Lake Sediment Pollen and Charcoal from Uncle Seth's Pond on Martha's Vineyard MA from 13389 BP to Present

Aim
We analyzed a dataset composed of multiple palaeoclimate and lake-sediment pollen and charcoal records from New England to explore how postglacial changes in forest composition and spatial patterns of vegetation and fire were controlled by regional-scale climate change, a subregional environmental gradient, and landscape-scale variations in soil characteristics.

Location
The 120,000-km2 study area includes parts of Vermont and New Hampshire in the north, where sites are 150-200 km from the Atlantic Ocean, and spans the coastline from southeastern New York to Cape Cod and the adjacent islands, including Block Island, the Elizabeth Islands, Nantucket, and Martha’s Vineyard.

Results
Boreal forest featuring Picea and Pinus banksiana was present across the region when conditions were cool and dry 14,000-12,000 calibrated 14C yrs before present (ybp). Pinus strobus became regionally dominant as temperatures increased between 12,000 and 10,000 ybp. The composition of forests in inland and coastal areas diverged in response to further warming after 10,000 ybp, when Quercus and Pinus rigida expanded across southern New England, while conditions remained cool enough in inland areas to maintain Pinus strobus. Fire severity was high during 10,000-8000 ybp. Increasing precipitation allowed Tsuga canadensis, Fagus grandifolia, and Betula to replace Pinus strobus in inland areas during 9000-8000 ybp, and also led to the expansion of Carya across the coastal part of the region beginning at 7000-6000 ybp. Abrupt cooling at 5500-5000 ybp caused sharp declines in Tsuga in inland areas and Quercus at some coastal sites, and the populations of those taxa remained low until they recovered around 3000 ybp in response to rising precipitation. Throughout most of the Holocene, sites underlain by sandy glacial deposits were occupied by Pinus rigida and Quercus.

Main conclusions
Postglacial changes in the composition and spatial pattern of New England forests were controlled by long-term trends and abrupt shifts in temperature and precipitation, as well as by the environmental gradient between coastal and inland parts of the region. Substrate and soil moisture shaped landscape-scale variations in forest composition. Climate and fuels largely controlled fire severity in New England during the postglacial interval.

目标
我们分析了一个包含新英格兰地区多个古气候（palaeoclimate）、湖泊沉积物花粉及木炭记录的数据集，旨在探究冰后期森林组成的变化以及植被与火的空间格局如何受区域尺度气候变化、亚区域环境梯度及景观尺度土壤特征变异的调控。

位置
研究区域面积达120,000平方公里，涵盖北部佛蒙特州与新罕布什尔州的部分区域（这些区域的采样点距大西洋150-200公里），并横跨从纽约东南部至科德角及邻近岛屿的海岸线，包括布洛克岛、伊丽莎白群岛、楠塔基特岛和玛莎葡萄园岛。

结果
在14000-12000校正碳14年（距今，ybp）的凉爽干燥时期，整个区域分布着以云杉属（Picea）和班克松（Pinus banksiana）为主的北方针叶林。随着12000-10000 ybp期间气温升高，东部白松（Pinus strobus）成为区域优势物种。10000 ybp后，进一步变暖导致内陆与沿海地区森林组成出现分化：南部新英格兰地区的栎属（Quercus）和刚松（Pinus rigida）扩张，而内陆地区仍保持足够凉爽以维持东部白松的生长。10000-8000 ybp期间火强度较高。降水增加使得9000-8000 ybp期间内陆地区的加拿大铁杉（Tsuga canadensis）、大果山毛榉（Fagus grandifolia）和桦属（Betula）取代东部白松，并于7000-6000 ybp开始推动该区域沿海部分的山核桃属（Carya）扩张。5500-5000 ybp的突然降温导致内陆地区铁杉属数量骤降，部分沿海站点栎属数量减少，这些类群的种群数量持续低迷，直至约3000 ybp时降水增加才得以恢复。在全新世大部分时期，砂质冰川沉积层上的站点被刚松和栎属占据。

主要结论
新英格兰森林组成及空间格局的冰后期变化受温度与降水的长期趋势及突然转变、以及区域内沿海与内陆间环境梯度的调控。基质与土壤湿度塑造了森林组成的景观尺度变异。在冰后期，气候与可燃物在很大程度上控制了新英格兰地区的火强度。