Schizolobium Parahyba Research Articles

Bee–plant interactions identified by pollen analysis of honey from the stingless bee Tetragonisca fiebrigi (Schwarz, 1938) in southern Brazil

ABSTRACT Pollen analysis of honey reveals information about bee–plant interactions and networks that, in some cases, are lost through mere observation of bees on flowers. This information on bee–plant interactions is valuable for the protection of bees and vegetal speciesand pollination of crop plants. To provideinsights into bee–plant interactions, palynological evidence was developedfromthe collection of honey. The objective of this study is to determine the plants that the bees (Tetragonisca fiebrigi) visit for honey production in southern Brazil (Rio Grande do Sul). For this, 24 honey samples were collectedfrom five regions of northeastern Rio Grande do Sul, southern Brazil. A total of 64 pollen types were found in the honey samples fromT.fiebrigi in southern Brazil, mainly from trees. The most common pollen types in the samples were from Schinus terebinthifolia, Schizolobium parahyba, Handroanthus sp., Morus nigra, and Rosa cf. grandiflora. The pollen grains show a high diversity of plants, including those with important ecological functions.

Correlation of anatomy with physical properties of wood species from an agroforestry system

When the premise is the best final use of wood, evaluation of anatomical variables is recommended, bearing in mind that they are correlated with the properties of this material. The present study aimed to evaluate the correlation between anatomy and the physical properties of wood from Parapiptadenia rigida (Benth.) Brenan, Peltophorum dubium (Spreng.) Taub., Eucalyptus grandis W. Hill × Eucalyptus urophylla S.T. Blake (hybrid) and Schizolobium parahyba (Vell.) Blake, from an agroforestry system. For this purpose, five trees of each species, aged 9 years old, were selected, and samples were collected from the diameter at 1.30 m height from the ground for analysis of the anatomical characteristics and physical properties of the wood. Anatomical variables, with the exception of fiber length and cell wall thickness, correlated with the physical properties of wood and influenced their values. The higher the cell wall fraction (0.79), vessel frequency (0.44) and ray frequency (0.92), the greater the basic density of the wood. The greater the fiber diameter (0.94), lumen diameter (0.88), vessel diameter (0.88), ray height (0.86) and ray width (0.84), the higher the moisture content of the wood.

Plant Growth-Promoting Rhizobacteria: A Promising Strategy To Optimize The Development Of Schizolobium Parahyba

Objective: To investigate the efficacy of plant growth-promoting rhizobacteria (PGPR) in enhancing the early development stages of Schizolobium parahyba, a critical species for the timber industry, aiming to optimize reforestation and agroforestry practices for sustainable forestry. Theoretical Framework: The research is grounded in the exploration of symbiotic relationships between PGPR strains and plant species, focusing on their potential to improve seed germination, plant growth, and biomass production. The study examines how these interactions can be leveraged to enhance agricultural productivity and sustainability, with a specific emphasis on the benefits of employing PGPR in forestry. Method: The study utilized an experimental approach, assessing the impact of four PGPR strains (Serratia marcescens, Pseudomonas protegens, Enterobacter absuriae, and Acinetobacter calcoaceticus) on S. parahyba seedlings. These were cultivated in three different substrates, with variables such as germination rate, above-ground and root growth, and biomass production meticulously measured to evaluate the effects of bacterial inoculation. Results and Conclusions: The application of PGPR notably improved all measured growth parameters in S. parahyba seedlings, with A. calcoaceticus and P. protegens specifically enhancing stem and root development, respectively. A synergistic effect was observed in substrates containing peat, underscoring the significant potential of PGPR in boosting the productivity and sustainability of early-stage forestry cultivation. The findings advocate for further field studies to fine-tune these interactions, aiming to establish more resilient and ecologically sustainable agricultural practices. Originality/Value: This research contributes novel insights into the utilization of PGPR in forestry, highlighting its substantial promise in enhancing the early growth stages of Schizolobium parahyba. By demonstrating the specific benefits of PGPR strains and their interactions with different substrates, the study offers a promising strategy for improving the sustainability and productivity of reforestation and agroforestry efforts.

Wood Basic Density in Large Trees: Impacts on Biomass Estimates in the Southwestern Brazilian Amazon

Wood basic density (WD) plays a crucial role in estimating forest biomass; moreover, improving wood-density estimates is needed to reduce uncertainties in the estimates of tropical forest biomass and carbon stocks. Understanding variations in this density along the tree trunk and its impact on biomass estimates is underexplored in the literature. In this study, the vertical variability of WD was assessed along the stems of large trees that had a diameter at breast height (DBH) ≥ 50 cm from a dense ombrophilous forest on terra firme (unflooded uplands) in Acre, Brazil. A total of 224 trees were sampled, including 20 species, classified by wood type. The average WD along the stem was determined by the ratio of oven-dry mass to saturated volume. Five models were tested, including linear and nonlinear ones, to fit equations for WD, selecting the best model. The variation among species was notable, ranging from 0.288 g cm−3 (Ceiba pentandra, L., Gaertn) to 0.825 g cm−3 (Handroanthus serratifolius, Vahl., S. Grose), with an average of 0.560 g cm−3 (±0.164, standard deviation). Significant variation was observed among individuals, such as in Schizolobium parahyba var. amazonicum (H. ex D.), which ranged from 0.305 to 0.655 g cm−3. WD was classified as low (≤0.40 g cm−3), medium (0.41–0.60 g cm−3), and high (≥0.61 g cm−3). The variability in WD along the stem differs by wood type. In trees with low-density wood, density shows irregular variation but tends to increase along the stem, whereas it decreases in species with medium- and high-density wood. The variation in WD along the stem can lead to underestimations or overestimations, not only in individual trees and species but also in total stocks when estimating forest biomass. Not considering this systematic bias results in significant errors, especially in extrapolations to vast areas, such as the Amazon.

Induction of epicormic sprouts of Schizolobium parahyba var. amazonicum (paricá): effect of seasonality and stump height

Coppicing technique is recognized as an effective method for inducing epicormic sprouts and promoting reinvigoration in Brazilian native tree species. However, there remains a knowledge gap regarding efficient reinvigoration techniques for vegetative rescue of paricá trees. This study aimed to evaluate the coppicing technique's efficacy in inducing epicormic sprouts in paricá trees, considering different seasons and stump heights. A 2x3 factorial experimental design was employed, encompassing two seasons (rainy and dry) and three stump heights (0 = root collar; 10 cm above root collar; 30 cm above root collar). Stumps were monitored over a 90-day period. Results showed that all stumps remained viable, with significant differences observed in sprouting frequency between the rainy and dry seasons at 15 and 30 days, favoring the former. Furthermore, the number of sprouts per stump varied significantly across seasons at 15, 30, and 45 days, with higher counts recorded during the rainy season. Notably, the high percentage of stumps producing sprouts underscores the species' robust response capacity. Additionally, the occurrence of two sprouts per stump suggests a species-specific trait at these stump heights. Evaluation of sprout length and circumference revealed significant differences between seasons, with greater growth observed during the rainy season. These findings are crucial for informing management decisions related to epicormic sprout development through the coppicing technique in paricá trees. Overall, the results indicate the technique's potential to induce epicormic sprouts across all seasons and stump heights evaluated, with superior outcomes observed during the rainy season.

Carbonization temperature at 400°C and the behavior in the visual degradation of 15 wood species

Wood is an anisotropic material and its exposure to carbonization leads to reduced humidity and increased deformation due to the loss of its aesthetic and functional profile. Moisture may be an explanatory factor for the damage caused to the surface region of the coal. For this work, they were defined according to a basic density gradient, that is, involving species of low, medium and high densities, native and exotic, hardwood and conifers, as well as commercial and non-commercial uses. Among the species selected were: (Qualea sp.) Mandioqueira, (Aspidosperma sp.) Peroba, (Erisma uncinatum) Cedrinho, (Pinus elliotii) Pinus, (Eucalyptus.sp) Eucalipto, (Araucaria angustifolia) Pinheiro do Paraná, (Couratari sp.) Tauari, (Dipteryx sp.) Cumaru, (Tabebuia sp.) Ipê, (Peltogyne sp.) Roxinho, (Apuleia leiocarpa) Garapeira, (Goupia glabra) Cupiúba, (Astronium lecointei) Muiracatiara, (Hevea brasiliensis) Seringueira and (Schizolobium parahyba) Guapuruvu. At temperatures of 400 ºC, damage occurred in all species, with the influence of the temperature applied on the degradation suffered in the samples studied. The images produced can contribute to the understanding of charcoal as a material in its various temperature passages and thermal processes, in addition to analyzing the anatomy of charred samples, using the terms: ruptures and fissures as damage to charred wood as parameters.

Growing Coffea canephora in agroforestry systems with Brazilian firetree, Brazil nut, and teak

Planting coffee in agroforestry systems (AFSs) provides diverse advantages to farmers interested in producing environmental services, such as increased local biodiversity, reduction in soil erosion, improvement in water infiltration into the soil, and regulation of climate extremes. It can also be economically attractive due to the possibility of serving alternative markets that have higher and more stable prices for coffees integrated into alternative systems and the generation of products complementary to coffee. This study aimed to evaluate the effects of different planting densities of three forest species on the composition of AFSs with coffee plants under the conditions of the southwestern Amazon region. The study was conducted from November 2014 to June 2021 in the experimental field of Embrapa in Ouro Preto do Oeste, RO, Brazil. The coffee plants were intercropped with three forest species: i) Brazilian firetree (Schizolobium parahyba var. amazonicum), ii) Brazil nut (Bertholletia excelsa), and iii) teak (Tectona grandis). The treatments used in each experiment were four plant densities of plants: zero (coffee plants only, in full sun), 111 plants ha−1 (10 × 9 m), 222 plants ha−1 (10 × 4.5 m), and 444 plants ha−1 (5 × 4.5 m). The experiments were conducted in a split-plot arrangement, with plots consisting of plant densities and subplots consisting of harvest periods (crop seasons). The experimental design was completely randomized, with nine replications. The part of the plot used for data collection consisted of one planted row with 12 coffee plants. The average and accumulated productivities of coffe plants were evaluated over five harvests (2017-2021). Afforestation of the coffee field with Brazilian firetree plants reduces the mean yield and cumulative yield of C. canephora ‘Conilon’ in the first five commercial crop years. Brazil nut and teak planted at densities of up to 222 trees per hectare did not lead to a reduction in the mean and cumulative yield of coffee plants.

Schizolobium parahyba var. amazonicum seedling growth by Trichoderma spp. strains under nitrogen rates

This study evaluated the initial development of paricá (Schizolobium parahyba var. amazonicum) seedlings under different nitrogen rates with the application of Trichoderma spp., using a randomized complete block design in a 4x5 factorial scheme (strains and rates) with seven replications. The evaluated traits were plant height, stem diameter, leaf and stem fresh weights, leaf and stem dry weights, and aerial part dry and fresh weights. Trichoderma spp. strains did not satisfactorily promote paricá seedlings (Schizolobium parahyba var. amazonicum) under high nitrogen rates. However, the Trichoderma harzianum IBLF 006 WP strain was efficient only under low nitrogen availability.

GROWTH PROMOTION OF Schizolobium parahyba var. amazonicum SEEDLINGS USING STRAINS OF Trichoderma spp. UNDER PHOSPHORUS RATES

Fungi of the genus Trichoderma are significantly important for promoting the growth of different plant species. Moreover, they have been connected to high nutrient absorption. Thus, the objective of this study was to evaluate the initial development of seedlings of Brazilian firetree [ Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby ] with application of Trichoderma spp. and phosphorus (P) rates. A randomized block design with seven replications was used, in a 4×5 factorial arrangement (strains and P rates); the P rates were applied using 0, 64, 128, 192, and 256 mg dm -3 of P 2 O 5 (triple superphosphate). The characteristics evaluated were plant height (PH), stem diameter (SD), leaf fresh weight (LFW), leaf dry weight (LDW), stem fresh weight (SFW), stem dry weight (SDW), shoot fresh weight (SHFW), and shoot dry weight (SHDW). The results showed that Trichoderma spp. promotes satisfactory conditions for growing Schizolobium parahyba var. amazonicum , and the strain Trichoderma harzianum IBLF 006 WP at P 2 O 5 rate of approximately 128 mg dm -3 provided the highest increase in the evaluated variables.

INFLUENCE OF ANATOMY ON THE MECHANICAL RESISTANCE OF WOODS IN AN AGROFORESTRY SYSTEM

This study aimed to evaluate the influence of anatomy on the mechanical resistance of Parapiptadenia rigida (Benth.) Brenan, Peltophorum dubium (Spreng.) Taub., Eucalyptus grandis × Eucalyptus urophylla, and Schizolobium parahyba (Vell.) Blake from an agroforestry system. For this purpose, twelve 9-year-old trees were felled. To evaluate the anatomical properties, the specimens were taken from the diameter region at breast height (DBH at 1.30 m from the ground). To determine the mechanical characteristics, central planks from the DBH of the tree logs were removed to produce test specimens with dimensions of 2.5 × 2.5 × 41.0 cm. The modulus of elasticity, modulus of rupture, tension of the proportional limit, and maximum force were then evaluated. Conversely, test specimens with dimensions of 5 × 5 × 15 cm for were used for the transversal and longitudinal Janka hardness and perpendicular compression tests. The higher the cell wall fraction, vessel frequency, and ray frequency values, the better the mechanical properties. Conversely, with the increase in the fiber diameter, lumen diameter, vessel diameter, height, and width of rays, the values of the mechanical properties of wood are lower.

Improving Campus Sustainability and Resilience by Selecting Climate - Appropriate Plants

The purpose of this study is to determine the planting species in a campus environment and assess their suitability for enhancing the quality of life. The study area chosen for this research is the Universiti Malaysia Kelantan (UMK) Campus Bachok, Kelantan. The objectives of this study are to identify the functions of planting at campus area and to make the suggestions of right planting selection. Using mix methods approach, survey and expert interviews was used to collect data in order to address the objectives to the fullest extent possible. A total of 200 respondents, including both staff and students from the faculty of Architecture and Ekistics, took part in the survey. The results shows the thirteen (13) dominant of planting species located around the campus area which are Samanea saman (Rain tree), Salix babylonica (Chinese weeping willow), Terminalia Mantaly (Umbrella tree), Khaya senegalensis (Mohagany), Tabebuai rosea (Trumpet tree), Acacia mangium (Brown salwood), Hopea odorata (Merawan siput jantan), Filicium decipiens (Fern tree), Syzygium polyanthum (Salam tree), Plumeria Frangipani (Kemboja), Schizolobium parahyba (Yellow jacaranda), Ixora Javanica (Siantan), Monoon Longifolium (Mempisang). Results indicate that functions of planting such as a barrier between roads, provided shaded area and to prevent landslide on the shore of the lake.

Arbuscular mycorrhizal fungi activity in the rhizosphere of tree seedlings subjected to residual herbicides.

Trees occurring on the margins of agricultural areas can mitigate damage from residual herbicides. Rhizospheric microbial activity associated with trees is one of the main remedial capacity indicators. The objective of this study was to evaluate the rhizospheric microbiological activity in tree species subjected to the herbicides atrazine and sulfentrazone via the rhizosphere. The experiment was designed in four blocks and a 6 × 3 factorial scheme. The first factor consisted of six tree species from Brazil and the second of atrazine, sulfentrazone, and water solutions. Four herbicide applications were performed via irrigation. The total dry mass of the plants, mycorrhizal colonization, number of spores, basal respiration of the rhizospheric soil, and survival rate of bioindicator plants after phytoremediation were determined. Trichilia hirta had higher biomass when treated with atrazine and sulfentrazone. Herbicides decreased the microbial activity in Triplaris americana and did not affect the microbiological indicators of Myrsine gardneriana, Schizolobium parahyba, and Toona ciliata. Fewer bioindicator plants survived in soil with Triplaris americana and sulfentrazone. Microbiological indicators were influenced in different ways between species by the presence of herbicides in the rhizosphere.

A modificação térmica influencia na resistência mecânica da madeira de espécies florestais

ABSTRACT: This study evaluated the effects of thermal modification at different temperatures and for different durations on the mechanical strength of wood of selected species from an agroforestry system. To this end, three 9-year-old (approximate age) individuals, each from four species of forest trees-Parapiptadenia rigida (Benth.) Brenan, Peltophorum dubium (Spreng.) Taub., Eucalyptus grandis × Eucalyptus urophylla hybrid, and Schizolobium parahyba (Vell.) Blake-were evaluated. After obtaining initial measurements, samples from the four species under went heat treatment for 2 h and 4 h and were subsequently subjected to heat using an oven at temperatures 120°C, 150°C, 180°C, and 210°C; respectively, in addition to the control. For evaluating mechanical strength, the technical standard ASTM D 143-94 was used to obtain the values of the moduli of elasticity and rupture, tension at the proportional limit, and maximum force of the subjects. It was observed that different durations and temperatures altered the mechanical strength of the wood of the four species studied. The 2 h residence time is the most recommended for conducting thermal modification. This procedure modifies the mechanical resistance of wood in a positive manner, with exposure temperatures ranging between 120 ºC and 180 ºC being the most recommended. The thermal treatment carried out for 4 h is not recommended for structural purposes because of the decrease in flexural strength.

Physical and mechanical characterization of paricá LVL panels (Schizolobium parahyba var. amazonicum (Huber x Ducke)) glued with urea-formaldehyde

RESUMO O trabalho teve como objetivo determinar as propriedades físicas e mecânicas de painéis LVL de paricá (Schizolobium parahyba var. amazonicum (Huber x Ducke)) colados com resina ureia-formaldeído. Foram produzidos 6 painéis LVL com 17 lâminas de 2,5 mm de espessura, sendo 14 lâminas de paricá e 3 lâminas de marupá (Simarouba amara Aubl.). Para a condição de umidade padrão de 12%, foram realizados ensaios de teor de umidade, densidades aparente e básica (caracterização física), resistências à compressão paralela e perpendicular às fibras, tração paralela às fibras, cisalhamento na linha de cola e flexão estática flatwise e edgewise (caracterização mecânica). Na condição de saturação total da madeira, foram realizados ensaios de compressão paralela às fibras e cisalhamento na linha de cola do LVL. Os resultados mostraram que os painéis LVL se enquadram na classe de resistência D30, caracterizado com média densidade. Foi observado o modo de ruptura do tipo frágil em todos os ensaios mecânicos, exceto nos ensaios de compressão paralela e perpendicular às fibras. O aumento do teor de umidade, decorrente da saturação total da madeira, influenciou de forma negativa nas resistências à compressão paralela às fibras e ao cisalhamento na linha de cola. O LVL apresentou desempenho mecânico compatível com as solicitações estruturais.

Effects of Shading on Anatomical Aspects and Chlorophyll and Carotenoid Contents in Paricá

Paricá (Schizolobium parahyba variety amazonicum) is an important species for reforestation programs in the Amazon; nevertheless, the anatomical and physiological parameters of the seedlings of this species under shading are not yet fully understood. This study evaluated the chlorophyll and carotenoid contents, the stomatal structure, and the stomatal position in the leaf epidermis under shading of paricá seedlings. The experiment comprised a randomized block design in a subdivided plot scheme, with two sources (Belterra and Urupá) and different shading levels (full sun, 30%, 50%, and 70%). At 100 days after sowing, we performed the analyses of photosynthetic pigment concentration and leaf anatomy. We found that the leaf is hypoestomatic with paracitic stomata and unicellular filiform trichomes on both sides. Higher levels of shading increased the contents of chlorophyll a and b and reduced the stomata density and carotenoid contents in the leaves of young paricá, showing that paricá has phenotypic plasticity to shading.

Does biochar contribute to close nutrient cycles of tree plantations on degraded Ultisols in the Ecuadorian Amazonia?

AbstractThe use of biochar is expected to improve soil fertility and close nutrient cycles in degraded strongly weathered tropical soils. We, therefore, hypothesized that biochar amendment to tree plantations (a) increases nutrient fluxes with litterfall alone and with mineral fertilizer plus lime and (b) reduces N losses reflected by lower δ15N values of litterfall and soils than in unamended controls. We grew the native leguminous Schizolobium parahyba var. amazonicum (Ducke) Barneby and the exotic Gmelina arborea Roxb at two sites. We used a replicated full factorial split–split plot design of amendment of mineral fertilizer plus lime, 3 and 6 t ha−1 biochar, and a control. We collected litterfall biweekly (2012–2013) and topsoil samples (0–0.25 m) in 2009 before tree planting, in 2011 and 2013. Fertilizer plus lime increased the mean annual concentrations of P, Ca and Zn in litterfall but decreased that of Mn. At the same time, fertilizer plus lime increased the annual fluxes of nutrients, Na and Al with litterfall. During the dry season, biochar decreased the N concentration in litterfall and the K flux with litterfall. During the rainy season, biochar increased the concentrations of Ca and Zn in litterfall and their fluxes with litterfall. Biochar did not influence the δ15N values of soil and litterfall after 51 months of tree growth. Fertilizer plus lime decreased the δ15N values of soil, because of the lower δ15N value of the used urea (−0.30‰) than the soil (4.5‰–7.8‰). Moreover, fertilizer plus lime increased the δ15N values of litterfall, possibly because of enhanced 14N leaching from the N‐rich canopies. The amendment of up to 6 t ha−1 biochar did not contribute to close nutrient cycles.

Growth of Schizolobium parahyba var. amazonicum seedlings by strains of Trichoderma spp. under boron rates

Brazil has many important native species, which includes Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby, however, the growth of this species is inhibited in soils with low boron contents, or excess boron, which causes phytotoxicity. Applications of strains of Trichoderma spp. increase the plants' tolerance to abiotic stresses, including tolerance to low or excess levels of nutrients such as boron (B). Thus, the objective of this work was to evaluate plant development and the effect of strains of Trichoderma spp. in Schizolobium parahyba var. amazonicum seedlings grown under different boron rates. A randomized block experimental design was used, with a 4×5 factorial scheme, consisting of 4 strains of Trichoderma spp. and 5 B rates (0, 0.5, 1.0, 1.5, and 2.0 mg dm-3), with seven replications, in greenhouse. Plant height, stem diameter, fresh and dry mass, leaf, stem and total were evaluated at 120 days after emergence. The stains of Trichoderma spp. and B rates presented significant interaction for all evaluated variables, decreasing phytotoxicity. The strain IBLF006WP (T. harzianum) showed a higher capacity of increasing the plants' tolerance to boron, followed by URM5911 (T. asperellum). However, the beneficial effect of increasing this tolerance with the application of these strains is only feasible for soils with high contents of this micronutrient in the soil.

Could trees change future behaviour in xylogenesis to improve fitness based on past and current conditions? A tropical case of study

Carbon allocation is the Achilles' heel of forest models, due to the difficulty to predict responses induced by environmental changes. Structural-functional models involve the plant's strategy to split its resources between organs and functions. An important functional characteristic is xylem architecture, which is connected to water use strategy and plant productivity besides one of the most important C-sink (that absorbs carbon). Our goal is to use the information present in the tree rings of Schizolobium parahyba, to expand the possibilities of teleonomic approaches in structural-functional models of tree species. In a comparative xylem rings analyses, we established relationships among specific gravity, vessel traits as hydraulic conductivity potential, double wall thickness, and autofluorescence intensity of lignin. The analyses showed that growth ring characteristics seem to have been modulated not only by water availability of the period of wood formation but also by the water availability of previous years. This relationship would be occurring due to the greater capacity of accumulation of reserve carbohydrates in years whose climatic conditions were favourable. This pattern of behaviour entails the formation of two distinct growth ring patterns, one with high and the other with low structural cost. This case study shows that the species can change future behaviour in xylogenesis to improve fitness based on past and current conditions. Our study may help to extend the possibilities of teleonomic approaches in structural-functional models of tree species, which will assist in a greater understanding of how trees balance their carbon allocation in wood according to changes in the environment.

Multi-year, post-harvesting impact assessment in a neotropical secondary Atlantic Forest

Subject to overexploitation in the past centuries, the Atlantic Forest is subject to very rigorous protection rules. However, the law is a controversial issue since landowners are not compensated for the limited choice of land use possibilities. We believe that, alternatively to a general timber harvest ban, sustainable forest management of the Atlantic Forest has the potential to generate income for the landowners while sustaining important ecological functions of the forest. Such choice would require better understanding of the potential effects of timber harvesting on the forest ecosystem and on species composition and succession over time. In this context, we assessed the harvesting impact of a conventional harvesting method (CM) and compared it to an alternative harvesting method (AM) in three different stands (stands A, B and C) of a secondary forest fragment in southern Brazil. Results from three comprehensive forest inventories over a period of two years were used to assess the timber harvesting impact. Measurements of species composition (i.e., number of species, life form, ecological group), forest structure (i.e., density, basal area, DBH, volume) and saplings density formed the basis of the impact assessment. The inventories were carried out before, immediately after and two years after harvesting. Intensities of damage on remnant trees immediately after harvesting and two years after harvesting were also measured. Before harvesting, a total of 114 tree species (trees, tree fern and palm tree) belonging to 49 families were identified in the study site’s three research stands. Palm trees and secondary species, such as Euterpe edulis, represented the majority of recruited individuals (DBH ≥ 5 cm) two years after harvesting. However, new saplings (DBH ≤ 5 cm) after two years were mainly pioneer woody tree species, such as Cecropia glaziovii and Schizolobium parahyba. On average, AM reduced damage to saplings by 5%. Most of the damages caused by CM were moderate to severe, while AM caused light to moderate damages. Binary logistic regression indicated dependency of the mortality rates on the independent variables “stand, stem and leaning damages.” On the other hand, the recovery rates of damaged trees were dependent on crown, stem and leaning damages. Therefore, two years after harvesting a higher mortality rate of low-dimensional trees was observed in stands with high density of smaller trees and high density of improvement felling. Although crown damages were not related to mortality rates, high intensity of crown damages reduced recovery rates over time.

The role of soil communities on the germination of a pioneer tree species in the Atlantic rainforest

Climate change has been modifying precipitation and temperature in many regions of the world, prompting changes in plant communities. It also affects soil microbial communities, indirectly influencing plant species distribution through plant-soil feedbacks. Here we report an experiment designed to test seed germination responses to global change, addressed through the interaction between increased temperature and soil microbial communities in a tree species in the Atlantic rainforest, a global biodiversity hotspot. Our objective was to test plant-soil feedbacks in an early colonizer tree species, Schizolobium parahyba, and their interaction with warming. We assessed the role of increased air temperature and soil microbiota in controlling seed germination as a function of distance to mother tree. Higher germination percentages were recorded with extracts of soil microbial communities from the edge of the canopy than with microbial extracts obtained closer to the trunk. These manipulations evidenced that soil microbiota influenced seed germination, being responsible for Janzen–Connell effects. Warming produced major changes in microbial composition but the effect on germination was unclear. Our results may help understand species distribution and coexistence in secondary patches of Atlantic rainforest under warmer conditions, and may contribute to the design of successful restoration programs.