Millennial scale climate-fire-vegetation interactions in a mid-elevation mixed coniferous forest, Mission Range, northwestern Montana, USA
Millennial scale climate-fire-vegetation interactions in a mid-elevation mixed coniferous forest, Mission Range, northwestern Montana, USA
复制标题
美国蒙大拿州西北部 Mission Range 中海拔混合针叶林的千年尺度气候-火灾-植被相互作用
DOI：
10.1017/qua.2018.25
复制
发表时间：
2018
影响因子：
2.3
通讯作者：
C. Whitlock
中科院分区：
文献类型：
--
作者：
Mio Alt;D. McWethy;R. Everett;C. Whitlock
摘要 混交针叶林广泛分布在落基山脉北部的中海拔地区，但人们对其长期植被和火灾历史知之甚少。蒙大拿州西北部 Mission Range 地区 Twin Lakes 的花粉和木炭记录提供了过去 15,000 年来混合针叶林发展和火灾活动的信息。这些数据表明在距今 13,500 卡路里之前有一个开放的公园和最小的火灾活动，这与寒冷、干燥的条件一致。 13,500 Cal yr BP 之后松树花粉的增加表明向封闭森林的过渡，并且随着条件变暖和燃料生物量的增加，火灾活动略有增加。距今 10,000 至 6000 卡路里之间的高含量艾蒿花粉表明，全新世早期存在着开阔的森林，当时的环境比现在更温暖、更干燥。低度火灾可能维持了开阔的森林/灌木丛，但在此期间几乎没有产生木炭。当今的混交针叶林是在过去的 6 ka 中建立的，包括具有低火情（黄杉/黄松）和高火情（云杉/冷杉）特征的森林类群。在过去的几千年里，当气候条件变得凉爽和湿润时，气候变化的增加和人为燃烧可能有助于维持异质的混合针叶林。
Abstract Mixed coniferous forests are widespread at middle elevations in the Northern Rocky Mountains, yet relatively little is known about their long-term vegetation and fire history. Pollen and charcoal records from Twin Lakes, in the Mission Range of northwestern Montana provide information on mixed-coniferous forest development and fire activity over the last 15,000 years. These data suggest an open parkland and minimal fire activity before 13,500 cal yr BP, consistent with cold, dry conditions. Increases in Pinus pollen after 13,500 cal yr BP indicate a transition to closed forests, and a slight rise in fire activity as conditions warmed and fuel biomass increased. High levels of Artemisia pollen between 10,000 and 6000 cal yr BP suggest an open forest during the early Holocene when conditions were warmer and drier than present. Low-severity fires likely maintained open forest/shrublands but produced little charcoal during this interval. Present-day mixed-coniferous forests were established in the last 6 ka and included forest taxa characteristic of low- (Pseudotsuga-Larix/Pinus ponderosa) and high-severity fire regimes (Picea/Abies). Increased climate variability and anthropogenic burning may have helped maintain heterogeneous, mixed-coniferous forests during the last several millennia when climate conditions became cooler and wetter.