Development of Computer Assisted Tree Ring Dating System

在国家科学基金会的支持下，亚利桑那大学的马尔科姆·休斯博士和他的同事们将开发一种计算机辅助系统，用于树木年轮的测定。目前，所有树状年代学实验室完全依赖非常耗时但准确的人工技术，而拟议的系统将提高速度但保持准确性，这将对可以分析的样本数量产生重大影响。由于树木年轮的特征受温度和湿度的影响，年轮的厚度每年都不同，因此有可能构建按时间顺序固定在现在的时间序列，这些序列可以追溯到数千年前。在此基础上，人们可以提取古老的木片(通常是木炭的形式)，将它们与主序列进行匹配，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，也要对未知年龄的样品进行测年。这个项目之所以重要，有两个原因。第一个问题涉及其广泛的科学影响。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许多科学家都要求对过去的事件进行准确的年代测定，而树木年代学就提供了这种信息。例如，科学家使用这些数据来研究生态演替的速度和气候变化在物种灭绝中的作用。通过分析树木年轮中包含的氧同位素，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，NSF气候动力学计划多年来一直支持亚利桑那州年轮实验室和主年表的开发。其次，这个项目非常重要，因为亚利桑那州的原型如果被开发出来，将成为美国和国外其他树轮实验室的模型。尽管挑战是巨大的，但显然需要一个计算机辅助系统。树状年代学是在亚利桑那大学创立的。该实验室为许多树状年代学家提供培训，其方法创新迅速扩散。

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.