Fire regime in a conservation reserve in Chihuahua, Mexico

Fire regime characteristics were reconstructed from fire-scarred trees in the Tutuaca reserve, a newly resignated protected area in the Sierra Madre Occidental of western Chihuahua. The reserve was reated to protect thickbilled parrot nesting habitat (large snags) and a relict forest of Chihuahua spruce (Picea Chihuahuana Martínez). We collected fire-scarred samples from conifers (Pinus ayacahuite Ehrenb., Pinus durangensis Martínez, and Pseudotsuga menziesii (Mirb.) Franco) in three 25-ha sites arrayed at different watershed positions, from a low site adjacent to the spruce trees up to the watershed divide. Fire analysis periods began in 1702, 1704, or 1761 and continued through the final fire in 1955 (two sites) or 1995. All sites had frequent fire regimes (mean fire interval (MFI) 3.9–5.2 years; MFI for years in which 25% or more of the samples were scarred: 6.9–8.4 years). Almost all fires occurred before cambial growth began or early during the season of cambial growth. Fire years were significantly dry, and the years immediately preceding fire were significantly wet. After 1955, no further fires occurred at two of the three study sites, a pattern similar to that observed elsewhere in northern Mexico. The third site had fires in 1987 and 1995. The extended firefree period in portions of the Tutuaca landscape may result in fuel accumulation and eventually in severe wildfire. For effective conservation of fire-susceptible habitat features, managers should seek to incorporate surface fire as a management tool

Analysis of challenges, costs, and governance alternative for peatland restoration in Central Kalimantan, Indonesia

Restoration of degraded tropical peatland is considered to be one of the most cost-efficient measures in reducing greenhouse gas emissions and conserving biodiversity. Although benefits of restoration are often expected to substantially exceed the costs, most restoration projects are being carried out without clear cost analyses. This study provides empirical assessments of challenges and costs of the four peatland restoration projects managed by different proponents in Central Kalimantan, Indonesia based on key informant interviews, a follow-up survey and document analyses. We also reviewed existing policy contexts that can address some of the challenges to propose a governance alternative to sustain peatland restoration efforts. We found that many ecological challenges of peatland restoration projects were created by drainage canals leaving the peat to be dry and fire prone. Peatland degradation has been exacerbated by human activities and human-caused fires, and restoration efforts have faced many challenges due to lack of secure funding and complexity of governing the project implementation. The key informants we interviewed easily recognized direct costs for implementing restoration activities, but often left out indirect costs of addressing social challenges, such as expenses to engage local communities, in their assessments of the costs. Although our accounting is far from exhaustive, we found that indirect costs can add up to half of the total cost of peatland restoration projects. Current funding mechanisms for these projects mostly rely on international donors and private sectors, which make the long-term sustainability of the projects questionable. We argue that hybrid governance for a green business model, such as restoration and ecosystem services enterprises, with active participation from the public sector should be mainstreamed. The accounting framework developed in this study can be applied in other projects and should be further revised to systematically assess cost-effectiveness of restoration interventions

Dendrochronology-based fire history of Pinus nigra forests in Mount Taygetos, Southern Greece

In the past few decades there is an increasing trend of both fire activity and area burned in many regions of the world. Moreover, there is a worldwide concern regarding the increasing presence of crown fires in forest types that were historically prone to surface fires. Among the recently affected mountainous forest ecosystems are those of Pinus nigra, an ecologically and economically important species that is widely distributed around the Mediterranean Basin. Mount Taygetos, a mountainous landscape in Peloponnese, Greece, that was severely burned in 2007, was selected to carry out the first landscape-scale fire history reconstruction in P. nigra of the eastern Mediterranean. The aims of the study were to investigate whether fire-regime attributes can be reconstructed from fire-scarred trees and also to examine the consistency of fire occurrence and spatial extent through time within the area selected. Partial cross-sections were sampled within the perimeters of the more recent known large fires in the region, those of 2007 and 1998. The overall mean fire interval between 1845 and 2007 was 4.9. years, while for the larger fires this time window was 16.2. years. Even at the individual-sample scale, with the sample mean fire interval equaling 29.5. years, the fire frequency still falls within the range of the ''predictable stand-thinning fire'' regime. The majority of fire scars recorded were dated to the warm and dry season of summer to fall. During the last 165. years of fire reconstruction, neither fire frequency nor percentage of trees scarred by fires varied significantly. Nevertheless, the size of the area burned as well as the type of fire seem to have changed, with the 2007 event being the most extended crown fire encountered so far. Our study has provided additional evidence that P. nigra is indeed a fire-resistant tree species provided that it is exposed to surface fires, even if they are recurrently occurring. Shifts from this pattern may lead to local extirpation of the species, as in the case of severe and extended crown fires. © 2013 Elsevier B.V

Increasing extremes of heat and drought associated with recent severe wildfires in southern Greece

Mountains of the northern Mediterranean basin face two major threats under global change. Aridity and available fuel are both expected to increase because of climatic and land-use changes, increasing fire danger. There may already be signs of such effects in the case of the Pinus nigra and Abies cephalonica forests on Mt. Taygetos (southern Greece). We reconstructed climate (mid- to late-fire-season drought) using tree-rings for the last 150 years and compared it with the mountain's fire history reconstructed from P. nigra fire scars. Seven, out of the ten, large fires Mt. Taygetos experienced were associated with below-normal precipitation (P) or above-normal maximum temperature (T max). The largest fires occurred in late summer of 1879, 1944, 1998, and 2007. However, only the recent fires (1998 and 2007) had both low P and high T max, also confirmed from long-term meteorological data. The synergy between climate and fuel availability may explain the very high intensity of 1998 and 2007 fires that burned mostly as stand-replacing crown fires. The other two large fire events (1879 and 1944) most likely occurred under reduced availability in burning fuel and were related to above-normal T max. Our findings are among the first based on long-term and site-specific empirical data to support the prediction that Mediterranean mountainous areas will face a very large threat from wildfires in the twenty-first century, if socioeconomic changes leading to land abandonment and thus burning fuel accumulation are combined with the drought intensification projected for the region under global warming. © 2013 Springer-Verlag Berlin Heidelberg

Tree growth-climate relationships in a forest-plot network on Mediterranean mountains

In this study we analysed a novel tree-growth dataset, inferred from annual ring-width measurements, of 7 forest tree species from 12 mountain regions in Greece, in order to identify tree growth – climate relationships. The tree species of interest were: Abies cephalonica, Abies borisii-regis, Picea abies, Pinus nigra, Pinus sylvestris, Fagus sylvatica and Quercus frainetto growing across a gradient of climate conditions with mean annual temperature ranging from 5.7 to 12.6 °C and total annual precipitation from 500 to 950 mm. In total, 344 tree cores (one per tree) were analysed across a network of 20 study sites. We found that water availability during the summer period (May–August) was a strong predictor of interannual variation in tree growth for all study species. Across species and sites, annual tree growth was positively related to summer season precipitation (PSP). The responsiveness of annual growth to PSP was tightly related to species and site specific measurements of instantaneous photosynthetic water use efficiency (WUE), suggesting that the growth of species with efficient water use is more responsive to variations in precipitation during the dry months of the year. Our findings support the importance of water availability for the growth of mountainous Mediterranean tree species and highlight that future reductions in precipitation are likely to lead to reduced tree-growth under climate change conditions. © 201

Indigenous fire management and cross-scale fire-climate relationships in the Southwest United States from 1500 to 1900 CE

Prior research suggests that Indigenous fire management buffers climate influences on wildfires, but it is unclear whether these benefits accrue across geographic scales. We use a network of 4824 fire-scarred trees in Southwest United States dry forests to analyze up to 400 years of fire-climate relationships at local, landscape, and regional scales for traditional territories of three different Indigenous cultures. Comparison of fire-year and prior climate conditions for periods of intensive cultural use and less-intensive use indicates that Indigenous fire management weakened fire-climate relationships at local and landscape scales. This effect did not scale up across the entire region because land use was spatially and temporally heterogeneous at that scale. Restoring or emulating Indigenous fire practices could buffer climate impacts at local scales but would need to be repeatedly implemented at broad scales for broader regional benefits.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]