Experimental Examination of Vegetative Propagation Methods of Nothofagus antarctica (G. Forst.) Oerst. for Restoration of Fire-Damaged Forest in Torres del Paine National Park, Chile

Nothofagus antarctica (Antarctic beech) is one of the main woody plants in the temperate deciduous forests and anti-boreal forests of the southern hemisphere. Since colonization of the Andean-Patagonian region by European settlers, however, stands of this species have been severely affected by fires caused by human activities, considerably reducing their area. To restore these forests to their area occupied before the fires, it is necessary to use artificial regeneration, relying on production of transplants in forest nurseries. Due to the low capacity for seed propagation, we focus on possibilities of producing seedlings by vegetative propagation. In a trial, we collected cuttings during three sets of dates, and attempted to root them using three combinations of substrate and ten combinations of stimulators. Using the most favorable combination of collection period, substrate and stimulator tested resulted in rooting of 23% of the cuttings, which exceeds the documented germination rates for this species.

Marca Chile: “Todo Chile es un Torres del Paine”

Este artigo pretende ser uma proposta metodológica sobre o caso do turismo no Chile, colocando-se como paradigma o caso das Torres del Paine e a possibilidade de que todo o Chile bem administrado e gerido turisticamente possa converter-se em um Torres del Paine. O Chile apresenta um elevado nível de qualidade de vida no contexto da América Latina e do Caribe (ALC), alcançando pleno consenso em aproveitar de maneira sustentável e soberana a riqueza turística do país para benefício de todos os seus habitantes. O conceito “Turismo, um segundo soldo para o Chile” propõe-se com base no que se considera que o cobre ainda com seus atuais altos preços se constitui como o primeiro soldo do Chile. Em segundo lugar, atualmente as exportações de frutas, madeiras e vinos poderiam haver se considerado durante os últimos vinte anos como uma das rentabilidades económicas mais importantes do país. Logo, o atual e acelerado crescimento da industria turística, as entradas de visitantes, a inteligencia de mercado necessária de desenvolver e as rendas que deixam para o país e os empreendimentos turísticos, transformarão o turismo na segunda fonte de renda de maior relevancia como industria, sendo além disso uma industria daquelas denominadas limpas ainda quando presente também impactos negativos pela quantidade de visitantes que se produz e as atividades inherentes à indústria turística.

Vulnerability of soils to degradation by wildfires in Torres del Paine National Park (Patagonia, Chile)

<p>Wildfires are a common phenomenon across the world, but some ecosystems are more adapted to this perturbation than others. In this work we show some results of a study conducted in the Torres del Paine National Park (Chile) that suffered a big forest fire in 2011 affecting 17,666 ha. Based on vegetation coverage, five areas of the park were sampled in 2019 following the transects where a vegetation recovery study has been monitored in order to know the status of the ecosystem and how fire and post-fire conditions affected.</p><p>The study area is in a temperate cold rainy climate zone without dry season. The park is located in the transitional forest-steppe zone whose annual rainfall varies between 1500 mm and 300 mm. Plant communities goes from Patagonian steppe, pre-Andean scrub to Magallanic forest. The soils of the region vary from Cryorthents and Udorthents to Haplocryolls (Soil Survey Staff, 2014), most of them with scarce development.</p><p>A total of 69 composite soil samples were taken, and the following parameters were analysed: texture, soil water repellency (WR), organic matter (OM), and aggregation, including total content of macroaggregates (TCA; % of sample that are forming macroaggregates) and their stability (AS; % of macroaggregates that resist the energy of a rainfall simulation of known energy).</p><p>The results showed high values of OM, with an average of 10.5%. Three of the five areas showed statistically lower values of OM in burned samples. WR (from slight to severe) was present in the 75% of the samples, and without differences between burned and unburned samples. The correlations analyses indicated that WR is more related with the OM quality than with quantity, since better correlations were obtained when only samples from same area -thus similar vegetation- were included in the analyses, and no correlation when all samples from different sites are pooled together. The results of aggregation indicated that these soils have a poor structural development. The TCA varies from 16 to 50%, and the AS is not very high (average of 66 %), being the higher in the area with lower TCA, and more affected by the fire and erosion processes. This suggests that the higher values of AS are consequence of the destruction and loss of the less resistant fraction after the fire.</p><p>WR is a natural property in these soils. The combination of the high sand content (low specific surface area) and high OM make them very susceptible to develop WR. Since these soils have a scarce development with a poor structure, the combination of these factors make them very vulnerable to erosion processes after the fire. This could be verified in three of the five study areas and specially the one with plant community in transition between steppe to scrub, which was the one more affected by the perturbation caused by the fire and post-fire erosion processes. Measures to protect the soils or accelerate the recovery are recommended in these areas when new human caused wildfires will occur.</p>

Numerically modeling routes of sequential magma pulses in the upper crust

<p>Understanding the evolution and generation of large scale igneous bodies is important to understand the evolution of the crust. The way igneous bodies are constructed and the timescale of construction control the location, volume and composition of melt (Annen, 2015). Despite many previous studies that address the construction of igneous bodies, it remains unclear why melt focusses within a specific area. Igneous bodies are usually the result of multiple magmatic pulses that solidify in the same location. In many cases the time between subsequent pulses is sufficiently long for the magma of one pulse to completely solidified before the next pulse arrives.</p><p>Magma will rise when the buoyancy of the magma is greater than the resisting forces in the host rock. The rising magma will however not always follow a vertical path to the surface. Variables like the direction of the least compressive stress, the presence of folding or faulting and weak contacts between layers are all factors that can cause melt to follow a different pathway. In the case of multiple pulses, the effects of earlier pulses can alter these factors. Thermal and chemical alteration is thought to lead to new preferred paths for the melt.</p><p>The granitic laccolith in Torres del Paine natural park in the south of Chile is a particularly well-studied example where magma seems to have followed the same path from the lower magma chamber to the present location of the laccolith over multiple pulses. This laccolith consists of three pulses of granitic magma that intruded into folded sedimentary materials over a timespan of approximately 90ka (Michel et al., 2008), all through the same same deeder channel. The time between pulses was sufficiently long for the magma to completely solidify. Therefore, thermal weakening can possibly be excluded as a reason why the magma followed the same path multiple times. Yer, why the feeder zone stayed in the same location for all pulses remains poorly understood.</p><p>Here, we therefore present numerical simulations in which we model multiple magma pulses and track whether multiple pulses follow the same path. The pulses start in a mid-crustal magma chamber and rise upwards through a folded host rock. We will employ a newly developed, thermomechanical parallel staggered finite difference code for that takes visco-elasto plastic rheologies into account. Systematic simulations are presented in which we test the effect of pulse-intervals, fold wavelengths of the host rocks, intrusion temperature and viscosities as well as the effect of preexisting weaknesses on the subsequent pathways of the magma.</p><p> </p><p>[1] Annen, C., Blundy, J. D., Leuthold, J., & Sparks, R. S. J. (2015). Construction and evolution of igneous bodies: Towards an integrated perspective of crustal magmatism. <span><em>Lithos</em></span><span>, </span><span><em>230</em></span><span>, 206-221.</span></p><p><span>[2] Michel, J., Baumgartner, L., Putlitz, B., Schaltegger, U., & Ovtcharova, M. (2008). </span>Incremental growth of the Patagonian Torres del Paine laccolith over 90 ky. <em>Geology</em>, <em>36</em>(6), 459-462.</p>

Reaction progress of clay minerals and carbonaceous matter in a contact metamorphic aureole (Torres del Paine intrusion, Chile)

This study reports on reaction processes in a transition zone from contact to regional metamorphism by using Raman spectroscopy on carbonaceous matter (RSCM), illite “crystallinity” (Kübler index, KI), chlorite geothermometry, and thermal modeling. The thermal effect due to the emplacement of the Torres del Paine intrusion (TPI, assembly time of ca. 150 kyr) had different consequences for inorganic and organic compounds of the host rock. The thermal alteration of the pre-intrusive regional metamorphosed host rock is documented by elevated RSCM temperatures, high-temperature chlorite generations, and the appearance of epidote and retrograde Fe-rich chlorite. Microprobe analysis on chlorite indicates incomplete re-equilibration as evidenced by various chlorite populations of individual contact metamorphic samples. This study indicates that the maturity of organic matter is the most reliable and unequivocal indicator on timescales of several thousand years to determine the lateral extension of the TPI contact aureole. Raman geothermometry reveals that the lateral extension of the contact-influenced zone expands up to a distance of 1.5 km and, thus, expands to ca. 1.1 km further out than the macroscopically mappable hornfels contact aureole. The best match between measured (Raman geothermometry) and calculated (thermal modeling) ΔTmax values (ΔT=54 ∘C) is achieved with a total intrusion assembly time of 150 kyr, a magmatic temperature of 800 ∘C, a two-batch model (batch repose time of 10 kyr) with five pulses per batch, short heating durations (3 kyr), and long pulse repose times (15 kyr).

Linking soil C pools and N in radiotraced soils of Grey lake area (Torres del Paine, Chilean Patagonia)

<p>The Grey Glacier, located in the Torres del Paine region, belongs to the Patagonian ice sheet that suffered several glacial fluctuations during the Quaternary resulting in spectacular glacial landscapes. Similar as in other world mountains, glaciers in the Andean Patagonia are declining and the Grey Glacier has experienced during the last 80 years a clear retreat. Important ice mass collapses occurred in 1996 and recently in 2017 and 2019. In the proglacial environment of Grey Lake, the most characteristic glacial landforms are the Last Glacial Maximum moraine belts while landforms of the Little Ice Age reveal the advance of ice in modern times in the lake surroundings. At present the most active formations are composed of glacial deposits exposed after the recent retreat of Grey glacier. In this rapidly changing environment new soils are developing becoming a relevant framework to assess the trends in the pedogenesis dynamic and the variations of nutrient pools.</p><p>During a 15 days field campaign in the frame of the IAEA INT5153 project main proglacial landforms were identified and soil sampling was undertaken to assess if there were differences in the soil status and the nutrients pools in function of the geomorphic characteristics. Previous research in the area (Navas et al., 2019) revealed the usefulness of combining <sup>137</sup>Cs with soil organic carbon (SOC) for deriving information on soils generated on recently exposed glacial deposits linked to soil redistribution patterns. Our study aims to evaluate what is the status of the SOC pool in soils formed in the Grey Lake area in relation to <sup>137</sup>Cs proxies of soil stability. Analyses of <sup>137</sup>Cs (Bqkg<sup>-1</sup>), and of contents of SOC and its fractions, and nitrogen (N) were done for characterizing the soils of the study landforms. We found that the most recent glacial deposits that are highly unstable in this paraglacial environment had the lowest contents of SOC and N along with negligible activities of <sup>137</sup>Cs. In parallel with the highest <sup>137</sup>Cs activity found in more developed soils on forest slopes, high SOC and N contents though less than in swamps indicated higher soil stability in forest slopes than in recently exposed glacial deposits. In the C pool, the stable fraction was most abundant in soils on forest slopes and on vegetated moraines in accordance with more abundant vegetation cover on relatively more developed soils. Though all landforms had much higher proportion of the active fraction, specially swamps, the contribution of the active fraction to SOC was also much higher in swamps, followed by forest and vegetated moraines. However, in comparison with the rest of glacial deposits and forest slopes, swamps presented the lowest contribution of the stable fraction to SOC evidencing their fragility to degradation processes that would rapidly eliminate the more labile fraction disrupting the natural cycle of C towards more stable fractions. Our results show that combination of <sup>137</sup>Cs derived information with data from nutrients pools can be an important aid for interpreting changes in paraglacial landscapes where soils are forming on recently exposed glacial deposits.</p>