El bosque petrificado Piedra Chamana: un recurso científico de importancia global / The Piedra Chamana Fossil Forest: A scientific resource of global importance

Resumen El Bosque Petrificado Piedra Chamana, cerca del pueblo de Sexi en Cajamarca, registra la vegetación de los trópicos de Sudamérica de hace 39 millones de años, la que existió en los inicios de la historia de los bosques tropicales del Nuevo Mundo y antes del levantamiento de los Andes. En este bosque, descubrimientos notables incluyen el manglar del género Avicennia, un género de árboles forestales emergentes (Cynometra), y el segundo dipterocarp conocido del Nuevo Mundo. La importancia de los fósiles se basa en sus circunstancias únicas de preservación, es así como fósiles de plantas y suelos antiguos permiten la reconstrucción detallada del bosque y el medio ambiente en que existieron, contribuyendo con el conocimiento del cambio climático. Los sitios como este bosque fósil son muy vulnerables al disturbio y pérdida de los recursos fósiles. El monitoreo muestra que las actividades humanas y la erosión están teniendo efectos serios y que son necesarias medidas urgentes para su conservación. La importancia de los fósiles para la ciencia, la belleza de esta área de los Andes, y el potencial para la educación y turismo justifican el reconocimiento del Bosque Petrificado Piedra Chamana a nivel internacional. El bosque tropical representado por los fósiles es muy diferente del bosque diverso esclerófilo de hoja ancha que se encuentra actualmente en el sitio. La pérdida del suelo y la erosión del substrato suave y poroso por alteración de la cubierta vegetal son una amenaza para la biota nativa y los fósiles. Por lo tanto, las medidas de conservación necesarias para proteger los fósiles tendrían múltiples beneficios para la ecología del área.

Abstract The Piedra Chamana Fossil Forest, near the village of Sexi in central Cajamarca, records the vegetation of the South American tropics 39 million years ago, early in the New World tropical forests history and before the rise of the present-day Andes. In this fossil forest, notable discoveries have included the mangrove genus Avicennia, a genus of emergent forest trees (Cynometra), and the second dipterocarp known from the New World. The significance of the fossils rests on the unique circumstances of preservation, the detailed reconstruction of the forest and environment that is possible based on the plant fossils and ancient soils, and the importance of this record for the study of climate change. Sites like the fossil forest are particularly vulnerable to disturbance and loss of the fossil resources. Ongoing monitoring shows that human activities and erosion are having serious effects and, conservation measures are urgently needed. The importance of the fossils for science, the beauty of this area of the Andes, and the potential of the site for education and tourism justify recognition of the fossil forest at an international level. The lowland tropical forest represented by the fossils is very different from the diverse broad-leaf sclerophyllous forest or woodland now growing in the area. Soil loss and erosion of the soft, porous volcanic substrate when the vegetation cover is disturbed poses a threat to both the native biota and the fossils. The conservation measures needed at the fossil site would have multiple benefits for the ecology of the region.

The Piedra Chamana fossil woods and leaves: a record of the vegetation and palaeoenvironment of the Neotropics during the late middle Eocene.

BACKGROUND AND AIMS: The Piedra Chamana fossil forest in northern Peru is an assemblage of angiosperm woods and leaves preserved in volcaniclastic rocks dated to 39 Mya (late Middle Eocene). We analysed the anatomical and morphological features of the fossils to reconstruct the palaeoenvironment during this time of global warmth, taking advantage of the co-occurrence of woods and leaves to compare different proxies and analytical approaches. METHODS: Wood characters analysed include vessel-related functional traits, traits linked to Baileyan trends, and quantitative features such as vessel diameter and density. Diameter-distribution and diameter and position plots are used to represent vessel diameter and arrangement. Leaf margin and area analysis provides additional climate estimates. KEY RESULTS: The fossil woods show many similarities with modern tropical-forest woods and tropical fossil-wood assemblages; closest correspondence within the Neotropics is to semi-deciduous lowland tropical forest with moderate precipitation (~1000-1200 mm). Features unusual for the modern South American tropics are mainly vessel-related characters (semi-ring porosity, grouped vessels, helical vessel thickenings, short vessel elements) linked to water stress or seasonal water availability. Leaf analysis indicates mean annual temperature of 31 °C (n = 19, 100 % entire-margined) and mean annual precipitation of 1290 mm (n = 22, predominantly microphylls and notophylls). CONCLUSIONS: The palaeovegetation was clearly lowland tropical forest with a dry aspect, but anomalous aspects of the wood anatomy are consistent with the high temperatures indicated by the leaves and are probably explained by differences in seasonality and water stress compared to the present-day Neotropics. A close modern analogue may be in very seasonal regions of Asia. Pronounced monsoonal (summer-rain) conditions may relate to a location (palaeolatitude of 13°S) outside the near-equatorial tropics.

Using forest historical information to target landscape ecological restoration in Southwestern Patagonia.

Ecotonal zones between eastern semi-arid steppes and Nothofagus spp. forests in western Patagonia are the result of broad ecosystem changes, which have intensified in the last 140 years. Our objectives were to determine historical changes in land use, land cover, and forces driving such changes in Nothofagus ecosystems in the Río Verde district in southern Chile, to support future management recommendations. This interdisciplinary study used historical records including scientific and military expeditions, Landsat imagery, and other archival sources. Forest cover changed radically between the late nineteenth and mid-twentieth centuries, from subsistence use by indigenous peoples, to forestry and livestock industries. The main driving forces of landscape change have been anthropogenic forest fires, logging, exotic pasture establishment, and mining. Future perspectives suggest that conserving the cultural values and natural resources of this region will depend on ecologically sound landscape planning, reversing forest fragmentation, restoring riparian corridors, and preserving indigenous archaeological sites.

The history of soil use by forests in the region of campos de Lages, Santa Catarina, Brazil / A trajetória do uso do solo por florestas na região dos campos de Lages

The history of soil use by forests during XX century in Campos de Lages region, Santa Catarina state, Brazil was studied. The changes in the soil use and its relations to sociotechnical contexts have been approached, along with how these relations have affected the meaning and the value of forest soils in the Regions history. To understand the relations among soils, forests and society, a conceptual arrangement was used based on Actor-network Theory (ANT). Since the early XIX Century, when the Region insertion in Minas Gerais network through the tropeirismo occurred, cattle creation has been the typical scenario of the native landscape use. In 1940´s, changes on sociotechniques initiated the cycle of the pine, with intense Araucaria angustifolia wood exploitation. At the end of XX Century, the soil forest vocation was modified by forestry. However, existing controversies about the reforestations might change the meaning of the soil used by forests, creating a new confl ict. The study concludes that the forest use was more diverse. The forest soil had assumed distinct meanings for different actors in the course of time, although keeping the same sociallogic of land use.

Estudou-se a história do uso do solo por florestas durante o século XX na região dos Campos de Lages, em Santa Catarina, Brasil. Abordaram-se as mudanças no uso do solo e suas relações com contextos sóciotécnicos, e como estas relações afetaram o significado e o valor dos solos florestais ao longo da história da região. Para compreender as relações entre solos, florestas e sociedade, foi adotado um arranjo conceitual com base na Teoria do Ator-rede (ANT - Actor-network Theory). Trabalhou-se com a hipótese de que a história florestal da Região está relacionada com a dinâmica da ocupação do território e a percepção do valor dos solos ocupados por florestas, mudando esta de acordo com o contexto e as redes socioeconômicas na qual estava inserido o território, mantendo, no entanto uma sociológica similar. Desde a inserção da região na rede das Minas Gerais através do tropeirismo, no início do século XIX, a pecuária tem sido o retrato do uso de uma paisagem campestre nativa, até que, a partir da década de 40, mudanças sociotécnicas dessem início ao ciclo do pinho, com intensa exploração da madeira da Araucaria angustifolia. No final do século XX a silvicultura altera a vocação florestal do solo, mas controvérsias existentes sobre os reflorestamentos ressignificam o solo utilizado por florestas, instaurando um novo conflito socioambiental. Em todo o período, os solos florestais a

The history of soil use by forests in the region of campos de Lages, Santa Catarina, Brazil / A trajetória do uso do solo por florestas na região dos campos de Lages

The history of soil use by forests during XX century in Campos de Lages region, Santa Catarina state, Brazil was studied. The changes in the soil use and its relations to sociotechnical contexts have been approached, along with how these relations have affected the meaning and the value of forest soils in the Regions history. To understand the relations among soils, forests and society, a conceptual arrangement was used based on Actor-network Theory (ANT). Since the early XIX Century, when the Region insertion in Minas Gerais network through the tropeirismo occurred, cattle creation has been the typical scenario of the native landscape use. In 1940´s, changes on sociotechniques initiated the cycle of the pine, with intense Araucaria angustifolia wood exploitation. At the end of XX Century, the soil forest vocation was modified by forestry. However, existing controversies about the reforestations might change the meaning of the soil used by forests, creating a new confl ict. The study concludes that the forest use was more diverse. The forest soil had assumed distinct meanings for different actors in the course of time, although keeping the same sociallogic of land use.

Estudou-se a história do uso do solo por florestas durante o século XX na região dos Campos de Lages, em Santa Catarina, Brasil. Abordaram-se as mudanças no uso do solo e suas relações com contextos sóciotécnicos, e como estas relações afetaram o significado e o valor dos solos florestais ao longo da história da região. Para compreender as relações entre solos, florestas e sociedade, foi adotado um arranjo conceitual com base na Teoria do Ator-rede (ANT - Actor-network Theory). Trabalhou-se com a hipótese de que a história florestal da Região está relacionada com a dinâmica da ocupação do território e a percepção do valor dos solos ocupados por florestas, mudando esta de acordo com o contexto e as redes socioeconômicas na qual estava inserido o território, mantendo, no entanto uma sociológica similar. Desde a inserção da região na rede das Minas Gerais através do tropeirismo, no início do século XIX, a pecuária tem sido o retrato do uso de uma paisagem campestre nativa, até que, a partir da década de 40, mudanças sociotécnicas dessem início ao ciclo do pinho, com intensa exploração da madeira da Araucaria angustifolia. No final do século XX a silvicultura altera a vocação florestal do solo, mas controvérsias existentes sobre os reflorestamentos ressignificam o solo utilizado por florestas, instaurando um novo conflito socioambiental. Em todo o período, os solos florestais a