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的碳。这些森林，假设大多是'老增长'和无火表现出显着的特点，他们正在获得相当于一辆小汽车的质量，每年每公顷森林地上生物量（0.89毫克/公顷/年）。这些收益归因于大气CO2的增加，这对树木生长有施肥作用。然而，在这些“古老的”森林火灾可能比预期的更近（在过去的几个世纪），从火再生长与土壤木炭，这有一个肥力效应，可能会与CO2施肥共同促进观察到的生物量增加，在这些显然成熟的森林。目前对这些增加的驱动因素的理解受到以下因素的限制：㈠用于监测变化的地块的火灾历史未知，㈡缺乏关于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。我们对土壤木炭的放射性碳定年火的初步分析表明，即使是最潮湿的亚马逊雨林也被烧毁，被认为是“古老”的森林在过去几个世纪内被烧毁，70%的地块（n=70）含有可见的土壤木炭碎片。在大约450年前欧洲人殖民化之后，美洲原住民在人口崩溃之前的周期性干燥气候和火灾使用可能导致火灾频率高于目前观察到的频率。在被认为“未受干扰”的森林中，这些火灾和最近的火灾可能仍在发生森林再生，例如，在亚马逊河流域中部，有些树木可能生长到980岁，因此，随着长寿树木在火灾后成熟，被认为是“古老生长”的森林可能仍在接近平衡。火还产生土壤热解碳（PyC），作为木炭，在考古遗址中发现的terra preta土壤和亚马逊河流域的高地土壤中远离人类定居的证据。土壤PyC增加了土壤肥力，否则养分贫乏的土壤，并耐分解，可能增加了整个亚马逊的土壤肥力。因此，前现代火和土壤热解碳是了解亚马逊森林目前如何运作的两个重要组成部分。我们将确定在亚马逊河流域的“古老”永久森林地块中，过去的火和土壤热解碳肥力影响后的再生长是否有助于观察到的碳汇。我们已经开发了一个全流域的地面样本网络，因为测量森林的方法是完全标准化的，甚至在国家之间，它们代表了一个很好的机会来测量亚马逊森林对历史火灾和土壤PyC的反应。在整个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库存，以及这些库存如何受到气候，土壤条件和火灾强度的影响; 3）使用（1）和（2）的结果，确定亚马逊河流域热带森林地上树木的生产力和碳收益的空间格局是否与历史火灾干扰的再生一致我们的研究将提高对亚马逊长期森林地块（用于估计当前碳汇的相同地块）火灾模式的理解。我们将提供第一个量化：土壤PyC库存，土壤PyC库存的全流域环境驱动因素，以及土壤PyC水平较高的土壤肥力是否更高。这将是第一次大规模测试森林生产力，结构和碳的增加是否可以归因于历史火灾和土壤PyC肥力效应的再生长。这些结果对于保护规划、估计碳汇的寿命以及减少森林砍伐和退化所致排放（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

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

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

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