Do past fires explain current carbon dynamics of Amazonian forests?

过去的火灾能否解释亚马逊森林当前的碳动态？

• 批准号: NE/N011570/1
• 负责人: Ted Feldpausch
• 金额: $ 69.62万
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FN011570%2F1
• 关键词: Do; past; fires; explain; current

Amazon forests process and store large quantities of carbon in vegetation and soils. These forests, assumed to be mostly 'old-growth' and fire-free are exhibiting a remarkable feature-they are gaining the equivalent mass of a small car every year in aboveground biomass per hectare of forest (0.89 Mg/ha/yr). These gains are attributed to increasing atmospheric CO2, which has a fertilization effect on tree growth. However, fire in these 'old-growth' forests may be more recent than expected (in the last few centuries), and regrowth from fire together with soil charcoal-which has a fertility effect-may be contributing together with CO2 fertilisation to the observed increases in biomass in these apparently mature forests. Current understanding of drivers of these increases is limited by, (i) an unknown fire history of plots used to monitor change, and (ii) lack of information of how resource change affects these forests. The effects of pre-modern fire on forest regrowth and the gain have not been evaluated. Our pilot analysis of radiocarbon dated fire from soil charcoal indicates that even the wettest Amazon rainforest has burned, with forests considered to be 'old-growth' having burned within the last few centuries, and 70% of plots (n=70) containing visible soil charcoal fragments. Periodic drier climate and fire use by Native Americans before their populations collapsed ~450 years ago following Europeans colonisation may have resulted in a higher fire frequency than currently observed. Forest regrowth from these and more recent fires may still be occurring in forests considered to be 'undisturbed', e.g., some trees may grow to be 980 years old in central Amazonia, so that forest considered 'old-growth' may still be approaching equilibrium as long-lived trees mature following fire. Fire also produces soil pyrogenic carbon (PyC) as charcoal that is found in archaeological sites in terra preta soils and in upland soils across Amazonia far from evidence of human settlement. Soil PyC increases soil fertility on otherwise nutrient poor soils, and being resistant to decomposition, may have increased soil fertility across the Amazon. Pre-modern fire and soil PyC are therefore two important ingredients in understanding how Amazonian forests currently function.We will determine whether regrowth following past fire and soil PyC fertility effects in 'old-growth' permanent forest plots across Amazonia contributes to the observed carbon sink. We have developed a basin-wide network of on-the-ground sample plots, and because methods of measuring the forest with these are fully standardised even across nations they represent an excellent opportunity to measure the response of Amazon forest to historic fire and soil PyC.In permanent forest plots across the Amazon Basin our Objectives are:1) determine spatial patterns in 'time since last fire'; 2) determine soil PyC stocks, and how these are affected by climatic, edaphic conditions, and fire intensity;3) using results from (1) and (2), determine whether spatial patterns of productivity and carbon gains in aboveground tropical forest trees in Amazonia are consistent with regrowth from historical fire disturbance and by soil PyC acting as a soil fertility enhancerOur research will improve understanding of fire patterns across the Amazon for long-term forest plots (the same plots used to estimate the current carbon sink). We will provide a first quantification of: soil PyC stocks, basin-wide environmental drivers of soil PyC stocks, and whether soil fertility is greater where soil PyC levels are higher. This will be a first large-scale test of whether forest productivity, structure, and increases in carbon can be attributed to regrowth from historic fire and soil PyC fertility effects. The results are vital for conservation planning, to estimate the longevity of the carbon sink, and for policy such as Reducing Emissions from Deforestation and Degradation (REDD+).

亚马逊森林在植被和土壤中处理和储存大量碳。这些被认为大部分是“古老的”且无火的森林表现出一个显着的特征——每公顷森林的地上生物量每年增加相当于一辆小型汽车的质量（0.89毫克/公顷/年）。这些收益归因于大气中二氧化碳的增加，这对树木的生长具有施肥作用。然而，这些“古老”森林中的火灾可能比预期的要晚（在过去的几个世纪中），并且火灾与土壤木炭（具有肥力效应）一起重新生长可能与二氧化碳施肥一起对观测到的森林造成了影响。这些明显成熟的森林中生物量的增加。目前对这些增长驱动因素的理解受到以下因素的限制：(i) 用于监测变化的地块的火灾历史未知，以及 (ii) 缺乏资源变化如何影响这些森林的信息。前现代火灾对森林再生和收益的影响尚未得到评估。我们对土壤木炭放射性碳测年火灾的初步分析表明，即使是最潮湿的亚马逊雨林也已被烧毁，被认为是“古老森林”的森林在过去几个世纪内也曾被烧毁，并且 70% 的地块 (n=70) 含有可见光土壤木炭碎片。大约 450 年前，在欧洲人殖民之后，美洲原住民的人口锐减之前，周期性的干燥气候和用火可能导致火灾发生频率比目前观察到的要高。这些火灾和最近发生的火灾造成的森林再生可能仍在被认为“未受干扰”的森林中发生，例如，亚马逊流域中部的一些树木可能已经有 980 岁了，因此被认为是“古老生长”的森林可能仍接近平衡就像长寿的树木在火灾后成熟一样。火还会产生木炭形式的土壤热原碳（PyC），这种木炭存在于黑土考古遗址和亚马逊流域远离人类居住证据的高地土壤中。土壤 PyC 提高了营养贫乏土壤的土壤肥力，并且具有抗分解性，可能提高了整个亚马逊地区的土壤肥力。因此，前现代火和土壤 PyC 是了解亚马逊森林当前功能的两个重要因素。我们将确定亚马逊流域“古老”永久林地块过去的火和土壤 PyC 肥力效应后的再生是否有助于观察到的碳汇。我们开发了一个全流域的地面样地网络，而且由于使用这些方法测量森林的方法甚至在各个国家都是完全标准化的，因此它们提供了一个绝佳的机会来测量亚马逊森林对历史火灾和土壤 PyC 的响应在亚马逊流域的永久森林地块中，我们的目标是：1) 确定“自上次火灾以来的时间”的空间模式； 2) 确定土壤 PyC 储量，以及这些储量如何受到气候、土壤条件和火灾强度的影响；3) 使用 (1) 和 (2) 的结果，确定地上热带森林树木的生产力和碳增益的空间模式是否亚马逊地区与历史火灾干扰和土壤 PyC 作为土壤肥力增强剂的再生一致。我们的研究将提高对亚马逊地区长期森林地块（与用于估计当前碳汇的相同地块）火灾模式的了解。我们将提供以下方面的首次量化：土壤 PyC 储量、土壤 PyC 储量的全流域环境驱动因素，以及土壤 PyC 水平较高的地方土壤肥力是否较高。这将是首次大规模测试，检验森林生产力、结构和碳增加是否可归因于历史火灾和土壤 PyC 肥力效应的再生。结果对于保护规划、估计碳汇的寿命以及减少森林砍伐和退化造成的排放（REDD+）等政策至关重要。

项目成果

Drier tropical forests are susceptible to functional changes in response to a long-term drought

• DOI: 10.1111/ele.13243
• 发表时间: 2019-05-01
• 期刊: ECOLOGY LETTERS
• 影响因子: 8.8
• 作者: Aguirre-Gutierrez, Jesus;Oliveras, Imma;Malhi, Yadvinder
• 通讯作者: Malhi, Yadvinder

Climate defined but not soil-restricted: the distribution of a Neotropical tree through space and time

• DOI: 10.1007/s11104-021-05202-6
• 发表时间: 2021-11
• 期刊: Plant and Soil
• 影响因子: 4.9
• 作者: F. Alvarez;P. Morandi;B. H. Marimon‐Junior;Reginal Exavier;Igor Araújo;Lucas H. Mariano;A. Muller;T. Feldpausch;B. Marimon

Assessing MODIS Vegetation Continuous Fields tree cover product (collection 6): performance and applicability in tropical forests and savannas

评估 MODIS Vegetation Continuous Fields 树木覆盖产品（集合 6）：热带森林和稀树草原的性能和适用性

• DOI: 10.5194/bg-2020-460
• 发表时间: 2021
• 作者: Adzhar R

Evolutionary heritage influences Amazon tree ecology.

• DOI: 10.1098/rspb.2016.1587
• 发表时间: 2016-12-14
• 期刊: Proceedings. Biological sciences
• 作者: Coelho de Souza F;Dexter KG;Phillips OL;Brienen RJ;Chave J;Galbraith DR;Lopez Gonzalez G;Monteagudo Mendoza A;Pennington RT;Poorter L;Alexiades M;Álvarez-Dávila E;Andrade A;Aragão LE;Araujo-Murakami A;Arets EJ;Aymard C GA;Baraloto C;Barroso JG;Bonal D;Boot RG;Camargo JL;Comiskey JA;Valverde FC;de Camargo PB;Di Fiore A;Elias F;Erwin TL;Feldpausch TR;Ferreira L;Fyllas NM;Gloor E;Herault B;Herrera R;Higuchi N;Honorio Coronado EN;Killeen TJ;Laurance WF;Laurance S;Lloyd J;Lovejoy TE;Malhi Y;Maracahipes L;Marimon BS;Marimon-Junior BH;Mendoza C;Morandi P;Neill DA;Vargas PN;Oliveira EA;Lenza E;Palacios WA;Peñuela-Mora MC;Pipoly JJ 3rd;Pitman NC;Prieto A;Quesada CA;Ramirez-Angulo H;Rudas A;Ruokolainen K;Salomão RP;Silveira M;Stropp J;Ter Steege H;Thomas-Caesar R;van der Hout P;van der Heijden GM;van der Meer PJ;Vasquez RV;Vieira SA;Vilanova E;Vos VA;Wang O;Young KR;Zagt RJ;Baker TR
• 通讯作者: Baker TR

Representation of disturbance in the Joint UK Land Environment Simulator Vn4.8 (JULES)

• DOI: 10.5194/gmd-2018-149
• 发表时间: 2018-07
• 期刊: Geoscientific Model Development Discussions
• 作者: Chantelle Burton;R. Betts;M. Cardoso;T. Feldpausch;A. Harper;C. Jones;D. Kelley;E. Robertson;A. Wiltshire