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Prosopis alba is the most important native species in the semi-arid Chaco for afforestation with multiple objectives. More than 50% of the planted area in Santiago del Estero, Argentina, has been established in areas with very different site quality, generating a heterogeneous growth behavior. It is proposed to evaluate the influence of edaphic factors on the growth of plantations Prosopis alba Griseb (algarrobo) in areas of the semi-arid Chaco, information that will facilitate silvicultural decision making and will allow predicting the quality of sites with forestation potential based on conditions of the soil. The correlation between dasometric and edaphic variables was evaluated in relation to 3 kinds of site quality (CI, CII and CIII). A dominant height projection model expressed as a Site Index with the most correlated edaphic variables was determined, which explains 42% of the variation in growth. The electrical conductivity has a threshold of 10 dS m-1 for the CI and CII with Site Index of 10 and 8 respectively; for higher EC values ​​the growth of the mass decreases. The concentration of soluble cations varies in relation to the site index, the CI and CII have low sodium concentrations, with a critical value of approximately 39 mEq L-1. Growth is conditioned by chemical properties of the soil, the presence of salts would further explain the impact on growth, with a saline threshold from which growth is compromised from a productive approach.

O objetivo deste trabalho foi avaliar o potencial das madeiras de Eucalyptus benthamii, Eucalyptus dunnii, Eucalyptus grandis, Eucalyptus saligna e Eucalyptus urophylla, para produção de painéis colados lateralmente (EGP) e madeira laminada colada (MLC). As propriedades físicas e químicas das madeiras foram determinadas com base nas normas COPANT 461/459:1972 e TAPPI 204/252:2002. Foram confeccionadas juntas coladas com adesivo acetato de polivinila (PVA), com gramaturas de 150 g m-2 e 200 g m-2, e resorcina-formaldeído (RF), com 200 g m-2 e 300 g m-2. A qualidade de colagem foi avaliada por meio de ensaios de cisalhamento, com base na norma EN 13354:2008. Todas as espécies apresentaram densidade básica de média a baixa e anisotropia de contração de média a alta. O teor de extrativos totais e pH estão dentro da faixa referenciada na literatura. As avaliações dos resultados com base nos requisitos da norma EN 15353:2008 para 5º percentil inferior indicaram que as espécies E. benthamii, E. dunnii, E. grandis e E. saligna, apresentam potencial para produção de painéis EGP com adesivo PVA, para o uso interno, e externo com cobertura. Para a colagem com adesivo RF, o E. dunni apresentou melhores resultados, sendo indicativo do seu bom potencial para a produção de madeira laminada colada, visando aplicações estruturais em ambientes interno úmido e externo. Para os dois tipos de adesivos o aumento na gramatura não afetou os resultados de cisalhamento das juntas coladas.

El aprovechamiento sustentable de los recursos forestales consiste en utilizarlos para generar riqueza, mejorando indicadores sociales y evitando el desequilibrio ambiental. El objetivo del estudio fue determinar la sustentabilidad ambiental de las concesiones forestales en el departamento Huánuco, Perú, mediante el análisis multicriterio basado en el uso de indicadores. Se construyeron indicadores que incluyen la diversidad de macrofauna edáfica evaluada hasta 30 cm de profundidad, como evidencia del estado de conservación y mantenimiento del suelo. Los indicadores fueron estandarizados mediante escala de 0 a 4.0, siendo 4.0 el mayor valor de sustentabilidad; posteriormente, fueron ponderados multiplicando la escala por un coeficiente, según su importancia respecto a la sustentabilidad. Una concesión forestal es ambientalmente sustentable, si el índice de sustentabilidad ambiental (ISA) es ≥ 2.0. La encuesta elaborada se aplicó a titulares y trabajadores de las concesiones forestales. Para conocer si el ISA en 60% de concesiones forestales supera el valor 2.0, se empleó la prueba estadística no paramétrica chi cuadrada; también se realizó entre indicadores, la correlación de Pearson con un 95% de confiabilidad. La prueba chi cuadrada confirma que las concesiones forestales con aprovechamiento forestal manual (60% del total), son ambientalmente sustentables (X2 = 0.056, p-valor = 0.814). Se registró fuerte correlación positiva estadísticamente significativa (r = 0.970, p-valor < 0.05) entre los indicadores “conservación y mantenimiento del recurso suelo” y “conservación de flora silvestre”. El aprovechamiento forestal manual mantiene armonía con el entorno natural, y aunque el aprovechamiento forestal mecanizado sea de impacto reducido, genera daños al ecosistema.

Nursery fertilization is a cultural practice with potential to improve seedling quality, but it is necessary to define adequate fertilization levels for each specie. This study evaluated the effect of fertilization levels on seedling quality of Pithecellobium dulce during the nursery stage. The applicated levels were nine; they consisted in regimes in which a controlled-release fertilizer (CRF) 18-6-12, in three doses (4 g L-1, 6 g L-1, and 8 g L-1 of substrate) was mixed with a water-soluble fertilizer (WSF) 20-20-20, in concentrations of nitrogen of 0 mg L-1, 75 mg L-1, and 150 mg L-1. The fertilization regimes effects were determined by assessing morphological attributes of seedling quality, net assimilation rates (NAR), and nutrimental status of N-P-K on four-month old seedlings. A seedling-quality test was designed to undergo the seedlings to a stress condition of both nutrient’s deficiencies and biomass loss, thereby measuring their resprouting capacity and growth. Statistical differences were observed by the effects of the fertilization regimes. Overall, an increase of the morphological quality and NAR was promoted by the mix of 8 g of CRF with 150 mg N L-1 of WSF, although the main responses in relation to the nutrimental status were of deficiency and dilution. In the seedling-quality test, the seedlings had limitations to induce either their resprouting or their growth according to the amount of nutrimental reserves. The fertilization with CRF and WSF have potential to enhance the seedling quality of P. dulce during nursery culture.

In the last decade, biomass has become a renewable energy option; however, the absence of studies to understand its market limits its implementation. Therefore, the present study analyzed the perception of the actors that make up the vegetable biomass market for energy purposes from the perspectives of producers, intermediaries and consumers. For which 52 producers, 33 intermediaries and 55 consumers of tree biomass from the North Zone of Costa Rica were surveyed, studying the market from a technical, environmental, financial and social perspective, and identifying the variables that limit the market. The results showed that, for environmental and social aspects, there is a similarity of perception between the three sectors; however, in the financial and technical aspects there are significant differences, specifically in the price of biomass, homogeneity of biomass and the associated costs in addition to the competition from other sources of agro-industrial biomass. The analysis showed that biomass variability in terms of presentation affects 40.5% of the market, species variation 24.8%, moisture content 10.6%, biomass availability over time 8.4%. Finally, the organization and structuring of the market by 8.9% and other variables add up to the remaining 6.8%, being necessary an organization regarding the sale of biomass and the corresponding articulation between the sellers and consumers with the participation of intermediaries for the viability of the biomass market in Costa Rica.

The foliage of some trees can be used for feeding small ruminants, when the chemical quality and the content of secondary metabolites are suitable. The use of Erythrina americana as feed requires knowledge of its nutritional composition at different regrowth ages. The objective of the study was to determine the influence of the regrowth age of E. americana on the content of phenolic compounds and chemical composition of the foliage, from 24 trees that are part of the live fences of a sheep farm. A completely randomized design was used; the fixed factor was the regrowth age of E. americana (60 days, 90 days and 120 days). The response variables were: dry matter, crude protein, ash, organic matter, neutral detergent fiber, acid detergent fiber, total polyphenols, non-tannin phenols, condensed tannins, hydrolysable tannins and total tannins. The regrowth age affected (P < 0.05) the content of crude protein, structural carbohydrates, total polyphenols and tannins (condensed, hydrolysable and total); the rest of the variables was not affected (P> 0.05). At 90 days, the highest crude protein content was detected. The lowest structural carbohydrates content was between 90 days and 120 days. As the regrowth age increased, a higher condensed tannins concentration was detected. Crude protein, condensed tannins and structural carbohydrates in foliage of E. americana, at an age of regrowth of 90 days, allow to consider it as a complementary food for small ruminants.

Allometric equations are an important tool for accurate estimation of aboveground biomass of trees and their components. This document presents additive equations for estimating aboveground biomass in Pinus cembroides Zucc trees. In October 2017, a total of 21 trees of different diameter classes (5 cm to 40 cm) were felled and sectioned into three structural components: stem, branches and twigs with leaves to obtain their biomass. Two systems of non-linear equations were developed, in which the additivity was guaranteed by establishing the total aboveground biomass (Bt) as the sum of the biomass estimates of each component of the tree. The system that integrated the diameter at breast height and the total height of the tree as predictor variables explained more than 92% of the variation observed in the biomass data of the components and 98% of variability of the Bt. The average proportion of biomass in the stem, branches and twigs with leaves comprised 43.2%, 41.2% and 15.5% of the tree Bt, respectively. The equations generated in this study will contribute to improve the precision in biomass estimation and carbon inventories in P. cembroides forests.

The eucalyptus gall wasp Leptocybe invasa, is an Australian native pest that affects plantations of Eucalyptus spp. E. camaldulensis is the most susceptible host; worldwide it is used for sawn wood and pulp or used as urban tree in many Mexican cities. The exotic nature of L. invasa and its development in galls, impedes its natural regulation for native entomophagous in Mexico, which represents a threat for the producing regions of eucalyptus and urban areas. Thus, the present study evaluated the efficiency of insecticides in greenhouse conditions, by means of soil and foliar applications, on the immature stages: egg, young larva, mature larva and pupa, using plants of E. camaldulensis less than one year old. Major mortality was registered in egg (35% to 79%) and young larva (40% to 75%) when Carbofuran or Imidacloprid was applied to the soil. The efficiency of these products diminished (mortality < 5%) in the stages of mature larva and pupa. The application of Spirotetramat stood out in the application on leaves, but it is not enough on its own to control the plague (mortality < 40%). Based on the results of this investigation, and previous studies published in the specialized literature, it is suggested that chemical management on L. invasa in greenhouses is feasible but only as an emergency measure. This, using Carbofuran or Imidacloprid in application to the soil, alternating with an application on the leaves after Spirotetramat.

Black cherry (Prunus serotina Ehrh.) is a tree native to North America, and almost all parts of this plant have some potential use. This species makes up a complex of five subspecies with morphological differences distributed in diverse habitats. Several biological aspects of the species are currently being debated or remain poorly studied, hindering the successful planning of conservation and exploitation strategies for the species. This review aims to highlight its biological, cultural and commercial importance, and the need to include it in programs of sustainable genetic resources conservation and use. Seven relevant aspects to this aim were reviewed: subtle morphological differences among subspecies, undefined phylogeny, hypothetical variation in ploidy level, molecular variability, traditional and modern exploitation, domestication and ethnobotanical relevance, and potentiation of its genetic resources. This article argues that thre is the need of persistent and rigorous studies on these, and other aspects, in order to better harness the genetic resources of black cherry; and emphasizes that, in the near future, in Mexico the exploitation of the forestry and logging potential of this native species must be fostered.

Biomass modeling in forest plantations is an alternative to quantify carbon stored in vegetation. Predictions are important for management decisions or efforts to mitigate climate change. An important relationship is that of soil moisture (q) with biomass. The 3-PG model was used to predict biomass production in different scenarios of q in a Eucalyptus globulus plantation in subtropical climate. From 2007 to 2009, we measured q in the 0 m - 1.8 m soil profile, leaf area index and the diameter at breast height. Precipitation was registered and crop and potential evapotranspiration were estimated for one year based on the water balance, with values of 959 mm, 514.3 mm and 1303 mm, respectively. The predictions of leaf area index and evapotranspiration overestimate observed data. At eight years, biomass was modeled as 165.5 Mg ha-1, of which 23.1 Mg ha-1 is stored in roots and 59.5 Mg ha-1 in aboveground biomass. In conclusion, minimum soil moisture data are necessary to model diameter at breast height and it is desirable to assemble models instead of selecting a single model or using the average of them.