SCOT2K: Reconstructing 2000 years of Scottish climate from tree-rings

SCOT2K项目旨在利用树木年轮数据重建苏格兰高地过去2000年的夏季气温。这种对英国北部的气候重建，以及在斯堪的纳维亚开发的类似的树木年轮数据集，不仅将提供关于中世纪气候、过渡到小冰河期（~公元1300年）和当前区域气候变化的重要信息，而且还将有助于确定北大西洋对西北欧洲地区气候的影响。树木对各种环境因素作出反应。通过了解这些生物对这些因素的反应，不仅可以利用树木年轮测量来重建过去的气候，还可以评估过去的管理措施是如何影响树木生长的。在苏格兰高地，苏格兰松树的树龄很少超过200-300年。因此，为了研究1700年以前的环境变化，需要利用当地保存的木质材料将活松的年代学延长到过去。有两个潜在的材料来源；来自建筑物的历史木材和保存在泥炭/湖泊沉积物中的亚化石材料。该项目将利用这两种保存完好的松木材料来延长活着的年表。一般来说，在相对较大的区域内，同一物种的树木对环境条件的反应是相似的。因此，在同一地区的同一树种的所有树木之间存在一定程度的共同生长变异性。这种共同的可变性导致了宽环和窄环的共享模式（如条形码），可以在样本之间进行匹配，从而允许样本之间的测年。这种同步或模式匹配过程被称为“交叉约会”。通过交叉定年，历史或亚化石木质材料可以按日历定年，只要与已经定年的参考年表有合理的重叠（~80年）。初步结果表明，在提议的SCOT2K项目的时间框架内，2000年的年表是可行和现实的目标，而8000年的年表，尽管更具挑战性的长期目标，在理论上是可能的。该项目建议对苏格兰高地的历史建筑和湖泊中保存下来的松树材料进行取样，对样本进行交叉比对，得出该地区2000年气候敏感的树木年轮年表。除了环宽（RW）数据外，还将从样品中测量最大密度（MXD）和最小蓝色强度（BI）数据。MXD和BI都是衡量年轮晚木中木质素含量的指标，其含量受夏季温度的强烈控制。利用RW、MXD和BI，可以为苏格兰高地开发一个强大的、强校准的夏季温度重建。从SCOT2K项目获得的数据不仅将提供过去两千年来英国北部气温的重要信息，而且还将提供北大西洋变化的关键信息，北大西洋变化控制着不列颠群岛的年代际和长期气候变化。这项工作的重要性将通过与在斯堪的纳维亚进行类似研究的研究小组（其他树木年轮科学家和气候建模者）的互动而大大增强。建议在项目的第三年举办一个综合讲习班，以促进这一重要的合作。

The SCOT2K project aims to reconstruct summer temperatures in the Scottish Highlands for the last 2000 years using tree-ring data. Such a climate reconstruction for Northern Britain, along with similar tree-ring data-sets being developed in Scandinavia, will not only provide important information on medieval climate, the transition into the Little Ice Age (~1300 AD) and current regional climate change, but will also help ascertain the influence of the North Atlantic on the climate of the NW European region.Trees respond to a variety of environmental factors. By understanding how these organisms respond to such factors, it is possible to use tree-ring measurements to not only reconstruct past climate but also assess how management practises may have influenced tree-growth in the past. In the Scottish Highlands, Scots pine trees rarely attain ages greater than ~200-300 years. Therefore, to study past environmental change prior to ~1700, living pine chronologies need to be extended back in time using preserved local woody material. There are potentially two sources of material; historic timbers from buildings and sub-fossil material preserved in peat/lake sediments. This project will utilise both sources of preserved pine material to extend the living chronologies back in time.In general, trees of the same species respond in a similar way to environmental conditions over relatively large areas. There is therefore a certain degree of common growth variability between all trees of the same species from the same region. This common variability results in a shared pattern of wide and narrow rings (i.e. like a bar code) that can be matched between samples allowing between sample dating. This synchronising or pattern matching process is termed "crossdating". Through crossdating, historical or sub-fossil woody material can be calendar dated, so long as there is reasonable overlap (~80 years) with an already dated reference chronology. Initial results indicate that a 2000 year chronology is a feasible and realistic objective within the timeframe of the proposed SCOT2K project and that an ~8000 year long chronology, an albeit more challenging long term aim, is theoretically possible in the future.This project proposes to sample preserved pine material from both historic structures and lakes in the Scottish Highlands, crossdate the samples and derive a 2000-year long climatically sensitive tree-ring chronology for the region. As well as ring-width (RW) data, maximum density (MXD) and minimum blue intensity (BI) data will also be measured from the samples. MXD and BI are both measures of lignin content in the latewood of a tree-ring, the amount of which is strongly controlled by summer temperatures. Using RW, MXD and BI, a robust, strongly calibrated summer temperature reconstruction can be developed for the Scottish Highlands. The data obtained from the SCOT2K project will not only provide important information of past temperatures over the last two millennia for northern Britain, but will also provide key information on North Atlantic variability which controls decadal and longer term climate variability over the British Isles. The importance of this work will be greatly enhanced by interaction with research groups (other tree-ring scientists and climate modellers) undertaking similar research across Scandinavia. A synthesis workshop is proposed for Year 3 of the project to facilitate this important collaboration.