ABSTRACT Background: Harvesting, especially skidding operations have a significant impact on the forest soil properties. This study aimed to advance understanding of how timber harvesting may influence soil respiration in forested ecosystems. We investigated the impact of soil respiration for some of the skidding techniques after skidding operations depending on slope and stand types. Results: We measured soil CO2 efflux to evaluate the skidding techniques on soil, depending on the slope and stand type. Thus, three skidding techniques with tractor for harvesting (1-suspended skidding, 2-using a skidding cone, 3-cable-pulling) were used in 6 different study site and the variations in soil respiration and soil properties were examined at 3 different slopes (0-20%, 20-33%, >33%), 2 different stand types (b-bc, c-cd) at topsoil (0-5 cm). Also soil respiration was measured at intervals of 5 days (on days 1, 5, and 10) after skidding operation. In addition, pH, EC (electrical conductivity), and soil moisture were evaluated depending on slope and stand type in the study. Conclusion: It was determined that respiration increased on the first day but decreased on day 5 and 10. It was found that the slope and stand type have no effect on soil respiration. It was determined that the skidding technique that reduces the soil respiration the most is suspended skidding with a rate of 90%. However, the skidding technique that reduced respiration the least was skidding by using a skidding cone suspended skidding with a rate of 64% when evaluated on day 10.

ABSTRACT Background: Forests in the Atlantic Forest Domain are increasingly threatened by fire, which disrupts their structure, biodiversity, and resilience. This study investigates how fire impacts functional diversity, community structure, and regeneration in fragmented forest patches near urban areas. Results: We analyzed three types of forest patches: Closed Forest, Perturbed Forest (Once-burned Forest), and Burned Forest (Twice-burned Forest). Significant differences were found in species composition, diversity, and structural parameters among these vegetation types. Closed Forests exhibited the highest levels of functional diversity, structural complexity, and species richness. In contrast, Perturbed and Burned Forests showed reduced functional diversity, lower community-level traits, and diminished resilience. Functional metrics, such as functional divergence (Fdiv) and functional richness (Fric), were notably lower in fire-affected areas. Additionally, fire occurrence influenced dispersal modes, with animal-dispersed species predominating and a notable absence of large-seeded species. Conclusion: The study highlights the significant impact of fire on forest regeneration. Recurrent fires lead to decreased species diversity and functional redundancy, transforming closed-canopy forests into more open, savanna-like landscapes. The absence of large-seeded and animal-dispersed species further impedes the regeneration and resilience of fragmented Atlantic Forests. These findings underscore the need for targeted conservation and management strategies to support forest recovery and maintain biodiversity in fire-prone regions.

ABSTRACT Background: The study aimed to assess the effectiveness of restoration practices following the Fundão disaster in the Brazilian Atlantic Forest, a key region for global biodiversity. Focusing on affected areas in Mariana, MG, the study used seed bank analysis as a key indicator to understand environmental recovery progress. The study compared active and passive restoration areas with a reference ecosystem by collecting 168 soil samples, which were subjected to germination in a greenhouse. Results: The results revealed a high germination rate of herbaceous seeds, predominantly native species. Significant differences were found in floristic composition among the different restoration types studied. Areas undergoing active restoration showed greater similarity to the reference ecosystem, emphasizing the importance of Distance from Forest Fragment, Percentage of Forest Area in the Surroundings, and species diversity for restoration success. Conclusion: The results highlight the crucial importance of landscape connectivity for the success of ecological restoration. Active restoration strategies play a fundamental role in accelerating environmental recovery and bringing degraded areas closer to the floristic composition of reference ecosystems.

ABSTRACT Background: The development and application of new technologies and solutions are extremely important to manage and monitor urban forestry to prevent accidents resulting from falls that often result in social and property damage. To evaluate the internal conditions of a tree, it is recommended to use indirect methods, both for the trunk and the root system. However, existing methods can predict trunk properties at the lower level in some situations, that can lead to a misinterpretation of the actual phytosanitary status of the evaluated specimen and cause the incomplete assessment. Thus, the present work aimed to evaluate, with acquisition and software development, the use of geophysical method of electrical resistivity (ER), with longitudinal profiles along the trunk, every 45º, for internal and non-destructive analysis of two specimens of Eucalyptus sp. and one of Pachira aquatica trees. In these trees, data were acquired and compared each other’s by ER, mechanical impulse tomography and resistograph. Results: This approach allows for the investigation the entire length of the trunk, in a reduced time. From the results, it was possible to establish qualitative (from images) and some quantitative (physical property values) relationships between the ER, impulse tomography and resistography, by the internal image generated and the physical properties obtained. Conclusion: Both in the interpretation of the generated images and the values obtained, they exhibited different characteristics of the studied wood, demonstrating the potential of the developed methodology for rapid and precise application in urban trees.

ABSTRACT Background: Brazil has the largest tropical forest cover in territorial extension, although it is subject to different forms of threat. We analyzed a time series of the firewood and charcoal production from the extractivism of native forests between the years 2010 and 2020 in Northeast Brazil, in order to support future reflections on the impacts of these uses on the sustainability of the production chain of exploration and on the conservation of native forests in the region. Considering the time frame from 2010 to 2020, data on the volume of firewood and charcoal produced from plant extraction in the Northeastern, were obtained via the official platform of Brazilian Institute of Geography and Statistics. Results: The total production of firewood was 157,771,059 m3 and charcoal 4,137,418 t., while the states of Bahia (29.3%), Ceará (21.4%) and Maranhão (14.1%) accounted for 74.8% of total firewood produced in the Northeastern. As for charcoal production, Maranhão (51.0%), Bahia (20.3%) and Piauí (23.8%) accounted for 95.1% of total produced. Production stationarity was found for all states, with the exception of Paraíba and Piauí in firewood, and Paraíba and Rio Grande do Norte in charcoal. A downward trend was identified in most states, with the exception of Paraíba and Piauí in firewood and Paraíba and Rio Grande do Norte in charcoal, both without any type of trend. Conclusion: Considering the economic sustainability of the production chain, efforts to encourage energy plantations should focus on regions with lower production, using species of fast-growing species that can meet demand and conserve native caatinga vegetation.

ABSTRACT Background: Türkiye is a very rich country in terms of the distribution and diversity of plants. Despite these current conditions, natural plant species are not sufficiently used in designing urban landscapes. The research aims to reveal an ecological model approach to urban planting by determining the ecological indicator values (EIV’s) and coexistence in nature of the species detected in the natural vegetation, revealing the potential of plants to come together. Results: Within the scope of research, natural areas in Düzce Plain and at the points touching the plain were determined according to the CORINE land cover classification, and 5 different habitat types were determined as forest habitat, riparian areas, rocky habitat, wetlands and meadow habitat. In this study, 420 plant taxa belonging to 89 families which were taken from 33 points and 168 sample areas, were identified. Both natural plant species determined by collecting plant species from the area and plant species diversity will be revealed by determining the ecological demands of the plants. After determining whether the coexistence of plant species collected and identified in these habitat types is distributed in an interdependent manner, scenarios regarding the coexistence of plants were constructed with the help of the latent variables model (LVM’s) by R software program. Conclusion: Some of the plant species with the highest percentage of presence according to the plant layers were selected, and plant compositions with high coexistence were proposed according to the LVM’s.

ABSTRACT Background: Quantifying aboveground biomass (AGB) is crucial for studying the carbon cycle and estimating mitigation potential of climate change. Combining field inventory data and remote sensing such as Landsat imagery, is a common approach for landscape-Level AGB analysis. However, uncertainties in biomass estimations persist, highlighting the need for improved statistical methods. The objectives of this study were (i) model the AGB of temperate forests managed for timber production using Landsat 8 data and three regression algorithms (linear regression, generalized additive models [GAM], and random forests), and (ii) quantify interannual AGB variations (2013-2022) across a forest landscape. Predictor variables included spectral bands, vegetation indices (VI), textural metrics, and stand age. Results: The RF algorithm showed the best performance with accurate estimates, explaining 76% of the AGB variability. It also showed an RMSE of 32.93 Mg ha-1 when stand age was included as a predictor variable. The AGB showed a spatial variation from 9 to 289 Mg ha-1, and an inventory of 113,408.81 Mg (±11,663.13 Mg) in a landscape of 823.6 ha, ranging from 101,904.70 Mg in 2013 to 127,915.60 Mg in 2022. The 10-12-year-old stands showed the highest increment of biomass after a decade, increasing from 71.06 Mg ha-1 (±19.81) in 2013 to 153.37 Mg ha-1 (±14.13) in 2022. Conclusion: The study evaluated a practical methodology to estimate the spatiotemporal variation of AGB in managed temperate forests. This approach can be implemented to support the evaluation of the potential contribution of managed forests to climate change mitigation.

ABSTRACT Background: There is a need to find a simpler sampling strategy that still maintains the accuracy of the results. This work aimed to assess different sampling strategies for measuring the basic wood density of Eucalyptus clones along the tree trunk. Results: The basic wood density of most Eucalyptus clones was affected by the sampling strategy employed. The average density varied between samples, ranging from 476.69 to 449.61 Kg m-3. In this study, the base positions generally showed lower density averages. Traditional sampling best represented the variation trend in Composite sampling due to their similar behavior. Depending on the clone and sampling methodology, the diameter at breast height represented 91.85 to 99.74% of the overall average stem. All adjusted equations were significant, allowing the basic density to be estimated through smaller sampling regions along the tree trunk. When the goal is to evaluate the property at four sample points, the best model corresponds to the heights in the upper half of the stem, which are the higher regions. Conclusion: The analyzed base-top sampling strategies did not show significant differences between them, except for the one that only considered the diameter at breast height, which underestimated the basic density value of the wood. Sampling Removal of extremes effectively estimated the average density when considering all clones as a single material, which is the best strategy for measuring basic density under the conditions in the present study. Sampling positions at 50% of the tree’s commercial height were more associated with the basic density.

ABSTRACT Background: The prediction of hollows in standing trees is an expensive operation, but it is essential for decision-making about harvesting in managed forests in the Amazon. The hollow test that is currently used has strong limitations for correct prediction of the presence of hollows in a tree of commercial interest. The objective of this research was to select and validate generalized linear logistic models to estimate the occurrence of hollows in trees of fifteen commercial species and to compare the efficiency of the models to the results from the traditional manual method of hollow testing in the state of Pará, Brazil. A database of 27,380 trees was used to adjust models by species. To validate the equations, 9,915 trees from an independent area were used. Results: Diameter at breast height (DBH), commercial height (hc) and stem quality (SQ) were important predictors of the occurrence of tree hollows, while wood density (WD) did not generate significant gains in the models. Species are determinants of the probability of a tree being hollow. From a DBH of approximately 100 cm, the probability of occurrence of hollows in the trees reaches about 80% for Manilkara bidentata (A. DC.) A. Chev., and for and Mezilaurus itauba (Meisn.) Taub. ex Mez and Astronium lecointei Ducke, for example, hollows occur in diameters of about 120 cm. Logistic equations are more efficient in predicting the presence of a hollow when a tree contains one, compared to the hollow test. Conclusion: It is possible to accurately predict the occurrence of hollows in commercial trees, which may be an alternative to the current hollow test used in managed areas in the Brazilian Amazon.

ABSTRACT Background: Scarce information is available on soil-plant interactions to guide management practices for the Khaya genus. This study aims to evaluate the influence of seasonality on the accumulation of litter during two different rainfall periods, as well as to determine its nutrient and carbon content and stock in stands of Khaya at 10.6 years of age. The samples were collected using a template measuring 0.25 m × 0.25 m (0.0625 m²) in a zigzag pattern with a minimum distance of 4 m between points. Results: Nutrient contents were quantified, including macronutrients (N, P, K, Ca, Mg, and S) and micronutrients (Fe, Zn, Cu, Mn, and B), as well as organic carbon in the plant tissue of three species of Khaya (K. grandifoliola, K. ivorensis, and K. senegalensis). In terms of C content, no statistical differences were found between the species during the rainy season. However, for the same period, higher stocks of macronutrients were observed in the following order: Ca > N > Mg > K > S > P. Among micronutrients, Fe showed the highest and Cu showed the lowest stocks. Conclusion: K. ivorensis species exhibited the highest biomass production and the best nutritional quality.

ABSTRACT Background: Acacia mearnsii and Eucalyptus dunnii are species planted mainly for tannin and cellulose production. However, its woods have characteristics favorable to their use for energy generation, being commercialized in the form of firewood, chips or charcoal too. Biochar is a stable form of carbon that can be obtained by converting small particles of wood in the pyrolysis process and that can be used as solid fuel, among other applications as a soil conditioner. In this study, the properties of biochar produced in a horizontal reactor using wood of these species and under milder temperatures were evaluated. Results: Temperature of 350 oC and the reaction time of 30 minutes promoted an increase in higher calorific value of 33% for A. mearnsii and 51% for E. dunnii, with gravimetric yield of 39% and 32%, respectively. it was found that the 250 and 300 oC was not efficient to carbonize the wood of both species. An increase in specific surface area is observed with increasing carbonization temperature. Bigger increases were produced at temperatures of 350 oC for E. dunnii and 420 oC for A. mearnsii, with increase in porosity. At these temperatures, there was an increase in surface area and a decrease in pore size. Conclusion: In temperatures of 350 oC, the woods of both species provided a good quality biochar with porosity, surface area, pore size and pyrolysis yield suitable for energy use. For soil conditioning use, considering these aspects, suggested to test the appropriate temperatures for each species, between 350 and 420 oC.

ABSTRACT Background: The determination of seed moisture content is of utmost importance for the evaluation of its quality. Near-infrared (NIR) spectroscopy has been successfully applied to estimate properties of biological materials. However, studies using this technique on forest seeds are still scarce. Thus, the aim of this study was to explore the potential of NIR spectroscopy for estimating the moisture content of E. uniflora seeds. NIR spectra were obtained using optical fiber from 100 individual seeds that were dehydrated in silica gel for 2, 7, 14, and 21 days. Subsequently, the seeds were subjected to the moisture test by the oven method, and had moisture contents of 52.4%, 41.7%, 33.1%, 21.8%, and 18.1%, respectively. Results: Principal component analysis (PCA) of the spectral signatures explained 100% of the data variability. The moisture content was associated with the spectra by partial least squares regression (PLS-R) and the predictive model presented a coefficient of determination in cross-validation (R²cv) of 0.88 and the root mean square error of cross-validation (RMSEcv) was 5.43%. Conclusion: The statistics associated with the models indicate that NIR spectroscopy has potential for estimating the moisture content of E. uniflora seeds.

ABSTRACT Background: Eucalyptus globulus Labill. is a species of great interest to the pulp industry. However, it has a low rooting capacity, which makes it difficult to clone on a commercial scale. In micropropagation, the supply of cytokinins is necessary to stimulate proliferation, but the type and concentration of cytokinins can negatively affect adventitious rooting. This study evaluated the effect of metatopoline (mT) and benzyladenine (BA) on in vitro multiplication, elongation, and rooting of E. globulus clones. In the multiplication medium, concentrations of 0.44 and 0.88 µmol BA, 0.41 and 0.83 µmol mT, and a control medium without cytokinins were supplied. Results: During the multiplication phase, mT increased the proliferation rate. In addition, mT presented lower production of small explants, less than 0.5 cm in height. In the rooting phase, easy rooting clones treated with 0.41 µmol of mT reached rooting percentages of 91%, while with the use of BA it was 50%. However, in clones with difficult rooting, no differences were observed in relation to the type of cytokinin. Explants treated with mT developed longer roots than those originated with BA, which presented roots similar to those of the control treatment (T). Conclusion: With the use of mT in the multiplication medium, the in vitro elongation, proliferation and rooting of E. globulus was improved, therefore improving the quality of the in vitro explants for the acclimatization stage.

ABSTRACT Background: The water deficit characteristic of semi-arid regions can cause negative changes in plant physiology. Arbuscular mycorrhizal fungi can meet water needs by associating with plant roots, improving seedling quality. The physiological parameters and the quality of the seedlings of Parkia platycephala Benth. were evaluated as a result of the association of isolated strains of Gigaspora rosea, Gigaspora margarita, Acaulospora koskei, Acaulospora morrowiae, intercalated strains (a mixture of the four strains mentioned above) and a control (without inoculation) under two conditions of water regime (with and without stress). Results: Artificial inoculation of AMF is a promising management technique in the production of P. platycephala Benth seedlings for improving the physiological state, increasing seedling quality, and drought resilience. Under restriction water restriction conditions, the seedlings showed lower values of net CO2 assimilation, leaf transpiration, stomatal conductance, and higher values of internal CO2 concentration. Under these conditions, the G. rosea strain stood out with the lowest rate of net CO2 assimilation (A), leaf transpiration (E), and stomatal conductance (gs) with increases of 34, 49, and 70 %, respectively, compared to the control. Conclusion: Stomatal closure is a strategy used by Parkia platycephala Benth. seedlings to prevent excessive water loss, and the Gigaspora rosea strain is responsible for mediating the best physiological conditions and better quality seedlings.

ABSTRACT Background: The insertion of stand variables allows for generalized mixed-effects height-diameter model, and the inclusion of random effects aids in model flexibility and application to new databases through calibration. This study aimed to develop a generalized mixed-effects model capable of accurately predicting the total height of Pinus taeda trees, subjected to different management regimes and at different ages. Results: Experimental data between 4 and 27 years of age collected from stands of Pinus taeda located in the State of Santa Catarina were used. The experiment covers a combination of different planting densities and thinning intensities. The Lasso method was used to select the model’s independent variables, and mixed modeling was implemented, with calibration using BLUP (best linear unbiased predictor). Dominant height and quadratic mean diameter were selected in different formulations by the Lasso method to compose the predictor variables of the model, along with diameter at 1.3 m (dbh). Random effects were entered into the intercept and inverse of dbh terms of the model. Conclusion: The results show that the generalized model developed presents flexibility and can be applied to Pinus taeda stands in southern Brazil using the calibration of random effects, when necessary, by collecting a small sample of plot data.