FOREST MANAGMENT EFFECT IN DIVERSITY AND TREE COMPOSITION OF A TEMPERATE FOREST IN NORTHWESTERN MEXICO
EFECTO DEL MANEJO FORESTAL EN LA DIVERSIDAD Y COMPOSICIÓN ARBÓREA DE UN BOSQUE TEMPLADO DEL NOROESTE DE MÉXICO
/ pages 189-199
In the present study, the effect of silvicultural practices in diversity and composition of tree species in a temperate forest in northwestern Mexico was evaluated. Forty six plots were evaluated every 10 years (1986, 1996 and 2006). Indices of alpha and beta diversity of the community of trees, abundance, dominance, frequency and importance value index (IVI) of each species were estimated. The results show that logging changes the diversity and composition of the tree strata. The tree community maintains the number of species, but decreases the Margalef and Shannon-Wiener indices of alpha diversity, and composition was changed in 16 % (beta diversity). Pinus increases its relative abundance, dominance, frequency and IVI, meanwhile Quercus declines. Pinus arizonica and P. durangensis are the species of greater ecological importance.
DEFORESTATION RATES IN SAN LUIS POTOSÍ, MÉXICO (1993-2007)
TASAS DE DEFORESTACIÓN EN SAN LUIS POTOSÍ, MÉXICO (1993-2007)
/ pages 201-215
It is important to know the deforestation rates for the design of regional programs under the particular approach of Reducing Emissions from Deforestation and Forest Degradation (REDD+) initiative. In order to evaluate the current deforestation rate in San Luis Potosí state, a spatial intersection analysis of land use and land cover maps (series II, 1993; series IV, 2007) was done. This study focused on four biogeographical zones: 1. Altiplano, 2. Centro, 3. Media and 4. Huasteca. The annual deforestation rates were calculated for each biogeographical zone: Altiplano (0.11 %), Media (0.16 %), Centro (-0.12 %, recovering) and Huasteca (0.51 %). A change from shrubland to grassland was more evident in arid and semiarid zones whereas rainforest was the most affected vegetation in the Huasteca zone. The annual deforestation rates obtained were lower than the national average value (0.43 %, from 1976 to 2000), except for the Huasteca zone. These results provide valuable information when focusing initiatives oriented to stop deforestation process in San Luis Potosí, Mexico.
IDENTIFICATION OF LANOSTEROL DERIVATES FROM THE CULTIVATED FUNGUS Pisolithus arhizus (Scop.) Rauschert
IDENTIFICACIÓN DE UN DERIVADO DE LANOSTEROL PROCEDENTE DEL HONGO CULTIVADO Pisolithus arhizus (Scop.) Rauschert
/ pages 217-224
Mycorrhizal fungi can be found in association with the roots of many plants, including almost all tree species such as the Pinaceae family. Some triterpene derivatives of lanosterol have been isolated both in the mycelium as well as in the fruiting bodies of the ectomycorrhizal fungus Pisolithus arhizus. In order to determine, what type of compounds can be found as well as any possible ecological implications involved in the case of a Mexican strain cultivated under asymbiotic conditions in the present research work, a strain isolated from P. arhizus from pine woods from Oaxaca was grown under laboratory conditions. These results confirm that the strain isolated from the forests of Mexico presents the same type of triterpenes unfunctionalized at carbon-23 in the in vitro liquid fermentation of mycelium, like other strains from forests in Europe and Brazil, despite the fact that they we used a PDA medium culture instead of a half Melin-Norkrans medium culture.
URBAN GREENING, A CHALLENGE TO URGANIZATION
NATURACIÓN URBANA, UN DESAFÍO A LA URBANIZACIÓN
/ pages 225-235
Greening cities, defined as growing vegetation in urban areas, is an effective way to reduce the imbalance between urbanization and environmental protection. This review article describes the main environmental, hydrological, waste management, health and social problems solved by greening cities. The greening systems were classified according to their complexity and the urban surface greened. The basic layers of a greening system and the materials used are analyzed. Finally, an overview of the state-of-the-art in urban greening systems created to help achieve sustainable city development is presented.
LOGGING AND INDUSTRIALIZATION OF TWO GMELINA ARBOREA PLANTATIONS WITH DIFFERENT DEGREES OF SLOPES
APROVECHAMIENTO E INDUSTRIALIZACIÓN DE DOS PLANTACIONES DE GMELINA ARBOREA DE 15 AÑOS DE EDAD EN DIFERENTES CONDICIONES DE PENDIENTE
/ pages 237-248
The main objective of this study was to determine the logging and industrialization of two 15 years-old Gmelina arborea un-managed plantations with two different slopes: 30 % and 60 %. Trees had an average diameter at breast height (DBH) of 31.23 cm and a total height of 14.87 m. Three logs per tree were extracted. Only 22 % of total standing volume in the plantation is usable as end product for market sale. The non-sawlog (waste) was 42.57 in standing tree (42.57 %), to extract log from tree filled (14.43 %), to saw in central block (26.27 %) and commercial lumber (22.10 %). The lumber recovery was 53.22 % in extracting a central block from logs and final lumber recovery in commercial lumber was 45.88 %.
LITTER FALL PRODUCTION AND NUTRIENT RETURNS THROUGH LEAVES IN A MICROPHYLLUS DESERT SCRUB, NORTHEASTERN MEXICO
PRODUCCIÓN DE HOJARASCA Y RETORNO DE NUTRIENTES VÍA FLIAR EN UN MATORRAL DESÉRTICO MICRÓFILO EN EL NORESTE DE MÉXICO
/ pages 249-262
Litterfall and macro (Ca, N, P, Mg and K) and microminerals (Fe, Mn and Zn) components of the leaves were compared in two sites for 12 months (September 2008-Agust 2009). Site 1 was located in El Llano de La Soledad, Galeana, Nuevo León, Mexico (1863 m) and site 2 in San José del Alamito, Saltillo, Coahuila, Mexico (1895 m). A total of 10 litter traps (1 m2) were randomly located at each site to collect litterfall. The annual litterfall at site 2 was higher (407 g·m-2·year-1) than at site 1 (162 g·m-2·year-1). Leaves (47.7 and 53.2 %: site 1 and site 2, respectively) constituted the highest component, followed by branches (24.6 and 20.3 %), reproductive structures (21.3 and 20.2 %) and others (4.3 and 7.6 %). The deposition of macro and microminerals was higher at site 2 than at site 1. The spatio-temporal differences in litterfall and mineral return might have been related to the extreme temperatures, plant species composition and chemical soil properties.
ESTIMATING DAILY NET RADIATION FROM MULTIPLE LINEAR REGRESSION MODELS
ESTIMACIÓN DE LA RADIACIÓN NETA DIARIA A PARTIR DE MODELOS DE REGRESIÓN LINEAL MÚLTIPLE
/ pages 263-271
Knowledge of daily net radiation (Rn) is basic to quantifying energy used in various processes occurring at the surface level such, as evapotranspiration. This study applies a Multiple Linear Regression Model (MRLM) for the estimation of Rn in a subhumid-humid zone of Argentina. In the model we used weather data of solar radiation, temperature and relative humidity, Rn (measured with a Kipp & Zonen net radiometer) and inverse relative distance earth-sun. As a result, eight estimation equations of Rn were obtained. The MRLM models were evaluated using the statistics Mean Bias Error (MBE) and Root Mean Square Error (RMSE). The results showed good adjustment and low error at daily scale, highlighting those equations involving solar radiation, temperature, relative humidity and inverse distance earth- sun, allowing calculation of Rn with errors less than 19 W∙m-2.
MEASURING AND ESTIMATING THE BELOW-CANOPY LIGHT ENVIRONMENT IN A FOREST. A REVIEW
EVALUACIÓN DE LA SUSTENTABILIDAD DEL ACUÍFERO CUAUTITLÁN-PACHUCA MEDIANTE EL USO DE LA METODOLOGIA MESMIS
/ pages 273-285
The aquifer Cuautitlan-Pachuca occupies the northern portion of the basin of the Valley of Mexico, justifying its name from the presence of Cuautitlan in the State of Mexico and Pachuca in Hidalgo. This aquifer is overexploited at present, because the recharge is less than abstraction, for this reason in this work was estimated sustainability of the aquifer, using the framework for assessing management systems incorporating natural resources sustainability indicators (MESMIS). We performed a longitudinal study comparing of two systems, the first was analyzed for the period 1970-1990 (reference system) and the second for the period 1991-2010 (alternative system). They analyzed 14 environmental indicators, economic and social, for the two periods. We found that environmental and economic aspects present the greatest setbacks over the years, in the case of social indicators showed progress toward equity. We also found that 9 of the indicators presented closer to the optimum value proposed in the reference system and only five showed a close to optimal in the alternative system. The results show that the aquifer is less sustainable today.
SKRINKAGES AND PHYSICAL PROPERTIES OF ACACIA MANGIUM, TECTONA GRANDIS AND TERMINALIA AMAZONIA PLANTATION WOOD FROM COSTA RICA
CONTRACCIONES Y PROPIEDADES FÍSICAS DE ACACIA MANGIUM, TECTONA GRANDIS Y TERMINALIA AMAZONIA, MADERAS DE PLANTACIÓN EN COSTA RICA
/ pages 287-303
Based on ASTM standards D 2395-02 and D 143-94, total and normal shrinkage in radial (RS), tangential (TS) and volumetric (VS) directions and the total and normal TS/RS ratio were determined in the plantation woods Acacia mangium Willd., Tectona grandis L.f. and Terminalia amazonia A. Chev. Also, physical properties such as basic specific gravity (BSG), SG12% and SGovendry, green density (GD) and normal density (ND), fiber saturation point (FSP) and moisture content (MC) were determined. Some classification criteria, proposed by other researchers, were used to categorize the dimensional stability and physical properties of these species. Significant differences were found among the species for total RS, TS, VS and TStotal/RStotal, as well as for the physical properties BSG and FSP. The TStotal/RStotal ratio indicated that T. grandis has better dimensional stability. The linear regression (R2= 0.7769) indicated that FSP is a good indicator of VStotal magnitude. The plantation species of this study compared with those of the natural forest have similar dimensional stability but lower BSG.
ECOLOGY, HARVESTING AND COMMERCIALIZATION OF THE ORIGAN (Lippia graveolens H. B. K.) IN MAPIMÍ, DURANGO
ECOLOGÍA, APROVECHAMIENTO Y COMERCIALIZACIÓN DEL ORÉGANO (Lippia graveolens H. B. K.) EN MAPIMÍ, DURANGO
/ pages 305-321
The oregano, Lippia graveolens H. B. K., is a plant adapted to arid conditions with the ability to thrive under varying degrees of harvesting pressure. In Mapimí, Durango, the plant has been gathered and marketed for years and provides a vital source of income for families that harvest it, although wholesalers reap the biggest share of the profits. In the Mapimí region, several producing areas were evaluated in order to determine the dynamics of harvesting and their effects on the plant. For this, field trips, sampling and delineation of oregano distribution areas were conducted. In addition, the production process and marketing channels were analyzed in order to design a management alternative that ensures the sustainability of the activity. The production and marketing process was studied through open interviews with producers, field trips and visits to the processing and marketing companies, as well as the intermediaries involved in different stages of the process.