The conservation of tropical forests is recognized as one of the most important challenges for forestry, ecology and politics. Besides strict protection, the sustainable management of natural forests should be enhanced as a key part of the foundation for the maintenance of tropical rain forest ecosystems. Due to methodological reasons it has been complicated to attain reliable growth data to plan sustainable felling cycles and rotation periods. Tree ring analyses enable the estimation of growth rates over the entire life span of trees and their age as well as giving hints from forest dynamics in previous centuries. For tree ring analysis, stem disk samples were taken from three important commercial tree species (Cariniana micrantha, Caryocar villosum and Manilkara huberi) in the upland (terra firme) forests of the Precious Woods Amazon logging company near Itacoatiara, Brazil. Based on radiocarbon estimates of individual growth zones, the annual nature of tree rings was proven for the three species. Tree rings were measured and the results used together with height estimates to model diameter, height and volume growth. The age of the eldest tree, a C. micrantha, was 585 yrs with 165 cm in diameter. The species' diameter increments range from 0.20±0.12 cm yr-1 to 0.29±0.08 cm yr-1. At first sight, this is considerably lower than increments reported from other Amazonian or African timber species. Considering the respective wood density there is no significant difference in growth performance of dominant timber species across continents. The interpretation of lifetime tree ring curves indicate differences in shadow tolerance among species, the persistence of individuals in the understory for up to 150 years and natural stand dynamics without major disturbances. Management criteria should be adapted for the measured growth rates as they differed considerably from the Brazilian standards fixed by laws (felling cycle of 25-35 years and a common minimum logging diameter of 50 cm). Felling cycles should be increased to 32-51 years and minimum logging diameters to 63-123 cm depending on the species.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6684163 | PMC |
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0219770 | PLOS |
Trees (Berl West)
January 2025
Department of Geography, Johannes Gutenberg University, 55099 Mainz, Germany.
Key Message:
Abstract: Tree-rings are the prime archive for high-resolution climate information over the past two millennia. However, the accuracy of annually resolved reconstructions from tree-rings can be constrained by what is known as climate signal age effects (CSAE), encompassing changes in the sensitivity of tree growth to climate over their lifespans. Here, we evaluate CSAE in from an upper tree line site in the Spanish central Pyrenees, Lake Gerber, which became a key location for reconstructing western Mediterranean summer temperatures at annual resolution.
Plants (Basel)
January 2025
Department of Silviculture, Forest Inventory and Forest Management, G.F. Morozov Voronezh State University of Forestry and Technologies, 394087 Voronezh, Russia.
Pedunculate oak ( L.) is widely distributed across Europe and serves critical ecological, economic, and recreational functions. Investigating its responses to stressors such as drought, extreme temperatures, pests, and pathogens provides valuable insights into its capacity to adapt to climate change.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Silviculture, Poznań University of Life Sciences, ul. Wojska Polskiego 71A, Poznań, 60-625, Poland.
The study assessed the sensitivity of 20 provenances of European larch (Larix decidua Mill.) growing at provenance experimental trials located in lowland (Siemianice) and upland (Bliżyn) climate in Central Poland to air temperature and precipitation, including drought. The measure of the tree' sensitivity was their radial growth reactions, i.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Earth Sciences, Montana State University, Bozeman, MT 59717.
Climate-driven changes in high-elevation forest distribution and reductions in snow and ice cover have major implications for ecosystems and global water security. In the Greater Yellowstone Ecosystem of the Rocky Mountains (United States), recent melting of a high-elevation (3,091 m asl) ice patch exposed a mature stand of whitebark pine () trees, located ~180 m in elevation above modern treeline, that date to the mid-Holocene (c. 5,950 to 5,440 cal y BP).
View Article and Find Full Text PDFSci Total Environ
January 2025
Climate Change Impacts and Risks in the Anthropocene (C-CIA), Institute for Environmental Sciences, University of Geneva, Geneva, Switzerland; dendrolab.ch, Department of Earth Sciences, University of Geneva, Geneva, Switzerland; Department F.-A. Forel for Environmental and Aquatic Sciences, University of Geneva, Switzerland.
Over recent decades, global warming has led to sustained glacier mass reduction and the formation of glacier lakes dammed by potentially unstable moraines. When such dams break, devastating Glacial Lake Outburst Floods (GLOFs) can occur in high mountain environments with catastrophic effects on populations and infrastructure. To understand the occurrence of GLOFs in space and time, build frequency-magnitude relationships for disaster risk reduction or identify regional links between GLOF frequency and climate warming, comprehensive databases are critically needed.
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