Juniperus Deppeana Research Articles

Safety and efficacy of a feed additive consisting of an essential oil obtained from the wood of Juniperus deppeana Steud. (cedarwood Texas oil) for use in all animal species (FEFANA asbl).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of an essential oil obtained from the wood of Juniperus deppeana Steud. (cedarwood Texas oil), when used as a sensory additive for all animal species. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) concluded that the essential oil under assessment is safe up to the maximum proposed use levels in complete feed of 15 mg/kg for veal calves (milk replacer), cattle for fattening, sheep, goats, horses, dogs, salmonids and ornamental fish. For the other species, the calculated safe concentrations in complete feed were 5 mg/kg for chickens for fattening, 8 mg/kg for laying hens, 7 mg/kg for turkeys for fattening, 10 mg/kg for piglets, 12 mg/kg for pigs for fattening, 14 mg/kg for sows and dairy cows, 8.5 mg/kg for rabbits and 4 mg/kg for cats. These conclusions were extrapolated to other physiologically related species. For any other species, the additive was considered safe at 4 mg/kg complete feed. The use of cedarwood Texas oil in water for drinking was considered safe provided that the total daily intake of the additive does not exceed the daily amount that is considered safe when consumed via feed. No concerns for consumers and the environment were identified following the use of the additive up to the maximum proposed use level in feed. The additive under assessment should be considered as irritant to skin and eyes, and as a skin and respiratory sensitiser. Since the individual components of cedarwood Texas oil are recognised to flavour food and their function in feed would be essentially the same as that in food, no further demonstration of efficacy was considered necessary.

Cutting the Greenness Index into 12 Monthly Slices: How Intra-Annual NDVI Dynamics Help Decipher Drought Responses in Mixed Forest Tree Species

We studied the correspondence between historical series of tree-ring width (TRW) and the normalized difference vegetation index (NDVI, i.e., greenness index) values acquired monthly over an entire year by unmanned aerial vehicles. Dendrochronological techniques revealed differentiated responses between species and seasonality. Pinus engelmannii Carrière and Juniperus deppeana Steudel were affected by warm temperatures (TMAX) during the winter prior to growth and benefited from precipitation (PP) during the seasons prior to the spring period. The standardized precipitation–evapotranspiration index (SPEI) confirmed the high sensitivity of P. engelmannii to drought (r = 0.7 SPEI). Quercus grisea Liebm. presented a positive association with PP at the beginning and end of its growth season. Monthly NDVI data at the individual tree level in the three species (NDVI ~0.37–0.48) statistically confirmed the temporal differences. Q. grisea showed a drastic decrease during the dry season (NDVI = 0.1) that had no impact on drought sensitivity in the same period, according to the climate-TRW relationship. We conclude that a relationship is plausible between the crown greenness index and radial growth, although more extended temporal windows of the NDVI should be explored. Differences in susceptibility to drought found among the species would presumably have implications for the composition of these forests under drought scenarios.

Saprotrophic fungi from Juniperus deppeana (Cupressaceae) forest: isolation, identification, in vitro culture, and preservation

The alteration of forests due to anthropogenic activities and natural phenomena has led to the development of adaptive features so that organisms can tolerate it or use it to their benefit. In this study, saprotrophic fungi from a disturbed Juniperus deppeana forest were isolated and identified for in vitro propagation. Thirty-one specimens were collected and propagated on malt extract agar (EMA), potato dextrose agar (PDA), Kraft lignin agar (A-L) and mineral medium (MM). Taxonomic identification was performed on the basis of macro- and micromorphological characters of the basidiomata, and was complemented by phylogenetic analysis of ITS sequences. Only 7 strains grew under in vitro conditions; they grew best in EMA and PDA media. Room temperature (~22 °C) and preservation at 4 °C were the best conditions to maintain the viability of the strains. After 6 months, strains preserved in glycerol (15%) at 4° and -20 °C were not viable. The isolated fungi belong to the genera Agrocybe, Byssomerulius, Coniophora and Gymnopus. Given the environmental conditions where the strains were isolated, they represent new research prospects for obtaining biomolecules of biotechnological interest.

Effects of endozoochory and diploendozoochory by captive wild mammals on Juniperus deppeana seeds.

Carnivorous mammals disperse seeds through endozoochory and diploendozoochory. The former consists of ingestion of the fruit, passage through the digestive tract, and expulsion of the seeds, a process that allows scarification and dispersal of the seeds over long or short distances. The latter is typical of predators that expel seeds that were contained in the prey and the effects of which may differ from those of endozoochory with respect to the retention time of the seeds in the tracts, as well as their scarification and viability. The objective of this study was to conduct an experimental evaluation comparing the capacity of each mammal species in terms of the dispersal of Juniperus deppeana seeds and, at the same time, to compare this capacity through the two dispersal systems: endozoochory and diploendozoochory. We measured dispersal capacity using indices of recovery, viability, changes in testas, and retention time of seeds in the digestive tract. Juniperus deppeana fruits were collected in the Sierra Fría Protected Natural Area in Aguascalientes, Mexico, and were administered in the diet of captive mammals: gray fox (Urocyon cinereoargenteus), coati (Nasua narica) and domestic rabbits (Oryctolagus cuniculus). These three mammals represented the endozoochoric dispersers. For the diploendozoochoric treatment, seeds excreted by rabbits were incorporated into the diets of captive mammals: bobcat (Lynx rufus) and cougar (Puma concolor), in a local zoo. Seeds present in the scats were then collected, and recovery rates and retention times were estimated. Viability was estimated by X-ray optical densitometry and testa thicknesses were measured and surfaces checked using scanning electron microscopy. The results showed a recovery of seeds greater than 70% in all the animals. The retention time was <24 h in the endozoochory but longer at 24-96 h in the diploendozoochory (p < .05). Seed viability ( ± SD) was decreased in rabbits (74.0 ± 11.5%), compared to fruits obtained directly from the canopy (89.7 ± 2.0%), while gray fox, coati, bobcat, and cougar did not affect seed viability (p < .05). An increase in the thickness of the testas was also observed in seeds excreted from all mammals (p < .05). Through evaluation, our results suggest that mammalian endozoochory and diploendozoochory contribute to the dispersal of J. deppeana by maintaining viable seeds with adaptive characteristics in the testa to promote forest regeneration and restoration. In particular, feline predators can provide an ecosystem service through scarification and seed dispersal.

Natural durability of timber species exposed to xylophagous fungi in southern Durango, Mexico.

Wood is a natural resource used for construction and the manufacture of many products. This material is exposed to damage due to biotic and abiotic factors. An important biotic factor is wood-degrading fungi that generate large economic losses. The objectives of this study were to determine the effect of xylophagous fungi (Coniophora puteana and Trametes versicolor) on the natural durability of six timber species in southern Durango, Mexico, and to establish differences between fungal effects on each tree species. Samples of Pinus durangensis, P. cooperi, P. strobiformis, Juniperus deppeana, Quercus sideroxyla, and Alnus acuminata were exposed to fungi for 4 months under laboratory conditions according to European Standard EN350-1. Samples of Fagus sylvatica were used as control. Durability was determined as the percentage of wood mass loss for each species. Welch ANOVA tests were performed to establish differences among tree species. Welch t-tests were used to prove loss mass differences between fungi for each tree species. The most resistant species to C. puteana were P. durangensis, J. deppeana, P. cooperi and P. strobiformis, showing mean mass losses lower than 8.08%. The most resistant species to T. versicolor were J. deppeana, P. strobiformis and P. durangensis (mean mass losses lower than 7.39%). Pinus strobiformis and Q. sideroxyla were more susceptible to C. puteana effect; in contrast, P. durangensis and P. cooperi showed more damage due to T. versicolor degradation. Woods of P. durangensis, P. cooperi, P. strobiformis and Juniperus deppeana are well adapted to infection by these xylophagous fungi and are therefore highly recommended for commercial use in southern Durango, Mexico.

What Are Contemporary Mexican Conifers Telling Us? A Perspective Offered from Tree Rings Linked to Climate and the NDVI along a Spatial Gradient

Forest structure and composition have changed rapidly worldwide, presenting tendencies towards an increasing proportion of younger trees. From chronologies of tree-ring indices (TRI) and the reconstruction of the basal area increment (BAI), a dendroecological study was conducted from the perspective of the radial growth of twelve contemporary conifer species in a highly diverse region of the planet. From an elevational perspective, the TRI were associated with climate and the NDVI, while the BAI was also modeled as a potential proxy for forest productivity. Climate affects the species differently according to elevation: at 1900 m asl, Pinus caribaea, P. oocarpa and P. jeffreyi presented the lowest sensitivities to climate and drought. For their part, species occupying the intermediate part of the gradient (1901–3000 m asl), such as P. engelmannii, P. patula, P. johannis and P. maximartinezii, were very sensitive to maximum temperature (TMax), precipitation (PP) and drought during the winter–spring period. Finally, of the species distributed on the upper part of the gradient (&gt;3000 m asl), only Abies religiosa was associated with TMax and drought; Juniperus deppeana, A. hickelii and P. hartwegii did not seem to be vulnerable to drought. Complementarily, we found significant differences in the BAI as a function of elevation, with the sites at 1001–1500 m asl presenting higher BAI. The results suggest that the growth in these forests is impacted by droughts and follows a distinct spatial pattern, with greater restriction found in mid-elevation forests. Consistent implications are also observed in BAI trends. For its part, the NDVI demonstrated a decreasing tendency in greenness from south to north, although no elevation pattern was evident. The combined proxies utilized here produced parameters that improve our understanding of forest growth and should be considered in vegetation dynamics models in order to reduce their uncertainty in the face of climate vulnerability. These forests must be sustainably managed, and it is therefore crucial to determine the influence of ecological variables on their growth.

Incipient speciation, high genetic diversity, and ecological divergence in the alligator bark juniper suggest complex demographic changes during the Pleistocene.

The most recent glacial cycles of the Pleistocene affected the distribution, population sizes, and levels of genetic structure of temperate-forest species in the main Mexican mountain systems. Our objective was to investigate the effects these cycles had on the genetic structure and distribution of a dominant species of the “mexical” vegetation across North and Central America. We studied the genetic diversity of Juniperus deppeana, a conifer distributed from the Southwestern United States to the highlands of Central America. We combined information of one plastid marker and two nuclear markers to infer phylogeographic structure, genetic diversity and demographic changes. We also characterized the climatic niche for each variety to infer the plausible area of suitability during past climatic conditions and to evaluate climatic niche discontinuities along with the species distribution. We found a marked phylogeographic structure separating the populations North and South of the Isthmus of Tehuantepec, with populations to the South of this barrier forming a distinct genetic cluster corresponding to Juniperus deppeana var. gamboana. We also found signals of population expansion in the Northern genetic cluster. Ecological niche modeling results confirmed climatic niche differences and discontinuities among J. deppeana varieties and heterogeneous responses to climatic oscillations. Overall, J. deppeana’s genetic diversity has been marked by distribution shifts, population growth and secondary contact the North, and in situ permanence in the South since the last interglacial to the present. High genetic variation suggests a wide and climatically diverse distribution during climatic oscillations. We detected the existence of two main genetic clusters, supporting previous proposals that Juniperus deppeana and Juniperus gamboana may be considered two separate species.

Mycorrhizal Fungi Associated With Juniper and Oak Seedlings Along a Disturbance Gradient in Central Mexico

Competition for resources between arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) plants can alter belowground mycorrhizal communities, but few studies have investigated host effects on both AM and ECM communities. In Central Mexico, the AM plant Juniperus deppeana is frequently used for reforesting areas affected by soil erosion, while the surrounding native forests are dominated by ECM oak trees. Oaks are capable of associating with both AM and ECM fungi during part of their life cycle (a feature known as dual mycorrhization) but it is unclear whether junipers possess such ability. To assess how juniper planting may affect belowground fungal interactions with oaks, we investigated mycorrhizal associations in J. deppeana and Quercus rugosa seedlings along a disturbance gradient: a native oak forest, a mixed Juniperus-Quercus population in secondary vegetation and a juniper site severely degraded by mining extraction. We measured root colonization and identified fungal communities using soil and root meta-barcoding of the ITS2 rDNA region. ECM fungal community composition was strongly affected by disturbance (regardless of host), while the community composition of AM fungi was mostly host-dependent, with a higher AM fungal richness in J. deppeana. Importantly, the fungal communities associated with Q. rugosa seedlings significantly changed in the vicinity of juniper trees, while those of J. deppeana seedlings were not affected by the presence of oak trees. Even though ECM fungal richness was higher in Q. rugosa and in the native forest, we detected a variety of ECM fungi associated exclusively with J. deppeana seedlings, suggesting that this plant species may be colonized by ECM fungi. Our results indicate that J. deppeana can alter ECM native fungal communities, with implications for its use in reforestation of mixed oak forests.

Influence of Juniper on Montezuma Quail Habitat Use in Texas

ABSTRACTMontezuma quail (Cyrtonyx montezumae) inhabit oak (Quercus spp.)‐juniper (Juniperus spp.) woodlands throughout Mexico and the southwestern United States. In Texas, USA, Montezuma quail occur in the Edwards Plateau and Trans‐Pecos Mountains and Basins (Trans‐Pecos), 2 ecoregions with contrasting juniper patterns. Ashe juniper (Juniperus ashei) dominates in the Edwards Plateau and has been increasing over decades, whereas alligator juniper (Juniperus deppeana) is a co‐dominant in the Trans‐Pecos and appears to have stable Montezuma quail populations. Our objectives were to compare between ecoregions the relative abundance and habitat use of Montezuma quail in relation to juniper and quantify the influence of juniper on key features of Montezuma quail habitat (grass height, grass cover, forb cover, and forb species richness). We conducted a study from March–August 2018‒2020 in the Edwards Plateau (Kinney and Edwards counties) and Trans‐Pecos ecoregions (Jeff Davis County) to evaluate these objectives. We conducted call‐back surveys to estimate relative abundance (number of detections/hr) of Montezuma quail and identify used locations. We collected vegetation data at a micro‐scale (16‐m) at used (n = 32–30 points) and random locations (n = 70–60 points) in each ecoregion. Relative abundance of Montezuma quail was considerably lower in the Edwards Plateau (0.06 ± 0.01 detections/survey hr; ± SE) than in the Trans‐Pecos (1.10 ± 0.30 detections/survey hr). In addition, Montezuma quail selected areas of low Ashe juniper cover (&lt;23% cover), density (&lt;7 trees/80 m2), and height (&lt;2 m) in the Edwards Plateau but selected areas of high alligator juniper cover (&gt;18% cover), density (&gt;4 trees/80 m2), and height (2–8 m) in the Trans‐Pecos. Moreover, Ashe juniper cover had a significant, negative influence on herbaceous features, whereas alligator juniper exerted little to no influence. Our results suggest that these 2 juniper species have contrasting effects on Montezuma quail space use and their habitat, possibly as a result of the contrasting influence of these junipers on herbaceous understory. Creating habitat for Montezuma quail in the Edwards Plateau generally will involve the reduction of Ashe juniper and creating patches that possess juniper trees of small stature (&lt;2 m) with low amounts of cover (&lt;23%) and density (&lt;7 trees/80 m2), whereas management in the Trans‐Pecos will require site‐specific assessments based on current alligator juniper influence. © 2021 The Wildlife Society.

Assessment of Pellets from Three Forest Species: From Raw Material to End Use

This study aimed to evaluate and compare the relationship between chemical properties, energy efficiency, and emissions of wood and pellets from madroño Arbutus xalapensis Kunth, tázcate Juniperus deppeana Steud, and encino colorado Quercus sideroxyla Humb. &amp; Bonpl. in two gasifiers (top-lit-up-draft (T-LUD) and electricity generation wood camp stove (EGWCS)) in order to determine the reduction of footprint carbon. In accordance with conventional methodologies, we determined the extracts and chemical components (lignin, cellulose, holocellulose), and the immediate analyses were carried out (volatile materials, fixed carbon, ash content and microanalysis of said ash), as well as the evaluation of emission factors (total suspended particulate matter (PM2.5), CO, CO2, CH4, black carbon (BC), elemental carbon (EC), and organic carbon (OC)). The results were statistically analyzed to compare each variable among species and gasifiers. The raw material analyzed showed how the pH ranged from 5.01 to 5.57, and the ash content ranged between 0.39 and 0.53%. The content values of Cu, Zn, Fe, Mg, and Ca ranged from 0.08 to 0.22, 0.18 to 0.19, 0.38 to 0.84, 1.75 to 1.90, and 3.62 to 3.74 mg kg−1, respectively. The extractive ranges from cyclohexane were 2.48–4.79%, acetone 2.42–4.08%, methanol 3.17–7.99%, and hot water 2.12–4.83%. The range of lignin was 18.08–28.60%. The cellulose content ranged from 43.30 to 53.90%, and holocellulose from 53.50 to 64.02%. The volatile material range was 81.2–87.42%, while fixed carbon was 11.30–17.48%; the higher heating value (HHV) of raw material and pellets presented the ranges 17.68–20.21 and 19.72–21.81 MJ kg−1, respectively. Thermal efficiency showed statistically significant differences (p &lt; 0.05) between pellets and gasifiers, with an average of 31% Tier 3 in ISO (International Organization for Standardization) for the T-LUD and 14% (ISO Tier 1) for EGWCS, with Arbutus xalapensis being the species with the highest energy yield. The use of improved combustion devices, as well as that of selected raw material species, can reduce the impact of global warming by up to 33% on a cooking task compared to the three-stone burner.

Reconstruction of Piñon–Juniper Woodlands in the Sky Islands of the Davis Mountains, Texas, USA

Piñon (Pinus spp. L.)–juniper (Juniperus spp. L.) woodlands’ historical stand structures were recreated to provide reference conditions and document long-term changes in the Sky Islands of the Davis Mountains, Texas. Restoration of these isolated woodlands requires insights into the range of variability in current and historical stand structures, as well as an understanding of the spatiotemporal establishment and recruitment patterns of tree species. With drastic changes in forests and woodlands of the Southwestern United States widely reported, the main objective of this study was to reconstruct woodland tree temporal and spatial establishment patterns. A stratified random sampling approach was used to select two study sites each of 3600 m2 in area. Within each site, all individual trees were mapped, measured, and cored for age determination. Age and tree location data were used to recreate the spatiotemporal patterns of tree species establishment and recruitment. Increments in density of both Mexican piñon (Pinus cembroides var. cembroides Zucc.) and alligator juniper (Juniperus deppeana var. deppeana Steud.) reached 422 trees ha−1 in the 115-year period between 1890 and 2005; a yearly increment of 4 trees ha−1 that did not reflect a rapid rate of change in these piñon–juniper woodlands. Age distributions reflected the multi-cohort nature of these woodlands, and spatial autocorrelation measures were useful in the objective delineation of these cohorts. Temporal and functional niche differentiation of juniper was reflected in the development pattern where alligator juniper served as a pioneer species, exhibited a longer period of substantial recruitment, and had greater recruitment rates than that of Mexican piñon. Recruitment of Mexican piñon and alligator juniper occurred in an episodic fashion, with the majority of recruits being acquired between 1890 and 1949.

Nutrición inicial en una reforestación de Juniperus deppeana Steud. y su capacidad de rebrote posincendio

Las especies forestales de lento crecimiento son las menos estudiadas. Con un experimento de fertilización (N-P-K) se evaluó el caso de brinzales de Juniperus deppeana y su capacidad de rebrote posincendio. Se aplicaron tres niveles de N y P y dos de K para un total de 18 tratamientos con seis repeticiones. Adicionalmente, se comparó en plantas de uno y dos años de edad el incremento en diámetro a la base (IDB). Seis meses después de la fertilización solo la interacción N-P-K fue significativa (P&lt;0.06) para IDB. Los tratamientos con niveles más altos de N presentaron el mayor IDB. A los siete meses de establecido el experimento, se presentó un incendio, y a partir de ese momento se determinó la capacidad de rebrote y concentración de macronutrientes (N-P-K-Ca-Mg-S), para ello se consideró el antecedente de la fertilización. Los efectos evaluados en el experimento fueron la fertilización, edad de la planta y daño por incendio. El porcentaje de rebrote posterior al incendio fue de 84 %. Contrario a lo esperado, los rebrotes de brinzales con antecedentes de fertilización presentaron menor concentración de nutrientes. La recuperación de estos en los individuos de J. deppeana posincendio está determinada por la redistribución de las reservas de nutrientes en el suelo y la planta. Para especies de lento crecimiento, como J. deppeana, la planta de dos años de edad es más recomendable para el establecimiento en plantaciones, por sus mayores tasas de incremento.

Características estructurales y demográficas de Juniperus deppeana Steud. en dos localidades del estado de Tlaxcala

Juniperus deppeana es una especie tolerante a la sequía y al fuego, capaz de desarrollarse en suelos con condiciones adversas, razón por la cual se le considera una especie con potencial para la conservación de suelos. Sin embargo, en México ha sido poco estudiada, ya que no tiene un valor relevante en la industria forestal. En el estado de Tlaxcala existen poblaciones abundantes de este género, por lo que se seleccionaron las localidades El Pardo (EP) y Acopinalco del Peñón (RAP) para analizar las características estructurales y demográficas de los individuos presentes de J. deppeana; así como determinar la influencia de algunos factores abióticos. Los análisis de t de Student indicaron valores promedio significativos en la altura, diámetro mayor, diámetro menor y en la cobertura. No se obtuvo relación significativa entre las variables dasométricas con la pendiente y la orientación de las parcelas de muestreo. La relación del DAP con la cobertura fue significativa. La curva de supervivencia para ambas localidades presentó un patrón tipo III. Los análisis estadísticos confirmaron que la estructura de tamaños difiere entre los sitios de muestreo. Se deduce que el comportamiento poblacional de J. deppeana acusa una pérdida alta de individuos jóvenes, lo que supone un riesgo para su regeneración natural. Por otro lado, aunque los ejemplares en el predio sujeto a manejo forestal reúnen características dasométricas más favorables, se requiere de estudios a largo plazo bajo un enfoque más integral, a fin de determinar las posibilidades de conservación de esta especie.

Comprehensive profiling and identification of bioactive components from methanolic leaves extract of Juniperus deppeana and its in vitro antidiabetic activity

Juniperus plant species are rich sources of bioactive secondary metabolites and are traditionally used for the treatment of several illnesses, including those related to hyperglycemia and diabetes. The major bioactive compounds identified in certain species of this genus are terpenes and phenolics. Juniperus deppeana Steud. is mainly used as a wood resource and its chemical composition has been partially established. Our goal was to perform a comprehensive profiling of a methanolic extract of leaves of J. deppeana and determine its potential as a source of α-amylase and α-glucosidase inhibitors. Terpene and phenolic compounds were putatively identified based on their accurate mass spectrometric data. Regarding terpenes, we found mainly diterpenes, specifically dehydroabietic acid-like, hinokiol-like, agathic acid-like, and dihydroxyabietatrienoic acid-like compounds. Isopimaric acid was also identified and its identity was confirmed by coelution with an authentic standard via comparing retention time, mass spectrum, and collisional cross section values. For phenolic compounds, we identified mainly compounds with a chemical structure similar to the biflavonoids amentoflavone and bilobetin. Besides, the methanolic extract of J. deppeana leaves show inhibition of α-amylase (IC50 = 85.11 ± 11.91 μg mL−1) and α-glucosidase (IC50 = 32.50 ± 3.40 μg mL−1) enzymes, demonstrating a potential alternative for the search of antidiabetic natural products.

Regeneración y estructura vertical de un bosque de Pseudotsuga menziesii (Mirb.) Franco en Chihuahua, México

Para la caracterización de la estructura vertical de un bosque de Pseudotsuga menziesii en el ejido Chinatú, municipio Guadalupe y Calvo, Chihuahua, se realizó un muestreo aleatorio de ocho sitios circulares de 1 000 m2 dispersos en 80.46 ha. Con la información obtenida se analizó la estructura vertical de la regeneración y del arbolado mediante el Índice A de Pretzsch, se estimó la abundancia (N ha-1), los valores medios, mínimos, máximos y coeficiente de variación de la altura y diámetro normal y cobertura, así como la diversidad con base en el Índice de Shannon-Wiener (H ́) y el Índice de Margalef (DMg). Se registraron ocho especies para la comunidad vegetal regenerada, las familias con mayor presencia fueron Pinaceae con cinco especies y Fagaceae con dos; la comunidad vegetal madura registró 10 especies, las más predominantes fueron pinaceae con seis taxones y fagaceae con dos. Las alturas máximas del bosque fueron 8.0 m y 29.0 m para regeneración y arbolado maduro, respectivamente. Con el Índice A de Pretzsch se precisó que el mayor número de individuos se reúne en el estrato III (Bajo) para ambos tipos de árboles. Las especies con mayor regeneración son Abies durangensis, Juniperus deppeana, Quercus tuberculata y Pseudotsuga menziesii, la última de las cuales es dominante en el estrato arbóreo. El bosque estudiado cuenta con una riqueza y diversidad de especies baja, algunas de alto valor ecológico para conservación y con regeneración de la mayoría de las presentes.

Endozoochorous dispersal of forest seeds by carnivorous mammals in Sierra Fría, Aguascalientes, Mexico.

Some carnivorous mammals ingest fruit and disperse seeds of forest plant species capable of colonizing disturbed areas in ecosystems. The objective of the present study was to evaluate the dissemination of Arctostaphylos pungens and Juniperus deppeana seeds by the gray fox (Urocyon cinereoargenteus), coyote (Canis latrans), and other carnivores in the Protected Natural Area Sierra Fría, in Aguascalientes, Mexico. Scat collection was undertaken via transects using the direct search method, while the seasonal phenology of A. pungens and J. deppeana was evaluated by recording flower and fruit abundance on both the plant and the surrounding forest floor ground. Seed viability was assessed by optical densitometry via X‐ray and a germination test. It was found that the gray fox, coyote, ringtail (Bassariscus astutus), and bobcat (Lynx rufus) disseminated seeds of A. pungens (212 ± 48.9 seeds/scat) and J. deppeana (23.6 ± 4.9 seeds/scat), since a large proportion of the collected scat of these species contained seeds (28/30 = 93.33%, 12/43 = 27.9%, 6/12 = 50% and 7/25 = 28% respectively). The gray fox, coyote, ringtail, and bobcat presented an average of seed dispersion of both plant species of 185.4 ± 228.7, 4.0 ± 20.0, 12.1 ± 30.4, and 0.8 ± 1.5 per scat; the seed proportions in the gray fox, coyote, ringtail, and bobcat were 89.6/10.4%, 82.3/17.7%, 90.4/9.6%, and 38.1/61.9% for A. pungens and J. deppeana, respectively. The phenology indicated a finding related to the greater abundance of ripe fruit in autumn and winter (p < .01). This coincided with the greater abundance of seeds found in scats during these seasons. Endozoochory and diploendozoochory enhanced the viability and germination of the seeds (p > .05), except in those of A. pungens dispersed by coyote. These results suggest that carnivores, particularly the gray fox, the coyote, and the bobcat, play an important role in forest seed dissemination, and thus forest regeneration, by making both a quantitative and qualitative contribution to the dispersal of the two pioneer species under study.

Plant responses to fire in a Mexican arid shrubland

BackgroundFire responses of species in arid environments have only been scarcely studied. We studied four species (Dasyliron lucidum Zucc., Juniperus deppeana Steud., Echinocactus platyacanthus Link & Otto, and Agave potatorum Zucc.) in the Tehuacán-Cuicatlán Biosphere Reserve, Mexico. The objectives were to describe and quantify survival and resprouting, as well as the factors determining them, for the selected species. Six months after a 330 ha wildfire in 2014, 32 plots were established on three transects. Forest dasometric and fire severity variables were recorded. Logistic regression was utilized to obtain mortality and resprouting probability models, as well as linear regression to detect relationships among post- and pre-fire variables.ResultsAll species had high survival rates (74.5 to 97.7%). All surviving D. lucidum individuals resprouted apically. For J. deppeana, the probability of mortality was directly related to fire scar height on the trunk and inversely related to its diameter, whereas the probability of crown recovery was inversely related to the proportion of the tree height scorch. For E. platyacanthus, necrosed height was directly related to plant height. There was a positive relationship between basal area and the emission of new leaves for the A. potatorum.ConclusionsIn the different species, several traits that allowed high fire survival rates were observed (e.g., thick cortex or bark, fleshy non-flammable leaves, flammable leaves that reduce fire intensity, high volume to surface ratio). Many of these were primarily linked to drought resistance. All species gain fire resistance or tolerance as they increase in size. We concluded that the studied arid ecosystem of Mexico can withstand an altered or a base fire regime.

Desarrollo de ecuaciones alométricas de biomasa para la regeneración de cuatro especies en Durango, México

El objetivo del trabajo consistió en el desarrollo de ecuaciones alométricas para estimar la biomasa aérea por fracciones de grosor de la regeneración de Arbutus arizonica, Juniperus deppeana, Quercus sideroxyla y Pinus cooperi en la Unidad de Manejo Forestal (Umafor 1008) en el estado de Durango. Se utilizaron datos provenientes de 114 individuos (25, 29, 30 y 30, respectivamente), colectados mediante un muestreo destructivo para ajustar los modelos. La aditividad de las ecuaciones de estimación de biomasa se aseguró mediante el ajuste simultáneo de todas las ecuaciones, con el procedimiento estadístico denominado 3SLS (Three-Stage Least Squares). Los modelos desarrollados permiten estimar la biomasa en peso seco de los componentes, peso total, hojas, ramillas (&lt; 0.5 cm), ramas finas (0.51 – 2.5 cm), ramas gruesas y tronco (&gt; 2.51 cm). Las ecuaciones alométricas con mejor ajuste correspondieron al peso total, con valores de coeficiente de determinación ajustado de 0.97, 0.94, 0.95 y 0.97 para Arbutus, Juniperus, Quercus y Pinus cooperi, respectivamente. En general las ecuaciones mostraron un ajuste satisfactorio en cada una de las fracciones; con ellas se podrán hacer estimaciones no destructivas de la biomasa por categoría de grosor de la regeneración de las cuatro especies estudiadas, lo que mejorará las predicciones de biomasa y almacén de carbono por fracciones en los bosques con presencia de los cuatro taxa estudiados.

Durabilidad natural de la madera de siete especies forestales de El Salto, Durango

Para sentar las bases de una adecuada utilización de la madera, es importante conocer su durabilidad natural bajo la acción de agentes bióticos y abióticos, por lo que el objetivo de este estudio fue determinarla en madera de Pinus durangensis, P. cooperi, P. strobiformis, P. teocote, Juniperus deppeana, Arbutus spp. y Quercus sideroxyla procedente de la región de El Salto, Durango, mediante evaluaciones rápidas (microcosmos terrestre y exposición a hongos degradadores). La durabilidad en microcosmos terrestres se consideró como las pérdidas de masa y de módulo de elasticidad dinámico (MOEdin). Para la exposición a los hongos solo se tomó en cuenta la pérdida de masa. Los resultados de la durabilidad en microcosmos terrestre, de acuerdo con la Norma Europea EN 350-1, clasifican a la madera en tres categorías: moderadamente durable (Juniperus deppeana, P. cooperi y P. durangensis), poco durable (P. teocote) y no durable (P. strobiformis, Quercus sideroxyla y Arbutus spp.). En relación a la pérdida del MOEdin, las cuatro especies de pino y Juniperus deppeana registraron el menor valor, con 8.77 % en promedio; mientras que Quercus sideroxyla y Arbutus spp. Registraron hasta 25.63 %. En cuanto a la exposición a hongos, Trametes versicolor degradó en mayor medida la madera, con 16.15 % de pérdida de masa, destaca Quercus sideroxyla, con 32.57 %.

Anatomical and chemical characteristics of leaves and branches of Juniperus deppeana var. deppeana (Cupressaceae): A potential source of raw materials for the perfume and sweet candies industries

In North America, the genus Juniperus has a high commercial value because of the natural products derived from its wood, bark and leaves. In Mexico, the species of this genus are commonly known as junípero, sabino, enebro and táscate and they could represent potential sources of valuable products. To the best of our knowledge, this is the first report dealing with the anatomy and the phytochemistry of the endemic species Juniperus deppeana var. deppeana. From the first viewpoint, the resin canals are very large and they occupy one third of leaf volume. In the leaves, they are round, large and turgent, whereas in the branches, they merge and form large, elliptical cavities. The origin of resin ducts in branches is either the cortex or the phloem. They never form in the xylem. The phytochemical analysis of the crude extracts and essential oil of the leaves and branches showed that J. deppeana is a rich source of important polyphenolics and essences and might have the potential to be used in formulations containing this plant with applications in different areas, such as cosmetics, food and health care industries.