Development of Computer Assisted Tree Ring Dating System

在美国国家科学基金会（National Science Foundation）的支持下，亚利桑那大学（University of Arizona）的马尔科姆·休斯（Malcolm hughes）博士和他的同事将开发一种计算机辅助的树木年轮测年系统。目前，所有的树木年代学实验室完全依靠非常耗时但精确的人工技术，而拟议的系统将提高速度但保持准确性，这将对可分析的样品数量产生重大影响。由于树木年轮的特征受每年变化的温度和湿度的影响，年轮的厚度每年都不同，因此有可能构建在时间上锚定在现在的序列延伸到几千年前。在此基础上，人们可以将旧木片（通常以木炭的形式）与主序列进行比对，并确定它们的绝对年龄。由于气候的地理差异，必须为世界不同地区构建单独的序列，大多数实验室既要构建和扩展主序列，也要确定年龄未知的样品的年代。这个项目之所以重要，有两个原因。首先涉及到它广泛的科学影响。包括考古学家、古生物学家、生态学家、地质学家和气候学家在内的众多科学家都需要对过去的事件进行准确的测年，而树木年代学提供了这样的信息。例如，科学家利用这些数据来研究生态演替的速率和气候变化在物种灭绝中的作用。通过分析树木年轮中所含的氧同位素，有可能重建几千年来年温度和降雨量的详细变化。正因为如此，美国国家科学基金会气候动力学计划多年来一直支持亚利桑那州树木年轮实验室和主要年表的发展。其次，这个项目非常重要，因为亚利桑那州的原型，如果开发出来，将成为美国和国外其他树木年轮实验室的模型。尽管挑战很大，但对计算机辅助系统的需求是显而易见的。树木年代学在亚利桑那大学创立。该实验室为许多树木年代学家提供培训，其方法创新传播迅速。

With National Science Foundation support, Dr. Malcolm Hughs and his colleagues at the University of Arizona will develop a computer assisted system for tree ring dating. At the present time all dendrochronology laboratories rely solely on very time consuming but accurate manual techniques and the proposed system which would increase speed but maintain accuracy would have a major impact on the numbers of samples which could be analyzed. Because the characteristics of tree rings are affected by temperature and moisture which vary annually, rings differ in thickness from year to year and it has been possible to construct sequences which are chronologically anchored in the present extend back thousands of years in time. On this basis one can take old wood fragments (often in the form of charcoal) , match them against a master sequence and determine their absolute age. Because of geographic variation in climate, individual sequences must be constructed for different parts of the world and most laboratories work both to construct and extend master sequences as well as to date samples of unknown age. This project is important for two reasons. The first involves its broad scientific impact. A broad range of scientists includingarchaeologists, paleobiologists, ecologists, geologists and climatologists require accurate dating of past events and dendrochronology provides such information. For example, scientists use such data to study rates of ecological succession and the role of climate change in species extinction. Through analysis of oxygen isotopes contained in tree rings it is possible to reconstruct detailed changes in annual temperature and rainfall over several millennia. Because of this, for many years the NSF Climate Dynamics Program supported the Arizona Tree Ring Laboratory and the development of a master chronology. Secondly this project is extremely important because the Arizona prototype, if developed would serve as model for other tree ring laboratories both in the US and abroad. Although the challenge is significant, the need for a computer assisted system is evident. Dendrochronology was founded at the University of Arizona. The laboratory provides training for many dendrochronologists and its methodological innovations diffuse rapidly.