Investments in Pinus elliottii Engelm. Plantations: Real Options Analysis in Discrete Time

Background: The commonly used methods for the financial evaluation of plantation forest investment projects do not incorporate uncertainties and ignore the value related to flexibility. The real options analysis makes it possible to capture these values in investment projects, increasing their value and return. Despite this, studies involving real options in forest investment projects are scarce, specifically those related to Pinus spp. Therefore, this study aimed to: (a) analyze whether the real options analysis adds value to investment projects of Pinus elliottii Engelm. plantations; and (b) make the real options analysis more accessible to forest managers and potentially increase its use in the investment projects of Pinus spp. plantations. Methods: We evaluated two investment projects in P. elliottii plantations in southern Brazil, which differed in the way of obtaining the land for planting: with lease or purchase of land on a planning horizon of 21 years. In the real options analysis, we used deferral, expansion, and abandonment. Results: Individually, the deferral, expansion, and abandonment options add value to investment projects in Pinus elliottii plantations. The option to expand the forested area is one that adds the most value to the investment project with land lease. In the investment project with land purchase, it is abandonment. Conclusions: Investment projects in Pinus elliotti plantations that contemplate the land purchase analyzed through the real options analysis present higher financial returns than those that consider land lease, inverting the result provided by the traditional analysis.

Description of Cryptaphelenchus recticaudatus n. sp. (Aphelenchoidea: Ektaphelenchinae) in Pinus elliottii from the USA

Summary Cryptaphelenchus recticaudatus n. sp. is described and illustrated in Pinus elliottii from the USA. The new species is characterised by the female body 310-431 μm long with distinctly annulated cuticle, lateral fields with four lines, lip region separated from the body by a shallow depression, delicate stylet with small knobs, post-vulval uterine sac short, and rectum and anus invisible. Males are 228-314 μm long, spicules 9.8-12.4 μm long with a well-developed and broad condylus, and seven caudal papillae arranged as a single (P1) and pair (P2) of precloacal papillae plus two pairs of postcloacal papillae. Based upon the general female morphology, the new species most closely resembles C. baujardi and C. iranicus. The morphological differences with the aforementioned species and other species of the genus are discussed. The phylogenetic analyses based on small (SSU) and large subunit (LSU) D2-D3 expansion segments of ribosomal DNA of different individuals of the new species revealed that the new species fell into the Cryptaphelenchus clade in both SSU and LSU trees. The monophyly of the genus was retained after adding newly generated sequences of the new species.

Manejo nutrimental de árboles de pino híbrido y uso de ácido indolbutírico para su clonación por estacas

Las estacas de árboles jóvenes de pino presentan bajas tasas de enraizamiento, lo que dificulta su clonación; sin embargo, la fertilización y podas programadas promueven la producción de estacas juveniles. La aplicación exógena de auxinas favorece la formación de raíces. En este trabajo se analiza el efecto del manejo nutrimental de los árboles donadores, de cuatro años de edad, del híbrido Pinus elliottii var. elliottii × Pinus caribaea var. hondurensis y del ácido indolbutírico (AIB) en el enraizamiento de estacas. En un diseño de bloques completos con arreglo factorial, se evaluó la aplicación de cinco nutrimentos o mezclas de ellos a los árboles. Los tratamientos y dosis por árbol fueron: testigo, nitrógeno (80 g), fósforo (20 g), magnesio (10 g) y nitrógeno/fósforo (80/20 g). Además, se probaron dos dosis de AIB (0 y 3 000 ppm) para el enraizamiento. La supervivencia de estacas, el porcentaje de enraizamiento y la morfología de raíces, se registraron después de 90 días. El manejo nutrimental y el AIB mejoraron tanto la morfología de raíces primarias y secundarias, como el enraizamiento de estacas en más de 30 %, respecto a sus testigos. Lo anterior permitió una mayor supervivencia de estacas durante la formación de raíces. Con el tratamiento de N+P se obtuvo la mejor respuesta, superior a 60 %, en todas las variables evaluadas. La clonación de árboles jóvenes del híbrido, por el enraizamiento de estacas, es posible con el apoyo de un programa de fertilización, aplicado como parte del manejo del árbol donador y el uso de AIB.

Unravelling complex molecular mechanisms in pine with genome-wide association analysis and gene co-expression networks

Loblolly pine (LP), a long-lived tree species, is one of the most economically important forest trees in the world. Genetic improvement programmes for pine trees have focused on survival, early and rapid growth, resistance to diseases and pests, and stem shape. Most of these traits are quantitative and presumably influenced by the action of an unknown network of genes, interacting through complex molecular mechanisms. The extremely large size and high complexity of the Pinus genome have led to challenges in its characterization, sequencing and computational analysis. In this study, we present the first comprehensive integrated analysis of LP involving a genome-wide association study (GWAS) with gene co-expression networks to provide an improved characterization of the gene space and to identify patterns of selection among orthologous gene families. We used populations with full-sib progenies tested at seven sites of the Cooperative Forest Genetics Research Program in the 2nd cycle of Florida LP selection. A total of 1,999 individuals were phenotyped and genotyped using capture probes targeting putative genes based on an elite germplasm transcriptome from LP. A total of 31,589 SNPs were applied to perform a GWAS through a multilocus mixed model. For genome annotation and the construction of gene co-expression networks, three transcriptomes were assembled based on data from different pine species (Pinus taeda, Pinus elliottii and Pinus radiata). With the results obtained, we could select putative genes associated with the target traits and assess the cascade of related molecular mechanisms within co-expression networks. These results advance our understanding of the genetics influencing wood traits and reveal candidate genes for future functional studies and increase our understanding of quantitative genetics and the genomics of complex phenotypic variations in LP. Although the use of GWAS results coupled with genomics data sources did not allow a wide functional assessment of the molecular reactions associated with the traits used, the incorporation of transcriptomics enabled not only gene characterization but also the identification of relevant gene relationships.

Tree-Ring Based Reconstruction of Historical Fire in an Endangered Ecosystem in the Florida Keys

Big Pine Key, Florida, is home to one of Earth’s largest swaths of the critically-endangered dry forests. Known as pine rocklands, this fire-adapted ecosystem must experience regular fire to persist and remain healthy. Pine rocklands are composed of a sole canopy species: the South Florida slash pine (Pinus elliottii var. densa), along with a dense understory of various woody and herbaceous species, and minimal surface moisture and soil development. Slash pine record wildfire activity of the surrounding area via fire scars preserved within the annual tree rings formed by the species. Our study used dendrochronology to investigate the fire history of the pine rocklands on Big Pine Key, specifically within and around the National Key Deer Refuge (NKDR) because it is the largest segment of unfragmented pine rockland on the island. We combined the results found within the NKDR with those of a previous study completed in 2011, and incorporated historical documents and reports of prescribed and natural fires through November 2019 into our evaluation of fire history on Big Pine Key. We conclude that prescribed burning practices are vital to truly restore natural fire behavior, and repeated burning on these islands in the future must be prioritized.

Prediction and Utilization of Malondialdehyde in Exotic Pine Under Drought Stress Using Near-Infrared Spectroscopy

Drought is a major abiotic stress that adversely affects the growth and productivity of plants. Malondialdehyde (MDA), a substance produced by membrane lipids in response to reactive oxygen species (ROS), can be used as a drought indicator to evaluate the degree of plasma membrane damage and the ability of plants to drought stress tolerance. Still measuring MDA is usually a labor- and time-consuming task. In this study, near-infrared (NIR) spectroscopy combined with partial least squares (PLS) was used to obtain rapid and high-throughput measurements of MDA, and the application of this technique to plant drought stress experiments was also investigated. Two exotic conifer tree species, namely, slash pine (Pinus elliottii) and loblolly pine (Pinus taeda), were used as plant material exposed to drought stress; different types of spectral preprocessing methods and important feature-selection algorithms were applied to the PLS model to calibrate it and obtain the best MDA-predicting model. The results show that the best PLS model is established via the combined treatment of detrended variable–significant multivariate correlation algorithm (DET-sMC), where latent variables (LVs) were 6. This model has a respectable predictive capability, with a correlation coefficient (R2) of 0.66, a root mean square error (RMSE) of 2.28%, and a residual prediction deviation (RPD) of 1.51, and it was successfully implemented in drought stress experiments as a reliable and non-destructive method to detect the MDA content in real time.

Avaliação da viabilidade de produção de painéis de partículas fabricados com maravalhas integrais de Pinus e adesivo ureia-formaldeído

<p class="Normal1"><span>O processamento da madeira sólida gera grande quantidade de resíduos, que alternativamente ao descarte e a queima, podem ser utilizados na fabricação de outros produtos. Dessa forma, essa pesquisa objetivou, com o uso do mix de maravalhas na forma integral de madeiras de <em>Pinus elliottii</em> e <em>Pinus taeda</em> e do adesivo ureia-formaldeído, avaliar a viabilidade da produção de painéis de partículas de média e alta densidade, a influência da densidade dos painéis nas propriedades físicas e mecânicas e avaliar a possibilidade da estimativa de propriedades em função de outras por modelos de regressão lineares, considerando também parâmetros colorimétricos. Foram produzidos seis painéis de partículas de média e seis de alta densidade. As propriedades foram obtidas de acordo com as premissas e métodos de cálculo da norma brasileira, sendo os requisitos avaliados com base em normas brasileiras e internacionais. Em linhas gerais, a densidade dos painéis foi significativa em praticamente 50% das propriedades determinadas. Os painéis podem ser classificados como P2 pela norma brasileira, cabendo destacar que em algumas propriedades os valores superaram os requisitos da classe P7. A condutividade térmica indica ser apropriada a aplicações dos compósitos em edificações. Dos modelos de regressão, apenas quatro apresentaram coeficiente de determinação ótimos.</span></p>