Agriculture

  2010 MAR 11 - (VerticalNews.com) -- According to recent research from the United States, "The growth rings of eastern redcedar (Juniperus virginiana L.) often contain a high frequency of false intra-annual growth bands, which complicates the dendrochronology of this species. However, exactly dated false rings replicated among many trees can reflect major weather changes during the growing season."

  "Sixty-one trees from two sites (Oklahoma and Kansas) were dated and used to compile replicated chronologies of false rings at both locations extending from AD 1700-2000. False-ring events during the modern instrumental era were compared with the daily weather data from nearby stations. Significant false-ring events occurred at both locations during years that experienced a dramatic late-growing season weather reversal, when an extended period of high temperatures and drought was followed by prolonged cool and wet conditions. Synoptic weather maps for these events indicate that all ten replicated false-ring events in the instrumental era occurred during the highly unseasonable penetration of a cold front into the region. However, none of the significant false-ring events occurred in the same year at both sites," wrote J.R. Edmondson and colleagues, University of Arkansas ...read more

  2010 MAR 11 - (VerticalNews.com) -- According to recent research published in the journal Tree - Ring Research, "The performance of the Hugershoff curve on fitting the growth trends of tree-ring series was tested using ring-width series with different starting years. The fitted values tend to be biased by tree-ring series close to pith, a phenomenon that was referred to as the ''start-fitting problem'."

  "We determined three parameters with specific biological age-related meanings for the Hugershoff growth curve, i.e. the maximum growth, the maximum slope and the maximum changing ratio of slopes. A set of modified Hugershoff curves with different starting years was proposed to mitigate the start-fitting problem. Behavior of the modified Hugershoff curves on tree-ring series standardizations was tested and discussed," wrote K.Y. Fang and colleagues, Lanzhou University ...read more

  2010 MAR 11 - (VerticalNews.com) -- According to a study from Germany, "Although studies on stable-carbon isotopes in trees from temperate zones provide abundant paleoclimatic data, tropical trees are still understudied in this context. Therefore this study examined the variability of intra- and inter-annual stable-carbon isotopic pattern in several tree species from various tropical climates."

  "The delta C-13 Values of samples of 12 broadleaved trees (seven species) from various paleotropical and neotropical sites along a climatic moisture gradient were investigated. The inter-annual variability between species and sites was studied. Further the relationship between delta C-13 and precipitation time series was analyzed. tropical tree species show a similar variability in carbon isotopic composition as temperate tree species. Significant correlations between annual precipitation and tree-ring delta C-13 time series were negative. Successful crossdating of a tree-ring delta C-13 time series highlights the potential of carbon isotope measurements for tropical tree-ring analytical studies," wrote E. Fichtler and colleagues, University of Gottingen ...read more