Artículo Cíentifico
USES OF NON-LEGUMINOUS TREES IN SILVOPASTORAL SYSTEMS IN THE SOUTH OF THE STATE OF MEXICO
Usos de los árboles no leguminosos en sistemas silvopastoriles del sur del estado de México
Jaime Olivares-Pérez1*, Saúl Rojas-Hernández1, Francisca Avilés-Nova2, Luis M Camacho-Díaz1, Moisés Cipriano-Salazar1, Régulo Jiménez-Guillén3, Fredy Quiroz-Cardozo1
1 Unidad Académica Medicina Veterinaria y Zootecnia, Universidad Autónoma de Guerrero, Carretera Cd. Altamirano - Iguala km 3. Col. Las Querenditas, Pungarabato, Guerrero, México.
2 Centro Universitario de la Universidad Autónoma del Estado de México-Temascaltepec, Estado de México.
3 Instituto Nacional de Investigaciones Agrícolas, Forestales y Pecuarias (INIFAP) Campo Experimental Iguala, Guerrero, México. *Autor de correspondencia: saulrh@hotmail.com
Artículo recibido el 31 de agosto de 2015
Aceptado el 26 de octubre del 2015
ABSTRACT
The objective was to characterize the livestock production units (LPU) and identify the forage importance, uses, and density of non-leguminous trees in silvopastoral systems in the south of the State of México. Sixty-nine surveys were conducted to ascertain the current use of trees; on transects were evaluated their density, abundance and frequency; the diameter at breast height (DBH) and the height (h) of trees were measured metrically. The most important trees with regard to foraging were Guazuma ulmifolia (72.5 %) and Crescentia alata (63.8 %). These treeshad the highest number of uses at seven and nine, respectively. The density of scattered trees and trees used for living fences was highest for G. ulmifolia (4.5 trees ha-1 and one tree per 100 linear m) and C. alata (7.2 trees ha-1 and 0.54 trees per 100 linear m). The DBH for scattered trees was highest for C. alata at 44.4 cm, while in the case ofliving fences it was highest for Ficus glabrata at 114.5 cm. We conclude that the outstanding PU accounting uses,foraging preference, and dasometric characteristics are accounted for by C. alata and G. ulmifolia, which as múltiplepurpose trees can be integrated in silvopastoral systems in the study area.
Keywords: Uses, foraging preference, dasometric characteristics, trees, density
RESUMEN
El objetivo fue caracterizar las Unidades de Producción Pecuaria (UPP), e identificar la importancia forrajera, usos y la densidad de los árboles no leguminosos en los sistemas silvopastoriles del sur del Estado de México.Se realizaron sesenta y nueve encuestas para conocer el uso de los árboles; en transectos se evaluaron su densidad,abundancia y frecuencia; el diámetro a la altura del pecho (DAP), con la altura (h) del árbol se midieron métricamente. Los árboles con mayor importancia forrajera fueron Guazuma ulmifolia (72.5 %) y Crescentia alata (63.8 %); estosmismos árboles presentaron el mayor número de usos con siete y nueve, respectivamente. La densidad de árbolesdispersos y en las cercas vivas fue mayor para G. ulmifolia (4.5 árboles ha-1 y un árbol en 100 m lineales) y C. alata (7.2 árboles ha-1 y 0.54 árboles en 100 m lineales). El DAP en árboles dispersos fue mayor en C. alata con 44.4 cm yen árboles en la cerca viva fue en Ficus glabrata con 114.5 cm. Se concluye que en las UP los árboles más sobresalientes por sus usos, preferencia forrajeras y características dasométricas fueron C. alata y G. ulmifolia, y por ser árboles conusos múltiples, pueden ser integrados a los sistemas silvopastoriles en el área de estudio.
Palabras claves: Usos, preferencia forrajera, características dasométricas, árboles, densidad
INTRODUCTION
Given its edaphic, topographic, and climatic characteristics, México is rich in natural resources, mainly sustained by its diversity of tree species (Palma 2006). In some systems the use of trees as a forage resource is limited, even though it can represent a valuable food source for cattle and wild fauna (Olivares-Perez et al. 2013, Olivares et al. 2013, Rojas-Hernandez et al. 2015). A silvopastoral System is characterized by the interaction of trees, shrubs, grasses and pasture with animáis and soilin time and space (Guerreiro et al. 2015, Olivares-Perez et al. 2011). In any silvopastoral System, the aim is to establish multipurpose trees which should be able to adapt to diverse soil and climate conditions (Reis et al. 2010, Olivares-Perez et al. 2011). Among the required characteristics should be the ability to fix nitrogen, which restoressoil fertility, nutrient recycling, sequestering of carbon dioxide, and support of biodiversity (Nair et al. 2009, 2010, Lorenz and Lal 2014, McGroddy et al. ios2015). Nowadays, it is important to reevaluate traditional knowledge and uses of native species, since these are the basis for their integration in silvopastoral systems. This procedure has been developed in severa I systems where severa I uses ha ve been reported, such as fuel (firewood), wood, forage, human foodstuffs (flowers and fruits), medicine, industrial (dyes and resins), fences (posts and living uefences), and shade for livestock (OI ivares-Pérez et inal. 2011, Leon-Castro et al. 2015).
One way to maintain balance in the ecosystem and preserve plant species is to create technological alternatives that help to increase productivity. One such method is to use non-leguminous trees and shrubs, given the diversity of functions that they can have within tropical production systems and their important role in ruminant feeding (Rojas et al. 2012, 2013, Olivares et al. 2013, Jiménez-Ferrer et al. 2015). The objective of the present study was to identify the foraging importance, uses, and density of non-leguminous trees in silvopastoral systems in the Southern part of the State of México.
MATERIALS AND METHODS
The study was carried out in the communities of Bejucos of Sánchez Colin and Llano Grande inthe municipality of Tejupilco, State of México (18° 45' 30" and 19° 04' 32" north, 99° 59' 07" and 100° 36' 45" west). The climate is tempered sub-humid and semi-warm humid with rains in summer, with a mean annual temperature between 15 and 30 °C, an altitude of 1 340 m, and annual precipitation of 1 014 mm. Soil types are regosol (61.76%), leptosol (22.11 %), cambisol (6.99 %), luvisol (4.22 %), phaeozem (3.34 %) and vertisol (0.7 %) (Prontuario de información geográfica municipal de los Estados Unidos Mexicanos 2009).
Characterization of the production units (PU)
The populations have a census of 83 producers; 69 LPU were characterized, 54 in Bejucos and 15 in Llano Grande. A questionnaire was used in which the following aspects were considered: non-leguminous foraging trees they know, uses and/or benefits they obtain from them, parts consumed by livestock (based on empirical observaron by livestock farmers), place and season of consumption, spatial distribution within the LPU (Harvey and Haber 1999, Sosa et al. 2004).
Diagnosis of diversity, density, frequency, and relative abundance of tree species
Field measurements were taken in 878 ha, integrating six PU. In each of these, four 1 h transects were outlined to identify trees scattered inthe pastures, and four 100 linear m transects weremeasured to count trees in living fences (Camacho 2000). Through visual verification of the transectswe registered the density of scattered species in thepaddocks (trees per ha-1) and in the living fences, and relative frequency (Fr), calculated by dividingthe number of transects where each species wasfound by the total number of transects in the sam-ple.
Dasometric diagnosis
The trees identified in the transects were measured dasometrically to determine diameter at breast height (DBH) and height (h). Five adult trees of each identified species were randomly chosen; their height was measured with a Haglóf elec- isotronic clinometer (HEC) and DBH was measured mwith a tape measure 130 cm from the ground (Camacho 2000, Sosa et al. 2004). For botanical identificaron, the common ñame was registered and branches (stem, leaves, flower and/or fruit) of each species were collected. Identification was períseformed in the botany laboratory of the Temascaltepee University Center of the Autonomous University íssof the State of México, with the use of procedures and identificaron keys described by Pennington and Sarukhan (2005).
Statistical analysis
Relative abundance (Ar) was estimated by dividing the number of individuáis of each tree species by the total number of non-leguminous trees present in each sample area (Camacho 2000). The information on uses, density, relative frequeney, relative abundance, and variables related to the dasometric measurements of the trees were analyzed through descriptive statistics (Steel and Torrie 1988).
RESULTS
Characteristics of the production units
The size of the 69 LPU (6 356.5 ha) varied from 2 to 500 ha. The PU are characterized as follows: meat production (62.3 %), dual-purpose (34.8 %), and sheep-goats (2.90 %). The inventory of the animáis is: 4 273 cows which inelude beef breeds such as the European Swiss, Brahmán, Simmental, Simbrah, Beefmaster and Charoláis; 446 goats with production of creóle breeds and their crosses with Nubians and Boers; and 187 sheep with a majority of Pelibuey breeds and their crosses with Dorper sires. Some 86 % of them supplement in the dry season. The feeding system in the LPU is undergrazing with use of native grasses in 78.7% (4 854.4 ha) of the area devoted to livestock and with induced pastures in 21.3 % (1 315.1 ha) of the remaining surface, with predominance of the following grasses: Andropogon gayanus (1256.6 ha), followed by Cynodon nlemfuensis (23.5ha), Panicum maximun (23.5 ha), mulato hybrid (Brachiaria ruziziensis x Brachiaria brizantha) (10ha), and Brachiaria brizantha (1.5 ha). The predominant foraging crops are maize (471 ha) andsorghum (43 ha); 28 % of these crops are silagedand 72 % used as ground hay to supplement animalfodder. The main labor forcé in the PU is the family(86 %), while over 54 % of the LPU hire temporarylaborers and 52 % use permanent contracts.
Knowledge of the use of the trees in the LPU
Producers have ampie knowledge of the con-sumption of tree species by their animáis; despite this, only 4 % of them mentioned having harvestedfoliage or fruits from the trees to feed their con-fined animáis. Although the trees provide foliageand fruits to feed livestock, only 26 % of the LPUplant trees to reforest and 64 % of the producersmentioned that their animáis consume foliage andfruits in the dry season during grazing. The uses oftrees in the LPU are as shadow (36 % of the surveys highlighted Ficus glabrata, Spondias purpurea, Crescentia alata, Magifera indica, and Guazuma ulmifolia by its greater crown diameter; as livestock forage (42 % of the surveys highlighted G. ulmifolia, C. alata, F. glabrata, and M. indica); and as live fences (29 % of surveys listed G. ulmifolia, C. alata, F. glabrata, Ipomoea murucoides,S. purpurea, and Mastichodendron capiri) (Table 1). Limitations of the trees were singled out asinvasive species in 19 % of the surveys, and treesthat cause economic problems in 7 % of surveysfor I. murucoides and P. guajava for being specieswith high dispersal and seed production that require control practices of their density; The 3 %of livestock farmers mentioned that Licania arborea, Ficus cotinifolia and F. glabrata decreasesthe growth of pastures under the crown diameter.The distribution system of the trees in the LPUwas established as follows: 93 % of the trees infences, 96 % trees scattered in the grasslands, 19% fruit trees, 1.4 % trees in living fences, and55 % shrubbery as part of the original vegetation.
Parts of trees consumed by livestock
The frequency with which the producers mentioned foraging trees and the parts of the trees on which the animáis feed allow them. The experience of livestock farmers, it facilitated to select the species with higher foraging potential. G. ulmifolia and C. alata are the ones that the producers report as having the highest foraging potential. Producers mentioned that the fruits are the morphological component most favored by livestock, which account for 66.7 and 52.2 % of fruits from the aforementioned trees (Table 2).
Uses of trees in production units
Non-leguminous trees, besides being an important source of forage for livestock, have other uses in the LPU. C. alata had nine local uses, especially as shade (62.3 %), living fences (49.3 %), and medicine (52.2 %). G. ulmifolia had seven uses, most importantly as shade (65.2 %), living fences(52.2 %), and firewood (44.9 %). P. guajava, F. glabrata, and S. purpurea had six uses. It is important to mention that seven species are used asmedicinal plants, particularly C. alata and G. ulmifolia (Table 3).
Density, frequency, and abundance of non-leguminous foraging trees
Five native species are reported to be the product of natural regeneration, with a popularon of 291 trees (24 ha) scattered in the grass-lands at a mean density of 12.2 trees ha-1. Thetrees with the highest density were C. alata and G. ulmifolia, with 7.2 and 4.5 trees per ha-1,respectively (Table 3). The most abundant andfrequent species were C. alata (59.1 and 83.3%) and G. ulmifolia (36.8 and 83.3 %), respectively. In the fences, we found 46 trees (2 400 m)with a mean density of 1.75 trees. The specieswith the highest density is G. ulmifolia, making it the most important species in the LPU (Table 4).
Dasometric measurements of non-leguminous trees
In the two silvopastoral systems, scattered trees in pastures and living fences trees, the identified species were C. alata, G. ulmifolia, C. glabrata, F. cotinifolia, and S. purpurea (Table 5). For the scattered trees, the range of diameter at breast 294(DBH) was 30.1 to 44.4 cm, and height was 6.3 to 9.5 m, while for living fence trees it was 28.9 to 117.3 cm DBH and height was 4.9 to 28.0 m (Table 5). The trees that had higher natural regeneration were C. alata and G. ulmifolia in the silvopastoral System of trees scattered in the grasslands with a DBH minor to 1 cm and a total of 50 plantlets for C. alata and 19 plantlets for G. ulmifolia, respectively (Figure 1).
DISCUSSION
The results indícate that in most LPU the animáis feed on the foliage/fruits of the trees inthe field during grazing hours as much as they can, since only 4 % of the producers use a harvest andcarry system with the trees. Similar studies reportthat the number of producers using the foliage andfruits of the trees in a harvest and carry systemto feed livestock is limited (OI iva res- Pe rez et al.2011). Zamora et al. (2001) report differently thatproducers collect the foliage and collect and buy thefruits to feed the animáis when gramineae lose theirnutritious valué, making the fruits and dry leavesthe main forage source. In Colombia, during thedry season, 83 % of producers depend on foragingtrees to feed their livestock, especially those pro-ducing pods and/or fruits (Cajas and Sinclair 2001).Therefore, the use of trees as forage is limited tobrowsing on living fences or trees in the paddock. Itis necessary to train producers in the managementand preservation of tree resources in their LPU tomaximize their use. With regard to the benefitsthat trees have for the LPU, livestock feeding is ofgreat importance (42 %) (Cajas and Sinclair 2001,Guerreiro et al. 2015, Jimenez-Ferrer et al. 2015);however, trees also favor the organic carbón en-try and increased the nutrient content soil (Nair etal. 2009, 2010, Lanna et al. 2010, McGroddi et al. 2015). With regard to the limitations of trees in the LPU, the answers of the producers agree with data reported by Harvey and Haber (1999) in that 45 % of the LPU control tree density beca use 330they produce too much shade and invasive species are eliminated because of their high capacity to regenérate.
Parts of trees consumed by livestock
The higher foraging potential of G. ulmifolia and C. alata (Table 2) coincides with studies carried out in Jamaica and Honduras, where producers prefer to use the foliage and fruits of G. ulmifolia and C. alata with harvest and carry management to feed their livestock (Barrance et al. 2003). The foliage of G. ulmifolia is consumed during the rainy season; however, during the dry season, when the fruitsripen and dehydrate because of the sun, they falloff and are eaten by the livestock (Olivares-Perez etal. 2011). Producer preference for certain speciesdepends on the Services and products that the treeoffers the LPU, which can be implemented and de-veloped in silvopastoral systems (Olivares-Perez etal. 2011). This facilitates the producers becomingparticipants in the technological development oftheir LPU (Pinto et al. 2005).
Use of trees in the production units
Most of the trees identified have múltiple uses and are important components of the natural vegetation in the area, with good adaptationto the local environmental conditions (Table 3).These results coincide with studies performed in other States in the country (México); in Morelos (Solares 2004), Quintana Roo (Sosa et al. 2004) , Tejeda, Veracruz (Couttolenc et al. 2005), Angostillo, Veracruz (Villa et al. 2009), Sierra of Tabasco (Grande et al. 2010), The Limón, Veracruz (Bautista et al. 2011); and in other countries, in Rio Frió, Costa Rica (Villacis et al. 2003), in the Caribbean, Colombia (Cajas and Sinclair 2001), in the Pacific, Costa Rica (Harvey and Haber 1999). This shows that the use of trees in different regions is similar; generally speaking, producers prefer to keep trees that offer more products and Services to the LPU (Esquivel et al. 2011).
Density, frequency, and abundance of non-leguminous trees
Although the study was centered around non-leguminous trees (Table 4), the density coincides with studies done in Cañas, Costa Rica (Esquivel et al. 2011) and in the State of México (Olivares-Perez et al. 2011). The low density of some trees in the grasslands and living fences may be to the result osof damage and the mortality of plantlets, caused by the livestock in the paddock, the application of herbicides, and weeding done by the producers in their regular control practices (Olivares-Perez et al. 2011, Guerreiro et al. 2015). The predominant species show characteristics that facilítate their natural regeneration, abundant seed production and the ability to be spread by livestock after consumption. These aspects are important for the natural repopulation of these species (Villacis et al. 2003). The use of trees in living fences is beginning to become more important because of their durability andthe economic saving to be made, especially in areas where the original vegetation has been disturbed by the múltiple Services provided by the trees (Olivares-Perez et al. 2011, Jiménez et al. 2015).
Non-leguminous foraging trees are found scattered in the grasslands and in living fences, and they play an important role in the preservation of biodiversity in silvopastoral systems by preserving habitats for wild animáis, important for the natural spreading of tree seeds for natural regeneration(Olivares-Pérez et al. 2011, Gonzalez-Valdivia etal. 2014). At the same time, they act as biologicalcorridors (Mastrangelo and Gavin 2014, Talamo etal. 2015).
Dasometric measurements of non-leguminous trees scattered in the grasslands and in livingfences
The observed DBH rangesof30.1 (+ ES12.3) to 44.4cm (+ ES 15.0) constitute an indicator ofthe low regeneration rate of the trees scattered inthe grasslands and in living fences (Table 5). Notrees were found with < 10 cm DBH for F. glabrata,F. cotinifolia, and S. purpurea (Figure 1). Studiesperformed in the dry tropics report DBH similar tothose in this study (Tovar and Ibrahim 2010, Esquivel et al. 2011). Though natural regenerationof species was observed in the study, the livestockfarmers control the density of the trees in theirprairies. The high variation in DBH of some treesscattered in the grasslands and in living fences maybe related to the handling practices of the producersregarding their grasslands and living fences (use ofherbicides, frequency of trimming and weeding) thatcause changes in growth (Tovar and Ibrahim 2010,Esquivel et al. 2011). This hinders the developmentof the trees and their production of abundant fruitsfor their natural regeneration. The above indicatesthat with time some desirable species in producers’systems might have low natural regeneration and,consequently, may be lost (Esquivel et al. 2011).
CONCLUSIONS
Non-leguminous trees are important in production units, both for their foliage and fruit supply for animal feeding in the low forage availability sea-son and for their versatility, since they provide shade,firewood, posts and foliage in the LPU. The mostimportant species, given their density and abundance, are C. alata and G. ulmifolia, which are se-lected by producers for their easy reproduction andbecause they are not invasive.
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