Fire Ecology

An assessment of the proximate causes, effects and factors contributing to fire prevalence was conducted in three districts covered by miombo woodlands in Eastern Tanzania. Three miombo woodlands under different management regimes and governance structures (central government forest reserve, local government forest reserve and village land forest) each were investigated in Handeni, Kilosa and Kilwa districts. Data were collected from three villages selected in each District through household surveys, Participatory Rural Appraisal (PRA), interviews of key informants and field observations. The analysis of data involved content analysis for documentary materials, descriptive statistical analysis for household surveys and Chi square was used to test whether there were differences in responses of local communities across forest management regimes. Results indicate that the major five human activities contributing to fire prevalence across the miombo woodlands include farm preparation (34.1%), hunting (28.5%), arson (21.5%), livestock grazing (9.3%) and charcoal making (0.7%). The causes were fairly the same across forest management regimes. August, September and October were the peak fire months and they were not influenced by different management regimes but by geographical locations within Eastern Tanzania. Results further show that fires in miombo woodlands usually start inside the woodland (67.2%), around residential area (22.9%) and from farms (9.9%). The origin of fire inside the woodland becomes more serious because it combines the hunting, arson, livestock grazing and charcoal making which are usually done inside the woodland. Chi-square test indicates significant difference on origin of fires across the forest management regimes (χ² = 13.341 and p = 0.031). The local communities acknowledged fires having both positive and negative effects and these effects were the same across the management regimes. Further, across the surveyed villages, strong social ties existed between fires and the daily life of local communities. Poverty, ignorance, weak law enforcement and climatic factors were identified as underlying factors contributing to fire prevalence. Fire incidences are predicted to increase given the increasing climate change. Potential strategies to reduce fires incidence identified were awareness creation, law enforcement, making fire breaks, introduction of alternative income generating activities, and improving agriculture practises. Furthermore, the use of prescribed burning to reduce effects of late fires and developing fire management plans to enhance miombo woodland management are among the strategies worth consideration by the local communities.

Remote mountainous regions are among the Earth’s last remaining wild spots, hosting rare ecosystems and rich biodiversity. Because of access difficulties and low population density, baseline information about natural and human-induced disturbances in these regions is often limited or nonexistent. Landsat time series offer invaluable opportunities to reconstruct past land cover changes. However, the applicability of this approach strongly depends on the availability of good quality, cloud-free images, acquired at a regular time interval, which in mountainous regions are often difficult to find. The present study analyzed burn scar detection capabilities of 11 widely used spectral indices (SI) at 1 to 5 years after fire events in four dominant vegetation groups in a mountainous region of northwest Yunnan, China. To evaluate their performances, we used M-statistic as a burned-unburned class separability index, and we adapted an existing metric to quantify the SI residual burn signal at...

This article analyzes the dynamic of forest fires in Costa Rica from a historical perspective. Its hypothesis is that changes in the productive structure as well as Costa Rica’s agricultural policy between 1950 and 1980 influenced on the current fire regimes. To explain this process uses theoretical and methodological references from Environmental History and Ecology of Fire. This study is based on information obtained in agricultural magazines, newspapers and other primary sources located the Biblioteca Nacional, Ministerio de Agricultura y Ganadería, Programa Nacional de Manejo del Fuego and Instituto de Desarrollo Rural. It also has a oral history part through personal and group interviews, field trips and workshops with students, farmers and government officials in the Parque Nacional Barra Honda and Parque Nacional Santa Rosa, Guanacaste, Costa Rica.

Rising temperatures are expected to increase wildfire activity in many regions of the world. Over the last 60 years in Mongolia, mean annual temperatures have increased ~2°C and the recorded frequency and spatial extent of forest and steppe fires have increased. Few long records of fire history exist to place these recent changes in a historical perspective. The purpose of this paper is to report on fire history research from three sites in central Mongolia and to highlight the potential of this region as a test case for understanding the relationships between climate change, fire and land use. We collected partial cross-sections from fire-scarred trees and stumps at each site using a targeted sampling approach. All three sites had long histories of fire ranging from 280 to 450 years. Mean Weibull fire return intervals varied from 7 to 16 years. Fire scars at one protected-area site were nearly absent after 1760, likely owing to changes in land use. There is limited synchrony in fir...

The general objective of this study is to analyse the Aguada society’s abandonment of the Ambato Valley and the evidence related to this process, focusing on palaeoenvironmental factors. This question was associated with fire regimes in the study area. Since several of the archaeological contexts from the area showed that multiple sites had been affected by fires, (Martínez 2, Piedras Blancas, and Iglesia de Los Indios), microcharcoal evidence was used to evaluate, analyse, and identify past fire sequences and fire regimes in pursuit of a link between fires and abandonment. The specific subject of the analysis was the frequency and sequences of the fires, and new techniques and methods based on earlier studies were developed in order to achieve this research objective. The data collected shows that the ecosystem in the Ambato Valley was frequently impacted by recurrent fires since at least 4,500 years B.P., based upon the oldest AMS radiocarbon dates obtained. This study argues that fires have been a recurrent part of this environment and landscape and an integral part of the surroundings of the people inhabiting the area, the Aguada society. There are certain areas which seem to have been struck by more intense and severe fires than others, with some periods also showing stronger fire signals with abundant microcharcoal remains, indicating a the presence of fires that were more intense, frequent, and severe. These wildfires are assumed to have been both natural and cultural in origin, created by both natural events such as lighting strikes as well as by human action.

ABSTRACT A new accessible and easy method for studying past fire events using ‘dry sediments’ is presented. The method was developed for analysing samples from 17 locations in the Ambato Valley, NW Argentina, to study fire regimes in the area. Based on earlier researchers’ methods, guidelines to use microcharcoals in ‘dry’ sediments as a palaeoenvironmental proxy are provided. The procedures outlined include sampling/extraction in the field, preparations of the samples, laboratory analysis and quantification of the samples. The new approach was useful to meet the objectives and answer the questions initially proposed in our research about past fire regimes affecting the past Aguada society.

Fire is an integral part of almost all ecosystems on Earth and an important factor in shaping our surroundings. Based on pedoanthracological research, we have reconstructed part of the past landscape and the paleoenvironmental context in an area that was populated by the Aguada Culture around 1000 CE. Pedoanthracology gives us the opportunity to recreate past fire events, including both natural fires such as wildland fires and fire produced by human activity. To understand past fire regimes and to be able to analyze the past archaeological landscape and the paleoenvironmental scenario, we focused our study on the past fire events in the Balcosna Valley, Catamarca Province, North-western Argentina, using microcharcoals extracted from sediments sampled from eight different locations in the area with a sediment corer. In total, 91 samples from the eight stations were analyzed, indicating that the Balcosna Valley was frequently affected by regular fire events in the past. These events, in turn, must have affected the people living in the area in various ways, thus creating a particular interaction between humans and fire.

Reseñamos en este artículo las principales líneas de investigación llevadas a cabo en los últimos 15 años de investigaciones en el valle de Ambato (Catamarca, Argentina). Presentamos asimismo algunas de las discusiones y aportes al proyecto general surgidos a lo largo de estos años desde la arqueoantracología y la pedoantracología. Estas herramientas han permitido una aproximación a dos vínculos particulares que estamos actualmente repensando: humanos-plantas y humanos-climas en el seno de Aguada de Ambato.

O objetivo desta revisão é apontar alguns campos de investigação atuais em ecologia do fogo e os impactos do fogo na vegetação da Amazônia. A ocorrência de incêndios na Amazônia úmida parecia uma contradição até bem pouco tempo. O fogo é independente da existência de humanos e o mesmo sempre atuou na estruturação da vegetação. Entretanto hoje, com as anomalias e as mudanças climáticas globais, os regimes de fogo têm se alterado em todo o mundo e também na Amazônia. O fogo impacta de forma diferente, dependendo da região amazônica em que ocorre, e isso pode estar relacionado ao solo, bem como à morfologia e idade das plantas. Muitas espécies podem responder de forma positiva, possuindo mecanismos de sobrevivência ou rebrote pós-fogo. É necessária uma melhor compreensão de como as plantas da Amazônia respondem ao impacto do fogo, no sentido de entender o quanto a floresta tropical Amazônica ainda é de fato imune aos incêndios, e de que modo o fogo poderia contribuir com a chamada “sav...

Despite the fire is the least studied impact among the current disorders affecting tropical American palms, the Arecaceae family is ideal for studies of resilience and impacts. The present study was the first to quantify and describe the postfire palm resprouting in the Amazon rainforest. We tested a set of juveniles and mature individuals of 10 palm species, to assess which morphological characteristics are related to postfire mortality or resprouting, so the aim of this study was to 1) record the possible response strategies of understory palms to fire disturbance; 2) compare the postfire responses between undergroundstemmed and aerial stem species, and 3) compare the postfire responses between species with and without clonal ability. For all species of palm trees subjected to this experiment, the fire was not capable of eliminating all individuals, and after ~140 days after fire, we found that aerial stems had more basal sprouts than underground stems. Underground-stemmed species...

INTRODUÇÃO: As fitofisionomias da Amazônia estão ameaçadas por diversos impactos e os incêndios florestais atualmente são considerados como principais modificadores da estrutura e diversidade das florestas, principalmente do sub-bosque. Indicadores de severidade são utilizados para melhor descrever o impacto dos incêndios e para posterior modelagem da mortalidade. O destino da planta após o impacto do incêndio florestal é consequência das injúrias provocadas pelo calor à planta e o resultado é binário: sobrevivência ou morte. Este destino tem direta relação com a morfologia, fisiologia e com o comportamento do fogo. Prever a mortalidade pós-fogo pode ser difícil, pois a mesma é resultado de múltiplos processos complexos atuando conjuntamente: i) queima da copa; ii) queima do caule e iii) aquecimento da raiz. Queima da copa é causada pela energia de calor da fumaça convectiva e da radiação, necrosando galhos, folhas e gemas, e é mensurada tanto em altura quanto em proporção. A queima...