Andricus quercuslaurinus Melika & Pujade-Villar (Hymenoptera: Cynipidae) is a gall wasp from the branches (asexual reproduction) and leaves (sexual reproduction) of the Quercus affinis Scheidw. oak in Acaxochitlán, Hidalgo, Mexico. Severe infestations on the leaves cause a delay in growth and, given time, the death of trees with large levels of damage. This study evaluated the effectiveness of the pesticides Imidacloprid, Spirotetramat, Acephate and Abamectin when applied through foliar spray on the adult population of wasps that oviposit on the leaves, as well as on the eggs and larvae of the oak galls. Acephate prevented oviposition on the treated foliage. The least number of oak galls was found on the trees treated with Acephate; furthermore, they had no larvae. On the other hand, Spirotetramat had not been evaluated for the control of Cynipidae; alongside Imidacloprid, these pesticides were effective in reducing the survival of eggs and larvae. Spraying the pesticides Acephate (1.20 kg·ha^-1), Spirotetramat (0.75 L·ha-1), and Imidacloprid (1.00 L·ha-1) on Q. affinis foliage are options to be considered for the control of A. quercuslaurinus given their significant effects (P = 0.05) on the mortality of the eggs with regard to the control.

The modulus of rigidity of wood is useful for the structural calculus and manufacture of wood products. The objective of this research was to determine the modulus of rigidity (GLT) of seven species of Mexican woods, performing torsional vibration tests. The density, moisture content and natural frequency of smaller specimens were also determined. The GLT values of the seven species are similar to those proposed by the revised authors for woods with comparable density and moisture content. The moduli of rigidity varied between 695 MPa and 2,807 MPa. The values for each species oscillate around the linear prediction proposed by the elastic model of the wood. The wood density and the natural frequency of vibrations in torsion are predictors of the dynamic modulus of rigidity with coefficients of determination of 0.98 and 0.81 respectively.

Michoacán is the fifth state with the greatest diversity of plant species, excelling due to its richness in families, genera and species of flowering trees in Mexico. Therefore, in this paper the potential distribution of 12 species of Pinaceae was evaluated in current conditions and future climate change scenarios through ecological niche models. Data on the current climate, future scenarios, soil properties and digital elevation model were used as environmental predictors. The modeling was done using the Maxent software. 75 % of the data on the species presence was used for the training of the models and the remaining 25 % for model validation. The output grids were classified into three categories of area for the species distribution: unsuitable, marginal and suitable. The models show that there will be a 16 to 40 % decrease in suitable areas in the 2015-2039 and 2075-2099 periods, respectively. The species most affected by the decrease in their distribution will be Abies religiosa, Pinus leiophylla and Pinus teocote.

Frosty pod rot in cacao (Moniliophthora roreri) is the main limitation on the production of cacao (Theobroma cacao) in Mexico. A sustainable alternative for the control of the disease is the use of the Trichoderma mushroom. The objective of this study was to select isolates that are native to Trichoderma with the best antagonist and physiological in vitro characteristics for the control of M. roreri. For this, 50 isolates of Trichoderma obtained in the cacao agroecosystem were characterized. Mycelial growth and the production of conidia at 25, 30 and 35 °C were considered the physiological variables. Mycoparasitism, antibiosis and potential antagonism were the antagonist variables. Significant differences (P = 0.0001) were found in all evaluated variables. The interval of the optimal temperature for mycelial growth and the production of conidia was 25 to 30 °C. Mycoparasitism varied between 0 and 100 %, and only the isolates of six species showed this characteristic. Antibiosis varied between 6.8 and 55.5 % and potential antagonism varied from 3.4 to 69.0 %. Trichoderma virens (TTC017) and T. harzianum (TTC090, TTC039, TTC073) showed the best potential in vitro biocontrol, so they are promising strains for future investigations on biological control of cacao moniliasis.

Great efforts are carried out at a global level in order to determine the effect of fire on the mortality of tree species, like the Pinus genus. This paper evaluated the influence of fire on the probability of mortality of young Pinus hartwegii trees in the Izta-Popo National Park, a protected natural area in central Mexico. The effects of a medium to high intensity fire that occurred in March 2013, a low intensity prescribed burning applied in April of the same year, and a control area without recent fire presence were evaluated and compared.  The  results  showed  that  after  18  months  of  the  applied  treatments,  the  tree mortality in the area with prescribed burning was 13 %, whereas tree mortality in the area with  fire  and  in  the  control  area  was  28  and  4  %,  respectively.  Six  logistic  models  were obtained in order to predict mortality; the percentage of damaged canopy, scar height, and normal bark diameter were the significant predictive variables (P < 0.05). The results suggest that a decrease in the photosynthetic rate and nutrients,transport associated with damage to the canopy and cambium, are closely related to the probability of mortality.

A crown profile model for Pinus cooperi Blanco in UMAFOR 1008 (El Salto, Pueblo Nuevo, Durango) was developed from data corresponding to 92 sampled trees. Trees with well-formed crowns were selected from stands varying in age, density and site quality. Diameter at breast height, total height, crown width, crown length, and crown profile were measured  in  each  tree.  To  predict  the  crown  profile,  basic  geometric  shapes  and  several mathematic models were evaluated. The model developed by Hann (1999) best described the experimental data of the total crown, light crown, and shaded crown, accounting for over 92 % of the observed variability.

Wood energy crops in a short rotation coppice (SRC) commonly consist of single-stem tree individuals in the first short cycle, but from the second cycle onward numerous sprouts or shoots emerge from each stump, resulting in interesting challenges when estimating their biomass. The aim of this study was to identify species, rotation length and types of allometric models used to estimate biomass in SRC through a  detailed  search  of  the  scientific  journals  in  the  Scopus  and  Web  of  Science  databases. Among the most commonly used models to estimate biomass (y) is the typical exponential model,  which  has  the  following  predictors:  diameter  at  breast  height  (D)  (y=b₀D^b1), stem  basal diameter (Db) (y = b₀Db^b1) and the combination of diameter at breast height squared by total height (D²H) ( y= b₀ + b₁ D²H) 1 D 2H), stands out. The genera with the largest number of different models were Populus, Salix and Eucalyptus. The first two are the most studied. The rotation length used in the crops studied ranged from one to 15 years.

A new generalized taper model for Pinus radiata is presented in some types of soils. This is a non-linear model fitted with data from 264 trees aged between 15 and 31 years, harvested in 27 stands located in 11 communes from the Biobío and the Araucanía, Chile, in three different types of soils, i.e. volcanic sand, volcanic ash and marine sediments. The generalization of the model was achieved by incorporating stand state variables, and the subsequent simplification of it incorporating site variability in its parameters. The volume function obtained from the numerical integration of the taper model predicts over 97% of the variation in stem volume without bark estimated by the formula of Smalian in the three types of soils.

Given the growing demand for harvest residues for energy generation from Pinus radiata forest  plantations  in  south-central  Chile,  models  for  estimating  site-specific  forest residue production are needed. In this study, allometric models were fitted to estimate the potential biomass resulting from the harvest of P. radiata plantations located in volcanic sand,  recent  volcanic  ash  and  sedimentary  soils,  taking  into  consideration  management gradients and site productivity, in characteristic sites of south-central Chile. The fitted models allowed estimating conversion factors and developing estimation models at individual tree and stand level. Results suggest that conversion factors for changing from stem biomass to potential  residue  biomass  have  a  negative  exponential  relationship  with  tree  size.  Models fitted  for  estimating  at  individual  tree  level,  starting  with  diameter  and  height  variables, suggest that the models depend on soil origin, while in the case of stand-level estimates the fitted model is independent of soil origin, gradient management and productivity.