Interception loss, gross precipitation, throughfall and stemflow solution chemistry beneath pine (Pinus pseudostrobus Lindl.), oak (Quercus sp.) and pine-oak natural forest canopies in northeastern Mexico were measured. Coefficients of variation for throughfall were 12% in pine and oak canopies and 17% in the mixed pine-oak canopy. The variability of stemflow averaged 66, 126 and 73% for pine, oak and the mixed pine-oak canopies, respectively. Linear regression analysis of net versus gross precipitation for the three canopies showed highly significant correlations (r = 0.974-0.984). Total precipitation during the experimental period was 974 mm and estimated interception loss was 19.2, 13.6 and 23% for the pine, oak and pine-oak canopies, respectively. Stemflow did not occur following rainfall events of less than 4 mm and, in all canopies, stemflow represented a minimal proportion of gross precipitation (0.60, 0.50 and 0.03% for pine, oak and pine-oak, respectively). Throughfall pH in pine (6.2), oak (6.3) and pine-oak (6.3) canopies was significantly more acidic than gross precipitation (6.6). Stemflow pH ranged from 3.7 (pine) to 6.0 (oak). The pine-oak canopy registered the highest throughfall and stemflow electrical conductivities, 104 and 188 microS cm(-1), respectively. Net nutrient leaching of K, Mg, Na, Fe, Mn and Zn was significantly higher from the pine-oak canopy than from the pure pine and oak canopies. Mean depositions of Ca and Cu in throughfall behaved similarly among the three types of canopies. A greater proportion of Zn in gross precipitation was absorbed by the oak canopy than by the pine and pine-oak canopies. Enrichment factors beneath the pine-oak canopy relative to gross precipitation varied from 1.2 to 3.2 for macro-nutrients (Ca, K, Mg and Na) and from 1.4 to 3.1 for micro-nutrients (Cu, Fe, Mn and Zn). Stemflow depositions of Ca, K, Mg and Cu were higher in the pine-oak canopy, whereas stemflow depositions of Na, Fe, Mn and Zn were higher in the pine canopy.

BackgroundTrough collections of plants and interviews with 110 individuals, an ethnobotanical study was conducted in order to determine the knowledge and use plant species in Rayones, Nuevo Leon, Mexico. The aim of this study was to record all useful plants and their uses, to know whether differences exist in the knowledge about the number of species and uses between women and men, and to know if there is a correlation between the age of individuals and knowledge of species and their uses.MethodsA total of 110 persons were interviewed (56 men, 56 women). Semistructured interviews were carried out. The data were analyzed by means of Student t test and the Pearson Correlation Coeficient.ResultsA total of 252 species, 228 genera and 91 families of vascular plants were recorded. Astraceae, Fabaceae and are the most important families with useful species and Agave and Opuntia are the genera with the highest number of useful species. One hundred and thirty six species are considered as medicinal. Agave, Acacia and Citrus are the genera with the highest number of medicinal species. Other uses includes edible, spiritual rituals, construction and ornamentals. There was a non-significant correlation between the person’s age and number of species, but a significant very low negative correlation between the person’s age and number of uses was found.ConclusionsKnowing their medicinal uses is an important issue for the people of Rayones. Boiling and preparing infusions are the main ways of using plants by residents. The leaves, the branches, and the fruits are the most commonly used parts. Almost 18% of the flora is used for wood and construction purposes. Several uses such as cosmetic, shampoo, firming skin tonics and health hair products recorded in Rayones has not been reported for other areas in the state of Nuevo León. In Rayones, women have a greater knowledge about plants and their uses than men, particularly, medicinal plants, but, men have a greater knowledge about wood and construction species.

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Background: Urbanized slope areas in Sierra Madre Oriental are prone to sediment related disasters mainly caused by heavy rainfall episodes during hurricane season, knowledge on the factors on soil-roots dynamics are required to mitigate or lessen those disasters. Questions and hypothesis:The mechanical properties of roots of native species vary according species. The mechanical properties of the roots are influenced by the morphology of root: diameter. Species studied: Quercus rysophylla, Pinus pseudostrobus and Acacia berlandieri. Study site and dates: Sierra Madre Oriental, Chipinque Ecological Park in Monterrey, Nuevo Leon. From middle of December 2014. Methods: Selection of species was made base on widespread distribution and predominance in degraded areas. Samples were taken at field and tensile tests to calculate maximum force to root breakage were conducted using a laboratory dispositive, calculations of tensile strength and modulus of elasticity were calculated using formulas. The corresponding relations between root diameter and mechanical properties were established. Results: Results confirmed that bigger diameters require bigger forces to break. In other hand, results confirmed the negative relationship between diameter and tensile strength and diameter and modulus of elasticity. Pointing out that roots of bigger diameter have less tensile strength and elasticity. The order of importance of the species studied according its mechanical properties was found like: Acacia berlandieri > Quercus rysophylla > Pinus pseudostrobus. Conclusions:The results of this study begin the data contribution of the mechanical properties of native species of Sierra Madre Oriental in order to use it in the application of soil bioengineering practices on urbanized slopes prone to disasters.

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Throughfall and stemflow measurements in a 60-year-old white oak stand (Quercus serrata Thunb.) were carried out during two periods totalling eleven months, from August to November 1993 and from May to November 1994, in order to clarify the rainfall partitioning of this forest. Troughs and spiral-type stemflow gauges connected to tipping bucket-gauges were used for throughfall and stemttow measurements. Seventy-five storms were analyzed individually. Coefficients of variation for throughfall and stemflow ranged between 5 -25% and 20-70% respectively. Partitioning of net rainfall in throughfall and stemflow represent 72% and 10% of the gross rainfall respectively. Multiple regression analyses were carried out to determine the stemflow variability. It was determined that maximum rain intensity was highly correlated with stemflow and this variable explained a further 5.5% of the stemflow variation. Estimates of averaged lag time and drainage after rain cease for stemflow were 290 and 164 min, while estimates for throughfall were 60 and 104 min. respectively. The canopy saturation was estimated from continuous storms and showed a value of 0.6 mm. The trunk storage capacity was estimated at a value of 0.2 mm, The interception loss from the forest canopy was estimated in 18%. Interception loss was heighly correlated with rainfall characteristics such as duration and intensity.

Se determinó la composición y estructura de la vegetación en tres sitios del estado de Nuevo León: Los Ramones (S1), China (S2) y Linares (S3), los cuales forman parte del Matorral Espinoso Tamaulipeco (MET). En cada uno de ellos se ubicaron aleatoriamente 10 parcelas de 10 x 10 m, en las que se determinaron parámetros dasométricos de altura, cobertura y densidad de los individuos, así como los indicadores ecológicos: abundancia, dominancia, frecuencia y valor de importancia (VI). La diversidad de especies se estimó con el índice de diversidad Shannon-Wiener y la similitud entre sitios mediante el índice de Jaccard. Para las temporadas seca y húmeda se registraron 1 251 y 2 457 individuos, respectivamente. En ambas se identificaron 57 especies, y de ellas comparten 34; las familias son Fabaceae y Cactaceae; los géneros mejor representados: Acacia (5), Croton (3), Echinocereus (3) y Opuntia (2). El índice de diversidad de Shannon-Wiener mostró diferencia significativa para la combinación sitio*temporada y caracterizó a los sitios en una diversidad intermedia; el índice de Jaccard evidenció mayor similitud para el S3 y menor para el S2, entre las dos épocas. La cobertura promedio para los tres sitios de estudio en los dos periodos fue de 1 061 y 1 847 m2; S3 presentó los valores más altos. Prosopis laevigata registró el mayor VI en verano y otoño (S1 y S2); y en el S3 fueron Lantana macropoda y Turnera diffusa. En general, la diversidad de especies entre sitios y temporadas tiende a ser homogénea.

En el verano de 2007 se determinó la composición y diversidad de la vegetación arbustiva y arbóreaen cuatro sitios del estado de Nuevo León. El sitio 1 (S1, Bosque Escuela) a una altitud de 1600 m seubicó en el municipio de Iturbide, Nuevo León, México. Los sitios S2 (Crucitas, 550 m), S3 (Campus, 370m) y S4 (Cascajoso, 300 m) se ubicaron en el municipio de Linares, Nuevo León, México. En cada sitiose establecieron aleatoriamente 10 cuadrantes de 10 m x 10 m, en los cuales se estimaron los valoresrelativos de abundancia, dominancia, frecuencia y valor de importancia (VI) de los árboles y arbustospresentes. Además, se determinaron parámetros dasométricos como altura y diámetro de copa. La diversidadde especies para cada sitio se estimó con el índice de Shannon Wiener. La similitud entre sitios sedeterminó con el índice de Jaccard. Se registraron un total de 13 710 individuos pertenecientes a 28familias, predominando los géneros y especies de la familia Leguminosae (10) seguidos por Fagaceae(4), Rutaceae (4), Euphorbiaceae (3), Oleaceae (3), Cupressaceae (3), Rhamnaceae (2) y Verbenaceae(2). Dieciocho familias sólo presentaron una especie. El sitio con el mayor y menor índice de Shannonfueron el Cascajoso (2,08) y Bosque Escuela (1,64), respectivamente. El índice de Jaccard sólo mostróigualdad de especies entre S2, S3 y S4. Las especies de plantas más frecuentes fueron: en S1, Quercuscanbyi, Pinus pseudostrobus y Rhus pachyrrachys (con 11,9%); en S2 Havardia pallens (9,9%); en S3Havardia pallens y Forestiera angustifolia (con 9,8 %) y en S4 Acacia rigidula, Cordia boissieri y Karwinskiahumboldtiana (con 9,8%). Los sitios S2 y S3 presentaron la mayor riqueza específica de especies,posiblemente debido a tener mayor precipitación pluvial.