SURVIVAL AND NATURAL REGENERATION OF FOREST ESSENCES CULTIVATED IN ALTERED AREAS THIRTY-FIVE YEARS AFTER PLANTING

The evaluation of the survival and natural regeneration of tree species in a 35-year-old plantation was carried out to identify the species established in the area, aiming at their recommendation in forest restoration plantations in the State of Acre. In the 1980s, 138 forest species were planted in two experimental units (EU), of 1.38 ha each, in the Zoobotanical Park (ZP) of the Federal University of Acre, Rio Branco campus. The main activities carried out in the area, prior to planting, were agriculture and cattle raising. Survival status was measured through a census of all individuals planted at the time, who were still alive. In addition, all regenerating individuals from planted species were surveyed in the effective planting area of the experimental units. At the time of evaluation, living individuals of 41 and 46 species were found in experimental units 1 (EU-1) and 2 (EU-2), respectively. The species Syagrus sancona, Talisia esculenta, Acacia polyphylla, Couepia bracteosa, Mangifera indica, Syzygium cumini and Copaifera multijuga showed survival rates above 90% in at least one of the experimental units. Only Syagrus sancona and Handroanthus serratifolius presented high survival rates in both experimental. Regenerating individuals of the species Aspidosperma vargasii, Couepia bracteosa, Euterpe precatoria, Handroanthus serratifolius, Oenocarpus mapora, Onychopetalum periquino and Stryphnodendron pulcherrimum were found in the two EU.

HAND-ARM VIBRATION IN DIFFERENT OPERATING CONDITIONS WITH A CHAINSAW

The mechanization of forest harvesting is a trend in Brazil. However, small and medium-sized companies in the forestry sector, even today, opt for semi-mechanized harvesting, using chainsaws for the harvesting and sectioning of trees. Despite technological advances, when operated continuously, chainsaws may cause damage to the operator’s body, acting as a stressor, and vibration excess is responsible for numerous health disorders, among them the Raynaud syndrome. In this sense, this study aimed to determine the vibration levels to which a chainsaw operator is subjected, during the transversal cut (tracing) of the wood, in different forest species and cutting sets. The treatments consisted of three forest species (Eucalyptus grandis, Eucalyptus dunnii and Acacia mearnsii De Wild) and two cutting sets, consisting of square tooth chains of the semi-chisel and chisel types. The vibration assessment was based on the criteria established by the Regulatory Standards NR15, NHO10 and ISO 2631-4. The results of vibration levels were higher than the reference limits established by ISO 2631-4, and, for both cutting sets, the highest vibration levels occurred on the “x” axis. After the data processing, the acceleration values resulting from the normalized exposure to hand-arm vibrations showed significant differences for the “y” and “z” axes. Therefore, it can be inferred that the chainsaw operation is a stressor, potentially capable of causing damage to workers' health.

Effects of nitrogen and phosphorus availability on the early growth of two congeneric pairs of savanna and forest species

In the tropical region, savannas and seasonal forests, both highly diverse biomes, occur side by side, under the same climate. If so, that mosaic cannot be explained solely by climatic variables, but also by fire, water availability and soil status. Nutrient availability in the soil, especially nitrogen and phosphorus, has been postulated to explain the abrupt transitions between savannas and seasonal forests in tropical regions. Plants from these two biomes may present different nutritional strategies to cope with nitrogen and phosphorus limitation. We used two congeneric pairs of trees — each pair with a species from the savanna and another from the neighboring seasonal forest — to test whether savanna and forest species presented different nutritional strategies during their early development. We cultivated 56 individuals from each of these species in a hydroponics system with four treatments: (1) complete Hoagland solution, (2) Hoagland solution without nitrogen, (3) Hoagland solution without phosphorus, and (4) Hoagland solution without nitrogen and phosphorus. After 45 days, we harvested the plants and measured total biomass, root to shoot ratio, height, leaf area, and specific leaf area. Overall, savanna species were lighter, shorter, with smaller leaves, higher specific leaf areas, and higher root to shoot ratios when compared to the forest species. Nitrogen increased the performance of species from both biomes. Phosphorus improved the performance of the forest species and caused toxicity symptoms in the savanna species. Hence, savanna and forest species presented different demands and were partially distinct already as seedlings concerning their nutritional strategies.

Epidemiological study of Colletotrichum spp. associated with Enterolobium cyclocarpum (Jacq.) Griseb. and Platymiscium pinnatum (Jacq.) Dugand in the Colombian Caribbean Region

Epidemiological analyzes of foliar diseases associated with Colletotrichum spp. in Enterolobium cyclocarpum and Platymiscium pinnatum were performed under field conditions and without any type of intervention. At the Universidad del Magdalena (Santa Marta, Colombia), four trees for each species and four equidistant monitoring sites per tree were established. The incidence and severity were recorded for 33 weeks (March to November 2016), including two follow-up periods: dry and rainy season. Disease development curves were elaborated. Moreover, the development rate (r) and the area under the disease progress curve (AUDPC) were calculated for each follow-up period. The effect of the meteorological variables was statistically analyzed by correlation and multiple regression. In E. cyclocarpum, the highest incidence and severity were recorded between September and November with 100 and 19.6%, respectively, showing a positive correlation with relative humidity and negative with average temperature, solar radiation and wind speed. In P. pinnatum, the maximum values of incidence and severity were observed between March and April with 68.9 and 1.3%, respectively. However, correlation analyzes did not support their relationship with the environmental factors. The r values during the dry months were 0.136 and 0.107 units week-1 and the AUDPCs were calculated at 51 and 4 units week-1 for E. cyclocarpum and P. pinnatum, respectively. In the rainy months, the r values were 0.187 and 0.016 units week-1 and the AUDPCs were 186 and 2 units week-1, respectively. In conclusion, the development of the disease varies according to the forest species, time of year and some meteorological variables.

In vitro germination of Abricó-de-Macaco (Couroupita guianensis aubl.)zygotic embryos in different culture media and light spectra

ABSTRACT: Couroupita guianensis Aubl. is an Amazonian forest species with important medicinal and ornamental value. This study evaluated the effect of different culture media and light spectra on the in vitro germination and development of the zygotic embryos of C. guianensis. The culture media, MS and WPM, were evaluated without the addition of plant growth regulators and were associated with four LED light spectra: white (CW), 70% red + 30% blue (R2B), 100% red (R), and 100% blue (B). One hundred percent of the seeds successfully underwent in vitro germination, and the culture media did not interfere with embryo development. In addition to this, the different light spectra induced in vitro morphogenesis and R2B treatment significantly promoted the production of secondary roots. This effect may aid in the rooting and acclimatization of seedlings of this species.

Biochemical markers in crop and forest species: a systematic review

Proteins and enzymes are informative biochemical markers frequently used in plant studies. The objective of this work was to present the studies with enzymes and proteins used as biochemical markers in crops and forest species—the articles prospected in the Scopus and Web of Science scientific databases in December 2020. The keywords were a combination of "agricultural" or "forest" with the Boolean operator and the enzymes' name: alcohol dehydrogenase/ADH, malate dehydrogenase/MDH, alpha-amylase/AMS, peroxiredoxin/PERX, and LEA proteins. Eighty-two articles addressed enzymes in agricultural or forest species were included in the analysis. The articles were published from 1976 to 2020, with an average annual publication of 12.2. Three hundred thirty-seven authors developed the annual percentage growth rate of 2.52% and articles. The most studied crops are Oryza sativa L., Glycine max L., Zea mays L., Hordeum vulgare L., specimens of the genera Triticum and Brassica. The forest species were Pinus, Picea, Nothofagus, Quercus, and Sorbus, and Fagus sylvatica L. The main tissues used for extraction are leaves, seeds, buds, and roots. The studies mainly deal with enzymes or proteins as markers associated with abiotic stresses and the structure or genetic diversity.

Discrimination of forest species using medium spatial resolution images

This research aimed to evaluate the potential of orbital images from the Landsat-8/OLI and Sentinel-2 /MSI sensors in the distinction of species from a forest stand located in Campo Belo do Sul, State of Santa Catarina, Brazil. A total of 53 plots were allocated in the field, in which the central coordinate of the plot was collected using GPS receivers. In SIG environment, two images were used, one from each sensor, closely dated to the field campaign and with no clouds and other atmospheric factors. Then, the images were processed, and 17 vegetation indexes were calculated for each one. The indices were compared statistically by the t-Student test for independent samples. The indices that provided the best species differentiation were: CRI, GNDVI, NDI11, NDI12, NDVI, RDVI, SAVI, and SR. In addition, the species with greater prominence in the Landsat-8/OLI images was Eucalyptus spp. whereas Cunninghamia lanceolata (Lamb.) Hooker was easily distinguished in Sentinel-2 images. It was possible to differentiate the species from remote data derived from the Sentinel-2/MSI and Landsat-8/OLI sensors. However, further studies using other Remote Sensing data sources and other species are suggested.