Forest thinning and prescribed burning treatments reduce wildfire severity and buffer the impacts of severe fire weather

Fire Ecology, Год журнала: 2024, Номер 20(1)

Опубликована: Фев. 7, 2024

Abstract Background The capacity of forest fuel treatments to moderate the behavior and severity subsequent wildfires depends on weather conditions at time burning. However, in-depth evaluations how perform are limited because encounters between areas with extensive pre-fire data rare. Here, we took advantage a 1200-ha randomized replicated experiment that burned almost entirely in wildfire under wide range conditions. We compared impacts four fire severity, including two thin-only, thin-burn, burn-only, an untreated control. evaluated metrics—tree mortality, average bole char height, percent crown volume consumed (PCVC), affected (PCVA)—and leveraged from surface canopy fuels better understand mechanisms driving differences among they changed weather. Results found strong mitigating effects tree despite 20 years having elapsed since mechanical thinning 10 second entry prescribed fire. thin-burn treatment resulted lowest across all metrics control highest. All were positively associated loads, exception PCVC (a metric related behavior) was not load. which most effective varied metrics. Fuel benefit maximized intermediate burning index values for high PCVA, height PCVC. Conclusions conclude reducing bulk density via can help limit or more. is necessary scorching total mortality. Further, while effectiveness may decline severe it (bole charring torching). Our results provide evidence use mitigate resulting even extreme

Язык: Английский

---

Reimagine fire science for the anthropocene

PNAS Nexus, Год журнала: 2022, Номер 1(3)

Опубликована: Июль 1, 2022

Fire is an integral component of ecosystems globally and a tool that humans have harnessed for millennia. Altered fire regimes are fundamental cause consequence global change, impacting people the biophysical systems on which they depend. As part newly emerging Anthropocene, marked by human-caused climate change radical changes to ecosystems, danger increasing, fires having increasingly devastating impacts human health, infrastructure, ecosystem services. Increasing vexing problem requires deep transdisciplinary, trans-sector, inclusive partnerships address. Here, we outline barriers opportunities in next generation science provide guidance investment future research. We synthesize insights needed better address long-standing challenges innovation across disciplines (i) promote coordinated research efforts; (ii) embrace different ways knowing knowledge generation; (iii) exploration science; (iv) capitalize "firehose" data societal benefit; (v) integrate natural into models multiple scales. thus at critical transitional moment. need shift from observation modeled representations varying components climate, people, vegetation, more integrative predictive approaches support pathways toward mitigating adapting our flammable world, including utilization safety benefit. Only through overcoming institutional silos accessing diverse communities can effectively undertake improves outcomes fiery future.

Язык: Английский

---

Integrating plant physiology into simulation of fire behavior and effects

New Phytologist, Год журнала: 2023, Номер 238(3), С. 952 - 970

Опубликована: Янв. 25, 2023

Wildfires are a global crisis, but current fire models fail to capture vegetation response changing climate. With drought and elevated temperature increasing the importance of dynamics behavior, advent next generation capable capturing increasingly complex physical processes, we provide renewed focus on representation woody in models. Currently, most advanced representations behavior biophysical effects found distinct classes fine-scale do not variation live fuel (i.e. living plant) properties. We demonstrate that plant water carbon dynamics, which influence combustion heat transfer into often dictate survival, mechanistic linkage between effects. Our conceptual framework linking remotely sensed estimates could be critical first step toward improving fidelity coarse scale now relied upon for forecasting. This process-based approach will essential physiological responses warming conditions, strengthening science needed guide managers an uncertain future.

Язык: Английский

---

Methods to assess fire-induced tree mortality: review of fire behaviour proxy and real fire experiments

International Journal of Wildland Fire, Год журнала: 2025, Номер 34(1)

Опубликована: Янв. 7, 2025

Background The increased interest in why and how trees die from fire has led to several syntheses of the potential mechanisms fire-induced tree mortality. However, these generally neglect consider experimental methods used simulate behaviour conditions. Aims To describe, evaluate appropriateness provide a historical timeline different approaches that have been mortality studies. Methods We conducted review actual proxy further our understanding Key results Most studies assess laboratory settings make use proxies instead real fires cut branches live plants. Implications Further research should using plants paired combustion landscape experiments.

Язык: Английский

---

Stable isotope analysis in tree rings of conifer species relevant to fire history study

Philosophical Transactions of the Royal Society B Biological Sciences, Год журнала: 2025, Номер 380(1924)

Опубликована: Апрель 1, 2025

Smoke and particulate matter released from forest fires, affecting the photosynthetic rate stomatal conductance, may change isotope composition in tree rings. Therefore, analysis of tree-ring isotopes could be a promising approach to monitor fires. We hypothesized that fires influence abundance carbon (δ 13 C), oxygen 18 O) nitrogen 15 N) radial growth rings conifers through their impact on physiological processes. collected wood cores four coniferous species northern southern China. The these samples was analysed shed light correlation between fire occurrence isotopes. found led an increase δ C but decrease N whole wood, while significant increases above 0.5‰ 0.2 O α-cellulose were observed. Meteorological factors including precipitation relative humidity influenced abundance. Besides, inhibited conifer trees, particularly Cryptomeria fortunei . Our results suggest variations play essential role as indicator occurrence, providing additional insights into study history. This article is part theme issue ‘Novel regimes under climate changes human influences: impacts, ecosystem responses feedbacks’.

Язык: Английский

---

Ancient trees and modern wildfires: Declining resilience to wildfire in the highly fire-adapted giant sequoia

Forest Ecology and Management, Год журнала: 2022, Номер 511, С. 120110 - 120110

Опубликована: Март 9, 2022

Ancient giant sequoias Sequoiadendron giganteum (Lindl.) J. Buchholz are highly valued trees with limited distribution. They the most massive on earth, and they have exceptional longevity (>3,000 years). Given their extraordinary resilience to wildfire, insects, disease, managers hoped would be resistant anthropogenic change. However, warming climate fire exclusion-caused fuel build-up has dramatically increased amount of high-intensity wildfire in sequoia groves since 2015. To better understand recent effects large, legacy trees, we surveyed high- moderate-severity areas that burned three wildfires between 2015 2017. Within classified as high severity via remote sensing, ∼84% 162 large (>1.2 m diameter at breast height) were killed; moderate severity, ∼28% 239 killed. These rates varied fires but overall lower end mortality range been documented Sierra Nevada mixed-conifer forests. Across all areas, found was linked presence significant prior damage tree bole (i.e., scars or "catfaces"), crown ratios, elevations. At Black Mountain Grove, tracked through time total best predictors by year three, where sustained up ∼ 85% before succumbing injury. There, 52 204 dead one-year postfire, 71 three. Overall, these caused concerning levels ancient yet impact 2017 dwarfed comparison more 2020 Castle Fire, 2021 Windy Fire KNP Complex Fire. With push increase forest treatments reduce catastrophic risk across Western U.S., immediate triage protect irreplaceable resources is needed activity rapidly increases. Our study suggests prioritizing management action creates unburned groves, maintains reduction benefits accrued past wildfires, will critical avoid continued losses exceptional, old growth

Язык: Английский

---

Terrestrial carbon dynamics in an era of increasing wildfire

Nature Climate Change, Год журнала: 2023, Номер 13(12), С. 1306 - 1316

Опубликована: Дек. 1, 2023

Язык: Английский

---

Death from hunger or thirst? Phloem death, rather than xylem hydraulic failure, as a driver of fire‐induced conifer mortality

New Phytologist, Год журнала: 2022, Номер 237(4), С. 1154 - 1163

Опубликована: Сен. 2, 2022

Summary Disruption of photosynthesis and carbon transport due to damage the tree crown stem cambial cells, respectively, can cause mortality. It has recently been proposed that fire‐induced dysfunction xylem plays an important role in Here, we simultaneously tested impact a lethal fire dose on nonstructural carbohydrates (NSCs) hydraulics Pinus ponderosa saplings. Saplings were burned with known dose. Nonstructural assessed needles, main stems, roots whole plants, hydraulic conductivity was measured stems up 29 d postfire. Photosynthesis plant NSCs declined Additionally, all saplings showed 100% phloem/cambium necrosis, had reduced compared unburned defoliated We further show that, contrary patterns observed NSCs, water unchanged by there no evidence deformation experienced heat from fire. conclude phloem cambium mortality, not failure, probably causes death these These findings advance our understanding physiological response injuries conifer trees.

Язык: Английский

---

Nonstructural carbohydrates explain post-fire tree mortality and recovery patterns

Tree Physiology, Год журнала: 2023, Номер 44(2)

Опубликована: Дек. 20, 2023

Abstract Trees use nonstructural carbohydrates (NSCs) to support many functions, including recovery from disturbances. However, NSC’s importance for following fire and whether NSC depletion contributes post-fire delayed mortality are largely unknown. We investigated how affects NSCs based on fire-caused injury a prescribed in young Pinus ponderosa (Lawson & C. Lawson) stand. assessed crown (needle scorch bud kill) measured of needles inner bark (i.e., secondary phloem) branches main stems trees subject at an adjacent unburned site. pre-fire six timesteps (4 days–16 months). While all initially survived the fire, concentrations declined quickly burned relative controls over same period. This decline was strongest that eventually died, but those recovered levels within 14 months post-fire. Two post-fire, relationship between stem strongly negative (Adj-R2 = 0.83). Our results tree survival suggest is part related reduced photosynthetic leaf area subsequently limits carbohydrate availability maintaining function. Crown commonly metric tree-level severity often linked outcome or mortality). Thus, our finding may be mechanistic link will help improve models forest recovery.

Язык: Английский

---

Boreal forest tree growth and sap flow after a low-severity wildfire

Agricultural and Forest Meteorology, Год журнала: 2024, Номер 347, С. 109899 - 109899

Опубликована: Янв. 25, 2024

Boreal forests are exposed to larger and more frequent fires due climate change, with significant consequences for their carbon water balances. Low-severity (trees charred but surviving) the most common fire regime in Eurasian boreal forest, we still lack understanding on how they impact tree functioning. This study focused dynamics of transpiration stem growth Pinus sylvestris central Sweden after a large wildfire 2018. We compared stand impacted by low-severity (LM) an unburnt (UM), over three years following (2020–2022). found that was average lower variable within at LM UM. also had consistently UM, resulting accumulated site second fourth year fire. Our results highlight complex effects cycling, both direct (damage xylem roots) indirect impacts (due loss understory vegetation changes soil properties). Trees affected exhibited reduced resilience shortages. Considering expected increase frequency droughts forest higher northern latitudes, such may put additional pressure forest.

Язык: Английский

---