronomia1@gmail.com; migueluribe123@gmail.com; alarab_11@hotmail.com).


Abstract

The aim of this research is to identify native trees with dendroenergy potential serve to design agroforestry technologies in the common Los Sauces, municipality of Tepalcingo, Morelos. It is systematizing traditional knowledge of species and harvesting process, for which we start from the assumption that in the common Los Sauces there are tree species dendroenergy potential for designing agroforestry technologies and these are the ones most demand among consumers. According to the quality of the wood species selected are: tepehuaje (Lysiloma acapulcense), tlahuitol (Lysiloma divaricata), tecolhuixtle (Mimosa benthamii), brazilwood (Haematoxylum brasiletto), licorice (Eysenhardtia polystachya) and white cubata (Acacia pennatula). Regarding agroforestry technologies for the common Los Sauces, scattered trees in pastures and hedgerows were proposed because land use is associated with livestock and fuelwood needs can be covered with trees arranged in these fields. The methodology consisted of interviews with housewives and their husbands and sons in charge of chopping wood, with which the most sought-native species were located, to select the greatest potential for integration into agroforestry technologies. Its heat of combustion variables, ash, moisture, density and germination protocol were determined to measure the quality of firewood.

Keywords: agroforestry; dendroenergy; tropical dry forest; wood quality; wood

Resumen

El objetivo de la presente investigación es identificar árboles nativos con potencial dendroenergético que sirvan para diseñar tecnologías agroforestales en el ejido Los Sauces, municipio de Tepalcingo, Morelos. Se trata de sistematizar el conocimiento tradicional de las especies y su proceso de aprovechamiento, para lo cual partimos de la hipótesis de que en el ejido Los Sauces existen especies arbóreas con potencial dendroenergético para el diseño de tecnologías agroforestales y que estas son las que tienen mayor demanda entre los consumidores. De acuerdo a la calidad de la leña las especies seleccionadas son las siguientes: tepehuaje (Lysiloma acapulcense), tlahuitol (Lysiloma divaricata), tecolhuixtle (Mimosa benthamii), palo Brasil (Haematoxylum brasiletto), palo dulce (Eysenhardtia polystachya) y cubata blanca (Acacia pennatula). Respecto a las tecnologías agroforestales para el ejido Los Sauces, se propusieron árboles dispersos en potreros y cercos vivos, ya que el uso del suelo se asocia con la ganadería y las necesidades de leña pueden ser cubiertas con los árboles dispuestos en estos campos. La metodología consistió en entrevistas a amas de casa y sus esposos e hijos encargados de cortar la leña, con las cuales se ubicaron las especies nativas más demandadas, para seleccionar las de mayor potencial de inserción en tecnologías agroforestales. Se determinaron sus variables de calor de combustión, cenizas, humedad, densidad y protocolo de germinación para medir la calidad de la leña.

Palabras clave: agroforestería; bosque tropical caducifolio; calidad de la madera; dendroenergía; leña

Introduction

The dendroenergy (wood energy) is all the energy obtained from solid biofuels, liquid or gaseous primary or secondary derived from forests, forest plantations, urban woodlands and trees in general. It represents the energy produced after combustion of wood fuel, such as firewood, charcoal, pallets, briquettes, etc., and corresponds to the net calorific value of the fuel (Guyat, 2004).

The extraction and use of firewood negatively impact forest resources, either for self-consumption or sale (Ortiz, 2009). Most users of firewood in Mexico is concentrated in the states of Chiapas, Guanajuato, Guerrero, Hidalgo, Michoacán, Morelos, Oaxaca, Puebla, Quintana Roo, Tabasco, Veracruz and Yucatán (Díaz, 2000), with an annual consumption of 38 million cubic meters (CONAFOR, 2007).

Firewood extraction is a very present activity in the communities of Morelos. There are 45 species used for this purpose, corresponding to 7.5% of the useful plants, but the species most in demand are: tepemezquite or tlahuitol (Lysiloma divaricata), brazilwood (Haematoxylum brasiletto), licorice (Eysenhardtia polystachya) and tecolhuixtle (Mimosa benthamii) (Atender, 2008).

The community Los Sauces, municipality of Tepalcingo, is located in the buffer zone of the Biósfera de la Sierra de Huautla (Rebiosh). It is located in the state of Morelos, between latitudes N 18° 33' 08" and 18° 37' 00" and lengths W 98° 58' and 98° 55', at an altitude of 1 216 m. The type of vegetation is tropical dry forest (Figure 1).

Figure 1 Macrolocation the common Los Sauces, Tepalcingo, Morelos. 

Some species representative of the community are Guazuma ulmifolia (cuahulote) and other amates and cuajiotes. There are also several secondary associations formed mainly by thorny bushes of the family Fabaceae. The climate is warm humid with rains in summer, with an annual rainfall of between 800 and 1 000 mm and an average annual temperature of 22 °C (INEGI, 2011).

The main economic activities in the common of Los Sauces are agriculture, livestock, collecting resins, picking fruit, mezcal production, collection of medicinal plants and firewood extraction; the latter is used mainly for cooking food and for sale between neighboring or nearby villages in order to achieve extraordinary income in the low water season when tasks decreases in other activities. Firewood, as one of the resources used as fuel for most people, is in high demand it represents pressure on plant resources and causes decrease in the availability of tree species with this use, a situation that intensifies with increase of the population.

Dendroenergy

The wood, besides being a renewable resource, is environmentally acceptable, since when used as fuel does not increase the concentration of carbon dioxide in the atmosphere to the level of fossil fuels, making energy production from biomass forestry is called clean dendro energy (Guyat et al., 2004). Organic compounds are mainly wood cellulose, hemicellulose and lignin. A small fraction corresponds to resins.

In the combustion process it is primarily lignin becomes fixed carbon. The other compounds are release das volatiles, whereby the burning of this fraction is carried out similar to those of a gaseous fuel reactions. In comparison, this gaseous fraction has about 40% higher than fixed solid carbon fraction calorific value. Wood-free water has a lower calorific value of 4 400 kcal kg3. This value is reduced to approximately 3 500 kcal kg air-dried wood with 20% residual moisture. With higher humidity, further it reduces the heating value (Drake et al., 2002).

Calorific value is the amount of heat generated by complete combustion of a specific mass of carbon in the presence of oxygen. The heating value represents the energy of combustion of carbon and hydrogen of organic matter and pyritic sulfur and partly organic (Vásquez and Herrera, 2006). Otero et al. (2004) define the quality of wood as a set of features that can be differentiated as equal, better or worse than others of its kind.

The density is probably the most studied variable and is most often used to determine the quality of the wood (Zhang, 1997) indicator. It is the weight of the unit volume of wood and depend largely on humidity. Conventionally the apparent wood density is taken less than 20% moisture. Bruzos (2009) classifies wood by its apparent density:

Very heavy: bulk density greater than 1 kg dm-3

Heavy: it is between 0.8 and 1 kg dm-3

Moderately heavy: between 0.5 and 0.8 kg dm-3

Light: if less than 0.5 kg dm-3

Situation of fuelwood in Morelos

In the municipalities of Amacuzac, Ayala, Coatlán del Río, Jojutla, Mazatepec, Puente de Ixtla, Tepalcingo, Tetecala, Tlaltizapán and Tlaquiltenango there are 49 033 occupied dwellings of which 60% use wood as a fuel source, with an average daily consumption 4 kg per household, which makes a total of 159 905.6 kg of firewood (160 tons per day), totaling 58 400 tons per year (Atender, 2008).

Monroy and Monroy (2003) recorded 18 tree species worth of energy use, same as the inhabitants of rural communities of Morelos classified, based on its combustion characteristics and hardness when cutting, as softwoods or mushy and hard or solid, traits that determine the ultimate fate of the wood, the total timber extracted and sold. Approximately 90% of the wood is obtained from a legume popularly known as tlahuitol (Lysiloma divaricata).

The firewood is the most widely used fuel in the Sierra de Huautla for food processing. Activity fire wood extraction is done both for self-consumption and for trade in nearby cities, for making bread. This practice is generally exercised by the householders. The species most in demand (preferred by the little smoke produced) are: brazilwood (Haematoxylum brasiletto), tepehuaje (Lysiloma acapulcense), tepemezquite or tlahuitol (Lysiloma divaricata), licorice (Eysenhardtia polystachya) and tecolhuixtle (Mimosa benthamii) (Maldonado, 1997).

Materials and methods

Local knowledge is understood as the body of knowledge, beliefs, customs and perceptions unique to a culture or a given society (Monu, 1997; Grenier, 1998). Generally, in the case of that knowledge linked to natural resources, derived from everyday observations and experimentation with ways of life, production systems and natural ecosystems (Mora, 2007).

Based on a series of interviews conducted previously by students of the 2010-2011 generation of expertise in agroforestry, for a more detailed local knowledge about the species most commonly used as firewood (dendroenergetic) questionnaire applied to 25 he was prepared % of families living in the community of Los Sauces. There are two types of interviews, one for woodcutters and one for housewives, because these groups do not have the same vision for firewood.

Once you know the list of species most commonly of wood energy use, through interviews, we proceeded to the collection of seed and logs of wood to make determinations protocol germination, heat of combustion, ash, density and moisture, taking these samples from trees with the best features.

According to the method of Kollman (1959), for obtaining density a piece of wood species was collected and three cubes of approximately 2 x 2 cm were removed, which were dried in the open for 24 hours, then spent a desiccator for 24 h to remove the air in the timber and allow the entry of water were then weighed using an electronic balance; to obtain the volume, the cubes were immersed in a glass of water with the aid of a dissecting needle and weighed to obtain the volume difference.

After this, the cubes were immersed in water for seven days, once after that time, they were weighed and put in an oven at 103 °C for four days to remove water contained in them, from the fourth day began weighing daily until no weight change these, then calculate the volume by the method of glass with water. Once taken data volume and dry weight basic density and moisture content were obtained.

The heat of combustion was determined by the method described by Soto and Núñez (2008) which consisted of grinding a piece of stem of each species until a gram of sample. 0.5 g of each species of wood sample was weighed, with two repeats (Figure 2).

Figure 2 Ground sample of the species studied and weighing them. 

The sample was placed in heavy cover support of the combustion chamber, placing 10 cm wire to initiate combustion (Figure 3).

Figure 3 Placing the wire and mounting the sample in the holder. 

This support was set at the oxygen pump, which was inserted by sealing oxygen (25 to 30 atmospheres).

Parallel to this process, two liters of water were heated to a temperature of 30 °C which were added into the cuvette of isoperibolic calorimeter, with hot water; the bomb was placed inside the calorimeter and sample data were introduced to computer software for reading the result.

After taking the data, the calorimeter was uncovered by removing the pump with pliers then open to the weather as it contains oxygen pressure; once opened wire unburned removed, the interior of the pump, the holder and cover with distilled water rinsed by pouring this solution into an Erlenmeyer f lask and then titrate with sodium carbonate, this in order to know whether there presence of acid. To obtain these two variables laboratory procedures proposed by Sosa (1979) were used. Statistical analysis was performed using the GLM procedure of SAS (2002). The tests compared with 0.05 mean statistical significance were performed using the Tukey test (Steel et al., 1997)

The methodology for the development of treatments germination was taken of the work that used the INE (2007) for tree seeds deciduous forest. Once the pregerminative treatment applied to seeds in trays were seeded styrofoam cavities 200, using as substrate peat moss to subsequently obtain the germination percentage and days of seedling emergence. To structure the design and agroforestry technologies proposed diagnostic methodology and design described by Raintree (1987) was used, which basically consists of five stages: pre-diagnosis, diagnosis, design and evaluation, planning and implementation.

Results

According to the results of the interviews conducted in the community of Los Sauces, there is a process of replacement of fuel wood for home, LP is the substitute fuel, which still fails to be established. Interests and vision around the wood of housewives is different from the lumberjacks, since the latter prefer the easy species to cut, linear chappy and quick drying, while women are inclined species smokeless and, depending on the needs, sometimes they require species that are slow and steady fire, as in the case of cooked beans; or, firewood rapid fire, "caught", which is required to make “tortillas”.

Household fuels are a necessity both in urban and rural communities, which are used for food preparation, but also to temper the water used for personal hygiene. Firewood is a proper fuel in rural communities to be replaced by fossil fuels to the extent that people have access to the latter and the necessary equipment and facilities for use.

The firewood in communities is a resource that is handled appropriately by rural dwellers, cut and processed for use, devices for use are very basic and are reduced to simple instrumental that the producers themselves made while the use of fossil fuels requires equipment and facilities to be acquired in the cities and are usually expensive and rarely available to the budget of marginalized farmers.

In addition, the value of fuel requires payment in cash, limiting situation for these people, so in the town of Los Sauces 40% of households use only firewood, do not have equipment for fossil fuel called "gas LP" which It corresponds to butane, sold in 20 kg cylinders at a cost of 235 pesos, while 60% of households combined firewood and "gas", which means a transition in relation to fuels. Despite this, the use of "gas" is sporadic, but possession of stoves, water heaters and grills, plus an enclosed space for kitchen and bathrooms, are part of the social prestige in the village, it represents to the family community economic capacity, many times associated with the migration of children abroad.

However,the culture of use of fire wood is rooted in the "taste" of housewives by the "best taste" of food or by obtaining simmered or "taken" necessary for cooking certain dishes therefore 90% of them prefer the wood. There are opinions on the matter: "no [would not stop cooking with firewood] because that makes it one tortillas and taste better, and beans also cook with firewood nicer" (Verónica, 49 years).

It also identifies with the culture of the older generations and even pejoratively calls the new: "for there [would not stop cooking with firewood] because i am old, and now girls [young women] are loose, too lazy turn the stove" (Gregoria, 60 years).

They establish the conditions in which the change is justified "gas stove itself is necessary for when you get sick at night, a quick tea on the stove, because in one of wood [stove] just do not burn the fire, and as not, and that's more a stove" (Victoria, 38 years). "The gas we use when, in the rainy season, the wood is wet but I like to use firewood because the food is cooked better" (Janet, 30 years).

The amount of fire wood used depends on the number of family members, small use only one to two loads per month, while in big can reach six. Highlights the fact that 90% of respondents are in the first case. Efficiency in the use of firewood is a concern of government programs, whose implementation has resulted in about 50% of families have saving stoves.

The dendroenergetic species possess characteristics associated with their use as firewood. Housewives have preferences according to the type of fire they get from each of them, as shown in Table 1.

Table 1 Species dendroenergetic, fuel characteristics, frequency of use and drying time. 

Fuente: elaboración con información de campo.

In contrast, wood burning is preferred to prepare fast foods that do not require to be long on the stove, like tortillas, in this case white cubata is the one with that feature. It highlights the preference of species that do not produce smoke or minimum. Also to reduce smoke emission drying of wood to be used in the stove is heading, you can burn with humidity however smoke emission is very evident.

For them, the species most in demand are the tlahuitol, brazilwood and tepehuaje, and because the size allows obtaining greater amount of wood per tree compared to any other species. On the other hand has white cubata, which has branches and stems rights. This, says Margarito lumberjack, 60 years old, "is very easy to cut with an ax and you cut a branch, not to cut brazilwood is very hard and the wood [stringy bark] entangles". The ease of cutting and acceptance of buyers led to the decline of this species to a near disappearance situation, which should be considered strategies rational use of white cubata.

The species used for firewood also have uses as fodder, timber,medicine,hedgerows and shade. This work confirms what Maldonado (1997) mentions about the species used as firewood in the the Biósfera de la Sierra de Huautla (Rebiosh), which are the tlahuitol, tepehuaje, tecolhuixtle, brazilwood and sweet stick with characteristic to produce a minimum amount of smoke.

Criteria for the quality of dendroenergetic species

The heat of combustion is the release of energy as heat, which causes food can cook. Statistical analysis showed that at least one treatment is different, using the Tukey test (p≤ 0.05) three groups are obtained in the list of species wood energy, where the tecolhuixtle and tepehuaje have the heat of combustion higher (4 490 and 4 429 cal g-1 respectively).

Drake et al (2002) mention that the free firewood water has a lower heating value of up to 4 400 cal g-1. In laboratory data were obtained, the above species have a value above the mentioned by the author and the following four species are below.

Analyzing the results obtained on the use of wood energy species and laboratory results, it is observed that the tepehuaje ranks second in amount of heat of combustion and why the frequency of use among the families of the common of Los Sauces explained because they know this information empirically. In the case of tecolhuixtle, it uses as wood energy species has declined by low stocks of copies in the region, even knowing that the wood is of good quality.

Discussion

Sosa (1979) states that higher ash less amount of organic matter and higher heat of combustion (Bravo, 1989), the organics responsible for the amount of combustion heat. Using the correlation between the data obtained from combustion heat and ash, tepehuaje and tlahuitol meet the rule, although the second produces a little ash.

Statistically analyzing the results obtain at least one treatment is different, using the Tukey test (p≤ 0.05) have four groups that exist where tlahuitol and tepehuaje produce the least amount of ashes (1.86 and 2.31% respectively), counterparty have the highest amount of organic matter (88.14 and 87.69% respectively). Here are other features that are corroborated based on the information obtained through interviews (local knowledge), since the ashes produce smoke and this has more than 200 chemical compounds, most of them toxic inhalants with a smaller diameter to 10 microns, causing breathing problems (Junemann and Legarreta, 2007).

Restrepo et al. (1983) mention "that the analysis of the composition of wood smoke has shown that it is a suspension of small particles in hot air and other gases resulting from incomplete combustion. The gases are variable but always contains carbon monoxide and carbon dioxide; if sulfur, whether in small quantities, sulfur dioxide, tar vapors and/ or unsaturated hydrocarbons occurs. The carbon particles are coated with combustible materials such as organic acids and aldehydes ".

The statistically analyzing the results we obtain that at least one treatment is different, using the Tukey test (p≤ 0.05) note that there are five groups where tepehuaje and tlahuitol have the lowest moisture content (6.36 and 6.96% respectively). Comparing the qualitative data (local knowledge) with laboratory, we get that wood energy species that they mention with more moisture are the same, this could be because when species were collected, they already had a week have been cut.

The dendroenergetic density species is the weight of the unit volume of wood and depends largely moisture (Bruzos, 2009); Otero et al. (2004) mention that greater density greater combustion heat; correlating data density heat of combustion and the rule is not met at all since the brazilwood and sweet stick rank first with respect to heat and combustion are in the second group. Statistically analyzing the data reveals that at least one treatment is different, using the Tukey test (p≤ 0.05) we have that there are four groups and the brazilwood and licorice are those with the highest density (0.81 and 0.78% respectively). Zhang (1997) mentions that the density has more to do with the quality of the wood which is corroborated by the information provided by the people in the community, which ensures that the hardest to cut trees are brazilwood, tlahuitol, sweet stick, tecolhuixtle, tepehuaje and white cubata.

The species that were collected seed licorice, white cubata and tepehuaje, using two treatments according to the recommendation of the INE (2007); which he was used to immerse licorice seeds for one minute in hot water at 50 °C obtaining a germination rate of 80%; they began to emerge seedlings six days after planting. The INE (2007) scored 60% seed germination, this is because the storage time decreases seed viability thereof (Arriaga et al., 1994); which he was used two years in those conditions, in the case of this work seeds having three months of storage were used.

For white cubata and tepehuaje treatment and sanding until change color, thinner seed coat was applied; 55% germination in the first case and 60% in the second were obtained; time of seedling emergence was 7 and 4 days respectively; comparing the results with the INE (2007), 90% of seed germination and seedling emergence five days was obtained; This is possibly because tepehuaje seeds and cubata sanded more damaging the embryo.

Conclusions

The species most used as firewood in the community Los Sauces are: tlahuitol (Lysiloma divaricata), white cubata (Acacia pennatula), tepehuaje (Lysiloma acapulcense), brazilwood (Haematoxylum brasiletto), licorice (Eysenhardtia polystachya) and tecolhuixtle (Mimosa benthamii).

In Los Sauces there is a process of replacing fuelwood by fossil fuels, however, despite the widespread, these are used sporadically and are perceived as a feature of "social prestige". There are also differences in species preference among housewives and lumberjacks.

Based on the analysis results, the species, in order of importance for their quality, are: tepehuaje (Lysiloma acapulcense), tlahuitol (Lysiloma divaricata), tecolhuixtle (Mimosa benthamii), brazilwood (Haematoxylum brasiletto), licorice (Eysenhardtia polystachya) and white cubata (Acacia pennatula).

The agroforestry technologies proposed for the common Los Sauces, municipality of Tepalcingo, Morelos, are scattered trees in pastures and hedgerows, as land use is associated with livestock and fuelwood needs they can be covered with trees arranged in these fields.

Literatura citada

Alvarado, M. S. V. 2012. Calidad de leña de especies nativas de la Sierra Gorda de Guanajuato y propagación de Arbutus glandulosa. Tesis de maestría, Universidad Autónoma Chapingo, Chapingo (UACH). Chapingo, Estado de México. 66 p. [ Links ]

Arriaga, M. V. V.; Cervantes, G. y Vargas, M. A. 1994. Manual de reforestación con especies nativas: colecta y preservación de las semillas, propagación y manejo de plantas. 1a edición. Facultad de Ciencias. Universidad Nacional Autónoma de México (UNAM), México, D. F. 186 p. [ Links ]

Atender. 2008. Aprovechamiento doméstico y comercial de leña y postería en la selva baja caducifolia del estado de Morelos, Temixco, Morelos. Ed. 65 pp. [ Links ]

Bravo, G. L. R. 1989. Procesos de degradación térmica de la madera. In: Primera reunión nacional sobre Dendroenergía. Chapingo, Estado de México. 348-362 pp. [ Links ]

Bruzos, T. 2009. Propiedades físicas de la madera. Maderas: Ciencia y tecnología. Universidad del Bio, Chile. 11(1):3-18. [ Links ]

Chacón, C. R. y Alfaro, R. J. C. 1990. Neumopatía asociada a la inhalación de humo de leña: Análisis de 11 casos. Servicio de Neumología, Hospital México, San José, Costa Rica. 7 p. [ Links ]

CONAFOR. 2007. Programa Nacional de Dendroenergía Forestal 2007- 2012. 12 p. [ Links ]

Contreras, H. J. R.; Volke, H. V.; Oropeza, M. J. L.; Rodríguez, F. C.; Martínez, S. T. y Martínez, G. A. 2003. Disponibilidad y uso de leña en el municipio de Yanhuitlán, Oaxaca. Terra Latinoam. 21:437-445. [ Links ]

Díaz, R. 2000. Consumo de leña en el sector residencial de México. Evolución histórica y emisiones de CO2. Tesis maestría en Ingeniería (energética), División de Estudios de Posgrado, Facultad de Ingeniería. Universidad Nacional Autónoma de México (UNAM). México, D. F. 113 p. [ Links ]

Drake, F.; Von, B.; Hellwig, M. D. y Mellado, A. 2002. Cadena de consumo de leña. Departamento de Análisis Instrumental. Universidad de Concepción, Colombia. 109 p. [ Links ]

Escobar, O. J. A.; Niños, C. N.; Ramírez, M. C. y Yépez, P. 2009. Diagnóstico participativo del uso y abastecimiento de leña en Chiapas, México. Ra Ximhai. 5(2):201-223. [ Links ]

Grenier, L. 1998. Working with Indigenous knowledge. 1a (Ed.). Centro Internacional de Investigaciones para el Desarrollo. Otawa, Canadá. 115 p. [ Links ]

Guyat, D. M.; Mercadet, P. A. y Padrón, P. R. 2004. La dendroenergía: consideraciones generales. Rev. Forestal Baracoa. 129:136. [ Links ]

INE. 2007. Reforestación productiva con leguminosas nativas, en el ejido de Amapilca, municipio de Alcozauca, Guerrero. SEMARNAT. 732 p. [ Links ]

INEGI. 2011. Anuario estadísticoMorelos 2005. México. http://www.inegi.org.mx/est/contenidos/espanol/sistemas/aee10/estatal/mor/defult.htm. [ Links ]

INIFAP. 2003. Importancia y Prácticas de Sistemas Agroforestales. Desplegable para productores Núm. 2. 2 p. [ Links ]

Jiménez, F. y Muschler, R. 2001. Introducción a la agroforestería. Funciones y aplicaciones de sistemas agroforestales. Módulos de enseñanza agroforestal CATIE/GTZ. 1-24 pp. [ Links ]

Junemann, A. y Legarreta, G. 2007. Inhalación de humo de leña: una causa relevante pero poco reconocida de enfermedad pulmonar obstructiva crónica. División Neumonología. Hospital de Clínicas, Universidad de Buenos Aires. 2:51-57. [ Links ]

Kollman, F. 1959. Tecnología de la madera y sus aplicaciones. Tomo I. Ministerio de Agricultura. Instituto Forestal de Investigaciones y Experiencias y Servicios de la Madera. Madrid, España, 359-447 pp. [ Links ]

López, T. G. 2007. Sistemas agroforestales 8. SAGARPA. Subsecretaría de Desarrollo Rural. Colegio de Postgraduados. Puebla. 8 p. [ Links ]

Maldonado, B. J. 1997. Aprovechamiento de los recursos florísticos de la Sierra de Huautla, Morelos. México. Tesis de maestría. Universidad Nacional Autónoma de México (UNAM), México, D.F.74pp. [ Links ]

Monroy, O. C. y Monroy, R. 2003. Saber popular, alternativa mexicana para conservar el bosque tropical caducifolio. In: XII Congreso Forestal Mundial, Bosques para la Gente, Québec, Canadá. 379 pp. [ Links ]

Monu, E. D. 1997. Farmer participation in research: implications for agricultural development. J. Soc. Develop. Africa. 12(1):53- 66. [ Links ]

Mora, J. 2007. Persistencia, conocimiento local y estrategias de vida en sociedades campesinas. Revista de Estudios Sociales. 29:196. [ Links ]

Otero, D. L. M.; Lobos, B. A.; Vera, S. y Kausel, K. T. 2004. Estudio: generación de antecedentes para la implementación de un Sistema Nacional de Certificación de Leña. CONAMA Región de La Araucanía. Temuco, Colombia. 91 p. [ Links ]

Palomeque, F. E. 2009. Sistema agroforestales. Huehuetan, Chiapas. http://www.monografias.com/trabajos-pdf2/sistemas-agroforestales/sistemas-agroforestales.pdf. [ Links ]

Raintree, J. B. 1987. Diagnosis and design user’s manual. An introduction to Agroforestry diagnosis and design. International Center for Research in Agroforestry. Nairobi, Kenia. 22 p. [ Links ]

Restrepo, J. P.; Reyes, P.; De Ochoa N. y Patiño, E. 1983. Neumoconiosis por inhalación de humo de leña. Acta Médica. Colombia. 8:191-204. [ Links ]

SAGARPA. 2005. Establecimiento y mantenimiento de sistemas agroforestales con cultivos bajo sombra. 8 p. [ Links ]

Sánchez, V. A. y Domínguez, A. F. A. 1989. Principales especies aprovechadas para leña en el Alto Balsas poblano. In: primera reunión nacional sobre Dendroenergía. Chapingo, Estado de México. 137-153 pp. [ Links ]

Sosa, M. E. 1979. Manual de procedimientos analíticos para alimentos de consumo animal. Universidad Autónoma Chapingo (UACH). Chapingo, Estado de México. 115 p. [ Links ]

Soto, G. y Núñez, M. 2008. Fabricación de pellets de carbonilla, usando aserrín de Pinus Radiata. Maderas. Ciencia y tecnología. 10(2):129-137. [ Links ]

Steel, G. D. R.; Torrie, J. H. and Dickey, D. A. 1997. Principles and procedures of statistics: a biometrical approach. The McGraw- Hill Companies, Inc. 637 pp. [ Links ]

Vásquez, S. E. B. y Herrera, B. J. E. 2006. Metodología para la caracterización de combustibles sólidos maderables del área metropolitana del Valle de Aburrá Amva, Colombia. In: Revista Facultad Nacional de Agronomía, Medellín. Universidad Nacional de Colombia. Medellín, Colombia. 59(2):176-198. [ Links ]

Zhang, S. Y. 1997. Wood quality: its definition, impact and implications for value-added timber management and end uses. In timber management to war wood quality and end - product value Zhang, S. Y.; Grosselin, R. and Chauret, G. (Eds.). Procedings of the CTIA/ IUFRO International Wood Quality Workshop Quebec City. Part I. 17-39 pp. [ Links ]

Received: March 2016; Accepted: June 2016

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