Pinus Caribaea Research Articles

Exotic tropical pine forest impacts on rainfall interception: Canopy, understory, and litter

Tropical forests have experienced rapid deforestation due to demand from agriculture, timber, and urbanisation. Throughout the Caribbean, planting resilient, fast growing exotic pine trees such as Pinus Caribaea or Pinus Oorcarpa have been used to reforest many degraded landscapes. However, little is understood on how these exotic pine forests alter hydrological processes and water resource availability. We examined the rainfall interception dynamics between an exotic pine and contiguous native secondary forest in Trinidad. Canopy, understory, and litter interception were quantified and examined along with throughfall variability, rainfall characteristics and canopy cover. Our results indicate that over a one-year period, the exotic pine forest intercepts 30% more of the incoming precipitation than the native forest, reducing the rainfall reaching the forest floor. The pine forest had a lower canopy cover but still had a higher storage capacity of 4.3 mm, leading to a higher annual interception of 29%. The native forest had a lower storage capacity of 2.6 mm and a lower annual interception of 24%. Understory vegetation played a critical role in the interception process in the pine forest storing an additional 29% of incoming rainfall increasing the total vegetative interception in the pine forest to 58% (763 mm). These findings point to the creation of drier conditions within pine forest and the need to re-examine the use of pine trees as a reforestation tool. This study highlights the importance of understory vegetation interception and stresses the need for more research on understory-precipitation interactions.

Plant communities in veredas: distribution of native tree/shrubby regeneration and of the invasive species Pinus caribaea Morelet

This work aimed to identify: (1) heterogeneity patterns in veredas, considering tree/shrubby regeneration and chemical and physical characteristics of the soil; (2) how the vereda zones (edge, intermediate and core) can influence the tree/shrubby regeneration and (3) which microenvironmental characteristics determine the distribution of native tree/shrubby regenerants and of the invasive species Pinus caribaea Morelet. For this, we collected environmental and biophysical data and sampled the regeneration of tree/shrubby species in 30 plots in two different veredas. The moisture and chemical characteristics of the soil, and regeneration composition were similar among the vereda zones, but showed important variations among sample units. In addition to soil moisture, soil chemical elements and canopy coverage characteristics also formed environmental gradients. The native tree/shrubby species occupied different positions along the environmental gradient of the veredas. The invasive species P. caribaea was more concentrated in less declined sites, in more basic and more humid soils, together with most native species. In general, the results demonstrate the absence of clear zoning, as well as the importance of environmental heterogeneity and the control of biological invasion for the maintenance of native tree/shrub regeneration.

Landscape heterogeneity increases survival of Pinus caribaea var. hondurensis juveniles in a frequently burned, humid savanna

AbstractWe characterized Caribbean pine (Pinus caribaea var. hondurensis) seedling and juvenile survival in lowland Belizean savannas with respect to environment and fire regimes. Plants in open and densely wooded environments had lower survival after fire. We hypothesize that facilitative or correlative mechanisms might promote positive relationships between shrubs and pine survival.Abstract in Spanish is available with online material.

Pest categorisation of Toumeyella parvicornis.

The EFSA Panel on Plant Health performed a pest categorisation of Toumeyella parvicornis (Cockerell) (Hemiptera: Coccidae) for the EU territory. This species is not included in EU Commission Implementing Regulation 2019/2072. T. parvicornis is a soft‐scale insect native to North America and has been introduced to the Caribbean region and the EU. It has been present in Italy since 2014 (Abruzzo, Campania, Lazio, and Apulia regions) and in France since 2021 (Provence–Alpes–Côte d'Azur region) and is under official control. It develops on Pinus spp. (Pinaceae), feeding on the needles and twigs, especially on new growth. It is sexually reproductive, has one or more generations each year (three in southern Italy), and adult females overwinter on the Pinus needles. It has a high fecundity, up to 1,014 eggs per female in Italy, with an average of 199 eggs for the summer generation and 730 for the overwintering generation. The main natural dispersal stage is the first instar, which crawls over the plant or may be dispersed further by wind and animals. The species can be transported over longer distances with plants for planting. Large populations cause yellowing, needle loss, reduction in growth and recruitment, flagging, dieback and tree mortality. It has had a significant impact to P. pinea (stone pine) in Italy and caused a catastrophic decline of P. caribbea var. bahamensis (Caribbean pine) in the Turks and Caicos Islands. Adult and immature T. parvicornis could enter the EU with Pinus plants for planting; however, the import of Pinus from third countries where the scale is found is prohibited. Host availability and climate suitability indicate that most of the EU would be suitable for establishment. Phytosanitary measures are available to inhibit further introductions and slow the spread within the EU. T. parvicornis satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Selection of Pinus spp. progenies in Lavras (Minas Gerais, Brazil) at 36 months of age

Background: The selection of superior genotypes and adapted to the edaphoclimatic conditions of the region of the introduction produces gains in productivity for forest stands. The objective of this study was to select progenies of Pinus spp. planted in Lavras, Minas Gerais (MG), Brazil. Methods: The experimental site was located on dystrophic Haplic Cambisol. The progeny test was designed as a randomised complete block with 30 replicates and single plot. The treatments corresponded to one progeny of Pinus massoniana, three Pinus caribaea var. bahamensis and 33 Pinus caribaea var. hondurensis arranged with a 3x3 m spacing. The traits height (H), diameter at breast height (DBH) and crown projection area (CPA) were measured at 36 months of age. Results: The results showed that heritability in the narrow sense was 0.24 for DBH, 0.27 for H and 0.50 for CPA. The DBH and H traits showed a high-magnitude positive correlation. The P7, P15, P27, P31 and P33 progenies showed better performance than the other progenies for the evaluated traits. Direct and indirect selection showed similar gains, which favors the use of indirect selection; i.e., when selecting progenies for DBH, progenies with better performance in H are also selected. Additionally, DBH may be used at advanced ages given the difficulty of measuring height. The progeny of Pinus caribaea var. hondurensis showed superior performance compared with Pinus caribaea var. bahamensis and Pinus massoniana for the region of Lavras, MG. Conclusions: This study suggests the possibility of expanding the production of Pinus caribaea var. hondurensis in the region of Lavras with progenies P7, P15, P27, P31 and P33, because in the initial assessments they showed greater adaptability to the edaphoclimatic conditions. Nevertheless, performing a future selection with the aim of evaluating resin production is recommended.

Biosorption of nickel ions Ni2+ by natural and modified Pinus caribaea Morelet sawdust

The potential of Pinus caribaea Morelet sawdust for the removal of nickel ions (Ni2+) and other metallic trace ions (Co2+, Cr3+, Mn2+) from aqueous solutions was investigated under batch conditions. Several parameters such as size of particles, contact time, pH, initial metal and biomass concentrations, desorption conditions and reusability were evaluated on natural biomass. Biosorption was fast, effective (73%) and biomaterial can be reused after five cycles. To enhance the removal capacity of nickel, pine sawdust was modified by acidic and oxidative treatments. Cellulosic residues from sawdust sequential extraction showed great biosorption capacity (96%). In the presence of a metal mixture, oxidized sawdust had better selectivity for Cr3+ ions than for Ni2+. Pinus caribaea biomass could be an environmental, inexpensive and renewable material for the depollution of water laden with metallic trace elements.

Atta laevigata (caribbean pine leaf cutting ant)

Atta laevigata (caribbean pine leaf cutting ant)

EFFECTS OF METEOROLOGICAL VARIABLES ON Pinus caribaea GROWTH IN DIFFERENT AGES AT THE AMAZON REGION.

This study compares the impact of five meteorological variables on the diametric growth of Pinus caribaea var. hondurensis Barrett & Golfari in Vilhena, Rondônia. One thousand nine hundred sixty-eight trees were evaluated and classified at different ages: 600 trees were one year old; 600 trees were two years old; 768 trees were 13 years. The diameter measurement at the soil level (SL) was conducted in young stands between one and two years old. In the stand with 13 years old, the diameter was measured at 1.3 m (DCH). Using a Pressler borer, 50 increment cores were removed at DCH to measure the tree rings in LINTAB™ 6. The diametric growth was evaluated through the Periodic Increment (PI) for young stands and Current Annual Increment (CAI) for adult stands. The following variables were considered: average temperature (°C), precipitation (mm), solar radiation (Kj m-²), real evapotranspiration (mm), and maximum relative humidity (%). The Pearson Correlation Coefficient (r) proposed by Callegari-Jacques and the coefficient of variation (CV%) were used to establish the relationship between growth and meteorological variables. For young stands, the variables with higher positive correlation were real evapotranspiration and maximum relative humidity. However, the variable with a higher positive correlation in adult stands was average temperature, demonstrating a strong correlation until the sixth year of the species.

Genetic Variation in Tropical Tree Species and Plantations: A Review

The global efforts to restore tropical forests and their productive and ecological functions through plantation forestry largely depend on the available genetic variation in the tree species used to establish the plantations. However, there is limited information on the levels and trends of the genetic variation and variability of different plantation tree species in the tropics. Therefore, this study reviews several marker-based studies that have investigated genetic variation. Most of the top economic species like Eucalyptus tereticornis and Mansonia altissima are attributed to low levels of genetic diversity, while others like Pinus caribaea and Swietenia macrophylla still exhibit high expected heterozygosity across different populations. However, the levels of genetic diversity assessed may depend on the markers used. Microsatellites, i.e., simple sequence repeats (SSRs), mostly give higher estimates when compared to other polymerase chain reaction-based markers. Other factors that typically contribute to the directional pattern of genetic variation in tropical tree species and populations include their distribution, density, seed dispersal, succession, and reproduction. Also, anthropogenic impacts like logging and fragmentation have contributed to the vast genetic base reduction of many tropical species and populations. Having adequate genetic variation within the plantation populations is significant in improving their fitness, resilience, fecundity, productivity, and other ecological functions. It also provides a basis for tree improvement and breeding in plantation forests. Although clonal forestry is becoming widespread and considered highly productive, it is attributed to specific economic, technical, and ecological risks, such as the increased spread of pests and diseases. Therefore, further discussions and recommendations to maximise genetic diversity in tropical (clonal) plantations are provided.

Assessment of the mixed timber combination effect of finger-jointed timber species using flexural and tensile strength

Off-cut wood is one of the wastes dumped by sawmills, and inadequate length of sawn timber materials fail to fully utilize the wood supply. Finger joint, a method that connects two small pieces of timber, is identified as a sound technique to minimize wastage. Different timber species should be bonded at the finger joint production process for making finger-jointed mixed boards. When mixing the different timber species, timber pieces should be matched based on the mechanical strength. This study was, therefore, conducted to find the strength properties of mixed finger-jointed timber species of wood, namely, Grandis (Eucalyptus grandis), Jack (Aartocarpus heterophyllus), Kumbuk (Terminalia arjuna) and Pine (Pinus caribaea), commonly used in Sri Lanka in the manufacture of furniture. The tests were carried out on timber samples with 19 mm finger lengths made of two sections bonded with an adhesive containing polyvinyl acetate (PVAc). The tensile strength and variation of the flexural strength of the finger length of the samples were studied. BS 373: 1957 was the standard used for the flexural tests. A Universal Testing Machine (UTM 100 PC) was used for the mechanical tests. Timber combination categories are not significantly different for the MOR tests. Pine-Pine vs. Pine-Grandis combination category is significantly different for Bending tests. According to overall results, timber combination categories are significantly different for the tensile tests except for Pine and Kumbuk combinations. The findings of this study will directly benefit the finger joint manufacturers in Sri Lanka.

Structural system based on tensioned wood panels: experimental and numerical validation

Housing in modern societies is a priority need. In the countries of industrial development, there are very sharp contrasts with respect to the housing deficit, affecting the great majority of the families with lower economic resources that solve their problem through subhuman constructions, elaborated, mostly, with residues of construction and disassembly of old buildings, highlighting the importance of the economy, from the financial point of the house built on the architectural quality and comfort. The need to create new building systems based on wood for homes arises when considering the few existing alternatives in developing countries that guarantee an economic, massive and fundamentally sustainable construction. In this sense, this research aims to make a contribution to the implementation of new structural elements for the sustainable construction of wooden houses, which can be manufactured by low technology processes, allowing easy use and appropriation by the general population. The system is called TENSO-WOOD, which is conceived as a system of solid wood plates of Caribbean pine, developed by means of low technology processes that allow an easy appropriation by the population in general. This paper presents a frame structural system using tensioned wood panels as structural elements. It is a lightweight prefabrication system for the construction of two-storey wooden houses. The system consists of bolted wood elements, creating different structural panels such as beam and column. An experimental program was carried out, which allowed knowing the mechanical behavior of each panel of the frame structure. In addition, it permits to know their maximum stress and deformations. The numerical models were compared with the experimental tests to validate and calibrate some parameters in the simulations. Therefore, the numerical models can be able to compute the load capacity and deformation of the wooden elements, obtaining behavior curves.

Pinus elliottii and P. elliottii x P. caribaea hybrid differently cope with combined drought and heat episodes

Extreme climate change events, such as long periods of drought and heat waves, are predicted to increase throughout this century. Pinus species are important economic resources. However, it remains unknown the vulnerability of most species to climate change-related stresses. We aimed to compare the performance reconfiguration of two resin/timber important species [Pinus elliottii var. elliottii (PE) and the hybrid Pinus elliottii var. elliottii × Pinus caribaea var. hondurensis (PE × PCH)] to face combined stress of drought+heat. Young PE and PE × PCH plants were grown at optimal conditions, then exposed to water deficit for 5 days, and in the last day of water deficit, plants were additionally exposed to a heat shock. The physiological responses, antioxidant capacity and oxidative stress were evaluated immediately and 5 days (recovery) after drought+heat treatment. Under control conditions, the hybrid displayed higher photosynthetic and biochemical performance (e.g. higher net CO2 assimilation rate, transpiration rate, photosynthetic pigments and anthocyanins levels, carbohydrates and antioxidant enzyme activities). Immediately after the drought+heat episode, plant water status decreased in both species, as well as the PSII photosynthetic parameters (ФPSII and Fv’/Fm’), while non-photochemical quenching increased. However, the gas-exchange parameters of PE and the hybrid responded differently to the combined stress. The hybrid suffered a stronger reduction on the net CO2 assimilation rate and transpiration rate, and presented higher levels of lipid peroxidation, but with no cell membrane permeability injuries. Principal component analysis supports that the different profile of both species is possibly associated to the stronger antioxidant capacity of PE under stress conditions. Moreover, these differences were still observed during recovery and photosynthesis was re-established totally only in PE. The hybrid clearly demonstrated less ability to restore the gas-exchange in the same period, possibly due to stomata re-opening limitations. The low net CO2 assimilation rates in the hybrid after stress relief could also result in the necessity to use the starch reserves to maintain TSS pools available for stress recovery. We conclude that the hybrid perform better under control conditions, and the PE seems better prepared to cope with the predictable global climate change scenarios forecast for the next decades. The hybrid is more affected by drought+heat, but is able to keep a photosynthetic performance close to the PE under stress, although less efficient during recovery.

Unsupervised spectral-spatial processing of drone imagery for identification of pine seedlings

Reliable and accurate monitoring of replanted forest areas is a vital component of the plantation cycle if sustainable management practices are to be maintained following resource extraction. Unmanned aerial vehicles (UAVs) can rapidly survey newly planted forest areas using high resolution imagery. Automated image processing techniques can cost-effectively examine large quantities of data. Correctly combined, such technologies can efficiently create accurate maps of seedling locations, which offers the prospect of management practices for forestry and ecology operations that involve less fieldwork. This paper presents a technique based on unsupervised machine learning for detecting healthy young pinus caribaea (Caribbean pine) and pinus radiata (Monterey pine) seedlings. The locations of individual trees requiring replacement are also determined based on the spatial distribution of the identified healthy trees. The approach was tested on data from 30 sites covering over 700 ha, with seedlings ranging from 9 months to 3 years’ old (mean tree heights 30–2 m). Test sites contained a range of geomorphologies and levels of weed infestation. The results indicate detection precision and specificity in excess of 90% and recall approaching 99% for dense point cloud resolution of 4–6 cm. As network pre-training is unnecessary, there is no need for high resolution imagery, which allows greater operational coverage per unit time. The algorithm may also be used on multi- or hyperspectral data; and may be useful if employed in conjunction with other supervised learning techniques to reduce the need for manual labelling of training data sets.

Comparing global and local maps of the Caribbean pine forests of Andros, home of the critically endangered Bahama Oriole.

Forest loss is occurring at alarming rates across the globe. The pine rockland forests of Andros, The Bahamas, likely represent some of the largest stands of Bahamian subspecies of Caribbean pine in the world. Given the unique species that inhabit these pine forests, such as the endemic and critically endangered Bahama Oriole, monitoring habitats on Andros is crucial to inform conservation planning. We developed a 2019 land classification map to assess the status of nine terrestrial habitats on Andros. Our Random Forest classification model predicted habitat classes with high overall accuracy. Caribbean pine was the dominant land class making up roughly one-third of the total terrestrial area. Whereas much of the pine forest area was found as small patches, most were close to other patches of pine suggesting isolation of forest patches is low. We compared our known intact forest areas to recent forest loss identified by the Hansen et al. Global Forest Change product and assessed areas of habitat disturbance in high-resolution imagery. Our results suggest that this global map overpredicted forest loss on Andros. The small degree of true forest loss on Andros was driven mostly by anthropogenic activity. A cross-tabulation of the Hansen forest loss with fire data showed that understory fires were frequently associated with falsely classified deforestation. Given the threats of climate change to this open forest type-intensifying fire regimes, strengthening hurricanes, and sea level rise-monitoring changes in open forest extent is a critical task across the Caribbean region and the world.

Hydrophysical characteristics in water-repellent tropical Eucalyptus, Pine, and Casuarina plantation forest soils

Abstract Soil water repellency (SWR) reduces the rates of wetting in dry soils and is known to interfere with water movement into as well as within the soils. The objective of this study was to investigate the hydrophysical characteristics of three water-repellent tropical exotic plantation forest soils in wet and dry seasons. The study sites were Eucalyptus grandis (EG), Pinus caribaea (PC), and Casuarina equisetifolia (CE) plantation forest soils located in the up-country intermediate zone (EG and PC), and low-country dry zone (CE). Field experiments were conducted to measure the infiltration rate, unsaturated hydraulic conductivity (k), water sorptivity (S W). Laboratory experiments were conducted to measure the potential SWR and water entry value (h we). All three soils showed higher SWR in the dry season, where CE soils showed the highest. The EG soils showed the highest SWR in the wet season. Although SWR in all soils decreased with increasing depth in the wet season, only CE soils showed a significant decrease in SWR with soil depth in the dry season. Compared with the wet season, the k(–1 cm) was lower and h we was higher in the dry season. However, S W did not show a significant difference between wet and dry seasons. Initial infiltration rate and k(–1 cm) showed a negative correlation with contact angle in all three soils. Soils showed positive linear correlations between k(–1 cm) and S W, and negative linear correlations between S W and h we showing that surface water absorption is related to both subsurface unsaturated water flow and surface water entry pressure. It was clear that the water entry into soils and the subsurface water flow were hindered by the SWR. High water entry values in the dry season predict high potentials for intensified surface runoff and topsoil erosion. Future research will be required on the interactions between soil biology and soil properties such as pore structure that would influence water flow into and within soils.

A new approach for predicting board MOE from increment cores

Key message Increment cores can provide improved predictive capabilities of the modulus of elasticity (MOE) of sawn boards. Multiple increment cores collected at different heights in a tree provide marginally increased accuracy over a single breast-height core, with higher labour costs. Approximately 50% of the variability of the static bending MOE of individual boards is explained by the predicted MOE obtained from a single increment core taken at breast height. Context Prediction of individual board MOE can lead to accurate optimisation of the value extracted from forest resources, and enhanced decision-making on the management and allocation of the resource to different processors, and improve the processors ability to optimise grade allocation. Aims The objective of this study is to predict the MOE of individual sawn boards from the MOE measured from cores collected from standing trees. Methods A five-parameter logistic (5PL) function and radial basis function interpolants are used to obtain a continuous distribution of MOE throughout a log. By developing a “virtual sawing” methodology, we predict the individual board MOE for sixty-eight trees consisting of locally developed F1 and F2 hybrid pines (Pinus caribaea var. hondurensis × Pinuselliottii var. elliottii). Results Moderate correlations for individual board predictions are observed, with R2 values ranging from 0.47 to 0.53. Good correlations between average predicted board MOE and average measured MOE are also observed, with R2 ≈ 0.83. A pseudo-three-dimensional approach, accounting for variation in height in the tree, affords marginally greater accuracy and predictive capability at the cost of increased data collection and processing. By using a single breast-height core, we can obtain a similar level of prediction of individual board MOE. Conclusion We have presented a novel non-destructive evaluation approach to predict the MOE of individual boards sawn from trees. This approach can be adapted to other wood properties, and other wood products obtained from trees.

Phenotypic integration approaches predict a decrease of reproduction rates of Caribbean pine populations in dry tropical areas

• Key message The combination of structural equation modelling and linear mixed-effects models opens a new perspective to investigate trait adaptation syndromes through phenotypic integration prediction at large geographical scales, a necessary step to understand the future of organisms under climate change. In the case of Pinus caribaea Morelet, reproduction limits the species suitability, decreasing towards southernmost latitudes where dry conditions increase.ContextCaribbean pine is an ecologically and economically important species planted in all the tropical regions of the world, where it shows optimal growth and survival but low reproduction rates.AimsThis study investigates Caribbean pine fitness-related traits, accounting for phenotypic plasticity and local adaptation, to detect co-variation among traits and predict their relationship across the tropics.MethodsI re-analysed earlier data of survival, growth, reproduction, stem quality and development stage from 25 provenances of Caribbean pine planted in 16 trials in the tropical regions in a two-step modelling approach including (i) structural equation modelling (SEM) based on the current knowledge of the species and theoretical expectations coming from other species; (ii) mixed-effects model accounting for trait-relationships as defined by SEM and allowing for trait prediction.ResultsGrowth, survival and reproduction showed a slight but significant provenance effect indicating population differentiation and a positive co-variation between growth and reproduction, suggesting that trees reached optimal growth before they reproduced. Models predicted low reproduction rates of Caribbean pine across the tropics, decreasing towards southern latitudes where dry conditions increased.ConclusionThis study opens new perspectives to investigate trait adaptation syndromes through phenotypic integration prediction at large geographical scales.

Performance Characteristics of a Cooking Stove Improved with Sawdust as an Insulation Material

In developing countries, energy demand from biomass has increased due to exponential population growth. This has translated into voluminous quantities of wood being used. The situation is exacerbated by the popular use of inefficient stoves with low thermal insulation, hence contributing to deforestation. In this study, the performance of a cooking stove improved with sawdust as an insulation material was assessed. An insulated fire stove prototype of 26 cm saucepan diameter was designed, constructed, and cast with sawdust and clay in a ratio of 1 : 1 (as the first layer) and sawdust alone as the second layer. The developed stove was tested using a water boiling test to establish its operating performance. The thermal efficiency of the stove was assessed using indigenous wood fuels used in rural Uganda (Senna spectabilis, Pinus caribaea, and Eucalyptus grandis). Computational fluid dynamics was used to simulate the temperature and velocity fields within the combustion chamber and for generating temperature contours of the stove. Obtained results indicated that S. spectabilis had the highest thermal efficiency of 35.5 ± 2.5%, followed by E. grandis (25.7 ± 1.7%) and lastly P. caribaea (19.0 ± 1.2%) in the cold start phase when compared with traditional stoves. The stove remained cold as hot air was restricted to the combustion chamber with decreasing temperature contours toward the outer wall up to the ambient temperature. The velocity flow remained constant as the chamber was colored green throughout due to the shielding of the stove with sawdust as insulation. The heat flux generated indicated that a thick layer of 6 cm or more could ensure good insulation, and this could be further reduced by introducing more sawdust. The designed stove has the potential to reduce biomass consumption and emissions when compared to traditional cookstoves. The inclusion of a chimney draught in the fire stove prototype could reduce smoke and increase thermal efficiency. Further studies should focus on minimizing the thickness of the clay-sawdust (first) layer and increasing the thickness of the sawdust layer to reduce the weight of the fire stove.

Interaction between edaphic mesofauna and organic carbon within water-stable aggregates in forestry systems: A case study in northeastern Brazil

Soil mesofauna plays an important role in soil aggregation, which conditions the physical protection of soil organic carbon (SOC). Thus, our study associates the evaluation of mesofauna and SOC quantification to generate relevant information on the influencing level of these organisms on organic matter dynamics in aggregates. It is even more important investigating these indicators in places where decomposition processes are more intense, such as forest systems under tropical soils, where little is known about the interaction between these variables. In this context, the present study aimed to evaluate: (1) the influence of homogeneous Pterogyne nitens and Pinus caribaea plantations on the edaphic mesofauna community and on SOC stocks and carbon in soil aggregate classes using a native forest as a reference; and (2) the interaction between edaphic mesofauna, SOC and aggregate carbon. This study was performed on Oxisol soil areas located in the municipality of Vitória da Conquista, Bahia, Brazil. The edaphic mesofauna was evaluated using the modified Berlese-Tullgren funnel method. Physical soil fractionation was carried out by wet sieving. The organic carbon contents of the soil and aggregates were determined by wet oxidation. Implantation of homogeneous Pterogyne nitens and Pinus caribaea stands causes a reduction in the edaphic mesofauna (abundance and average richness) and in the amount of soil macroaggregates. The differences between the forest systems are largely explained by the abundance of fauna, SOC and carbon of the macroaggregates, microaggregates and silt + clay. The edaphic mesofauna has a direct and positive influence on the SOC, which highlights its important role in regulating the soil carbon dynamics in the soil.

PHYSICAL PROPERTIES OF WOOD Pinus caribaea var. caribaea, Pinus caribaea var. hondurensis AND Pinus oocarpa FOR PENCIL PRODUCTION

The behavior of the physical properties of wood is important for its use in the industrial sector. Manufacturing for pencil production requires raw material with low specific mass and high dimensional stability. The objective of this study was to evaluate the properties of the physical specific basic mass properties, anhydrous and green, as well as the retractability of the 14 years old Pinus caribaea var. caribaea, 25 years old Pinus caribaea var. hondurensis and 35 years old Pinus oocarpa in the medulla sense of the bark, base and top of the trees. All species come from the Brazilian Cerrado region afforestation. As for dimensional stability, the Pinus caribaea var. caribaea and Pinus oocarpa had similar behaviors to the volumetric contraction, when evaluating the coefficient of anisotropy of wood species of Pinus caribaea var. caribaea had higher values of anisotropy coefficient, however, all tropical pine studied, qualify as a raw material for the pencil industry, being an alternative species traditionally used.