Introduction

Sustained timber yield is the ability of the forest to maintain its production at a similar level through time.

Objective

To propose a procedure to estimate a posteriori whether the long-term timber yield of a forest has been sustained by assessing the heights and diameters reached by same-aged trees but established in different years.

Materials and methods

Diameters were gotten from stem analysis and heights were estimated by linear interpolation. Trees were grouped by size, and heights and diameters of same-aged trees established in different years were regressed versus the Year at which Trees Reached that Age (YTRA). All the trees were analyzed by multiple regression, regardless of the size groups; the regression model included the reciprocal of the tree age and the YTRA as explanatory variables for height and diameter.

Results

Regression of heights and diameters versus YTRA at different ages (10, 20,…, 70) showed positive slopes, indicating that the more recently established trees had better growth and no evidence of deterioration of timber yield over time was found. The results on all the trees as a whole agreed with results for trees by size groups; these results coincided with what forest managers observed in situ.

Conclusion

The procedure provides user-friendly tools to detect any negative changes that may jeopardize timber yield sustainability, identify possible causes, and implement corrective management practices.

Introduction

Schinus molle L. (Anacardiaceae), known as pirul tree in Mexico, is a species rich in essential oil in leaves and fruits.

Objective

To characterize the phytochemical profile of essential oil obtained from S. molle leaves using two distillation systems and different extraction times.

Materials and methods

An intermediate scale Rayleigh batch distiller was used to extract essential oil from S. molle leaves collected in the central region of Mexico. The product obtained at different times was characterized by gas chromatography-mass spectrometry (GC-MS). The phytochemical profile was compared with the extract obtained in the Clevenger apparatus.

Results and discussion

The Rayleigh distiller had a higher extraction capacity, but the yield was 0.6 % lower (P = 0.05) than with the Clevenger apparatus at 120 min. A total of 37 compounds were found, of which 31 were present in the extract from the Rayleigh distiller, five were compounds of low concentration and one, classified as oxygenated sesquiterpene, had a high concentration (10.25 %) of essential oil. With longer extraction time, sesquiterpenes increased and oxygenated sesquiterpenes decreased. The essential oil had higher presence of hydrogenated monoterpenes, mainly α-phellandrene (21.20-28.57 %), limonene + β-phellandrene (19.07-27.78 %), camphene (3.32-9.93 %), α-pinene (5.74-8.56 %), β-mircene (2.95-6.91 %) and β-pinene (1.31-3.55 %).

Conclusions

The characterization of the extraction procedure and chemical profile of essential oil of S. molle can favor the exploitation of this species.

Introduction

Native Forest resources, mainly in the Brazilian caatinga biome, are important for the subsistence of the rural population as well as for the local red ceramic and gypsum industry.

Objective

To study the municipal disparity in the gross value of production of native timber products in Paraíba, Brazil.

Materials and methods

Data on the gross value of production (GVP) of forest products (firewood, charcoal and roundwood) of the municipalities of Paraíba, Brazil, from 1994 to 2017 were used. This information is available from the Brazilian Institute of Geography and Statistics (IBGE). Location indicators (location and redistribution coefficients) and specialization indicators (specialization and restructuring coefficients) were used.

Results and discussion

Firewood was the main timber product in the municipalities of Paraíba and there was a substitution effect between firewood and charcoal; the latter showed the best state redistribution and roundwood the lowest municipal production. The greatest specialization occurred in the municipality of Baía da Traição, represented by the exclusive production of charcoal. The municipalities of Tacima, Salgado de São Félix and Itapororoca showed greater restructuring, resulting from the change from charcoal to firewood production.

Conclusions

Firewood is the most important product in the state of Paraíba, Brazil. This study becomes an important source of information for the use of this resource.

Introduction

The city of Xalapa, Veracruz, faces a drinking water supply problem that increases every year due, among other factors, to deforestation and population growth.

Objective

To determine the willingness to pay (WTP) of domestic water users for forest conservation, taking into account the recharge zones of the Pixquiac sub-basin.

Materials and methods

A structured survey was designed and randomly applied to a representative sample of 113 households in Xalapa. The information was analyzed using an econometric model identifying the main social, economic and environmental aspects related to WTP for hydrological service for domestic use.

Results and discussion

The potential annual WTP amounts to 17 243 032.08 MXN by domestic water service users in Xalapa, Veracruz; 92.04 % of the population has an average monthly WTP of 10.23 MXN for the conservation of forest areas. This value is considered high in relation to other studies whose average contribution per person is 5.00 MXN and may be due to the high level of awareness that exists in the region about the importance of forests. Income, source of income, educational level and age are significant variables positively related to WTP.

Conclusion

There is WTP by users that can be used to encourage forest conservation in water recharge zones in the study area.

Introduction

Understanding the hydrological balance and canopy structure in forest ecology and reforestation can predict the productivity of plantations.

Objectives

To monitor an incident rainfall partitioning in a plantation of Schizolobium parahyba (Vell.) S. F. Blake and Samanea saman (Jacq.) Merr. and its relationship with canopy openness and leaf area index.

Materials and methods

Incident rainfall partitioning was monitored for one year in a plantation of S. parahyba (4.4-5.4 years) and S. saman (5.8-6.8 years) in Rionegro, Santander, Colombia. Each plantation had linear rain gauges installed under the canopy and around the stem of the trees selected.

Results and discussion

Throughfall (Tf), canopy interception losses (I) and stemflow (Sf) in the 12 months corresponded to 77.5, 22.3 and 0.44 %, respectively, in relation to open precipitation for S. parahyba (2 270 mm) and to 84.7, 15.3 and 0.05 %, respectively, for S. saman (2 140 mm). For both species, Ip and effective precipitation were higher (P < 0.05) in the two dry periods of the year, while I and Sf were higher in the two rainy periods. Canopy openness was correlated only with I and Tf in S. saman, while leaf area index was not correlated with any variable.

Conclusion

Rainfall partitioning points out different paths in the same studied environment. It is important to analyze the hydrological processes in reforestation environments by taking into account the morphology of the species involved.

Introduction

Anthropogenic disturbances such as dredging affect the structural and functional components of riparian forests, compromising their capacity to provide ecosystem services.

Objectives

To quantify the loss of vegetation cover of a riparian forest by dredging activities in the Pitillal River (Puerto Vallarta, Jalisco).

Materials and methods

The multispectral NDVI index was used with land use and vegetation change matrices to determine the extent, loss of vegetation cover and impact at the time of dredging and one year after the event.

Results and discussion

The dredging area was 6.93 ha, of which 2.82 ha (40.7 %) were severely affected areas with total loss of vegetation cover; bare soil increased in surface area by 736 %. One year after clearing, the beginning of a succession process was identified, with bare soil being replaced by herbaceous plants and shrubs.

Conclusion

This forest was severely damaged by dredging but showed possible recovery after the impact.

Introduction

Ectomycorrhizal associations are an essential component of nutrient cycling and forest health.

Objective

To evaluate the effects of spore inoculation of Pisolithus tinctorius (Pers.) Coker & Couch and Astraeus hygrometricus (Pers.) Morgan on Pinus arizonica Engelm. growth.

Materials and methods

Three mycorrhizal inoculation treatments (A. hygrometricus, P. tinctorius and Ectorrize®) were applied with three volumes (10, 25 and 50 mL: 10⁶ spores∙mL^-1) and a control group with no inoculum. The variables measured were mycorrhizal survival and colonization; plant height; shoot length and diameter; root length and biomass. The ectomycorrhizas were characterized and a mineral analysis of nutritional elements in the shoot and root was performed. The effects of fungal species and inoculum volume were determined by randomized ANOVA (α = 0.05).

Results and discussion

The volume of this inoculum had no significant effect (P > 0.05) on the variables, but there were differences between the fungal species and the control (P ≤ 0.05); with P. tinctorius having the greatest significant effect. Inoculated plants had higher survival rate and higher amount of minerals in the composition compared to non-inoculated plants (P ≤ 0.05). The ectomycorrhizas showed clear morphological differences; the Hartig net was observed as an indicator.

Conclusion

Inoculation with the ectomycorrhizal fungi improved the morphological development of P. arizonica. The smallest inoculum dose (10 mL: 10⁶ spores∙mL^-1) is recommended, mainly of the fungus P. tinctorius.

Introduction

In some forest regions of Mexico, it is common for short-sized logs to be hand-loaded; however, the efficiency of this operation has been poorly documented.

Objective

To evaluate the effect of log size and distances on manual loading productivity in forests in the region of El Salto, Durango, Mexico.

Materials and methos

A total of 738 manual loading cycles of 4 ft (1.22 m) logs were timed using the ‘back-to-zero’ method. Log volume and loading distances were taken by direct in-situ measurement. Average log diameters were divided into three categories and loading distances into four. The system yield was determined by relating log volume to total loading time.

Results and discussion

Manual loading yield was established from 3.80 to 16.42 m³∙h^-1, influenced by log diameter and loading distances, because 82 % of the loaded volume corresponds to logs with diameters from 10 to 30 cm, which are loaded every 12 s; logs larger than 30 cm require 27 s. Also, 91 % of the loading volume is carried out in the first 10 m of distance from the truck and takes 15 s per log, and, at longer distances, 35 s.

Conclusions

It is possible to increase the performance of the operation by considering maximum loading distances in the order of 10 m.

Introduction

Moringa peregrina (Forssk.) Fiori seeds have good health promoting properties and considerable potential as a biofuel. However, cultivation is limited by variable seed quality.

Objective

To study the effect of seed position in the pod and leaching treatment on germination and vegetative characteristics of seedlings.

Materials and methods

The seeds numbered 1 to 6 (the position near the attached part to stem was No. 1). To study the effect of leaching on germination and the vegetative characteristics, seeds were exposed to running water for 0, 24 and 48 h. The experiment was performed in a completely randomized design as a factorial arrangement.

Results and discussion

The position of the seed had a significant effect (P ≤ 0.05) on the variables, except for root fresh and dry weight and number of leaves; germination was higher for seeds in the middle position of the pod, which were also the heaviest (c. 0.73 g). There was a significant interaction between seed position and leaching, except for collar diameter and stem height. Leaching for 48 h increased germination to 88 %. This treatment produced the highest number of leaves (16.82) and the highest values for collar diameter (3.50 mm), dry weight of leaves (0.11 g), stem (0.08 g) and root (0.50 g), and root length (10.10 cm). The interaction of position and leaching was significant.

Conclusions

The overall germination performance and seedling growth can be improved by immersing seeds from the middle pod position in leaching treatment for 48 h.

Introduction

Loxaulus hyalinus is a cynipid (Hymenoptera) that attacks oak groves (Quercus laeta Liebm.) in Mexico City. The insect\'s biology and damage potential are unknown.

Objectives

Describe the biology of the sexual phase of L. hyalinus and its effects on Q. laeta, and list the associated inquilines and parasitoids.

Materials and methods

To determine the period of each stage of L. hyalinus, galls were collected from infested twigs and periodically dissected to describe their development and the presence of inquilines and parasitoids in the period 2019- 2022.

Results and discussion

Sexual generation began in October when the first symptoms of galls development were observed on twigs, and concluded in May of the following year, when adults emerged. The presence of many galls alters the growth pattern of the tree crown. Two Synergus species were found as inquilines and nine genera of chalcidoid parasitoids were associated with L. hyalinus.

Conclusions

Sexual generation of L. hyalinus develops in twig galls and its only host confirmed is Q. laeta. This pest causes no death of its host but severely affects the shape of the crown.