Growing Birch in Clear-cut Areas with Herbicide Application

Birch, being one of the main forest-forming tree species, has valuable and soughtafter timber. In production forest conditions, natural regeneration and crops of this species experience strong competition from both grass cover and undesirable hardwoods (aspen, gray alder and willow). Without carrying out high-quality maintenance (agrotechnical care, clearing), the formation of economically valuable birch forests is impossible. The most effective and economical is the chemical care method, which involves the use of modern environmentally friendly herbicides. However, if technological regulations and practical recommendations for the use of herbicides have already been developed for the care of coniferous species (pine, spruce and others), then there are currently no such recommendations for birch. The aim of the research is to develop a scientifically based method of caring for natural young birch stands (clearing, agrotechnical care) using selective herbicides on forest fund lands. The objects of research are seed and vegetative regeneration of birch in young stands formed in clear-cut areas, as well as undesirable herbaceous and tree-shrub vegetation. When laying the experiments and evaluating their results, we were guided by the generally accepted methodology for testing herbicides in agriculture. In field production and small-scale experiments with herbicides magnum, magnum super, mortira and anchor-85 in young stands with birch trees, the biological effectiveness of the action of the preparations on a wide range of undesirable vegetation was determined, as well as their selectivity with respect to birch. High efficiency of herbicides magnum (100–300 g/ha) and magnum super (100–200 g/ha) on dicotyledonous species of herbaceous vegetation and deciduous species – willow, aspen, gray alder and mountain-ash, as well as high resistance of birch to them at continuous spraying during the growing season was established. Herbicides mortira (100–200 g/ha) and anchor-85 (100 g/ha) were recognized as unsuitable for birch care. It was found that after a single application of herbicide magnum at rates of 100 and 200 g/ha in mixed young stands dominated by aspen, willow and gray alder and with participation of birch 1–2 composition units, stands dominated by the latter are formed. Acknowledgements: The study was financially supported by the Federal Agency of Forestry within the state assignment of the Saint Petersburg Forestry Research Institute approved by Order No. 1061 of 25.12.2018. For citation: Egorov A.B., Postnikov A.M., Bubnov A.A., Pavluchenkova L.N., Partolina A.N. Growing Birch in Clear-cut Areas with Herbicide Application. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 5, pp. 58–74. (In Russ.). https://doi.org/10.37482/0536-1036-2023-5-58-7

Connecting neutrino Astrophysics to Multi-TeV to PeV gamma-ray astronomy with TAIGA

Recent evidence for neutrinos in the PeV energy range from IceCube provides additional motivation for the search for the most energetic Galactic accelerators. Gamma-ray astronomy is a sound strategy to reach this goal, providing the energy range beyond 10\,TeV can be covered at a sufficient sensitivity level. The energy spectra of most known gamma-ray emitters only reach up to few 10s of TeV. The HEGRA IACT installation reported evidence for gamma-ray energies from the Crab Nebula as high as 80\,TeV. Uncovering their spectral shape up to few 100s of TeV could answer the question whether some of these objects are cosmic ray Pevatrons, i.e. Galactic PeV accelerators. Extending observations beyond this energy range requires very large effective detector areas, as planned by the TAIGA collaboration