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Austrocedrus chilensis and Nothofagus dombeyi are endemic species of the Andean-Patagonian forest, which grow in pure or mixed forests. Both have an important ecological role in the region and a great productive potential. However, knowledge about how humidity and radiation influence their early development is limited. In this study, we examined the combined effects of different light (95, 46 y 9 %) and soil moisture levels (100 - 80, 50 - 70 y 20 - 40 %) on survival and growth of N. dombeyi and A. chilensis over two growing seasons under nursery conditions. We also measured the effects of these factors on the following functional traits: leaf thickness and tensile strength, specific leaf area, total leaf area, leaf area / sapwood area to collar ratio, dry weight of the different compartments (leaves, branches, and roots), and internode length. Both species showed similar responses to the factors studied in survival and initial development, although N. dombeyi showed, in general terms, greater growth and lower survival than A. chilensis. The intermediate and high radiation level favored the growth of both species. The humidity levels did not have significant effects on growth, but they did show effects on some of the functional traits, generally interacting with radiation. Also, the lower level of humidity combined with the greater radiation, decreased N. dombeyi survival. It is concluded that the best performance of both species occurs in radiation conditions close to 50 %, which would correspond to forests of these species with 8-10 m² ha-1 of basal area. [ABSTRACT FROM AUTHOR]

Background: South America has the largest area of temperate forests in the Southern Hemisphere, which grow in diverse site conditions. The aim of this paper is to review the practices of silviculture applied and recommended for these temperate forests, and to discuss prospects to develop new silvicultural proposals to improve sustainability, adaptation and in-situ conservation of forest ecosystems. Methods: We reviewed the silviculture knowledge in four major forest types: 1) The Nothofagus-dominated forests of south-central Chile; 2) the Angiosperm-dominated evergreen forests; 3) the Nothofagus and Austrocedrus chilensis (D.Don) Pic. Serm. & Bizzarri forests in the Argentinean Northern Patagonia; and 4) the Cool temperate Nothofagus forests and Magellanic rainforests. Results: In Chile, both Nothofagus-dominated and Angiosperm-dominated evergreen forests are diverse in tree species, and mixed-species silviculture with commercially valuable species of variable shade tolerance is most promising. Some secondary forests can reach growth rates as high as 20 m³ha-1yr-1. After thinnings, stands with 35-60% of residual densities have shown the best responses in growth. Even-aged silvicultural methods have shown a rapid reorganization and development of new cohorts, although, where Chusquea species are conspicuous, regeneration establishment requires controlling competing vegetation. Preliminary results also show interesting prospects for single-tree selection cuts in uneven-aged forests. East of the Andes, in Argentina, mixed Nothofagus forests and pure and mixed Nothofagus and A. chilensis forests occur. The shelterwood method has been the most practised and successful in the mixed Nothofagus forests, with abundant regeneration, and good growth rates. For A. chilensis forests, an adaptive management approach is proposed, conditioned by the cypress disease attack (e.g., Phytophthora austrocedri). Conversion of pure A. chilensis to mixed A. chilensis--N. dombeyi forests could increase growth considerably. Finally, in the cool temperate Nothofagus forests and Magellanic rainforests, shared by Chile and Argentina, the regular shelterwood cuts have been the most common silvicultural method, with massive regeneration a decade after the regeneration felling. Since the two major Nothofagus species in these forests regenerate well in gaps, uneven-aged silviculture seems also promising. Conclusions: There is abundant knowledge about the silviculture of these forest types. However, there are opportunities for several silvicultural systems to better contribute to sustainable forest management, reverse forest degradation, and cope with climate change challenges, primarily through developing mixed and single-species productive and carbon-rich forests, with greater adaptive capacity. [ABSTRACT FROM AUTHOR]

Development of specific microsatellite primers is a relatively expensive and time-consuming process, so transferring already developed markers from one species to others is desirable, especially for non-model organisms with large genome structure such as conifers. In austral South America, the three Cupressaceae are monotypic genera of high conservation and evolutionary relevance. Although they had been the focus of numerous population genetic studies the lack of highly polymorphic markers as microsatellites for all species, has limited the possibility of evolutionary studies and the design of appropriate conservation plans. Thus the aim of this study is to transfer and test microsatellites primers early designed for Austrocedrus to Fitzroya and Pilgerodendron. Transferability of nine microsatellite primers and their utility were tested by comparing genetic parameters of 20 individuals of each species in six populations where the three species occur. Four markers were simultaneously transferred with success, representing the first study in conifers to achieve cross-genera transferability. This small set of primers yielded high levels of polymorphism for the three studied species and show unique alleles that separate pure taxa. These highly polymorphic markers provide relevant tools to study the evolutionary history of South American Cupressaceae and to generate information that could help to guide conservation efforts. [ABSTRACT FROM AUTHOR]

• Leaf litter traits have stronger control than rainfall on decomposition in Patagonia. • Controls on decomposition go beyond climate and lignin:N in Patagonian forests. • Litter decomposition is similar between forests with varying precipitation in Patagonia. • Litter decomposition is strongly associated with litter Mg in Patagonian forests. Temperate forests play an important role in the global carbon (C) cycle. Extensive research on litter decomposition in temperate forests in the Northern Hemisphere have greatly contributed to our conceptual framework of the controls of C cycling, where climate and litter lignin/N ratio have played a dominant role. However, there is a noteworthy lack of basic information on southern temperate forests, which have unique characteristics demonstrated by differences in ecosystem functioning and their response to human impact when compared to their northern counterparts. Patagonian forests are the most extensive temperate forests in South America and offer the opportunity to evaluate the importance of climate and litter traits in old growth forests with relatively little human impact. We compared litter decomposition of 10 dominant native tree species and of two non-native tree species (used as common substrates) in two native forests with varying precipitation and tree species composition: a Nothofagus mesic mixed forest (2200 mm MAP) and an Austrocedrus open dry forest (1350 mm MAP). In addition to rainfall, these forest types differed markedly in tree species composition and leaf litter traits that resulted in 1.5 times larger soil carbon and nitrogen pool in Austrocedrus open dry forest and 5 times higher soil inorganic nitrogen than in Nothofagus mesic forests. Nevertheless, decomposition of common litter substrates was similar between both forest types. In contrast, native tree species litter showed up to 10-fold differences in their decomposition rates in a common forest site. Litter mass loss and nitrogen dynamics were strongly associated with magnesium (Mg) and manganese (Mn) content of the litter, respectively. In contrast to dominant control of climate and litter lignin/N, our results demonstrate that native tree species traits may be more important than climate and its effects on plant-soil interactions in Patagonian forests. Our study also highlights the importance of macro- and micro-nutrients (Mg and Mn) in litter that are generally overlooked as determinants of litter decomposition in terrestrial ecosystems. These native Patagonian forests show distinctive controls of litter decomposition compared with other temperate forests of the world. They also highlight the importance of considering how management that affects tree species identity and composition may have far-reaching effects on ecosystem functioning that are currently not being considered. [ABSTRACT FROM AUTHOR]

The long-term history of fire regimes in the Mediterranean Andes of Chile is almost unknown. Subalpine woodlands of Austrocedrus chilensis include long-lived trees resilient to low-intensity fires, which can provide valuable tree-ring-based information about fire history. In this work, we performed an annually resolved multicentury reconstruction of past fires from fire-scar records identified in relict Austrocedrus wood found on steep highly-eroded and rocky slopes with coarser fuel structure in the upper Cachapoal Valley, central Andes of Chile. We compared this fire record with historical land-use changes and extensive reconstructions of regional precipitation and temperature, as well as large-scale climatic patterns. The highest fire frequencies were recorded in the Spanish settlement period (1541–1750), when land-clearing activities, cattle ranching, agriculture, and mining practices became widespread after the Spanish conquest. At an interannual time scale, fire occurrence and precipitation were unconnected during the Spanish settlement. By contrast, in the indigenous period (1200–1540), under the influence of the aboriginal Chiquillanes people, fires occurred in wet years with high vegetation productivity. In the livestock grazing period (1751–1950), when large cattle ranches were established, fires occurred in dry years after a wet year. Fires in this period were likely ignited under conditions of high fuel flammability to improve plant production and promote intensive livestock grazing. At a multidecadal time scale, fires were more frequent in cold periods throughout the whole record. These findings suggest that herbaceous fuel accumulation and flammability, modulated by climate variation and human land uses, were the main factors promoting fires spread in this Mediterranean subalpine area. Our research emphasizes the importance of relict Austrocedrus wood for fire history reconstruction and expands knowledge about fire regime shifts over the past eight centuries in southern South America. [ABSTRACT FROM AUTHOR]

The management of native forests in Northern Patagonia has great potential to provide multiple products with high market value, whose regional demand is growing continuously. Considering that economic profitability is key to guide sustainable forest management decisions, in this paper the effect of the discounting rate, which is a measure of the opportunity cost of funds and resources used in a project, was evaluated over the profitability of forest management options. Five management alternatives of native mixed shrublands through variable discount rates were analyzed. The costs and revenues were obtained from a woodshed experiment extraction in El Foyel, Río Negro (41°38'48.44" S; 71°29'59.06" O), consultation and local publications. It was found that with lower discount rates to 2.9 % the most attractive management alternative was the management that combined woodshed extractions and afforestation of Austrocedrus chilensis while at a higher discount rate, the most attractive alternative was the woodshed shrub management with intensive extraction. There was no rate that positioned the alternative replacement of the shrubland for afforestation of Pinus ponderosa as the best alternative. This work suggests that there are management alternatives of native forest that would be more profitable than that for single species forest plantations of P. ponderosa. [ABSTRACT FROM AUTHOR]

Cordilleran cypress ( Austrocedrus chilensis [D.Don] Pic. Serm. et Bizarri) forests occupy 140,000 ha along a sharp environmental gradient of central Andean-Patagonia in Argentina. Every summer, about 3200 ha of these forests are affected by wildfires, taking thereafter long time to recover. To accelerate forest recovery, we determined in xeric and mesic cypress stands burned 5 and 2 year before whether survival and growth of two planted cypress seedling stocktypes are affected by plant cover and contrasting precipitation conditions. Two experiments were conducted on each site, involving 100 replicates of two seedling stocktypes, having each significantly different morphological attributes. The experiments comprised a dry and humid growing season on each site. Both stocktypes performed similarly within stands, but differently between stands. In the xeric stand, plant cover had neutral effects on seedling survival, favored seedling height growth in the dry season, and was negative on collar diameter and stem growth. In the mesic site, high plant cover favored survival and height growth, but was inconsequential for collar diameter and stem growth. In this short-term post-fire period, and independent of precipitation received during both seasons (dry or humid), plant cover appears as playing a facilitative role, having neutral or even positive effects on survival and growth of planted seedlings. During the early post-fire successional stages, and besides seedling stocktype, there was a synergistic balance between light and soil moisture that seems to benefit planted seedling performance in burned cypress forests, and especially in mesic sites. [ABSTRACT FROM AUTHOR]

El "Ciprés de la Cordillera " ( Austrocedrus chilensis (D.Don) Pic. Ser. et Bizzarri) es la conífera nativa de mayor importancia económica de los bosques templados de Argentina. Se han detectado en la bibliografía imprecisiones respecto al rango latitudinal en el que se desarrolla, las que motivaron este estudio. Se determinaron los extremos de ese rango en base a antecedentes bibliográficos, información provista por pobladores y expertos regionales, y reconocimientos en el campo. El extremo septentrional se ubica a los 32º 39' S (Región V de Valparaíso, Chile), y el extremo austral se halla a los 43º 44' S (Provincia de Chubut, Argentina), lo que representa una distancia de unos 1230 km . Esta variación latitudinal y el carácter fragmentario de su distribución natural apoyan la hipótesis de la existencia de ecotipos en la especie.The "Patagonian Cypress" ( Austrocedrus chilensis (D.Don) Pic. Ser. et Bizzarri) is the most economically important native conifer of the temperate forests of Argentina. Some inaccuracy was detected in the bibliography with respect to its latitudinal range, what motivates the present study. The location of the latitudinal extremes was determined based on bibliographic antecedents, local settlers' and experts' information, and field surveys. The northernmost extreme is located at 32º 39' S (Region V of Valparaíso, Chile), while the southernmost extreme at 43º 44' S (Chubut Province, Argentina). This 11 latitudinal grades range represents a distance of 1230 km. This broad latitudinal range and the fragmentary feature of its natural distribution area support the hypothesis of ecotypes for this species.

Vegetation associated with lacustrine systems in Northern Patagonia was studied for heavy metal and trace element contents, regarding their elemental contribution to these aquatic ecosystems. The research focused on native species and exotic vascular plant Salix spp. potential for absorbing heavy metals and trace elements. The native species studied were riparian Amomyrtus luma, Austrocedrus chilensis, Chusquea culeou, Desfontainia fulgens, Escallonia rubra, Gaultheria mucronata, Lomatia hirsuta, Luma apiculata, Maytenus boaria, Myrceugenia exsucca, Nothofagus antarctica, Nothofagus dombeyi, Schinus patagonicus, and Weinmannia trichosperma, and macrophytes Hydrocotyle chamaemorus, Isöetes chubutiana, Galium sp., Myriophyllum quitense, Nitella sp. (algae), Potamogeton linguatus, Ranunculus sp., and Schoenoplectus californicus. Fresh leaves were analyzed as well as leaves decomposing within the aquatic bodies, collected from lakes Futalaufquen and Rivadavia (Los Alerces National Park), and lakes Moreno and Nahuel Huapi (Nahuel Huapi National Park). The elements studied were heavy metals Ag, As, Cd, Hg, and U, major elements Ca, K, and Fe, and trace elements Ba, Br, Co, Cr, Cs, Hf, Na, Rb, Se, Sr, and Zn. Geochemical tracers La and Sm were also determined to evaluate contamination of the biological tissues by geological particulate (sediment, soil, dust) and to implement concentration corrections. [ABSTRACT FROM AUTHOR]

Fosetyl-Al and metalaxyl, the most commonly used systemic fungicides against Phytophthora, were evaluated for their efficacy to control Phytophthora austrocedri, the pathogen that causes a serious disease at the Austrocedrus chilensis forests in Patagonia. The effect of the chemicals on pathogen development in vitro and in planta was analysed. Both chemicals were shown to protect plants from the pathogen. In vitro assays showed that asexual reproduction was sensitive to both chemicals. However, mycelial growth and sexual reproduction, which were clearly sensitive to metalaxyl, were sensitive only to high concentrations of fosetyl-Al. Fosetyl-Al and metalaxyl had almost the same efficacy when applied preventively by soil drench to seedlings. This difference between in vitro and in planta results can be attributed to the dual action of fosetyl-Al, not only inhibiting the pathogen but also stimulating host defence. In adult trees, preventive and curative treatments were tested, but only the fosetyl-Al preventive treatment was effective in the assayed conditions. Interestingly, seedlings pretreated with both fungicides were less susceptible to the effectors secreted by the pathogen. Our results indicate that fosetyl-Al and metalaxyl provide some resistance to the plant besides the fungistatic direct action on the pathogen. Further studies to elucidate a possible resistance-inducing activity of these chemicals and the mechanisms involved are underway. [ABSTRACT FROM AUTHOR]

Questions Is mal del ciprés, the widespread decline and death of Austrocedrus chilensis trees, caused by a single pathogen or multiple factors? Using a novel dendrochronological approach, we disentangled the influences of climatic variation on the radial growth decline and death of A. chilensis trees in declining forests. We distinguish possible causes of reduced radial growth and mortality from autogenic processes driven by stand development. We present a conceptual model of forest decline including multiple factors that predispose, incite and contributed to decreased radial growth and death of A. chilensis. Location A. chilensis forests on mesic sites in northern Patagonia, Argentina. Methods We used dendrochronology to determine the years of (1) onset of radial growth decline of 301 living and dead trees stratified by canopy position at decline onset, and (2) mortality of 339 trees stratified by radial growth patterns and canopy position at death. Events were years with low or high numbers of trees initiating decline or dying. We tested the hypothesis that onset of decline and mortality were concurrent with drought for individual trees, using contingency tables, and for events, using superposed epoch analysis. Results Climatic variability acts as an environmental stress inciting and contributing to stand-level forest decline. The onset of radial growth decline and mortality of individual trees were significantly associated with summer moisture deficits. High-magnitude onset-of-decline and mortality events were concurrent with adverse climatic conditions. Conclusions Climatic variation and drought incite and contribute to tree- and stand-level decline and mortality in A. chilensis forests. Deciphering the effects of stand development is critical as autogenic processes independently drive tree mortality and mediate the effects of climatic variability on A. chilensis forest decline. Based on our results, we present a conceptual model within the framework of a forest decline process, and conclude A. chilensis mortality is a forest decline process driven by complex interactions between allogenic abiotic and biotic factors and autogenic stand development processes. Site conditions, genetic variation and sex of trees are predisposing factors that likely interact with the pathogen Phytophthora. [ABSTRACT FROM AUTHOR]

In view of global climate change, it is important to understand the responses of tree species to climate changes in the past. Combinations of phylogeographic analysis of genetic evidence, coupled with species distribution models ( SDMs), are improving our understanding on this subject., We combined SDMs and microsatellite data from populations of the entire range of Austrocedrus chilensis, a dominant mesotherm (cold-sensitive) conifer of dryland forests of the southern Andes, to test the hypothesis of long-distance postglacial migration from northern and warmer refugia at the Last Glacial Maximum ( LGM)., The SDM indicated suitable conditions for Austrocedrus in northern Chile (western) at the LGM and largely unsuitable conditions in Argentina (eastern). Population genetic diversity and effective population sizes within populations decreased southward along the Andes, consistent with the hypothesis of long-distance dispersal from a northern refugium., Results support the hypothesis of one (or a few) warmer (low latitude) refugia in Chile for Austrocedrus. On balance, the evidence suggests that in contrast to cold-tolerant tree taxa with the capacity to fast-track postglacial warming thanks to local refugia, cold-sensitive species might have undergone long-distance range expansion, lagging behind progressive climate change throughout the Holocene. [ABSTRACT FROM AUTHOR]

The populations of the Andean Cupressaceae Austrocedrus chilensis have been severely affected by a disease caused by the phytopathogenic fungus Phytophthora austrocedri. A study was undertaken to disclose changes in the resin composition of P. austrocedri-infected individuals, including naturally infected and artificially inoculated trees, compared with healthy A. chilensis trees. GC-MS and 1H-NMR studies showed a clear differentiation among healthy and infected resins, with the diterpene isopimara-8(9),15-dien-19-ol as a relevant constituent in resins from infected trees. The effect of resin fractions from P. austrocedri infected trees on the pathogen was assessed by measuring the mycelial growth in agar plates. The most active fractions from resin obtained from infected trees inhibited fungal growth by nearly 50% at 1 mg/dish (35.37 μg/cm2). The main constituent in the active fractions were 18-hydroxymanool and the aldehyde torulosal. Both compounds are oxidation products of manool and can be a chemical response of the tree to the pathogen or be formed from the pathogen as a biotransformation product of manool by microbial oxidation. While the diterpene profiles from A. chilensis tree resins can easily differentiate healthy and P. austrocedri infected individuals, the possible conversion of manool to the antifungal derivatives 4 and 6 by the microorganism remains to be established. [ABSTRACT FROM AUTHOR]

Context: Fitzroya cupressoides (Molina) I. M. Johnst. and Austrocedrus chilensis (D. Don) Pic.Serm. & Bizzarri are two Chilean Cupressaceae that are naturally resistant to biodegradation. Secondary metabolites from these species display a variety of biological activities. Objective: To evaluate the antiproliferative activity of two lignans, a diterpene and a flavonol isolated from A. chilensis and F. cupressoides, to elucidate their cytological effects on P3X murine myeloma cells. Materials and methods: The antiproliferative activity of yatein, isotaxiresinol, ferruginol, and isorhamnetin was evaluated in vitro using the MTT assay. The effect of yatein at the cellular level, due to its high antiproliferative activity was evaluated. P3X cells treated for 24 h with 12.5 and 25 µg/mL of yatein were also examined at the cytological level using immunofluorescence and scanning and transmission electron microscopy. Results: Yatein, a lignan isolated from A. chilensis, potentially inhibited P3X murine myeloma cell proliferation, resulting in approximately 75% cell death in response to a 25 µg/mL treatment with the lignan. P3X cells lost membrane integrity at the nuclear and cytoplasmic levels, including organelles, in response to yatein treatment (12.5 µg/mL), and we observed changes in the cytoplasmic organization and distribution of microtubules. The other compounds tested had low activity. Discussion and conclusions: Yatein is a lignan precursor of podophyllotoxin, a key agent in anticancer drugs. Due to its structural similarities to podophyllotoxin, yatein could have similar cytoplasmic target(s), such as the microtubular apparatus. These findings suggest that yatein may be of potential pharmacological interest and warrants further investigation in human cell lines. [ABSTRACT FROM AUTHOR]

The relation of particular species of Acari with soil functions regarding organic matter decomposition and nutrient recycling is not clear. Furthermore it is not known if distinguishable Acari species are more efficient to lead to an increase in the rate of mass loss of leaf litter or to favour the development of the microflora on leaf litter. We tackled this dilemma by growing selected mites on defaunated leaf litter of Austrocedrus chilensis. We tested for changes in the biomass of leaf litter in the presence or the absence of the mites. We used four species of oribatid mites which are usual inhabitants of the leaf litter of Austrocedrus chilensis in forests of Argentina´s Northwestern Patagonia: Anderemaeus magellanis, Cosmochthonius semifoveolatus, Lanceoppia kovacsi and Nothrus peruensis. After 3 months, the development of fungal growth in the presence of mites was evident. Containers with only C. semifoveolatus and L. kovacsi showed greater development of fungal biomass than those with A. magellanis or N. peruensis, evidencing specific differences in the enhancement effect. In the presence of C. semifoveolatus, mycelial diversity diminished with respect to the blank favoring only the development of septate brown hyphae of Ascomycota. We found no significant differences between the fungal growth enhancement provoked by L. kovacsi and C. semifoveolatus. Entanglement of fragments and propagules of fungi among the branched setae of C. semifoveolatus could account for the enhancement of fungal growth. Repeated contact of faster L. kovacsi specimens with mycelia and adherence of mycelial fragments and fungi propagules on mite bodies could account for the effect. Mite size was also related to the fungal growth enhancement as smaller mites were more efficient in fungal growth enhancement. Our results showed that fungal growth is more intensive in the presence of mites than in their absence and that oribatid mites have a role in shaping the communities of fungi in soil. [ABSTRACT FROM AUTHOR]

Habitat fragmentation might significantly affect mating and pollen dispersal patterns in plant populations, contributing to the decline of remnant populations. However, wind-pollinated species are able to disperse pollen at longer distances after opening of the canopy. Our objectives were to characterize the mating system parameters and to estimate the average distance of effective pollen dispersal in the wind-pollinated conifer Austrocedrus chilensis. We sampled 19 'mother trees,' 200 progeny, and 81 additional adults (both male and female), in a fragmented population at the Argentinean Patagonian steppe. We registered the spatial positions of individuals and genotyped all samples with five microsatellite markers. We found a high genetic diversity, a moderated rate of biparental inbreeding ( t − t = 0.105), and a complete absence of correlated paternity ( r = −0.015). The effective number of pollen donors contributing to a single mother ( N) was 13.9. Applying TWOGENER, we estimated a low but significant differentiation among the inferred pollen pools (Φ = 0.036, p = 0.001) and a very large average pollen dispersal distance ( d = 1,032.3 m). The leptokurtic distribution ( b = 0.18) presumes a potential for even larger dispersal distances. The high genetic diversity, the mating patterns, and the extensive pollen dispersal presume that habitat fragmentation did not have a negative impact on pollen movement in this population of A. chilensis. Genetic connectivity among fragmented populations scattered in the Patagonian region is possible, and we stress the need of management policies at the landscape level. [ABSTRACT FROM AUTHOR]

This study was aimed at determining, under field conditions, early interactions between planted cypress seedlings and their associated shrubs in a mesic area of Andean Patagonia and, in a nursery, the effects of increasing light availability on cypress performance when soil water was not a limiting factor. The field experiment was performed in a former cypress-coihue mixed forest (42°02′S, 71°33′W), which was replaced in the 1970s by a plantation of radiata pine. In 2005, 800 cypress seedlings were planted under maqui shrubs in a clear-cut area of the pine stand. In 2007, two treatments were set: no-competition treatment ([NCT] i.e., the surrounding aboveground biomass was removed) and competition treatment ([CT] i.e., without disturbance). The nursery experiment (42°55′S, 71°21′W) consisted of two groups: 'shade' (grown under shade cloth) and 'sun' (grown at full sun) cypress seedlings. After one growing season, seedling survival and stem growth (in height and diameter) were determined at both sites. Furthermore, the growth rate of leaves, stems, and roots was determined in the nursery. In the field experiment, height growth and survival in NCT were significantly greater than in CT, and a competition process occurred between cypress and surrounding shrubs. In the nursery, sun plants grew more in diameter and increased root weight more than shade plants. Results also showed that in mesic areas of Patagonia, decreasing competition and increasing light levels produced stouter seedlings better adapted to support harsh environmental conditions. Therefore, the removal of protecting shrubs could be a good management practice to improve seedling establishment. [ABSTRACT FROM AUTHOR]

Morchella species are edible fungi in high demand and therefore command high prices in world markets. Phenotypic-based identification at the species-level remains inadequate because of their complex life cycles, minor differences and plasticity of morphological characteristics between species, and the lack of agreement between scientific and common names. In Patagonia–Argentina, morels are associated with native forests of Austrocedrus chilensis (Cordilleran or Chilean cypress) and Nothofagus antarctica (ñire) and several exotic conifers that were introduced from western North America. Little is known about their taxonomy and phylogenetic relationships with other species in the genus. This work focused on the identification of collections of Morchella from Patagonia and their phylogenetic relationships with other species from the Northern Hemisphere. The comparison was made by analysis of DNA sequences obtained from four loci: the nuclear ribosomal internal transcribed spacer region (ITS) and the partial RNA polymerase I gene ( RPB1 ) for the complete collection; and ITS, RPB1 , RNA polymerase II gene ( RPB2 ), and translation elongation factor ( EF1-α ) for the species-rich Elata Subclade. Analyses of individual and combined data sets revealed that Patagonian morels belong to the Elata Clade and comprised three strongly supported species-level lineages from both Patagonian native forest, and exotic trees introduced from western North America. One lineage was identified as Morchella frustrata phylogenetic species Mel-2 , which is known from the USA and Canada. The second lineage, which appeared to be ‘fire-adapted’, was identified as Morchella septimelata phylogenetic species ( Mel-7 ), which is also known from the USA. This species was collected from burned native forests mainly composed of A. chilensis and N. antarctica but also Pseudotsuga menziesii ( Mirb.) Blanco, which is native to western North America. The phylogenetic analyses suggested that the third species from Patagonia was nested within the species-rich Elata Subclade and represents a new species-level lineage (informally designated Mel-37 ) within Elata Clade. The present collections from Patagonia constitute the southernmost latitude from which Morchella has been reported to date. The identification of two Argentine morels as North American taxa is therefore a remarkable biogeographic pattern. In view of the hypothesis that the Elata Clade originated in western North America, we speculate that at least two of the lineages colonized South America from North America via long distance dispersal, migration or, more likely, they were introduced with the exotic tree species that they were collected near. [ABSTRACT FROM AUTHOR]

Abstract: Patagonian vegetation has dramatically changed in composition and distribution over the last 23,000 years. Although the vegetation history has been inferred from individual pollen records, the regional patterns and drivers of vegetation development are poorly understood. High resolution pollen and charcoal data from eleven sites located along the eastern flanks of the Patagonian Andes (41–43°S) were examined to reconstruct the Lateglacial and Holocene vegetation and fire history of steppe/forest ecotone and separate the relative influence of climatic versus non-climatic factors in shaping the patterns of ecological change. Pollen data indicate that, as the Lateglacial climate became progressively wetter, the initial steppe vegetation was replaced by open forest of Nothofagus in the Lateglacial and early Holocene periods, and by closed forest in the late Holocene. Fire activity was lowest during the Lateglacial/early-Holocene transition and gradually increased through the Holocene. Prior to ca 5000 cal yr BP, the conifer Austrocedrus chilensis possibly persisted in isolated populations along the eastern boundary of its modern distribution. Cooler/more humid conditions after ca 5000 cal yr BP allowed the development of the modern mixed Nothofagus–Austrocedrus forest. The paleoenvironmental record points to the sensitivity of the forest/steppe ecotone in the past, not only to climate but also to complex environmental feedbacks that amplified the effects of climate change. [Copyright &y& Elsevier]

Little is known about the changes in resin composition in South American gymnosperms associated with the different seasons of the year. The diterpene composition of 44 resin samples from seven Austrocedrus chilensis (Cupressaceae) trees, including male and female individuals, was investigated in three different seasons of the year (February, June and November). Twelve main diterpenes were isolated by chromatographic means and identified by gas chromatography-mass spectrometry and nuclear magnetic resonance (NMR). The diterpene composition was submitted to multivariate analysis to find possible associations between chemical composition and season of the year. The principal component analysis showed a clear relation between diterpene composition and season. The most characteristic compounds in resins collected in summer were Z-communic acid (9) and 12-oxo-labda-8(17),13E-dien-19 oic acid methyl ester (10) for male trees and 8(17),12,14-labdatriene (7) for female trees. For the winter samples, a clear correlation of female trees with torulosic acid (6) was observed. In spring, E-communic acid (8) and Z-communic acid (9) were correlated with female trees and 18-hydroxy isopimar-15-ene (1) with male tree resin. A comparison between percent diterpene composition and collection time showed p < 0.05 for isopimara-8(9),15-diene (2), sandaracopimaric acid (4), compound (7) and ferruginol (11). [ABSTRACT FROM AUTHOR]

Premise of research. The occurrence of six ovulate cones and six leafy branching systems, two of which show attachment of the ovulate cone, reveals a new cunninghamioid fossil conifer from the Cretaceous Apple Bay locality of Vancouver Island, Canada. This anatomically preserved plant expands our understanding of basal Cupressaceae in the fossil record. Methodology. Specimens were studied from anatomical sections prepared by the classic cellulose acetate peel technique. Pivotal results. Vegetative shoots have helically arranged Cunninghamia-like leaves with a single vascular bundle and one to three resin canals. Ovulate cones consist of numerous helically arranged bract/scale complexes with a large bract and a small ovuliferous scale with three separate tips. There are three inverted seeds/ ovules attached adaxially, immediately proximal to the free scale tips. Conclusions. This discovery reveals the presence of a new genus and species of basal Cupressaceae, Hubbardiastrobus cunninghamioides, in the Early Cretaceous (Valanginian; ~136 Ma) of the Northern Hemisphere. These data expand the species richness of fossil Cupressaceae and further document the Cretaceous evolutionary radiation of subfamily Cunninghamioideae. [ABSTRACT FROM AUTHOR]

Genetic information on adaptive traits is crucial for prediction of the evolution of natural populations in relation to global climate change. The seedling emergence process together with germination is a key adaptive stage in any seeding species. We aim to analyze variability in seedling emergence traits within and among marginal populations of Patagonian Cypress ( Austrocedrus chilensis (D.Don) Pic. Ser. et Bizzarri), which have been suggested to be of conservation relevance. We performed an emergence trial in a greenhouse with seeds collected from 177 open-pollinated trees from 10 populations. A sigmoidal curve was fitted to the cumulative emergence data (in percentage of the sown seeds) for each replicate of each family. Variability was estimated using ANOVA for six variables: emergence capacity ( EC), emergence energy ( EE), energy period ( EP), emergence initiation ( t), emergence cessation ( t) and emergence duration ( Dur). The overall trial mean for EC was 76.2 %, while EE was only 27.6 %. Hence, most seedlings emerged after the energy period, which is interpreted as a bet-hedging strategy. Both 'population' and 'family' factors significantly affected all variables. The proportions of 'family' variances were higher than 'population' ones for EC, EE, Dur and t, but the opposite was found for EP and t, which is evidence of differentiation among populations. Variability among families may be due to both genetic and environmental causes, including maternal effects. However, the relatively high proportion of family variability in EC and EE suggests acceptable levels of additive genetic variance, which would not hinder the potential to evolve in these specific traits. Conversely, the chances to adapt in EP and t are lower, and consequently local extinctions driven by global climate change seem possible. [ABSTRACT FROM AUTHOR]

Cost-distance model analyzes the relative difficulty in reaching each spot of the landscape for the object or species under study. It calculates the effective distance, which is the Euclidian distance modified by the friction to movement through different landscape elements. This work deals with the application of cost-distance analysis in forest pathology, considering Austrocedrus chilensis root rot caused by Phytophthora austrocedrae as an example. In this case, cost-distance analysis was used to determine the relative difficulty for the pathogen to reach healthy forest patches from the patches that are presently diseased. Friction values were assigned on the basis of abiotic conditions, biological characteristics of the pathogen and host presence. Since cattle may be a vehicle for Phytophthora dispersion, three hypothetical situations of ranching were considered. Cost-distance application resulted useful to define minimum risk areas for conservation purposes. In the study case, minimum risk area strongly varied in response to cattle presence. This study provided valuable information for A. chilensis disease management and showed one of the broad applications of cost-distance analysis in forestry. [ABSTRACT FROM AUTHOR]

Aims: We characterized the runoff and erosion from a volcanic soil in an Austrocedrus chilensis forest affected by a wildfire, and we evaluated the effects of a mitigation treatment. Methods: Rainfall simulations were performed in the unburned and burned forest, with and without vegetation cover, and under a mitigation treatment. Results: After the wildfire, the mean infiltration rate decreased from 100 mm h in unburned soils to 51 and 64 mm h in the burned with and without litter and vegetation cover, respectively. The fast establishment of bryophytes accelerated the recovery of soil stability. Sediment production was negligible in the control plots (4.4 g m); meanwhile in the burned plots, it was 118.7 g m and increased to 1026.1 g m in the burned and bare plots. Total C and N losses in the control plots were negligible, while in the burned and bare plots the organic C and total N removed were 98.25 and 1.64 g m, respectively. The effect of mitigation treatment was efficient in reducing the runoff, but it did not affect the sediment production. Conclusions: These fertile volcanic soils promoted the recovery of vegetation in a short time after the wildfire, diminishing the risk of erosion. [ABSTRACT FROM AUTHOR]

Background: Austrocedrus chilensis (D. Don) Pic. Ser. et Bizzarri commonly known as Patagonian cypress is a member of the Cupressaceae family, characterized by a high adaptive potential for growing in marginal areas and good timber quality. The species grows over a wide area and under a wide range of rainfall. This study assessed adaptive genetic variation at SNP level in candidate genes involved in response to drought stress. Results: A total of 18 single nucleotide polymorphisms (SNPs) were found among 1,428 bp. Average nucleotide diversity value (π = 0.00312) was similar to those previously reported in other Cupressaceae. The Fst average among genes and populations was 0.163 and the lowest differentiation was observed in continuous and humid populations. A number of neutrality tests were applied to find evidence of positive selection in our candidate gene set, but only AcAQP2 gene in Pedregoso and San Ramón populations revealed significant departures from neutrality with positive values suggesting balancing selection. Conclusions: In this study we report the levels of nucleotide diversity searched in some drought stress candidate genes in Austrocedrus chilensis and the selective factors that may be acting on this species. [ABSTRACT FROM AUTHOR]

• Context: Harsh environmental conditions in xeric sites of Andean Patagonia, affect the emergence, survival, and growth of either naturally grown or planted Austrocedrus seedlings. • Aims: We evaluated the effects of nurse shrubs and tree shelters on the survival and growth of Austrocedrus seedlings as compared to unprotected (control) areas and how differently produced seedling types perform under these treatments. • Methods: In 2006, two Austrocedrus seedling types (1 + 2 = S1 and Plug 2 + 1 = S2) were planted under shrub cover (C1), tree shelter (C2), and control (C3). Soil surface temperature and moisture were measured for each treatment during the first growing season, while seedling survival and height were recorded during 5 years. • Results: Survival was not affected by cover type the first year, but it was affected by seedling type (S1 > S2). After an extremely dry second growing season, seedling survival significantly decreased in relation to either cover or seedling type. Five years after plantation, survival was significantly higher for C1 and C2 (40-60 %) as compared to C3-S2 (18 %). Seedling height was significantly affected by cover, but not by seedling type. • Conclusions: The use of nurse shrubs and/or tree shelters is useful in Austrocedrus seedling restoration trials. Seedling morphology appears as relevant for survival in semiarid environments. [ABSTRACT FROM AUTHOR]

Along the eastern Andes, a sharp ecotone separates steppe from North Patagonian forest dominated by Nothofagus spp. and Austrocedrus chilensis. The longitudinal position of the ecotone is largely determined by effective moisture, which in turn is partly governed by the strength and latitudinal position of the Southern Westerlies. As a result, changes in the ecotone provide an opportunity to examine past climate variations. Holocene environmental history at two sites in close proximity is inferred from pollen and high-resolution charcoal data. Prior to 9000 cal. yr BP, vegetation resembled a steppe, in accordance with widespread aridity. Fires were infrequent, likely as a consequence of fuel discontinuity associated with low vegetation cover. At 9000 cal. yr BP, forest taxa expanded into steppe and fires became frequent, indicating that summers were arid enough to support fires but winter moisture was sufficient for Nothofagus spp. to expand. A two-step increase in effective moisture is inferred for the middle Holocene. The first step occurred at 8500 cal. yr BP, as interpreted from the increase in A. chilensis in the region, probably as a consequence of an eastward migration from glacial refugia. The second step at 5500 cal. yr BP is based on a Nothofagus spp. expansion into the steppe. Steppe readvances into the forest between 5250 and 3000 cal. yr BP indicate decreased temperatures and/or effective moisture. The last 3000 years are characterized by expansions of A. chilensis and an eastward shift of the ecotone, suggesting more humid conditions. European settlement is reflected in the establishment of non-native species and disturbance-adapted taxa. [ABSTRACT FROM AUTHOR]

Abstract: Satellite hyperspectral data were used to construct empirical spectral indices related to the canopy structure of a Cordilleran Cypress (Austrocedrus chilensis) forest located in the Andes of central Chile. Measurements of tree diameter at breast height (DBH) and tree height (TH) were performed for a set of plots located within a pure and unevenly aged stand of A. chilensis with moderate cover. Normalized difference vegetation indices (NDIs) related to DBH and TH were constructed from the corresponding hyperspectral data in Hyperion imagery. NDIs construction utilized the original spectral reflectance curve, its first derivative, and the continuum-removed reflectance in a two-step procedure that ranks NDIs based on their Spearman correlation with the response variable while controlling the false discovery rate. Several reflectance-based NDIs as well as a larger group of derivative-based NDIs were significantly related to DBH or TH (ρ >0.70). The NDIs most strongly related to the field variables were based on derivative bands located within the same spectral regions used by the broadband greenness index known as green normalized difference vegetation index. Most other significant NDIs used NIR bands, which are well-known for their sensitivity to foliage amount changes. The results obtained in this exploratory study mostly agreed with the spectral regions expected to be most sensitive to changes in the canopy structure of vegetation. Further research in other A. chilensis forests subject to different site and environmental conditions is needed in order to assess the applicability of the NDIs over a wider range of this endemic species. [Copyright &y& Elsevier]

Abstract: Patagonian vegetation has dramatically changed in composition and distribution over the last 16,000yr. Although patterns of vegetation change are relatively clear, our understanding of the processes that produce them is limited. High-resolution pollen and charcoal records from two lakes located at lat 41°S provide new information on the postglacial history of vegetation and fire activity at the forest–steppe ecotone, and help clarify the relative importance of local and regional drivers of late-Holocene ecological change. Our results suggest that late-glacial parkland was colonized by shrubs at ca. 11,200calyr BP and this vegetation persisted until 4900calyr BP, when increased humidity allowed for the establishment of Nothofagus forest. The late Holocene is characterized by oscillations in forest dominance largely driven by changes in humidity, possibly associated with the onset or strengthening of ENSO. In the last 4900yr, humid periods (4900–3800 and 2850–1350calyr BP) have promoted Nothofagus forest, whereas drier times (3800–2850 and 1350–450calyr BP) have favored Austrocedrus expansion. At intermediate moisture levels, however, the lower forest supported both taxa, and fire became an important control of community composition, with severe, infrequent fires facilitating Nothofagus regeneration and high fire frequency and intensity supporting Austrocedrus. [Copyright &y& Elsevier]

Austrocedrus chilensis is an endemic conifer of Patagonia that suffers a widespread mortality whose causes are a topic of discussion. Since Phytophthora austrocedrae is the most probable cause, we proposed that the spatial and temporal patterns of disease at small scale should reflect pathogen behavior. We aimed at characterizing the spatial and temporal patterns of diseased trees in different soil types and the effect of microsite variability on diseased trees spatial pattern. The spatial pattern of disease was influenced by soil type and tree density. In clay soils with low disease incidence (ca. 25%), the spatial pattern was random and not influenced by abiotic microsite conditions. When disease incidence increased (ca. 70%), concurring with denser plots, the spatial pattern was clustered, as a result of an infection process, and it was independent of microsite variability. In soils with better drainage conditions, that is, alluvial soils with volcanic ash input and coarse textured volcanic soils, the disease was clustered and associated with flat microtopographies. The progression of the disease at small scale was influenced by soil, precipitation and tree density. The spatial and temporal patterns of disease progression were associated with a contagion process and with environmental variables that affect drainage, coinciding with Phytophthora biology and requirements. Our results concur in pointing at Phytophthora as the cause of A. chilensis disease in the study area. Management practices should be urgently applied in order to minimize the spread of the inoculum. [ABSTRACT FROM AUTHOR]

Two different studies based on isozymes that include genetic structure analysis have arrived at contrasting conclusions regarding the minimum number of seed transfer zones for Patagonian cypress ( Austrocedrus chilensis) in Argentina that are required in order to avoid genetic contamination in restoration programs. Unfortunately, the more recent article lacks discussion on these controversial results, which is, therefore, the purpose of this article. The reliability of the markers used and the sampling performed in these studies are evaluated comparatively. The later study found higher levels of diversity and differentiation but paradoxically suggested that only two seed transfer zones would be enough to preserve the genetic identity of the natural populations of the species, whereas the earlier study concluded that at least five are necessary. Arguments are presented here for the case that definition of fewer than five genetically homogeneous groups is absolutely inappropriate and implies a probable risk of genetic contamination and maladaptation. [ABSTRACT FROM AUTHOR]

In South America, 94% of dry-temperate lands present some degree of environmental degradation, highlighting the need for ecological restoration. We analyzed geographic patterns of genetic variation in Austrocedrus chilensis, a dominant conifer of the steppe-forest ecotone in the eastern Andes, to examine its potential for restoration. We sampled 67 locations in Argentina and estimated genetic parameters to determine the effects of historical factors affecting diversity, together with inbreeding and gene flow, using 12 allozyme loci. Genetic diversity decreased southwards in eastern populations, which are marginal for the range of the species and patchily distributed, while high genetic admixture was detected in continuous western populations, possibly reflecting postglacial migrations from northern and eastern sources. Higher inbreeding ( FIS > 0.14) was recorded in northern compared with southern populations, attributed to the impact of recent bottlenecks resulting from anthropogenic fires. Gene flow was found to be moderate overall ( FST = 0.12). The implications of these results for restoration actions focusing on Austrocedrus were explored. Relatively small, inbred yet genetically diverse northern populations should be the subject of passive restoration efforts, while experimental common gardens should be established toward the south, to support active restoration approaches. This illustrates how ahead of time information on patterns of genetic variation can support restoration efforts for dryland tree species. [ABSTRACT FROM AUTHOR]