Fire regimes and forest composition in Canadian mixedwood boreal forest

加拿大北方混交林的火情和森林组成

• 批准号: 2390-2010
• 负责人: Bergeron, Yves
• 金额: $ 4.08万
• 依托单位: Université du Québec à Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=520478
• 关键词: Fire; regimes; forest; composition; Canadian

Landscape structure and its interactions with disturbance regimes are key elements to consider in understanding boreal forest mosaics. Several studies have demonstrated that frequent, large and severe fires may contribute to the creation of stands lacking late successional species as these species have to reinvade by seeds from unburnt areas. Fire severity, via its control of seed-bed availability and productivity, could also influence post-fire composition and successional development. My long term objective is to understand how fire regimes control forest composition and ecological processes in the boreal forest. In the next 5 years I propose to address this objective through 3 complementary projects. The first project aims to complete the reconstruction of long-term fire regimes in the Canadian mixedwood boreal forest. Previous works included territories in Quebec and in some parts of Ontario. This proposal will cover the gap to BC. Fire cycles will be reconstructed using time since fires maps and archives, and aerial photographs (since the 1930s) will be used to delineate fires that occurred during the twentieth century. The proportion of forests originating from older fires will be estimated using year of stand initiation as measured by dendrochronology. In a second project, I will use comparable aspen stands across a transect from eastern to western Canada to assess how fire regimes, acting at the regional and landscape level, control diversity and succession at the stand level. The third project will be undertaken in the eastern boreal where aspen, spruce and fir are abundant. I will assess how fire severity controls post fire forest composition and successionnal pathways. Low severity fires would be dominated by spruce and would favour mosses and exclude aspen and fir. The proposed research introduces a new spatio-temporal approach to interpreting vegetation mosaics in the boreal forest. Anticipated results will contribute towards understanding the effects of climate change on vegetation changes by determining ecosystem resistance to changes due to climate and disturbance regimes.

景观结构及其与干扰机制的相互作用是理解北方森林镶嵌结构时需要考虑的关键要素。几项研究表明，频繁、大规模和严重的火灾可能会导致缺乏后期演替物种的林分的形成，因为这些物种必须通过未燃烧地区的种子重新入侵。通过控制苗床的可用性和生产力，火灾的严重程度也可能影响火灾后的组成和演替发展。我的长期目标是了解火情如何控制北方森林的森林组成和生态过程。在接下来的 5 年里，我建议通过 3 个互补项目来实现这一目标。第一个项目旨在完成加拿大北方混交林长期火灾状况的重建。之前的作品包括魁北克省和安大略省的一些地区。该提案将弥补与 BC 的差距。将使用自火灾地图和档案以来的时间重建火灾周期，并使用航空照片（自 1930 年代以来）来描绘 20 世纪发生的火灾。 源自较早火灾的森林比例将根据树木年代学测量的林分萌生年份进行估算。在第二个项目中，我将使用加拿大东部到西部横断面的类似白杨林分来评估火势如何在区域和景观层面发挥作用，控制林分层的多样性和演替。第三个项目将在北方东部开展，那里盛产白杨、云杉和冷杉。我将评估火灾严重程度如何控制火灾后森林的组成和演替路径。低度火灾主要是云杉，有利于苔藓，排除白杨和冷杉。拟议的研究引入了一种新的时空方法来解释北方森林中的植被镶嵌。预期结果将有助于通过确定生态系统对气候和干扰制度引起的变化的抵抗力来了解气候变化对植被变化的影响。