Resumo em Inglês:

ABSTRACT Background: Litter is an important component of ecosystems, and its characteristics (e.g., production, decomposition, and nutrient and carbon content) are relevant for the ecological maintenance of different ecosystems. Previous studies on decomposition patterns have focused only on short time periods. Furthermore, there is no information regarding the actual decomposition time of organic matter in the Brazilian savanna biome known as the Cerrado. Thus, analysis of the total decomposition time can provide reliable estimates for other models. This study aimed to evaluate total litter decomposition (100%) and its relationship with seasonality and floristic composition in the savanna forest (Cerradão) formation in central Brazil. Litter bags were randomly distributed over the soil, with 10 samples collected per quarter from August 2014 to May 2020. Single- and double-entry linear regression models were used to analyze the total litter decomposition. Results: The half-life (time for which 50% of the litter was decomposed) occurred at 360 days, and 100% of litter decomposition occurred at 2070 days. The single-entry model was more satisfactory for estimating the decomposition speed. There was a positive correlation between litter decomposition and precipitation, and the floristic composition helped to explain the litter decomposition trends. Conclusion: Litter decomposition in the Cerradão is related to floristic diversity (quality of the material) and to the synergism of factors that occur mainly in the rainy season. Thus, the results of this study can contribute to conservation initiatives.

Resumo em Inglês:

ABSTRACT Background: Dragon′s blood is a well-known traditional Chinese medicine, isolated mainly from the trunks of Dracaena trees. Overexploitation of the Dracaena resource has resulted in this plant becoming endangered. This work aimed to assess the potential to use various tissues of the Dracaena cochinchinensis tree, such as leaves and roots, to produce dragon′s blood. Results: We found that many dragon′s blood components accumulated in the bark of trunk and roots of D. cochinchinensis under natural conditions. In addition, small amounts of loureirin A were detected in leaves, suggesting that the leaves could be a potential source of dragon′s blood. Real-time quantitative PCR analysis showed that most of the genes tested in this study, which encoded enzymes involved in the biosynthesis of dragon′s blood flavonoids, were highly expressed in the bark of roots and trunk. Conclusion: We confirmed that the bark of roots and trunk of D. cochinchinensis tree were the main tissues for the synthesis and storage of dragon′s blood under natural conditions. This study demonstrated the potential to extract dragon′s blood from the roots that have been abandoned due to mining difficulties without destroying the tree, a process which would be beneficial to the protection of the endangered wild D. cochinchinensis tree populations.

Resumo em Inglês:

ABSTRACT Background: Atmospheric methane (CH 4) is responsible for approximately 20% of global warming since the preindustrial era. Forests are land ecosystems whose role is crucial for mitigating the greenhouse effect due to their capacity to capture and store C and preserve other processes such as CH 4 oxidation in the soil. On the other hand, in the particular case of afforestation, there are contradictory results about the magnitude of CH 4 uptake variation due to changes in methanotrophic bacteria activity and its relationship with micro-environmental conditions. Results: The average potential CH 4 oxidation rate in the laboratory (MOL) of afforested soil was 186% greater than that of the grassland, which could be marginally attributed to differences in soil physicochemical parameters like bulk density, pH and organic matter. A seasonal pattern in MOL was observed in both land uses, with the highest values at the warm and rainy season. MOL magnitude increased with soil depth up to 10-15 cm, which corresponds with the mineral layer. Conclusion: Pine afforestation would improve the biological soil attributes linked to methane oxidising bacteria compared to the grassland systems.

Resumo em Inglês:

ABSTRACT Background: Korean pine ( Pinus koraiensis Siebold & Zucc.) is one of the primary plantation conifer species of economic and ecological importance in northeast China. Forest biomass estimation in the broader landscape has been receiving attention from researchers and forest managers. The development of forest stand biomass models is regarded an effective method to estimate forest biomass at large scales. This study was carried out for developing stand-level biomass models for Korean pine plantations. Four additive methods were compared: Aggregation 1, Aggregation 2, Adjustment, and Disaggregation. All the stand biomass additive modeling systems (i.e., total, root, stem, branch, and leaf) included both stand volume and biomass conversion and expansion factors (BCEFs) as predictors. Results: The predictive performance of the four additive methods and Constant BCEFs were ranked as follows: Aggregation 1 > Disaggregation > Adjustment > Aggregation 2 > Constant BCEFs. The prediction accuracy of the four additive methods was not consistent across the stand volume intervals. Conclusion: The model based on the Aggregation 1 method was recommended for predicting stand biomass. However, different additive method should be selected according to the stand volume intervals of the Korean pine plantations.

Resumo em Inglês:

ABSTRACT Background: Monodominant Eremanthus erythropappus forests are dispersed in neotropical montane regions of southeastern and northeastern Brazil, forming ecotonal areas among other high altitude phytophysiognomies, with no information from their fauna communities and how these communities vary between phytophysiognomies adjacent. We examined the bird community of three preserved and three managed E. erythropappus forests, and compared them two other coexisting phytophysiognomies (cloud forests and montane fields), being three samples of each, in an ecotonal region between two biodiversity hotspot domains (Cerrado and Atlantic Forest), in southeastern Brazil (1300 to 1570m high). Results: The bird community of the natural E. erythropappus forests was shared with other vegetation, while the managed E. erythropappus forests presented the lowest species richness. However, even though managed E. erythropappus forests has almost no exclusive elements, their community caused a balanced variation (a set of very similar species, only changing the representativeness), suggesting that the abundance of the registered species varies along these phytophysiognomies. Conclusion: The species associated with the natural E. erythropappus forests represented 50% of the total species, in contrast to the remaining 50% associated with the areas of cloud forests and montane fields, and their sharing behaves as an ecotonal community, since its community coincides with elements which are also present in the avifauna of the other two sampled phytophysiognomies. The composition of the avifauna from managed E. erythropappus forests was more similar to the community registered in the montane fields.

Resumo em Inglês:

ABSTRACT Background: Factors determining the coexistence of species have been recognized since Darwin, but empirical studies have brought the relationship between niche similarity and competition into question. Knowing the mechanisms of coexistence makes it possible to predict biological invasions and determine better species combinations for the restoration and recovery of degraded areas. The aim of this study was to test the competition-relatedness hypothesis for semiarid tree species. Thus, an experiment was carried out with a phylogenetic gradient of tree species, planted in pairs. The phylogenetically closest pair consisted of congeneric species of the same clade, the intermediate pair comprised congeneric species of distinct clades, and the more distant pair were species of the same family. Results: Our results show that the phylogenetically closest and the more distant pairs corroborated the competition-relatedness hypothesis, but the presence of one species with high competitive ability in the intermediate pair caused an unexpected pattern. Conclusion: Niche differences are important for coexistence, but it is necessary to know the competitive ability of each species and the specific associations that are more productive to improve the efficiency of restoration programs and to reveal the degree of aggressiveness in the case of invasive species.

Resumo em Inglês:

ABSTRACT Background: Amplified edge effects stemming from land use change interfere with the community dynamics of forests by altering abiotic conditions. However, the impact of oil palm plantation-induced edge effects on forest remnants is still not well understood. This study investigated the edge influences of an oil palm plantation on adjoining rainforest remnants’ microclimates and regeneration, along with variations in the effects imposed by oil palm stands’ structural differences. Parallel transects were established perpendicular to the forest border in four forest patches. Distance and magnitude of edge influence (DEI and MEI, respectively) were calculated for each response variable, and PCA and ANOVA tests were used to examine variations among the variables. Results: DEIs did not extend beyond 60 m, while the number of influenced variables decreased with increasing oil palm stand shade. MEI values were generally low, except for light intensity and seedlings. Significant differences were mostly observed only for variables at the forest fringe, and the reduction in edge influence was most prominent only with a minimum stand height of 8.5 m. Invasive undergrowth species penetrated less into the forest interior with more shade. Tree regeneration, especially of old growth species, was low, and seedlings were dominated by fast-growing trees. Conclusion: Forest remnants benefit from edge effect-minimizing shade, but by the timethis shade has formed, regeneration has already been impacted. Sustaining the ecosystem integrity of forest fragments consequently requires continuous shade from adjacent ecosystems coupled with intervention to boost old growth forest species’regeneration in low-shade areas.

Resumo em Inglês:

ABSTRACT Background: The objective of this study was the genetic characterization of remaining populations of the species Paratecoma peroba occurring in fragments of the Atlantic Forest, by estimating parameters of diversity and genetic structure. The study was carried out in two forest fragments, the Atlantic Forest Environmental Education Pole (area 1) and the Pacotuba National Forest (area 2), where 93 adult trees were identified. Results: Ten Inter Simple Sequence Repeats (ISSR) primers were used in genotyping, obtaining 112 amplified bands with 87.5% polymorphism. The genetic diversity estimated for the populations from the Nei (H*) and Shannon (I*) indices was higher for area 1. For the joint data, moderate genetic diversity was observed, referring to the average values of 0.26 and 0.40, obtained for the H* and I* indices, respectively. Molecular variance analysis resulted in moderate differentiation between populations (Φ ST = 0.143), while gene flow analysis (N m = 6.69) revealed the occurrence of similar alleles between them. However, the predominance of a single genetic group in area 2, revealed from Bayesian approach, indicates that its genetic structure, possibly generated by the current scenario of fragmentation of the Atlantic Forest and the distancing of populations, affecting the contemporary gene flow. Conclusion: Despite the moderate genetic diversity of the species for the area 2 population, actions toward inclusion of seedlings obtained from seeds from neighboring fragments, including area 1, and the increase in the connectivity of forest fragments through ecological corridors, could assist in augmenting its genetic variation.

Resumo em Inglês:

ABSTRACT Background: Understanding species’ reactions to environmental stressors (cold and drought) and characterizing drought tolerance can help us understand their ecosystem responses related to global change. This study aimed to understand and compare the drought and cold tolerance strategies of Juniperus excelsa, Juniperus foetidissima, and Juniperus oxycedrus, which are found in the Western Mediterranean Region. Water relation parameters [ΨTLP (osmotic potential at turgor loss point), Ψ100 (osmotic potential at full turgor), Ɛmax (bulk modulus of elasticity), V0/DW (symplastic water at the saturated point per dry weight of the shoot), RWC (relative water content)] in summer and winter were determined. Total soluble sugar and photosynthetic pigment content were identified in spring, summer, autumn, and winter. Results: J. foetidissima had lower Ψ TLP and higher Ɛmax in summer than other species. The species had similar Ψ TLP 1 Ψ 100 1 Ɛmax, V0/DW, and RWC in winter. A seasonal change was observed in total soluble sugar and photosynthetic pigment content. Total soluble sugar and photosynthetic pigment contents were related to mean air temperature and total precipitation. Conclusion: J. foetidissima was more tolerant to water deficit in the summer, whereas the three species reacted similarly to the cold in the winter.

Resumo em Inglês:

ABSTRACT Background: Neotropical species lack autecological information. Among these, are phenological studies, which help to understand forest dynamics and provide important contributions to the collection, restoration, and conservation programs. This research aimed to characterize the vegetative and reproductive phenological behavior of neotropical species Geoffroea spinosa Jacq. in a seasonally dry tropical forest, as well as to verify if there is a correlation between phenophases and environmental parameters. Twenty individuals were accompanied monthly for two years, to detect and tally the presence of floral buds, flowers, immature fruits, ripe fruits, leaf emergence, presence of mature leaves, and defoliation. A semi-quantitative evaluation was carried out with the Fournier method. Results: The results showed that the population had synchrony of reproductive events, with more than 50% of the individuals blooming and fruiting during the same time interval. Furthermore, the circular statistical test indicated a high seasonality for reproductive events (r ≥ 0.50 and p < 0.001). Among the vegetative events, all were classified as non-seasonal (r < 0.5). G. spinosa, showed a significant correlation (p ≤ 0.05) for all meteorological variables evaluated. Conclusion: The reproductive phenophases of G. spinosa showed strongly seasonal behavior, unlike vegetative events. the period between mid-February and the end of March was the most propitious for fruit collection. No seasonality was observed for the vegetative events. The species proved to be sensitive to El niño conditions. Follow-up phenological studies associated with meteorological variables are important for a better understanding of the dynamics of vegetative behavior in response to climate change.

Resumo em Inglês:

ABSTRACT Background: We conducted a study about how to determine best diversity ordering method for a community data set. Using 12 hypothetical and one ecological datasets, we tested the performances of 20 diversity ordering ( divo) methods based on four criteria. Number of intersections ( ints) amongst the diversity curves was taken the most important criterion into account. We defined the other criteria considering whether parametric values of a divo method contains SHD (species richness, Shannon entropy and Simpson index), potentially uSHD (unbiased values of SHD), and potentially true species diversity, tSHD (bias corrected values as effective number of SHD). All the criteria were collected into an equation called the relative selection value, \begin{equation}{rVd}_i \end{equation}. Results: According to the \begin{equation}{rVd}_i \end{equation} values of hypothetical community data sets, the best performances in seven community data sets were provided by \begin{equation}N_\alpha \end{equation}. This was followed by intrinsic diversity related methods with five community data sets. For ecological data set, the best results were obtained from the methods, \begin{equation}\left(i,\ M_i\right) \end{equation}, \begin{equation}\left(\log{i},\ k_i\right) \end{equation} and \begin{equation}N_\alpha \end{equation}, with the \begin{equation}{rVd}_i \end{equation} values of 6.883, 6.881 and 6.859, respectively. Conclusion: Findings suggest that the characteristics of community data sets play important role in defining the best diversity ordering method. This tells us that diversity is certainly a multifaceted phenomenon for a single community but perhaps it is a single phenomenon for a group of communities.

Resumo em Inglês:

ABSTRACT Background: Forest roads are among the most basic infrastructure used for forestry activities and services. To facilitate the increased amount of biomass harvesting adequately, the existing road network may require modifications to allow forest transportation within harvesting units that are not yet accessed by the roads. The construction of a forest road can trigger landslides, so the necessary constraints should be considered when the road is being planned to preclude such problems. Landslide Susceptibility Mapping (LSM) has become an integral part of the growing process of machine learning (ML), providing a more effective platform for practitioners, planners, and decision-makers. This study aims to reveal the most suitable alternative routes for a forest road, especially in areas susceptible to landslides, and to provide an effective tool for decision-makers. Results: For this purpose, two models were developed through ML: Logistic Regression (LR) and Random Forest (RF). Elevation, slope, aspect, curvature, Topographic Wetness Index (TWI), Stream Power Index (SPI), distance from the fault, the road, and the stream, and lithology were considered as the main landslide susceptibility factors in these models. The best model was obtained by the RF approach with an Area Under ROC Curve (AUC) value of 81.9%, while the LR model was 78.2%. LSM data was used as a base, and alternative routes were obtained through CostPath analysis. Conclusion: It has been shown that the ML methods used in this study can positively contribute to decision-making by providing more effective LSM calculations in studies to determine alternative routes in a forest road network.

Resumo em Inglês:

ABSTRACT Background: Diameter distribution models are one of the most important components of growth and yield models. Diameter distribution models, based on the Weibull function, were developed for even-aged mixed-oak stands (Turkey oak, Sessile oak, and Hungarian oak) in northwestern Turkey. Two modeling methods were considered. Weibull parameters were recovered from either equation predicting Dq and Dvar (method of moments) or equations predicting Dq and D 90 (hybrid method). For each modeling method, three estimation methods were considered: (a) Least Squares method, (b) CDF Regression method in which regression coefficients were estimated separately for each species, and (c) CDF Regression method in which regression coefficients were simultaneously estimated for all species. Results: Results indicated that the hybrid method coupled with the CDF Regression estimation method yield best results in this study. Similar results were obtained when the regression coefficients were estimated either separately for each species or simultaneously for all species. Conclusion: The proposed models enable one to predict diameter distribution of a given mixed-oak species stand in northwestern Turkey, using limited stand information. These models are useful tools for the inventory and management of mixed-oak stands.

Resumo em Inglês:

ABSTRACT Background: Tree height is an important variable in forestry, as it is commonly used to estimate volume and biomass, and to evaluate site productivity. In this study, we developed four generalized equations to model height-diameter ( h-d) relationships for coniferous and broadleaf species. For this purpose, we used information from 49 permanent sampling plots located in the natural forests of Puebla, Mexico. Non-linear fixed and mixed-effects modeling approaches were used to fit generalized versions of the Gompertz function to Pinus patula and the Pinus group, the Näslund function to Abies religiosa, and the Curtis function to the Quercus group. Results: Stand variables included in the models were the number of trees per hectare ( N), quadratic mean diameter ( dg), and basal area per hectare ( G). The results showed a model efficiency (EF) = 0.91 and root mean square error (RMSE) = 2.04 for P. patula, as well as an EF = 0.91 and RMSE = 1.63 for the Pinus group. The EF and RMSE for Abies religiosa were 0.88 and 2.21, while for the Quercus group these values were 0.72 and 1.9, respectively. From the mixed-effects model calibration, only a sub-sample of three trees from different quantiles of the diameter distribution is required to make accurate predictions. No stand-level variables related to tree height are included in any of the selected models, thus no additional measurements beyond tree diameter are required. Conclusion: Compared to conventional non-linear least squares (ONLS), mixed-effects models are more flexible and accurate and represent a new tool for sustainable forest management of natural forests in the study area.

Resumo em Inglês:

ABSTRACT Background: Although forest villages in Turkey do not differ from other villages in the country in terms of administrative divisions, the job possibilities of their residents are limited due to the location of the villages in areas with rugged terrain. Forest villages have the poorest economic status of all types of communities in the country in terms of per capita national income and socio-economic structure; limited agricultural land; inadequate transportation and infrastructure; and, most importantly, weak educational, health, and cultural services. Results: This study explains forest dependency and its relation to certain characteristics of householders by a case study. Data were collected from 150 households and were analyzed using the logistic regression model. Conclusion: The results showed that a householder’s age, duration of residence, and employment variables had a significant effect on the forest whereas other variables, gender, educational level, and household size, did not have a statistically significant effect on forest dependence.

Resumo em Inglês:

ABSTRACT Background: Forested wetlands are an important factor in carbon (C) sequestration. In this study, we compared the short-term effects (5 years) of three harvest intensities and two wildfire severities, and the mid-term effects (25 years) of four groundwater table depth (WTD) drainage for forestry on eco-system C storage and understory vegetation structures in Daxing’anling, northeast of China. Results: We found that: Low intensity harvest slightly enhanced ecosystem C storage, whereas moderate- and high-intensity harvest led to significant reductions (33.2-41.6%) in comparison with the control natural forested wetlands stand (274.54 t C·ha -1), and light and heavy burn caused the ecosystem C storage sig-nificant decreases by 27.8% and 45.2%. As for the drainage for forestry, the ecosystem C storage was higher at the low WTD (316.78 t C·ha -1), and diminished significantly by 24.1-28.1% with the increasing WTD on the forested wetland plantation transect. Compared with the control and high intensity harvest stands (8.28 t ha -1 yr -1, 5.08 t C·ha -1 yr -1 and 6.48 t ha -1 yr -1, 3.52 t C·ha -1 yr -1), significantly higher NPP (net primary productivity, defined by the biomass difference of two measurements) (69.1-83.2%) and annual C sequestration (52.0-78.7%) were observed in the low- and moderate-intensity harvest stands. Significant increases by 48.6% and decreases by 31.5% in NPP or by 52.9% in annual C sequestration were in light and heavy burn stands, respectively. In contrast, the NPP and annual C sequestration (3. 67-10. 34 t ha -1 yr -1 and 1. 59-4. 87 t C·ha -1 yr -1) showed a significant in-creasing trend with increasing WTD, respectively. The understory species diversity indices were generally lower in the harvest and burned stands than the control natural forested wetlands and more pioneer tree species regeneration occurred after the disturbances. Conclusion: Therefore, it seems that low intensity harvest and wildfire could sustain the ecosystem C sink and drainage for forestry is an effect way to restore C sequestration for this forested wetland type.

Resumo em Inglês:

ABSTRACT Background: Estimating forest productivity is critical for effective management and site assessment. The dominant height is used to calculate the Site Index (SI), which is commonly used to assess forest productivity. In this study, an algebraic difference approach was used to develop a dominant height model incorporating the rainfall effect for Eucalyptus grandis x Eucalyptus urophylla ( E. Grandis x E. Urophylla). The dataset consists of 75 permanent sample plots ranging in age from 0.5 to 11 years, as well as 7 rainfall stations spread across plantations in Coastal Zululand, South Africa. Using fixed and mixed-effects in the predictor function, twelve candidate models were derived from the Bertalanffy-Richards, Lundqvist-Korf, McDill-Amateis, and Hossfeld growth functions. A continuous-time autoregressive error structure was used to account for serial autocorrelation in the longitudinal unbalanced data. Model fit statistics and graphical methods were used to evaluate the candidate models. Results: The addition of the rainfall effect increased model precision by 37%. The mixed-effects formulation produced 18% more precision when compared to similar models with all parameters fixed. Due to their compatibility with expected biological behaviour and good performance on validation data, mixed-effects models based on Lundqvist-Korf and McDill-Amateis functions were chosen as the final models. Conclusion: Unlike similar models that do not take rainfall into account, these models can capture the effects of severe rainfall conditions such as drought and can thus be used in short-rotation pulp forests with fluctuating rainfall.

Resumo em Inglês:

ABSTRACTBackground: The germination ecology of P. guajava seeds collected in two regions of Brazil was investigated aiming to (1) characterize the seed batches; (2) determine the best temperature for germination; and (3) assess variations in seed desiccation tolerance (DT). For each batch, we determined seed water content and initial germination. To evaluate temperature effects, we tested seed germination. After, we generated the imbibition curves for the two provenance. To evaluate the loss of DT, the seeds were left to germinate along different time intervals. We monitored water loss by regularly weighing the seeds until achieving stabilization, keeping them under these conditions for 72 hours. After drying, the seeds were pre-hydrated and submitted to the germination test. Results:We identified variations in physiological characteristics between the seeds from north and southeast batches. At the temperature extremes, the seeds from both provenance failed to germinate. The highest germination percentages were observed at 20 and 25 °C (constant) and between 20-30 °C (alternating) for the two batches and, for the southeast batch specifically, at 30 °C. The imbibition curve displayed a triphasic pattern with a rapid increase in seed fresh weight in the first 48 hours. Conclusion: The southeast provenance seeds lost DT abruptly, until its complete loss after radicle protrusion, which occurred in both batches. The highest values of germination speed index (GSI) of both provenance were observed after a 9-day imbibition period, suggesting seed hydration memory. Drying resulted in necrosis of the root tissue and death of the seeds with visible roots.

Resumo em Inglês:

ABSTRACT Background: Curitiba prismatica (D.Legrand) Salywon & Landrum belongs to the Myrtaceae family and it is popularly known as murta. Endemic to the Mixed Ombrophilous Forest of south Brazil, is predominant in Faxinal System, which is a traditional agricultural system in the State of Paraná. This species also has several uses and potentials, such as wood for fence posts and essential oils with pharmacological properties. For this reason, this study aimed to select molecular markers and assess whether the Faxinal System contributes to the maintenance of the genetic diversity of the species, helping in its management and conservation. As such, 120 adult reproductive individuals were sampled, 60 in two areas managed in the Faxinal System, and 60 in two conservation areas. Results: Initially, 30 ISSR markers were selected, but only eight showed considerable variability, resulting in 68 polymorphic loci. The results show that the average diversity within populations is 80.54%. The Shannon (I) and Nei’s (He) diversity indices were 0.53 and 0.36, respectively. According to Nei’s genetic identity, the populations form two groups. With the analysis of the genetic structure of the populations, which indicated the existence of two distinct genetic groups (K = 2). Conclusion: Thus, the populations in the Faxinal System had higher rates of genetic diversity, despite constant human activity within the system. Therefore, the Faxinal System contributes to the conservation of C. prismatica genetic diversity; however, considering the economic potential of the species and to minimize impacts on the existing fragments, there is a need to work with the local population to ensure sustainable forest management of the species.

Resumo em Inglês:

ABSTRACT Background: The aim of this study was to investigate the effect of environmental factors on the essential oil yields (EOYs) and major essential oil components in the ripe fruits of Pistacia terebinthus L. (turpentine tree), which is a medicinal and aromatic plant. Fruit samples were collected from 34 different locations of the turpentine tree growing wild in the Lake District in the Mediterranean Region of Turkey. EOYs (%, v/w) and essential oil component ratios (%) were determined in fruit samples by hydrodistillation and GC-MS methods, respectively. The effect of environmental factors on these variables were analyzed using Pearson Correlation and Principal Component Analysis. Results: The essential oil yield of fruits collected from different localities ranged from 0.05% (v/w) to 0.19% (v/w). In terms of average values, α-pinene with 41.01% and limonene with 14.28% were the major components in the essential oils of ripe fruits. Among the environmental variables, longitude and sand % in 10-30 cm were the variables that made a statistically significant difference (p < 0.05) in fruit essential oil yield. According to the results of principal components analysis (PCA), α-pinene and Ocimene components were most affected by silt (%, 10-30 cm) and pH (%, 30-50 cm) ratios. The longitude and total annual precipitation (mm) were the most determining variables in the sabinene and limonene components, respectively. It was seen that the total lime ratios at different depth levels of the soils taken from the localities were the most effective variables for Myrcene and p-Cymene components. Conclusion: The study findings showed that EOYs and intended volatile component ratios in ripe fruits of turpentine trees grown under appropriate environmental conditions can be increased.

Resumo em Inglês:

ABSTRACT Background: In this study, the impact of Effective Microorganism (EM) applications on some physiological characteristics of 2+0 aged, containerized Taurus cedar (Cedrus libani A.Rich.) seedlings were investigated. EM-1, EM-A, EM-5, and EM-Gold were used as effective microorganism varieties. EM application was repeated twice at two different times. The first application was carried out in April-May 2017 at the beginning of the vegetation period, and the second application was carried out in June-July, when the growth of seedlings was the most active period, according to a randomized plot design with three replications. Results: Physiological measurements on seedlings were carried out at the end of the second vegetation period. According to the results of the study, it was determined that the EM type, dose and application time factors had a significant effect on physiological characteristics such as Chlorophyll a, Chlorophyll b, Total Chlorophyll, Photosynthesis Rate, Transpiration and Relative Humidity. EM-A had a positive effect on photosynthesis rate and EM-5 had a positive effect on all other measured physiological parameters. High dose of EMs had the most positive effect on relative humidity, while medium dose of EMs had the most positive effect on chlorophyll values, transpiration rate and photosynthesis rate. In addition, it was determined that EM application at the beginning of the vegetation period had an increasing effect on all measured physiological parameter values. Conclusion: According to the results of the study, it was concluded that EMs have a positive effect on the physiological quality characteristics of Taurus cedar seedlings and can contribute to the production of seedlings with higher adaptability in afforestation.

Resumo em Inglês:

ABSTRACT Background: Background: Eucalypt harvest residues are critical to nutrient balances and forest soil productivity mainly in areas with consecutive forest rotations. However, nutrient release and their relations over decomposition are still poorly understood in tropical sites. We aimed to understand how nutrients are released from leaves, branches, and bark (as harvest residues), and how nutrient concentrations could be limiting the decomposition of each fraction. We measured mass loss and nutrient release of Eucalyptus urophylla x Eucalyptus grandis harvest residues for 365 days in Southeast Brazil. Results: Results: Leaves fraction showed a faster decomposition rate than branches and bark, but nutrient accumulation was observed for all harvest residues, especially bark and branches at later stages of the decomposition. Decomposition of all harvest residues seemed to be P-limited with a stronger limitation occurring for leaf litter decomposers. The decomposition of more lignified residues such as bark and branches was less influenced by climatic variables than leaf decomposition. Conclusion: Conclusion: Eucalypt harvest residues had a great contribution to soil fertility, and retaining them in the soil systems will enhance soil fertility in the short (leaves) and long-term (branches and bark) and can partially supply the nutrients for the next rotation.

Resumo em Inglês:

ABSTRACT Background: This review aims to discuss alternatives for obtaining new clones of eucalyptus ( Eucalyptus spp.) with greater efficiency than current methods, as well as the feasibility of obtaining hybrid seeds. The commercial-scale use of eucalyptus hybrid seeds may reduce implantation costs and bring other advantages for forest exploitation. The proposal focuses on using inbred progenies (S 1, S 2...S g) to improve the species. Self-fertilization releases a greater proportion of undesirable alleles hidden in heterozygotes, increasing selection success. Results: From the best individuals of the inbred progenies, full-sibling (FS) progenies will be developed, allowing the selection of new clones and conduct recurrent selection programs. The hybrid seeds must be obtained, also from the FS evaluations, in each selfing generation (S g x S g). Simultaneously with the conduction of inbreeding generations, information must be gathered aiming to implement the strategy for obtaining hybrid seeds, such as verifying the feasibility of generating double haploid lines and looking for alternatives to facilitate the large-scale production of hybrid seeds. Conclusion: this review of research results can serve as an initial basis for obtaining new clones of eucalyptus with greater efficiency than current methods, as well as the feasibility of obtaining hybrid seeds.

Resumo em Inglês:

ABSTRACT Background: Leaf area index (LAI) is an important stand characteristic in terms of forest productivity and stand growth, and it shows significant correlations with other stand characteristics. In this study, it is aimed to reveal the relationships between LAI and some other stand characteristics, i.e. mean diameter, stand age, dominant height, site index, number of trees, stand basal area, stand density, total crown biomass and crown dimensions for Anatolian black pine (Pinus nigra J.F. Arnold subsp. pallasiana (Lamb.) Holmboe) stands in Kastamonu region, which is one of the economically important tree species in Türkiye, and to develop a regression model for LAI estimations by using these relationships. Results: The data obtained from 119 temporary sample plots were used in the study. According to the results, stand basal area, stand density, total crown biomass, dominant height, number of trees, mean diameter, and site index positively correlated with LAI. LAI values were significantly different in terms of stand density and site classes. Among the candidate models for LAI estimations, the model containing site index and stand density as independent variables was the most successful model with the adjusted coefficient of determination ( R adj 2 ) of 0,63 and the Akaike information criterion ( AIC) of -67,25. Conclusion: The LAI, which is difficult to measure directly in practice, of Anatolian black pine stands in Kastamonu region of Türkiye could be estimated accurately with the help of the equation developed.

Resumo em Inglês:

ABSTRACT Background: The use of tree plantations for energy purposes has shown an increase in their use in tropical regions due to the species' rapid growth and low cost of energy generation. This has led to the development of optimization studies of crop conditions. However, the determination of the effect of spacing on physical, chemical and energy properties has not been precise for Eucalyptus tereticornis, which limits the development of plantations with optimal silvicultural conditions. Results: The study analyzed the growth and chemical, physical and energetic properties in a four-year-old plantation. The results showed that mortality ranged from 29 to 69%, being the 1.0 x 2.0 m spacing the one that presented better yields with a significantly higher diameter and height (9.13 cm and 14.17 m, respectively) with a higher biomass accumulation (140.04 ton ha -1 without treetop) concentrated mainly in the stem. The other two spacings presented statistically lower and non-significant values. The physical properties were obtained densities of 0.57 to 0.66 g cm -3, with a specific density of 0.58 and moisture content of 57.7%. The chemical properties only showed differences in carbon concentration (50.11 to 69.16%). The energetic properties showed a caloric power between 4780 to 6059 kcal kg -1, with a variation in volatile content of 10.9% and 1.6% in ash. Conclusion: The planting spacing generates a gradient in the production, mortality and property of the biomass, being the spacing of 1.0 x 2.0 m being optimum for establishing the study species for Costa Rica.

Resumo em Inglês:

ABSTRACT Background: Multiple challenges are faced by industry and certification agencies when commercializing tropical species. Anatomical similarities of tropical hardwoods impair identification. Deep learning models can facilitate microscopic identification of wood by using sophisticated techniques such as deep convolutional networks (DCNN). Our objective was to microscopically identify 23 commercially available Brazilian wood species using a custom DCNN model. Results: Photographs from microscopic slides of each wood species were processed, and the final data set contained 2,448 images. We applied stratified k-fold cross-validation technique during training to increase model’s robustness and trustworthiness. Thus, the dataset was divided into approximately 80% training (1,958 images) and 20% validation (490 images) for each fold. A series of augmentations were performed only on training data to include variations in rotation, zoom, and perspective. Image augmentation was performed on-the-fly. The network consisted of convolutions, max pooling, global average pooling, and fully connected layers. We tested the performance of the DCNN against accuracy, precision, recall, and F1-score on the validation set for each fold. Conclusion: The custom machine learned model accuracy was higher than 0.90. The model’s worst performance was identified in distinguishing between Toona ciliate and Khaya ivorensis, which was due more to wood variability than to a machine learning deficiency. Future studies should focus on integration, verification/monitoring, and updating of current models for end user manipulation, trust, ethics, and security.

Resumo em Inglês:

ABSTRACT Background: The aim of this study was to investigate near infrared (NIR) spectroscopy ability to estimate nanofibril concentration, physical and mechanical properties of Kraft paper reinforced with cellulose nanofibrils (CNF). For this purpose, paper sheets were prepared by mixing unbleached Eucalyptus fibers and cellulose nanofibrils. Twelve treatments result from the combination of the nominal grammages 75, 85, 95 and 105 g m-² with the nanofibril concentrations of 1, 5 and 10wt%, with 7 sheets per treatment. NIR spectra measured directly on paper specimens were correlated with physical and mechanical properties values obtained through conventional laboratory analyzes. Results: Principal component analysis (PCA) revealed no separation among specimens related to nanofibril content. Partial least squares regression (PLS-R) models for estimating nanofibril content, tensile index, stretch and resistance to air passage yielded R 2cv ranging from 0.73 to 0.98. Partial least squares - discriminant analysis (PLS-DA) correctly classified up to 93% of the paper specimens both by grammage and nanofibril content using NIR spectra. Conclusion: This approach appears to be suitable for predicting physical and mechanical properties of Kraft papers and can detect cellulose nanofibril content in the cellulose handsheets.

Resumo em Inglês:

ABSTRACT Background: The Macaw palm ( Acrocomia aculeata) is a palm tree native to the Tropical America Forests. This palm has stood out due to its high potential for the production of oil for biofuels, being an excellent source of renewable energy. However, due to the rudimentary way of exploring the Macaw palm, mostly using native people labor, it is not possible to extract the maximum economical potential that this plant can provide. In order to use the Macaw palm in industrial scale, new strategies using high-performance machinery in several segments of the production chain should be employed. Results: For that, its seedlings production must be broadly expanded, using modern techniques for its propagation and production on an industrial scale, since its present low germination rates when the natural way is employed. In this way, the present paper has the objective of establishing a database of the mechanical properties of the endocarp of the Macaw palm when submitted to compression efforts, typically used for removing almonds from the endocarp. The inherent variability of its mechanical properties was quantified, using three different crops sites. Conclusion: Important information about the mechanical properties of the Macaw palm endocarp is presented, serving as guideline for future works to genetic improvement of the Macaw palm, in order to obtain fruits with less variability in the mechanical properties of the endocarp and consequently improve the production on an industrial scale.

Resumo em Inglês:

ABSTRACT Background: The fibres dimensions vary along a tree trunk, and these variations are related to the apical meristem and vascular cambium activities; understanding these variations would guide the best use of wood. There have been studies on the pattern of fibres dimensions variation along the tree trunk in the radial and longitudinal directions; however, the vast majority do not take into account the structure of the annual growth rings. Hence, this study aimed to obtain the pattern of fibres dimensions variation and their quality indexes along the tree trunk take into account the structure of the annual growth rings. Two Eucalyptus urophylla x Eucalyptus grandis hybrid clones were used in the study. Ten-year-old trees were selected and discs were removed from 13 longitudinal positions. The disks were prepared and the growth rings were subsequently identified and the samples used for maceration were collected. Twenty fibres were measured in the annual growth rings present in each longitudinal position. Results: In the longitudinal direction, within the annual growth rings, the fibre dimensions and their quality indices did not show a well-defined pattern of variation. In the radial direction, the length, cell wall thickness, wall fraction, and Runkel ratio of the fibres tended to increase following the pith-bark direction, while the lumen diameter and flexibility coefficient decreased. Conclusion: Nevertheless, the fibre width and fibre slenderness index did not present a well-defined pattern of variation in the radial direction.

Resumo em Inglês:

ABSTRACT Background: Nowadays, demands for more environmentally friendly and cost-effective preservatives are increasing, and new non-traditional procedures are being explored in wood protection field. Plant oils improve the dimensional stability, water repellency and equilibrium moisture content of wood, and protect wood against decay fungi by means of its hydrophobic properties. The aim of this study is to investigate the influence of heat treatment and oil impregnation with or without prior treatment with boron compounds on wetting characteristic of Scots pine ( Pinus sylvestris L.) and beech ( Fagus orientalis L.) wood. Wood specimens were impregnated with boric acid, borax and agricultural boron at concentrations of 1%, 2% and 5% followed by oil heat treated with waste and sunflower oil at 160ºC. Wettability was measured by contact angle with the sessile drop technique using water. Results: Water contact angles on oil treated specimens increased while wetting tension decreased, and the wood more poorly wetted by water compared to the controls. A change in the drop volume on the surface of double treated specimens was around 5% based on the initial drop volume. Waste oil treatment resulted in having the greatest water repellent efficiency. High loadings of boron compounds decreased the contact angle and therefore the quantity of water absorbed by the wood increased. Conclusion: Wettability was decreased in specimens pretreated with boron and this confirmed that the hydrophobic surface was created by oil. Wettability is a prerequisite for good adhesion, coating and painting and this feature may be reduced by the less hydrophilic surfaces created after oil heat treatment.

Resumo em Inglês:

ABSTRACT Background: In the study of biologically-based materials, nanocelluloses have been showing great prominence and positioned themselves as promising alternatives for the production of different industrialized materials. This polymer has received significant attention recently because it is produced from renewable sources and has unique properties offered by its organic nature and semi-crystalline structure. This work aimed to study the structural properties of suspensions and films by increasing MCC concentration in the form of powder with variations of 5 % (m/m) from 5 % to 30 %. Results: As expected, incorporating MCC increased the Segal index. The morphological analysis showed an increase in the diameters of the structures (NFC / MCC) in the suspensions when the presence of MCC was more significant, and films with cluster formations were observed. The films showed air permeability. Due to the MCC increase, the surface charge had results close to electrostatically stabilized nanosuspensions. An increase in the resistance to thermal degradation of the films was also observed Conclusion: NFC has promising properties for different applications; it provides a film with a stable structure and is resistant to oxygen and tensile stresses. In addition, MCC has excellent potential due to its high crystallinity, structural characteristics, and nature. The increase of the MCC content altered the properties of the suspensions and films produced with NFC, forming a cohesive and resistant film, and influencing the performance of the different properties of the materials evaluated in this study, like air permeability, suspension stability, and thermal resistance.

Resumo em Inglês:

ABSTRACT Background: Boiling, steaming, and microwave radiation treatments were used for softening and then manufacturing curved samples using three Brazilian hardwoods. Solid wood samples from Carya illinoinensis, Luehea divaricata and Platanus x acerifolia were characterized for bending quality, bending defects, minimum radius of bending, spring-back and moisture content. Results: Among the studied woods, Carya illinoinensis wood was the most suitable to conform curved samples since 96.7% of these wood samples reached a perfect curved shape. On the other hand, Luehea divaricata wood presented the worst behaviour, which was marked by only 36.7% of samples achieving a perfect shape. In general, the studied hydrothermal treatments and exposure times induced similar softening behaviours. Conclusion: In this sense, microwave heating seems to be a good option when compared to the other pathways, since it is known that this method require low consumptions of both time and energy.