Vegetation analysis of the Forest Park of Pocut Meurah Intan (THRPMI), Seulawah Subdistrict, Aceh Besar, Aceh Province

A study entitled “Vegetation Analysis of the Forest Park of Pocut Meurah Intan, Seulawah Subdistrict of Aceh Besar, Aceh Province” has been conducted since April 2019 until November 2019. A transect method and squares were used in this study. The transect method was used to record species composition throughout the observation stations (inventory of species), including stands of pine (Pinus merkusii) with ten stations transect, stands of eucalyptus (Eucalyptus urophylla), stands of cacao (Theobroma cacao), and natural forests within a radius of 2 km around the THRPMI office. The squares method was used to record the species in the same locations to replicate each station by ten squares of samples for vegetation analysis. The parameters measured in the field were frequency, density, and dominance of each species. Analysis of vegetation covered Importance Values (IV), Diversity Index (H ’), and the Similarity Index (SI). Results showed that there were 49 familia found with the composition of species in the entire observation stations comprising of 111 species with 58 species of trees, 12 species of shrubs, and 41 species of herbs. Additionally, the results showed that the species of vegetation with the highest IV were coarse grass (Imperata cylindrica), lawn pait (Axonopus compresus), and selasi (Vernonia cinerea) with IV of 72.01, 65.34, and 57.24, respectively. Results of analysis Species Diversity Index (H ’) showed that the Pinus merkusii had H’ of 2,134, whereas Eucalyptus urophylla had H ’of 1.965, and Theobroma cacao had H’ of 1,067. The results of the analysis of Community Similarity Index showed that all stations had the same relative SI of 75%. It can be concluded that the species composition of the study area dominated by tree species, species diversity index (H ’) in all observation stations varied ranging from 1.067 to 2.134, and the relative Community Similarity Index was 75%.

Effects of Trichoderma strigosellum in Eucalyptus urophylla Development and Leaf-Cutting Ant Behavior

Fungal endophytes can protect plants against herbivory and be used to control leaf-cutting ants. In this study, we aimed to evaluate the potential of endophytic colonization of Eucalyptus urophylla by three filamentous fungal species and their influence on the plant development and foraging behavior of Atta sexdens. The study design was completely randomized and comprised a factorial scheme of 4 × 3, three antagonistic fungal species (Escovopsis sp., Metarhizium anisopliae, and Trichoderma strigosellum) of the leaf-cutting ant, and one control and three inoculation methods (conidial suspension via foliar spray [FS] and soil drench [SD] inoculation, and seedlings inoculated with mycelium [SWM]). The SWM method allowed T. strigosellum to colonize all plant organs, and these plants exhibited higher height, leaf number, shoot dry mass, and total dry mass than the ones subjected to the other inoculation methods. The SWM method increased the plant height than the control plants and those inoculated with Escovopsis sp. and M. anisopliae. Trichoderma strigosellum, previously isolated from soil, colonized E. urophylla plants and positively influenced their development, as demonstrated by the SWM method. Trichoderma strigosellum promoted the increase in E. urophylla height compared with when the FS and SD methods were used (by 19.62% and 18.52%, respectively). Our results reveal that A. sexdens workers preferentially began cutting the leaves from plants not previously colonized by T. strigosellum. This behavior can be explained by modifications in the phenotypic traits of the eucalyptus leaves.

Differences in wood properties among Eucalyptus grandis and Eucalyptus grandis x Eucalyptus urophylla with different degrees of ploidy

We compared the anatomy, density, chemical contents, and bioenergy values of Eucalyptus grandis and hybrids of Eucalyptus grandis x Eucalyptus urophylla wood originating from diploids, triploids and tetraploids. We hypothesize that Eucalyptus grandis and hybrids of Eucalyptus grandis x Eucalyptus urophylla with different degrees of ploidy have variations as a result of different sets of chromosomes producing different phenotypic expressions and chemical constituents, such as variation in cell size and frequency, which would directly influence wood quality. Twenty-year-old trees were cut, eight for each ploidy: diploids and tetraploids are E. grandis; triploids are E. grandis x E. urophylla. We use standardized techniques. Our hypothesis was confirmed. Triploid and tetraploid trees presented wider trunks, taller trees with longer stems and wider crowns compared to diploid trees. Wood density showed significant radial variation only in diploids, while triploid and tetraploid trees were more homogeneous. In polyploid trees, the anatomical features did not clearly present a radial pattern. Triploid and tetraploid trees presented higher density wood than diploid trees. The chemical constituents varied from pith to bark in the three ploidies, but no differences between ploidies were found. For energy generation purposes, diploid and triploid trees are more desirable than tetraploid trees.

Comparison of the infection biology of Teratosphaeria destructans and Teratosphaeria epicoccoides on Eucalyptus

Leaf blight caused by Teratosphaeria destructans is one of the most important diseases of Eucalyptus planted in the sub-tropics and tropics. In contrast, the better-known Teratosphaeria epicoccoides, while also a primary pathogen of Eucalyptus, causes less damage to trees in these areas. Although T. destructans is an aggressive pathogen, nothing is known about its infection biology. In this study, the conditions for infection and disease development caused by T. destructans and T. epicoccoides were evaluated and compared on a Eucalyptus grandis x Eucalyptus urophylla hybrid clone. The optimal temperature for the germination of T. destructans ranged from 25 to 30 oC and 15 to 20 oC for T. epicoccoides. The germination of these pathogens was favored under conditions of light and high levels of relative humidity. Penetration by T. destructans and T. epicoccoides occurred via stomata and the hyphae colonized the intercellular spaces of infected leaves. Symptoms were clearly visible three weeks after inoculation by both pathogens and reproductive structures started to develop in substomatal cavities at four weeks after inoculation. The results of this study will facilitate the establishment of rapid screening trials based on artificial inoculations aimed at reducing the impact of disease caused by T. destructans.

Interaction of precipitation with tree canopy increases nutrient input

Given that atmospheric deposition is the first source of nutrient input into forest ecosystems, and that the precipitation partition serves as a nutritional source mainly when there is an interaction with the forest canopy, the objective of the present study was to quantify the nutrients input into rainfall, throughfall and stemflow in Eucalyptus urophylla stands with partial exclusion (E) and without exclusion (WE) of throughfall. The experiment was conducted in the northeast of the state of Paraná-Brazil, in the municipality of Telêmaco Borba. The partial precipitation exclusion system (E) is formed by a system of gutters that conduct 30% of throughfall out of the experiment. The nutrient input in rainfall was 55.7 kg ha-1 yr-1, while the sum of throughfall and stemflow was 64.1 kg ha-1 yr-1 in treatment (WE) and 39.8 kg ha-1 yr-1 in treatment (E). Interaction with the canopy of the trees enriched the rainfall with nutrients, mainly the elements potassium and chlorine, due to leaching of the vegetal tissues. The reduction of the water treatment system in partial exclusion of precipitation (E) reduced representative nutrient input. Although stemflow represents on average only 2.6% of the water volume, it is responsible for 6.7% of the amount of nutrients in relation to precipitation. Therefore, stemflow cannot be neglected in the balance of nutrient cycling. With a rotation of 7 years, the application of significant amounts of fertilizers can be avoided, considering the inputs of 449 and 277 kg ha-1year-1. Keywords: nutrient cycling, stemflow, throughfall.

Reporte de descripción técnico científica del Eucalyptus urophylla S.T. Blake introducido en Guatemala

El Eucalyptus urophylla es endémico de las islas de Indonesia y otras islas cercanas como Timor, Flores, Adonara, Lomblen, Alor, Wetar y Pantar. Es considerada una especie importante para plantaciones con fines industriales; por esto, tuvo gran dispersión en Brasil, Venezuela y Colombia. En el caso de Venezuela se establecieron ensayos que fueron utilizados como bancos de fuentes semilleros establecidos en el año de 1990, que posteriormente fueron introducidas en Guatemala, y dieron lugar a las primeras plantaciones por la compañía Plantaciones Forestales de Guatemala (PLANFORGUA), en el año de 2008. Debido a las condiciones edafoclimáticas, las plantaciones de E. urophylla en Guatemala constituyen una población con comportamientos y fenología diferentes a las condiciones encontradas en Brasil, por lo que se adaptaron a las condiciones de altitud, temperatura y precipitación en la finca Monterrey localizada en la Ciudad de Guatemala y en los bosques secos en la finca “Los Cocos” de Zacapa. El objetivo del estudio fue realizar un reporte de la descripción técnica científica del género E. urophylla S.T. Blake procedencia Monterrey y Zacapa en Guatemala por medio de investigación de campo descriptiva no experimental apoyada en la documental. Palabras clave: Eucalipto, procedencia, bancos de semillas, Zacapa y Monterrey.

Evaluation of the chemical composition of aquatic environments with leaf litter decomposition of Eucalyptus urophylla S.T. Blake (Myrtaceae) and their toxicity in Allium cepa L. (Amaryllidaceae)

Allelochemicals from eucalyptus released into the environment, mainly by leaves, can have a toxic effect on local biota, including in aquatic environments. Therefore, the present study evaluates the toxic activity of the water containing leaves of Eucalyptus urophylla S.T. Blake (Myrtaceae) in decomposition using Allium cepa L. (Amaryllidaceae) as a test organism. The toxicity and the cytotoxicity evaluation were performed using onion bulbs (A. cepa). The toxicity was assessed by inhibiting root growth. The cytotoxicity was evaluated by using a comparison of the mitotic index (MI) and the negative control. The extraction of eucalyptus metabolites from water of the decomposition tests and creek water was performed by solid-phase microextraction (SPME). The chemical characterization was done by gas chromatography coupled to mass spectrometry (GC-MS). There was inhibition of the root growth of A. cepa, indicating toxicity of the compounds released in the water during the decomposition. The cytotoxicity tests did not indicate a toxic effect. However, there were identified some mutations, cell death, and morphological changes in the roots. 26 compounds were identified on samples of water acquired from decomposition tests.Fenchone, 2-ethyl-1-hexanol, cis-dihydrocarvone, and trans-dihydrocarvone were identified in all samples. The results highlight the importance of studies and monitoring of aquatic environments near eucalyptus.