Duncan A. Christie

Universidad Austral de Chile · Instituto de Conservación Biodiversidad y Territorio (Laboratorio de Dendrocronología)

The Andes Cordillera acts as regional “Water Towers” for several countries and encompasses a wide range of ecosystems and climates. Several hydroclimatic changes have been described for portions of the Andes during recent years, including glacier retreat, negative precipitation trends, an elevation rise in the 0° isotherm, and changes in regional s...

Despite the great number and variety of glaciers in southern South America, in situ glacier mass-balance records are extremely scarce and glacier–climate relationships are still poorly understood in this region. Here we use the longest (> 35 years) and most complete in situ mass-balance record, available for the Echaurren Norte glacier (ECH) in the...

Stable oxygen isotopes records (δ18O) in tree-rings are commonly used to assess the response of trees to environmental variability being a valuable tool for studying past climate at different temporal and spatial scales. This is particularly relevant in semi-arid regions like the southern Tropical Andes, where ongoing environmental changes coincide...

Soil moisture (SM) is a crucial factor in the water cycle, sustaining ecosystems and influencing local climate patterns by regulating the energy balance between the soil and atmosphere. Due to the absence of long-term, in-situ measurements of SM, studies utilizing satellite-based data and tree-ring analysis have become valuable in assessing variati...

Tropical South American climate is influenced by the South American Summer Monsoon and the El Niño Southern Oscillation. However, assessing natural hydroclimate variability in the region is hindered by the scarcity of long-term instrumental records. Here we present a tree-ring δ¹⁸O-based precipitation reconstruction for the South American Altiplano...

La seguridad hídrica se define como la posibilidad de acceder al agua en cantidad y calidad adecuadas para el sustento humano, la salud y el desarrollo socioeconómico, considerando las particularidades ecosistémicas de cada cuenca y promoviendo la resiliencia frente a amenazas como la sequía, crecidas y la contaminación. Alcanzar la seguridad hídr...

Given the short span of instrumental precipitation records in the South American Altiplano, longer-term hydroclimatic records are needed to understand the nature of climate variability and to improve the predictability of precipitation, a key natural resource for the socioeconomic development in the Altiplano and adjacent arid lowlands. In this reg...

Linked to major volcanic eruptions around 536 and 540 CE, the onset of the Late Antique Little Ice Age has been described as the coldest period of the past two millennia. The exact timing and spatial extent of this exceptional cold phase are, however, still under debate because of the limited resolution and geographical distribution of the availabl...

We evaluated the radial growth response of adult Nothofagus pumilio (Poepp. et Endl) Krasser trees affected by tephra deposition following historical volcanic eruptions of the Puyehue–Cordón Caulle Volcanic Complex (PCCVC) in northern Patagonia. Standard tree–ring width chronologies were developed for trees from two sites that were affected by up t...

In this work we show the application of dendrochronology as an educational resource for schoolchildren and as a mean to disseminate science to society. Tree rings are popularly known in Chile due to the massive use of wood for construction, handicrafts and firewood. The visible tree rings generate a distinct, tangible and familiar curiosity in many...

Austrocedrus chilensis is a South American conifer broadly distributed across the subtropical and extratropical Andes that is widely utilized in tree-ring studies. This species has clear annual growth rings that are sensitive to the moisture supply and has been extensively used to reconstruct the past hydroclimate during the last millennium. Despit...

Plain Language Summary Understanding past climatic changes in the Central Andes in tropical South America is of great importance to contextualize current hydroclimatic conditions. Here, we present the first P. tarapacana tree‐ring stable oxygen isotope (δ¹⁸OTR) chronologies and analyze their value as environmental records for this region. Locally k...

Polylepis tarapacana is the highest-elevation tree species worldwide growing between 4000 and 5000 m a.s.l. along the South American Altiplano. P. tarapacana is adapted to live in harsh conditions and has been widely used for drought and precipitation tree-ring based reconstructions. Here, we present a 400-year tree-ring width (TRW) chronology loca...

The Calbuco volcano ranks third in the specific risk classification of volcanoes in Chile and has a detailed eruption record since 1853. During 2015, Calbuco had a sub-Plinian eruption with nega-tive impacts in Chile and Argentina, highlighting the need to determine the long-term history of its activity at a high-resolution time scale to obtain a b...

El Observatorio de Nieve fue desarrollado para analizar la evolución de la cubierta nival en las principales hídricas de Argentina y Chile en los Andes subtropicales (27°-37°S). La información de nieve es obtenida dos veces por día por el sensor MODIS a bordo de los satélites Terra y Aqua de la NASA (Hall y Riggs 2016). Los datos de base están disp...

https://sada.cr2.cl / Este Explorador WEB se basa en los datos de la publicación de la reconstrucción de aridez de Sudamérica (scPDSI) utilizando anillos de árboles https://doi.org/10.1073/pnas.2002411117. A través de el es posible visualizar mapas anuales de aridez, calcular mapas promedio de grupos de años, mapas de correlación con otras variabl...

The South American Altiplano is one of the largest semiarid high‐altitude plateaus in the world. Within the Altiplano, peatlands known as “bofedales” are important components of regional hydrology and provide key water resources and ecosystem services to Andean communities. Warming temperatures, changes in hydroclimate, and shifting atmospheric cir...

Tree growth is generally considered to be temperature-limited at upper elevation treelines. Yet, climate factors controlling tree growth at semiarid treelines are poorly understood. We explored the influence of climate on stem growth and stable isotopes for Polyepis tarapacana, the world's highest elevation tree-species found only in the South Amer...

South American tropical climate is strongly related to the tropical low-pressure belt associated with the South American monsoon system. Despite its central societal role as a modulating agent of rainfall in tropical South America, its long-term dynamical variability is still poorly understood. Here we combine a new (and world’s highest) tree-ring...

Significance The SADA is an annually-resolved hydroclimate atlas in South America that spans the continent south of 12°S from 1400 to 2000 CE. Based on 286 tree ring records and instrumentally-based estimates of soil moisture, the SADA complements six drought atlases worldwide filling a geographical gap in the Southern Hemisphere. Independently val...

Since 2010, Chile has experienced one of the most severe droughts over the last century, the so-called mega-drought (MD). The MD conditions, combined with intensive agricultural activities and the current water management system, have led to water scarcity problems in Mediterranean and Semi-arid regions of Chile. An emblematic case is the Petorca b...

Historical fire regimes are critical for understanding the potential effects of changing climate and human land-use on forest landscapes. Fire is a major disturbance process affecting the Andean Araucaria forest landscape in north-west Patagonia. The main goals of this study were to reconstruct the fire history of the Andean Araucaria–Nothofagus fo...

The high Andean peatlands, locally known as “bofedales”, are a unique type of wetland distributed across the high-elevation South American Altiplano plateau. This extensive peatland network stores significant amounts of carbon, regulates local and regional hydrological cycles, supports habitats for a variety of plant and animal species, and has pro...

The rivers originating in the southern Andes (18°–55°S) support numerous ecosystems and a large number of human populations and socio-economic activities in the adjacent lowlands of Chile, Argentina and Bolivia. Here we show that ca. 75% of the total variance in the streamflow records from this extensive region can be explained by only eight spatia...

Extreme climatic events, such as late frosts in spring during leaf flush, have considerable impacts on the radial growth of temperate broadleaf trees. Albeit, all broadleaved species are potentially vulnerable, damage depends on the particularities of the local climate, the species, and its phenology. The impact of late spring frosts has been widel...

El crecimiento de P. tarapacana es muy sensible a la variabilidad de la temperatura y ENSO durante el verano actual. Las precipitaciones del año en curso, dificultan el crecimiento; por el contrario, la lluvia del año previo, beneficia su desarrollo. Asimismo,las correlaciones con PDSI son negativas al año en curso, indicando que cuando las condici...

In May 2008, Chaitén volcano entered in eruptive process, one of the world largest eruptions in the last decades. The catastrophic event left different type of disturbance and caused diverse environmental damage distributed heterogeneously in the surrounding areas of the volcano. We went to the field to assess the early vegetation responses a year...

The deep-time dynamics of coupled socio-ecological systems at different spatial scales is viewed as a key framework to understand trends and mechanisms that have led to the Anthropocene. By integrating archeological and paleoenvironmental records, we test the hypothesis that Chilean societies progressively escalated their capacity to shape national...

En el siglo XXI, el desarrollo de Chile está en juego debido a las amenazas planteadas por el Antropoceno. Esta época se caracteriza por la influencia humana sobre el sistema terrestre. Sin embargo, si se enfrenta con audacia, ofrece una oportunidad para un desarrollo sostenible. Independientemente de si hemos entrado en una nueva era geológica, el...

The original version of this Article contained an error in the Data Availability section, which incorrectly read ‘All data will be freely available via https://www.ams.ethz.ch/research.html.’ The correct version states ‘http://www.ams.ethz.ch/research/published-data.html’ in place of ‘https://www.ams.ethz.ch/research.html’. This has been corrected...

Las sequías en el Altiplano tienen un alto impacto sobre la dinámica de los ecosistemas regionales y las actividades socioeconómicas de las poblaciones locales. Es por esto que identificar los patrones espaciales de distribución de las lluvias, su evolución temporal y sus proyecciones futuras resultan de gran prioridad. Los objetivos del presente e...

Though tree-ring chronologies are annually resolved, their dating has never been independently validated at the global scale. Moreover, it is unknown if atmospheric radiocarbon enrichment events of cosmogenic origin leave spatiotemporally consistent fingerprints. Here we measure the 14C content in 484 individual tree rings formed in the periods 770...

Since 2010 an uninterrupted sequence of dry years, with annual rainfall deficits ranging from 25 to 45 %, has prevailed in central Chile (western South America, 30–38∘ S). Although intense 1- or 2-year droughts are recurrent in this Mediterranean-like region, the ongoing event stands out because of its longevity and large extent. The extraordinary...

Tree-ring anatomical anomalies have received little attention in southern South American trees, however they can contain valuable intra-annual environmental information. This study addressed for the first time the three most frequent tree- ring anomalies recorded in the northern and oldest known Austrocedrus chilensis forest in central Chile (32-35...

In the Mediterranean Andes (MA; 30°S–37°S), the main rivers are largely fed by melting snowpack and provide fresh water to around 10 million people on both sides of the Cordillera. Water resources in the MA are under pressure due to the extensive development of industrial agriculture and mining activities. This pressure is increasing as the region...

The iconic conifer Araucaria araucana (Arau- caria), called Pehuén by native people, is an en- demic species of the Andes of northern Patago- nia in Chile and Argentina. Its range encompasses only three degrees of latitude (37 ◦ 20 � – 40 ◦ 20 � S) with a small outlying presence in the coastal moun- tains of Chile (Veblen et al. 1995). The species...

Sin ser un especialista en glaciares, sino que un paleoclimatólogo y científico de las ciencias de la tierra muy interesado en ellos, agradezco la invitación de los autores para comentar este bello libro sobre Balance de Masa Glaciar. Desde Valdivia tal vez encontremos que estamos en un lugar un tanto lejano al sujeto de estudio, sin embargo hace s...

As rainfall in South-Central Chile has decreased in recent decades, local communities and industries have developed an understandable concern about their threatened water supply. Reconstructing streamflows from tree-ring data has been recognized as a useful paleoclimatic tool in providing long-term perspectives on the temporal characteristics of hy...

Socio-economic and environmental changes are well known causes of demographic collapse of agrarian cultures. The collapse of human societies is a complex phenomenon where historical and cultural dimensions play a key role, and they may interact with the environmental context. However, the importance of the interaction between socio-economic and cli...

High latitud treelines have been shown not restricted by downstream photosynthetic product, in support to the growth limitation hypothesis. But the domain of tree-line photosynthetic characterization in southern-Andes is 40o latitud to north. South-patagonia high elevation forest has similar interannual behavior, according to dendrochronological st...

Sequías de uno o dos años han afectado de manera recurrente la zona central de Chile durante su historia, asociadas a variaciones climáticas de origen natural. Ocasionalmente, el déficit hídrico ha superado el 50% (como sucedió en los años 1925, 1968 y 1989) impulsando la construcción de embalses, la creación de subsidios agrícolas y otras medidas...

Plant growth at extremely high elevations is constrained by high daily thermal amplitude, strong solar radiation and water scarcity. These conditions are particularly harsh in the tropics, where the highest elevation treelines occur. In this environment, the maintenance of a positive carbon balance involves protecting the photo-synthetic apparatus...

Projected future trends in water availability are associated with large uncertainties in many regions of the globe. In mountain areas with complex topography, climate models have often limited capabilities to adequately simulate the precipitation variability on small spatial scales. Also, their validation is hampered by typically very low station d...

Plant growth at extremely high elevations is constrained by high daily thermal amplitude, strong solar radiation, and water scarcity. These conditions are particularly harsh in the tropics, where the highest elevation treelines occur. In this environment the maintenance of a positive carbon balance involves protecting the photosynthetic apparatus a...

Araucaria araucana (Araucaria) is a long-lived conifer growing along a sharp west–east biophysical gradient in the Patagonian Andes. The patterns and climate drivers of Araucaria growth have typically been documented on the driest part of the gradient relying on correlations with meteorological records, but the lack of in situ soil moisture observa...

Past global climate changes had strong regional expression. To elucidate their spatio-temporal pattern, we reconstructed past temperatures for seven continental-scale regions during the past one to two millennia. The most coherent feature in nearly all of the regional temperature reconstructions is a long-term cooling trend, which ended late in the...

Past global climate changes had strong regional expression. To elucidate their spatio-temporal pattern, we reconstructed past temperatures for seven continental-scale regions during the past one to two millennia. The most coherent feature in nearly all of the regional temperature reconstructions is a long-term cooling trend, which ended late in the...

The accumulation of snow during winter and its subsequent melting during warmer months provide most of the water needed for the human populations located along the semiarid western and eastern slopes of the Andes in central Chile and central-western Argentina. The societies in these regions can be characterized as 'hydraulic societies,' as social t...

Recent changes in the summer climate of the Southern Hemisphere extra-tropics are primarily related to the dominance of the positive phase of the Southern Annular Mode. This shift in the behaviour of the Southern Annular Mode--essentially a measure of the pressure gradient between Southern Hemisphere mid and high latitudes--has been predominantly i...

Throughout the second half of the 20th century, the Central Andes has experienced significant climatic and environmental changes characterized by a persistent warming trend, an increase in elevation of the 0 degrees C isotherm, and sustained glacier shrinkage. These changes have occurred in conjunction with a steadily growing demand for water resou...

The Andean snowpack is the main source of freshwater and arguably the single most important natural resource for the populated, semi-arid regions of central Chile and central-western Argentina. However, apart from recent analyses of instrumental snowpack data, very little is known about the long term variability of this key natural resource. Here w...