Efectos del vibrado del pino piñonero (Pinus pinea L.) en el vigor de los árboles: densidad de copa, crecimiento de guías y parásitos de debilidad

In the Northwest of Spain the mechanized harvesting of pine cones is more and more frequenIn order to quantify the effects of vibration on the vigor of the trees, parcels of stone pine were planted in plateau and countryside. Both the mechanized and manual harvests were analyzed in adult and young trees. The growth of the tree shoots was measured. The presence and abundance of three insect plagues was analyzed in those same trees: Tomicus piniperda, Rhyacionia buoliana and Thaumetopoea pityocampa. The average shoot length of those trees manually harvested was superior to that of those mechanically harvested. The difference was very significant in young trees (40-50 years old) in the countryside and in adult trees (more than 80 years) on the plateau. Rhyacionia buoliana was more abundant in adult trees that young trees, but the relation of its abundance with the harvest method was not seen. The presence of Tomicus piniperda was rare and was only detected in mechanically harvested stands. Thaumetopoea pityocampa was more frequent in trees harvested by hand than those harvested mechanically and was more abundant in young stands. The percentage tree of defoliation was low in all stands independent of harvest method.En el noroeste de España es cada vez más frecuente la recolección mecanizada de piña. Para cuantificar los efectos del vibrado sobre el vigor de los árboles se instalaron en montes de páramo y de campiña parcelas donde se realizó cosecha mecanizada y manual en arbolado adulto y joven. Se midió el crecimiento de los brotes y se analizó la presencia y abundancia de tres insectos plaga sobre estos árboles, Tomicus piniperda y Rhyacionia buoliana, considerados parásitos de debilidad, así como Thaumetopoea pityocampa. La longitud media de los brotes fue superior en árboles cosechados manualmente. La diferencia es importante en árboles jóvenes (40-50 años) de campiñas y en árboles adultos (más de 80 años) de páramos. Rhyacionia buoliana fue más abundante en árboles adultos que en arbolado joven, pero no se vio relación de su abundancia con el método de cosecha. Tomicus piniperda fue escaso y sólo se detectó en rodales cosechados mecanizadamente. Thaumetopoea pityocampa es más frecuente en rodales cosechados manualmente, y en rodales jóvenes lo que indica que selecciona los árboles de crecimiento más vigoroso para alimentarse. Los porcentajes de defoliación fueron bajos en todas las parcelas

Seed Movement Germoplasm for tropical forest tree species in southeastern Mexico

Vectorial information in shapefile format of germplasm movement zone

Seed Movement Germoplasm for tropical forest tree species in southeastern Mexico

Vectorial information in shapefile format of germplasm movement zone

Density management diagram for teak plantations in Tabasco, Mexico

Density management diagrams are valuable tools for managing specific forest species. The aim of this study was to obtain a density management diagram for teak (Tectona grandis L.) plantations in the State of Tabasco in Mexico. To achieve this objective, a set of 10 plantations were studied, in which 42 plots were established. Two equations were fitted simultaneously, including one related to the quadratic mean diameter, stand density and dominant height and the other which related the total stand volume to the quadratic mean diameter, stand density and dominant height. The results showed that the diagram had an acceptable predictability, thus indicating its usefulness and accuracy in planning silvicultural interventions. This diagram is a very powerful tool that can enable stakeholders to manage teak plantations in the State of Tabasco

CARBON STORAGE IN TREE BIOMASS AND SOILS IN SILVOPASTORAL SYSTEMS OF THE HUMID TROPICS

Background: The transformation native of forests into pasturelands for livestock farming, affects ecosystems carbon (C) stores and soil properties. Objective: Estimate the carbon stored in tree biomass (above and below ground) and determine soil organic carbon and some physical and chemical properties in two silvopastoral systems (SPS): scattered trees in paddocks (STP) and living fences (LF), taking grass monoculture (PM) as reference. Methodology: The C content in the above and below-ground biomass of the trees was estimated through allometric models, the C fraction of the soil from 0-100 cm was determined by chemical digestion, and the soil organic carbon (SOC) stock was estimated. The physical and chemical properties of the soil were determined. Results: SSPs with STP and LF stored a greater amount of total C (387.0 and 362.6 Mg ha-1 de C) compared to GM (312.5 Mg ha-1 de C), tree biomass contributed 6.3% and 8.4% for STP and LF respectively. Soils stored 90% of the total C in STP and LF. The tree component favorably modified soil pH, the bulk density, the organic matter, carbon, and nitrogen content. Implications: This study contributes with scientific information useful to develop low-emission livestock systems for transition towards climate-smart farming systems essential to meet the Sustainable Development Goals. Conclusions: Tree diversity and density in STP ADP and LF play an important role in the storage of total C, favor C accumulation in the deeper layers of the soil and improve the physical and chemical properties of the soil

Growth of four tropical tree species in petroleum-contaminated soil and effects of crude oil contamination

Under greenhouse conditions, we evaluated establishment of four tree species and their capacity to degrade crude oil recently incorporated into the soil; the species were as follows: Cedrela odorata (tropical cedar), Haematoxylum campechianum (tinto bush), Swietenia macrophylla (mahogany), and Tabebuia rosea (macuilis). Three-month-old plants were planted in soil with three treatments of heavy petroleum and a control (C0 0 mg kg−1; C1 18,000 mg kg−1; C2 31,700 mg kg−1; C3 47,100 mg kg−1) with four repetitions per treatment and species; the experiment was carried out for 245 days. Height and biomass of all species significantly diminished as petroleum concentration increased, although plant survival was not affected. The quantity of colony-forming units (CFU) of rhizospheric bacteria varied among tree species and treatments; petroleum stimulated bacterial CFU for S. macrophylla. The number of fungi CFU for S. macrophylla and T. rosea was significantly greater in C0 than in soil with petroleum, but among species and among different concentrations, no significant differences were found. The greatest percentage of total petroleum hydrocarbon (TPH) degradation was found in C1 for soil without plants (45 %). Differences from the remaining treatments (petroleum concentrations in soil and plant species) were not significant (P <0.05). Among all trees, H. campechianum had the greatest TPH degradation (32.5 % in C2). T. rosea (C1) and H. campechianum (C2) resulted in petroleum degradation at levels ranging from 20.5 to 32.5 %. On the basis of this experiment, the tree species used did not improve TPH degradation. However, all of them showed high rates of survival and vigor. So, as tree species provide goods and services, experiments with inoculation of hydrocarbonclastic microorganisms, addition of fertilizers, and mixture of tree and grasses are recommended