Estructura poblacional de bosques de Polylepis Ruiz & Pav. y el patrón de parasitismo por Tristerix chodatianus (Patschovsky) Kuijt a lo largo de una gradiente altitudinal en los Andes Centrales de Perú

Descargue el texto completo en el repositorio institucional de la Universidade Federal de Lavras: http://repositorio.ufla.br/jspui/handle/1/46635Evaluamos la estructura espacial y atributos anatómicos de dos bosques, uno de Polylepis incana y otro de Polylepis flavipila. También investigamos la estructura poblacional y patrón de parasitismo de Tristerix chodatianus, en estas dos poblaciones, a lo largo del gradiente altitudinal, en la Reserva Paisajistica Nor Yauyos Cocha, Laraos, Lima-Perú. Se muestrearon tres transectos de 20 m de ancho para cada especie, desde el inicio del bosque hasta la línea de árboles. Se muestrearon todos los individuos con diámetro a la altura del suelo ≥ 5 cm, de los cuales se obtuvo lo siguiente: posición espacial de los individuos, altura, número de individuos y área basal. Nuestros resultados demuestran que la pendiente, la altitud, la presencia de ganado y los senderos influyen en la ocurrencia y la estructura de la población de los bosques de Polylepis. La mayoría de las variables de respuesta no afectaron los atributos anatómicos de las especies evaluadas, las cuales mostraron marcadas diferencias en sus atributos solo en relación a las diferencias de altitud. Para evaluar y comparar la estructura poblacional y patrón de parasitismo de T. chodatianus a lo largo del gradiente ambiental, se muestrearon individuos de T. chodatianus, en los mismos transectos en todos los árboles (parasitados o no), con diámetro a la altura del suelo ≥ 5 cm. muestreados, entre los que se obtuvieron: posición espacial, altura total, diámetro a la altura del suelo, número de ramas y longitud de la rama más larga. La altura total difirió entre los individuos parasitados y no parasitados, en ambas especies, pero los árboles parasitados presentaron mayores alturas en comparación con los no parasitados. Ambas especies mostraron un patrón de distribución agregada, probablemente relacionado con el comportamiento del ave dispersora. Se observó que, en P. flavipila, los árboles de mayor tamaño (en diámetro y altura) están más parasitados, mientras que en P. incana la mayor presencia del parásito está relacionada con el aumento de altitud. Nuestros resultados contribuyen a comprender cómo se distribuye T. chodatianus y cómo la altitud influye en su crecimiento en entornos montañosos.Brasil. Programa de Alianzas para la Educación y la Capacitación (PAEC). Organización de Estados Americanos (OEA) - Grupo Coimbra de Universidades Brasileñas (GCUB

Growth and wood quality evaluation of 8 years Eucalyptus urophylla trees, of progeny tests, in order to produce charcoal

As metodologias de análise da qualidade do lenho e dos anéis de crescimento das árvores de eucalipto são importantes para a determinação do incremento anual do seu tronco, da densidade básica e aparente do lenho, dentre outros, visando os programas de melhoramento, como a seleção precoce de árvores geneticamente superiores para a qualidade da madeira, produção de carvão vegetal, etc. Pelo exposto, o presente trabalho avaliou a qualidade do lenho das árvores de Eucalyptus urophylla, de 8 anos,de um teste de progênie, visando a produção de carvão vegetal, instalado em novembro de 2003, no município de Itamarandiba, MG. Foram mensuradas a altura e o DAP de 6 árvores de E. urophylla, das parcelas lineares de 8 árvores, aos 13º, 21º, 38º, 60º e 82º meses, para a determinação do incremento corrente e acumulado do tronco.A qualidade do lenho das árvores em pé foi realizada em novembro de 2008, determinando a resistência do lenho com o equipamento Pilodyn.Em seguida, foram selecionadas, cortadas e desramadas 4 árvores dos blocos 1, 3, e 5, em um total de 312 árvores e cortados cilindros do lenho na base, DAP, 25, 50, 75 e 100% da altura comercial do tronco.Na seção transversal dos discos de lenho foi feita a caracterização macroscópica e a determinação da largura dos anéis de crescimento anuais do lenho. Na aferição da anuidade da formação dos anéis de crescimento foram analisadas as cicatrizes das injúrias da retirada de placa da casca e aplicação da agulha do pilodyn (novembro de 2008, correspondendo ao 5º anel de crescimento) e o diâmetro do tronco mensurado nos inventários florestais. Com base na largura dos anéis de crescimento foram obtidos os incrementos correntes e acumulados do tronco e comparados com os obtidos pela mensuração externa. A densidade básica dos discos de lenho (base, DAP, 25, 50, 75 e 100% da altura comercial do tronco) das árvores foi determinada; a densidade aparente do lenho do DAP de 12 árvores de 26 progênies foi determinada por densitometria de raios X, obtendo o perfil radial de densidade, a densidade aparente média, mínima e máxima dos anéis de crescimento e do lenho.The methodologies for analyzing the woodqualityand tree-rings of eucalyptus trees are important for determining the trunk annual increment, thebasic and apparent wood density, etc., seeking improvement programs, such as the early selection of genetically superior trees for quality timber, charcoal production, etc. With this aim, the present study evaluated the wood quality of 8 years- Eucalyptus urophyllatrees from a progeny test, installed in November 2003, in the municipality of Itamarandiba, MG, Brazil. The height and DBH of 6E. urophylla trees, in the linear plots of 8 trees were evaluated at 13º, 21º, 38º, 60º and 82º months, for determining the current and accumulated trunk increment. The wood quality of standing trees was conducted in November 2008, determining the wood hardnesswith equipment pylodin. Then, 4 trees were selected, cut and pruned from the blocks 1, 3 and 5, a total of 312 trees, and wood samples from the base, DBH, 25, 50, 75 and 100% of the commercial height were collected. In the wood cross was made the macroscopic characterization and determination of the anual tree-ring width. In assessing the annuity formation of tree-rings were analyzed scars due to the injuries to remotion of the plate of bark and the application of the needle (November 2008, corresponding to the 5th tree-ring), as well as, to thevalues of the trunk diameter measured in forest inventories. Based on the tree-ring thickness were obtained the current and accumulated increases of the trunk diameter and compared with those obtained by the inventory. Thewoodbasic density (base, DBH, 25, 50, 75 and 100% of the trunk height) were determined; also the wood apparent density of the DBH was determined by X-ray densitometry, obtaining the wood radial aparent density profile;the mean, minimum and maximum apparent density of wood and tree-rings

Socioeconomic Conditions and Landowners’ Perception Affect the Intention to Restore <i>Polylepis</i> Forests in the Central Andes of Peru

Research Highlights: Families more dependent on crops as the main source of income of properties have a greater intention of restoring Polylepis forest areas. However, this intention reduces with the increase of family dependence on subsistence products supplied by Polylepis forests. Properties where the chances of restoration of Polylepis forests are greater are those where the educational and technical level is better. Objectives: We aimed to comprehend which socioeconomic factors of rural properties and families’ perception were determinant for the intention to restore Polylepis forests in the Central Andes region of Peru. Material and Methods: We collected data through visits and the application of questionnaires. We selected 13 rural communities in the Tulumayo River Basin. We randomly sampled 10 to 20 families in each community, depending on its size, totaling 200 families. We used generalized linear mixed model (GLMM) to test which variables affect the intention to restore the forest. Results: When crops are the main source of income in the property, the families have more intention to restore Polylepis areas, on the other hand, when Polylepis forests are an important source of products for the family subsistence, the intention to restore forests reduces, indicating that higher technological status has a positive impact on restoration. The perception that Polylepis forests are important for the existence of water sources had a positive impact on the families’ intention to restore the areas. However, the perception that Polylepis forests are important for native flora persistence had a negative impact on the intention to restore their areas. Conclusions: Our results showed that investment in improving the productivity of the properties and in the education of their landowners should increase the success of eventual programs for restoration of Polylepis forests

Socioeconomic Conditions and Landowners’ Perception Affect the Intention to Restore Polylepis Forests in the Central Andes of Peru

Research Highlights: Families more dependent on crops as the main source of income of properties have a greater intention of restoring Polylepis forest areas. However, this intention reduces with the increase of family dependence on subsistence products supplied by Polylepis forests. Properties where the chances of restoration of Polylepis forests are greater are those where the educational and technical level is better. Objectives: We aimed to comprehend which socioeconomic factors of rural properties and families’ perception were determinant for the intention to restore Polylepis forests in the Central Andes region of Peru. Material and Methods: We collected data through visits and the application of questionnaires. We selected 13 rural communities in the Tulumayo River Basin. We randomly sampled 10 to 20 families in each community, depending on its size, totaling 200 families. We used generalized linear mixed model (GLMM) to test which variables affect the intention to restore the forest. Results: When crops are the main source of income in the property, the families have more intention to restore Polylepis areas, on the other hand, when Polylepis forests are an important source of products for the family subsistence, the intention to restore forests reduces, indicating that higher technological status has a positive impact on restoration. The perception that Polylepis forests are important for the existence of water sources had a positive impact on the families’ intention to restore the areas. However, the perception that Polylepis forests are important for native flora persistence had a negative impact on the intention to restore their areas. Conclusions: Our results showed that investment in improving the productivity of the properties and in the education of their landowners should increase the success of eventual programs for restoration of Polylepis forests

Using dendrochronology to trace the impact of the hemiparasite Tristerix chodatianus on Andean Polylepis trees

The high Andean forests of the genus Polylepis (Rosaceae) are threatened by extinction due to anthropogenic effects such as timber extraction, burning, and overgrazing. Some species are also affected by Tristerix chodatianus (Loranthaceae), a hemiparasitic plant which induces progressive host damage. To understand this hemiparasitic process, we evaluated the impact of T. chodatianus on growth and the wood anatomy of Polylepis flavipila using growth rings and digital image processing. We found that P. flavipila has a xeromorphic wood anatomy and that the ecological indices of mesomorphism and vulnerability decrease at higher elevations to avoid embolisms and vessel cavitation. Tristerix chodatianus causes anatomical changes in the host wood, mainly in the last 13 years measured. Alterations include a reduction in the vessel density, and an increase in the vessel diameter and Vulnerability Index, all of which are more evident in downstream sections of parasitized branches. These changes in the xylem tissues increase the vulnerability of the parasitized branches to embolisms and cavitation, thus leading to progressive death of the tree crown. Our study confirms that the analysis of the wood anatomy of parasitized branches can be used to determine the years of colonization of a tree branch by a hemiparasite and that it can be a useful tool to monitor the phytosanitary state of parasitized Polylepis trees

Land cover changes and comparison of current landscape metrics in a region of the Central Andes affected by population migration

The Andes region has a rich history of environmental and human interactions that has shaped the landscape for millennia. Our study quantified the land cover changes in the districts of Huanta and Luricocha after the human population abandoned the region due to the armed conflict with Peruvian authorities (1980 – 1990) and their progressive return (1990 – 2020). We analysed satellite images of various resolutions, including Landsat-5 for the years 1986, 1990, 2000 and 2010; Landsat-8 for the year 2020, Sentinel-2 for the years 2017 and 2020; PeruSat-1 for the years 2017 and 2020, to assess the temporal change of land cover and landscape metrics. The classification was based on the pixel approach for Landsat images and Sentinel-2 with an average accuracy of 88.29% and 92.13% respectively, and an object-based (GEOBIA) approach for Perusat-1 images, with an average accuracy of 87.75%. The dominant coverages are high Andean grasslands, scrublands and croplands. According to the obtained data, high Andean grasslands and scrublands have decreased, which is associated with an increase in population over time. Likewise, there has been an increase in the area of lagoons and the expansion of nearby wetlands due to the construction of dams, driven by an increase in demand for water for human consumption and agriculture. However, areas with degraded soils, rocky outcrops, and forest plantations have expanded. The results suggest that abandoned agricultural lands did not recover quickly enough and more research and action is needed for restoration of the high-mountain ecosystem. Landscape metrics such as Edge Density (ED), Euclidean Distance to Nearest Neighbor (ENN) and Aggregation Index (AI) were calculated for different land cover (LC/LU) to characterize composition and structure, showing their variation at different spatial resolutions. This indicates that increasing spatial resolution makes it possible to better define the landscape characteristics.</p