Hydrologic controls on carbon sequestration in different age afforested pine forests under changing climate

加拿大和美国东部森林的很大一部分是不同年龄的人工林(植树造林)或更新林。在过去的几十年里，这些森林一直是一个巨大的碳(C)汇，以抵消一些化石燃料的排放。然而，最近的研究表明，它们的碳固存能力正受到区域气候变化的影响。气候变暖除了增加冬/夏气温和热事件外，还加速了水文循环，导致蒸发量增加，干旱和洪涝事件更加频繁。森林水文循环的变化改变了土壤和植物的养分循环，而土壤和植物的养分循环对碳循环和水循环都有反馈作用，因此可能导致进一步的气候变化。迫切需要探讨森林中的水文、养分和碳循环之间的相互作用，特别是在绿化和管理的林分中，以充分了解它们的功能和对未来气候变化的反应。这项建议将调查水文和养分循环的变化对加拿大东部三个年龄固定(70年、35年、7年生)的温带松林固碳潜力的影响，以固持大气中的二氧化碳及其对未来气候变化(如变暖、干旱等)的反应。它还将侧重于进一步开发和测试在加拿大全球气候模型中使用的碳氮耦合陆地生态系统模型(CLASS-CTEM+N)以及水文模型(Mike-SHE)。很少有研究人员研究水文、养分和碳循环之间的整合，特别是在绿化林分中。这些知识将有助于制定适应森林生长和生存的战略，在未来气候变化的情况下，为社会提供许多生态和娱乐服务以及清洁的水。在加拿大全球气候模式中实施CLASS-CTEM+N模式将提供一种评估工具，为政策制定生成未来气候情景，并帮助加拿大履行其国际义务。

A significant portion of Eastern forests in both Canada and United States are plantation (afforested) or regenerated stands of different ages. These forests have been a large carbon (C) sink over the last many decades to offset some of the fossil fuel emissions. However, recent studies indicate that their C sequestration capabilities are being affected by changes in regional climate. Apart from increasing winter/summer temperatures and heat events, climate warming has accelerated the hydrologic cycle, resulting in increased evaporation and more frequent drought and flooding events. Changes to the forest hydrologic cycle alters soil and plant nutrient cycling, which feeds-back on both C and water cycles and hence, can induce further climate change. There is an urgent need to explore the interaction between hydrologic, nutrient and C cycles in forests--in particular in afforested and managed stands to fully understand their functioning and response to future climate change. This proposal will investigate the impact of changes in hydrologic and nutrient cycling on the C sequestration potential of three Eastern Canadian age-sequenced (70-, 35-, 7-year-old) afforested temperate pine stands, to sequester atmospheric CO2 and their response to future climate change (e.g. warming, drought, etc.). It would also focus on further developing and testing a C and nitrogen coupled terrestrial ecosystem model (CLASS-CTEM+N) used in Canadian Global Climate Model as well as a hydrologic model (MIKE-SHE). Few researchers have investigated the integration between hydrologic, nutrient and carbon cycling and particularly in afforested stands. This knowledge would help to develop adaptation strategies for the growth and survival of forests, which provide numerous ecological and recreation services and clean water to society, under changing future climates. Implementation of CLASS-CTEM+N model in Canadian Global Climate Model would provide an assessment tool to generate scenarios of future climate for policy development and help Canada meet its international obligations.