Establishing a Multi-Century, Annual-Resolution Climate Record from the Northeastern Caribbean

在中高纬度地区，树木年代学提供了一些最有价值的年度分辨率气候记录，其中大多数大大扩展了我们对气候的认识，可以追溯到仪器记录之前的时期。 相比之下，低纬度地区的树木年轮气候学记录很少，因为热带树木很少能产生可靠的年轮，从而无法进行树木年代学研究。 该研究项目的基础是发现加勒比海伊斯帕尼奥拉岛的原生松树Pinus octagentalis Swartz产生了对水分敏感的优秀年轮。 本种提供了一个有价值的替代降水记录，但只有当它生长在其范围内的最高海拔和水分胁迫的地点，海拔近3,000米，在稳定的块地和悬崖上。 研究人员从120个标本中收集了木材样本（核心和一些活树的切片，加上死树和残余木材的切片）。 在小子集上的初步工作显示出有希望的潜力。 该奖项支持通过表面处理、放大镜下的计算机环测量和年表统计分析（包括与现代气候数据的比较）对这些样本进行分析。 采样的林分中存在大量火痕，将分析该物种的火灾反应，以评估该物种为这些加勒比高地提供亚季节火灾历史信息的潜力。 稀有的亚化石残木碎片被发现在防火裸岩点内的立场，和调查人员将试图确定从这些标本使用放射性碳测年浮动年表的年龄分布，以估计最终潜在的记录长度从这些和类似的网站。 最后，该奖项将有助于资助正在进行的努力，以改善公共宣传活动在田纳西大学的树木年轮科学实验室。 这些努力包括帮助学生和其他人发现树木年轮研究的兴奋点。这个项目的重要性源于这样一个事实，即北美松生长在热带纬度，这个地区没有像温带地区那样见证基于树木年轮的气候记录的发展。 在地理上，最近的树木气候学记录是在西北1,700公里处的一个热带地区。 随着人们越来越认识到气候和气候变化对人类社会的重要性，提高对热带气候动态的认识的科学动力也在继续增长。 该项目将提供第一个热带地区降水量的陆地代用记录，该地区在气候方面与北美大陆密切相关。 它还将加强教育工作，让学生和公众了解树木年轮研究的过程和结果。

At middle and high latitudes, dendrochronology has provided some of the most valuable annual-resolution climate records available, most of which significantly extend our knowledge of climate back into time well before periods with instrumental records. In contrast, few dendroclimatological records from low latitudes exist, because tropical trees rarely produce reliable annual rings that allow dendrochronological research. This research project builds on the finding that Pinus occidentalis Swartz, the native pine of the Caribbean island of Hispaniola, produces excellent rings that are moisture-sensitive. This species provides a valuable proxy precipitation record, but only when it grows at the very highest-elevation and moisture-stressed sites within its range, near 3,000 meters in elevation, in stabilized blockfields, and on cliffs. The investigators have collected wood samples (cores and a few sections of living trees, plus sections of dead trees and remnant wood) from 120 specimens. Initial work on small subsets shows promising potential. This award supports analyses of these samples through surface preparation, computer-measurement of rings under magnification, and statistical analysis of the chronologies including comparison with modern climate data. Fire scars are abundant in the stands sampled, and the species' fire response will be analyzed to assess the potential of the species to yield sub-seasonal fire history information for these Caribbean highlands. Rare pieces of subfossil remnant wood are found in fire-protected bare-rock spots within the stands, and the investigators will try to determine the age distributions of floating chronologies from such specimens using radiocarbon dating in order to estimate the ultimate potential record length from these and similar sites. Finally, the award will help fund ongoing efforts to improve public-outreach activities at the University of Tennessee's Laboratory of Tree-Ring Science. These efforts include helping school children and others discover the excitement of tree-ring research.The importance of this project stems from the fact that Pinus occidentalis grows at tropical latitudes, a region that has not witnessed the development of tree-ring-based climate records as have more temperate locales. In geographic terms, the nearest published dendroclimatological record is 1,700 kilometers to the northwest in an extra-tropical location. As awareness of the importance to human society of climate and climate change increases, the scientific impetus to improve understanding of tropical climate dynamics continues to grow. This project will provide the first terrestrial proxy record of precipitation from a tropical region that is closely connected in climatic terms to the North American mainland. It also will enhance educational efforts to inform students and the public about the processes and outcomes of tree-ring research.