Managing burned landscapes: evaluating future management strategies for resilient forests under a warming climate

2014 ◽  
Vol 23 (7) ◽  
pp. 915 ◽  
Author(s):  
K. L. Shive ◽  
P. Z. Fulé ◽  
C. H. Sieg ◽  
B. A. Strom ◽  
M. E. Hunter
Keyword(s):  
Climate Change ◽  
Ponderosa Pine ◽  
Prescribed Burning ◽  
Fire Severity ◽  
Management Strategies ◽  
Basal Area ◽  
Forest Growth ◽  
Climate Change Effects ◽  
Ponderosa Pine Forests ◽  
And Shifts

Climate change effects on forested ecosystems worldwide include increases in drought-related mortality, changes to disturbance regimes and shifts in species distributions. Such climate-induced changes will alter the outcomes of current management strategies, complicating the selection of appropriate strategies to promote forest resilience. We modelled forest growth in ponderosa pine forests that burned in Arizona’s 2002 Rodeo–Chediski Fire using the Forest Vegetation Simulator Climate Extension, where initial stand structures were defined by pre-fire treatment and fire severity. Under extreme climate change, existing forests persisted for several decades, but shifted towards pinyon–juniper woodlands by 2104. Under milder scenarios, pine persisted with reduced growth. Prescribed burning at 10- and 20-year intervals resulted in basal areas within the historical range of variability (HRV) in low-severity sites that were initially dominated by smaller diameter trees; but in sites initially dominated by larger trees, the range was consistently exceeded. For high-severity sites, prescribed fire was too frequent to reach the HRV’s minimum basal area. Alternatively, for all stands under milder scenarios, uneven-aged management resulted in basal areas within the HRV because of its inherent flexibility to manipulate forest structures. These results emphasise the importance of flexible approaches to management in a changing climate.

scholarly journals Lowering Stand Density Enhances Resiliency of Ponderosa Pine Forests to Disturbances and Climate Change

2019 ◽  
Vol 65 (4) ◽  
pp. 496-507 ◽  
Author(s):  
Jianwei Zhang ◽  
Kaelyn A Finley ◽  
Nels G Johnson ◽  
Martin W Ritchie
Keyword(s):  
Climate Change ◽  
Tree Growth ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Ring Width ◽  
Basal Area ◽  
Stand Density ◽  
Site Quality ◽  
Climate Trends ◽  
Ponderosa Pine Forests

AbstractStand density affects not only structure and growth, but also the health of forests and, subsequently, the functions of forest ecosystems. Here, we integrated dendrochronology and repeated inventories for ponderosa pine research plots to determine whether long-term growth and mortality responded to climate trends and how varying stand density influenced the responses. The plots were established prior to 1975 on existing stands throughout northern California. Although annual temperature increased consistently for the last 65 years, ring-width indices produced by eliminating age and thinning effects failed to detect radial trend regardless of site quality. However, interannual variation for the indices was substantial, reflecting a strong influence of climate on tree growth. Plot-level basal area increments were significantly affected by tree mortality. Stand density index explained most variation of mortality. Lowering stand density enhanced remaining tree growth, reduced mortality, and increased stand resiliency to disturbances and climate change. Besides higher climate moisture indices or lower vapor pressure deficits, any treatments that improve tree vigor and reduce stress will have a similar effect to reducing stand density. Although neither biotic disturbances nor abiotic conditions can be controlled, forest managers can manage stand density appropriately to enhance resilience to climate change and disturbances.

Future climate affects management strategies for maintaining forest restoration treatments

2010 ◽  
Vol 19 (7) ◽  
pp. 903 ◽  
Author(s):  
Corinne Diggins ◽  
Peter Z. Fulé ◽  
Jason P. Kaye ◽  
W. Wallace Covington
Keyword(s):  
Climate Change ◽  
Ponderosa Pine ◽  
Forest Restoration ◽  
Prescribed Burning ◽  
Standard Form ◽  
Future Climate ◽  
Fire Season ◽  
Target Range ◽  
Climate Change Effects ◽  
Management Regimes

Forests adapted to frequent-fire regimes are being treated to reduce fuel hazards and restore ecosystem processes. The maintenance of treatment effects under future climates is a critical issue. We modelled forest change under different climate scenarios for 100 years on ponderosa pine landscapes in the south-western USA, comparing management regimes that included prescribed burning, tree cutting, and no-management. We applied the Forest Vegetation Simulator (1) in its standard form, and (2) with modifications of reduced tree growth and increased mortality to simulate the effects of two levels of climate change. Without climate change effects, several management regimes, including the use of frequent burning similar to the historical fire frequency (~5 year), maintained future forest structure within a target range of variability. In contrast, simulations that accounted for climate change effects indicated that burning intervals should be lengthened (~20 year) and future tree thinning should be avoided to minimise forest decline. Although it has been widely predicted that future climate conditions will support more burning (warmer, drier fuels, longer fire season), our modelling suggests that the production of fuels will decline, so there will eventually be a trade-off between increased fire, driven by climate, v. reduced fuel, also driven by climate.

Stand- and landscape-level effects of prescribed burning on two Arizona wildfires

2005 ◽  
Vol 35 (7) ◽  
pp. 1714-1722 ◽  
Author(s):  
Mark A Finney ◽  
Charles W McHugh ◽  
Isaac C Grenfell
Keyword(s):  
Prescribed Fire ◽  
Ponderosa Pine ◽  
Prescribed Burning ◽  
Wildland Fire ◽  
Fire Severity ◽  
Prescribed Burn ◽  
Fire Size ◽  
Ponderosa Pine Forests ◽  
Model Predictions ◽  
Landsat 7

Performance of fuel treatments in modifying behavior and effects of the largest wildfires has rarely been evaluated, because the necessary data on fire movement, treatment characteristics, and fire severity were not obtainable together. Here we analyzed satellite imagery and prescribed fire records from two Arizona wildfires that occurred in 2002, finding that prescribed fire treatments reduced wildfire severity and changed its progress. Prescribed burning in ponderosa pine forests 1–9 years before the Rodeo and Chediski fires reduced fire severity compared with untreated areas, despite the unprecedented 1860-km2 combined wildfire sizes and record drought. Fire severity increased with time since treatment but decreased with unit size and number of repeated prescribed burn treatments. Fire progression captured by Landsat 7 enhanced thematic mapper plus (ETM+) clearly showed the fire circumventing treatment units and protecting areas on their lee side. This evidence is consistent with model predictions that suggest wildland fire size and severity can be mitigated by strategic placement of treatments.

Fire-induced erosion and millennial-scale climate change in northern ponderosa pine forests

Nature ◽  
2004 ◽  
Vol 432 (7013) ◽  
pp. 87-90 ◽  
Author(s):  
Jennifer L. Pierce ◽  
Grant A. Meyer ◽  
A. J. Timothy Jull
Keyword(s):  
Climate Change ◽  
Ponderosa Pine ◽  
Pine Forests ◽  
Ponderosa Pine Forests ◽  
Millennial Scale

scholarly journals How random are predictions of forest growth? The importance of weather variability

2020 ◽  
Author(s):  
Joanna Horemans ◽  
Olga Vindušková ◽  
Gaby Deckmyn
Keyword(s):  
Climate Change ◽  
Uncertainty Analysis ◽  
Climate Models ◽  
Global Climate ◽  
Basal Area ◽  
Random Order ◽  
Forest Growth ◽  
Global Climate Models ◽  
Growth And Yield ◽  
Weather Variability

Quantifying the output uncertainty and tracking down its origins is key to interpreting the results of model studies. We perform such an uncertainty analysis on the predictions of forest growth and yield under climate change. We specifically focus on the effect of the inter-annual climate variability. For that, the climate years in the model input (daily resolution) were randomly shuffled within each 5-year period. In total, 540 simulations (10 parameter sets, 9 climate shuffles, 3 global climate models and 2 mitigation scenarios), were made for one growing cycle (80 years) of a Scots pine forest growing in Peitz (Germany). Our results show that, besides the important effect of the parameter set, the random order of climate years can significantly change results such as basal area and produced volume, and the response of these to climate change. We stress that the effect of weather variability should be included in the design of impact model ensembles, and the accompanying uncertainty analysis. We further suggest presenting model results as likelihoods to allow risk assessment. For example, in our study the likelihood of a decrease in basal area of >10% with no mitigation was 20.4%, while the likelihood of an increase >10% was 34.4%.

scholarly journals Limited Effects of Long-Term Repeated Season and Interval of Prescribed Burning on Understory Vegetation Compositional Trajectories and Indicator Species in Ponderosa Pine Forests of Northeastern Oregon, USA

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 834
Author(s):  
Harold S. J. Zald ◽  
Becky K. Kerns ◽  
Michelle A. Day
Keyword(s):  
Indicator Species ◽  
Ponderosa Pine ◽  
Prescribed Burning ◽  
Vascular Plant ◽  
Fire Behavior ◽  
Understory Vegetation ◽  
Forest Composition ◽  
Forest Fuels ◽  
Ponderosa Pine Forests ◽  
Over Time

Fire exclusion has dramatically altered historically fire adapted forests across western North America. In response, forest managers reduce forest fuels with mechanical thinning and/or prescribed burning to alter fire behavior, with additional objectives of restoring forest composition, structure, and ecosystem processes. There has been extensive research on the effects of fuel reduction and restoration treatments on trees, fuels, regeneration, and fire behavior; but less is known about how these treatments influence understory vegetation, which contains the majority of vascular plant diversity in many dry conifer forests. Of particular interest is how understory vegetation may respond to the season and interval of prescribed burning. The season and interval of prescribed burning is often determined by operational constraints rather than historical fire regimes, potentially resulting in fire conditions and burn intervals to which native plants are poorly adapted. In this study, we examined how understory vegetation has responded to season and interval of prescribed burning in ponderosa pine (Pinus ponderosa) forests in the Blue Mountains of northeastern Oregon, USA. Using over a decade (2002–2015) of understory vegetation data collected in stands with different intervals (5 versus 15 year) and seasons (spring versus fall) of prescribed burning, we quantified how season and interval of prescribed burning has influenced understory vegetation compositional trajectories and indicator species over time. Season of prescribed burning resulted in different understory communities and distinct trajectories of understory composition over time, but interval of burning did not. Indicator species analysis suggests fall burning is facilitating early seral species, with native annual forbs displaying ephemeral responses to frequent burning, while invasive cheatgrass (Bromus tectorum) increased in abundance and frequency across all treatments over time. These findings indicate that understory vegetation in these ecosystems are sensitive to seasonality of burning, but the responses are subtle. Our findings suggest season and interval of prescribed burning used in this study do not result in large changes in understory vegetation community composition, a key consideration as land managers increase the pace and scale of prescribed fire in these forests.

scholarly journals Thinning and Burning Effects on Long-Term Litter Accumulation and Function in Young Ponderosa Pine Forests

2020 ◽  
Vol 66 (6) ◽  
pp. 761-769
Author(s):  
Matt Busse ◽  
Ross Gerrard
Keyword(s):  
Ponderosa Pine ◽  
Forest Floor ◽  
Prescribed Burning ◽  
Mineral Soil ◽  
Pine Forests ◽  
Organic Layer ◽  
Litter Accumulation ◽  
Ponderosa Pine Forests ◽  
Essential Components

Abstract We measured forest-floor accumulation in ponderosa pine forests of central Oregon and asked whether selected ecological functions of the organic layer were altered by thinning and repeated burning. Experimental treatments included three thinning methods applied in 1989 (stem only, whole tree, no thin—control) in factorial combination with prescribed burning (spring 1991 and repeated in 2002; no burn—control). Forest-floor depth and mass were measured every 4–6 years from 1991 to 2015. Without fire, there was little temporal change in depth or mass for thinned (270 trees ha−1) and control (560–615 trees ha−1) treatments, indicating balanced litterfall and decay rates across these stand densities. Each burn consumed 50–70 percent of the forest floor, yet unlike thinning, postfire accumulation rates were fairly rapid, with forest-floor depth matching preburn levels within 15–20 years. Few differences in forest-floor function (litter decay, carbon storage, physical barrier restricting plant emergence, erosion protection) resulted from thinning or burning after 25 years. An exception was the loss of approximately 300 kg N ha−1 because of repeated burning, or approximately 13 percent of the total site N. This study documents long-term forest-floor development and suggests that common silvicultural practices pose few risks to organic layer functions in these forests. Study Implications: Mechanical thinning and prescribed fire are among the most widespread management practices used to restore forests in the western US to healthy, firewise conditions. We evaluated their effects on the long-term development of litter and duff layers, which serve dual roles as essential components of soil health and as fuel for potential wildfire. Our study showed that thinning and burning provided effective fuel reduction and resulted in no adverse effects to soil quality in dry ponderosa pine forests of central Oregon. Repeated burning reduced the site carbon and nitrogen pools approximately 9–13 percent, which is small compared to C located in tree biomass and N in mineral soil. Litter accumulation after burning was rapid, and we recommend burning on at least a 15–20-year cycle to limit its build-up.

Heterogeneity in fire severity within early season and late season prescribed burns in a mixed-conifer forest

2006 ◽  
Vol 15 (1) ◽  
pp. 37 ◽  
Author(s):  
Eric E. Knapp ◽  
Jon E. Keeley
Keyword(s):  
Sierra Nevada ◽  
Prescribed Burning ◽  
Fire Severity ◽  
Basal Area ◽  
Conifer Forest ◽  
Fuel Loading ◽  
Early Season ◽  
Late Season ◽  
Fuel Loads ◽  
In Fire

Structural heterogeneity in forests of the Sierra Nevada was historically produced through variation in fire regimes and local environmental factors. The amount of heterogeneity that prescription burning can achieve might now be more limited owing to high fuel loads and increased fuel continuity. Topography, woody fuel loading, and vegetative composition were quantified in plots within replicated early and late season burn units. Two indices of fire severity were evaluated in the same plots after the burns. Scorch height ranged from 2.8 to 25.4 m in early season plots and 3.1 to 38.5 m in late season plots, whereas percentage of ground surface burned ranged from 24 to 96% in early season plots and from 47 to 100% in late season plots. Scorch height was greatest in areas with steeper slopes, higher basal area of live trees, high percentage of basal area composed of pine, and more small woody fuel. Percentage of area burned was greatest in areas with less bare ground and rock cover (more fuel continuity), steeper slopes, and units burned in the fall (lower fuel moisture). Thus topographic and biotic factors still contribute to the abundant heterogeneity in fire severity with prescribed burning, even under the current high fuel loading conditions. Burning areas with high fuel loads in early season when fuels are moister may lead to patterns of heterogeneity in fire effects that more closely approximate the expected patchiness of historical fires.

scholarly journals Using JABOWA-3 for forest growth and yield predictions under diverse forest conditions of Nova Scotia, Canada

2012 ◽  
Vol 88 (06) ◽  
pp. 708-721 ◽  
Author(s):  
M. Irfan Ashraf ◽  
Charles P.-A. Bourque ◽  
David A. MacLean ◽  
Thom Erdle ◽  
Fan-Rui Meng
Keyword(s):  
Climate Change ◽  
Nova Scotia ◽  
Model Prediction ◽  
Prediction Accuracy ◽  
Basal Area ◽  
Forest Growth ◽  
Growth And Yield ◽  
Individual Tree ◽  
Forest Conditions ◽  
Forest Growth And Yield

Empirical growth and yield models developed from historical data are commonly used in developing long-term strategic forest management plans. Use of these models rests on an assumption that there will be no future change in the tree growing environment. However, major impacts on forest growing conditions are expected to occur with climate change. As a result, there is a pressing need for tools capable of incorporating outcomes of climate change in their predictions of forest growth and yield. Process-based models have this capability and may, therefore, help to satisfy this requirement. In this paper, we evaluate the suitability of an ecological, individual-tree-based model (JABOWA-3) in generating forest growth and yield projections for diverse forest conditions across Nova Scotia, Canada. Model prediction accuracy was analyzed statistically by comparing modelled with observed basal area and merchantable volume changes for 35 permanent sample plots (PSPs) measured over periods of at least 25 years. Generally, modelled basal area and merchantable volume agreed fairly well with observed data, yielding coefficients of determination (r2) of 0.97 and 0.94 and model efficiencies (ME) of 0.96 and 0.93, respectively. A Chi-square test was performed to assess model accuracy with respect to changes in species composition. We found that 83% of species-growth trajectories based on measured basal area were adequately modelled with JABOWA-3 (P > 0.9). Model-prediction accuracy, however, was substantially reduced for those PSPs altered by some level of disturbance. In general, JABOWA-3 is much better at providing forest yield predictions, subject to the availability of suitable climatic and soil information.

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