Long-term overstory and understory change following logging and fire exclusion in a Sierra Nevada mixed-conifer forest

Knapp, Eric E.; Skinner, Carl N.; North, Malcolm P.; Estes, Becky L.

doi:10.1016/j.foreco.2013.09.041

Cited by 109 publications

(97 citation statements)

References 60 publications

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“…Restoring the patchy composition and structure that is a byproduct of a more characteristic pyrodiversity of MSFire landscapes requires recreating or maintaining spatial heterogeneity at all appropriate scales (Franklin and Van Pelt, 2004;Franklin et al, 2002;Lydersen et al, 2013;Knapp et al, 2013;Skinner, 1995;Harrod et al, 1999;Hessburg et al, 2010Hessburg et al, , 2015North et al, 2009;Perry et al, 2011) 3,4 . Simply summarizing the amount of area in the different successional classes to meet some desired proportions is not appropriate because that leaves out critical aspects related to patch sizes and configuration.…”

Section: Strategy 6: Creating and Maintaining Successional Heterogeneitymentioning

confidence: 99%

“…An increasing number of studies from western US MSForests are available to define historical tree clump and gap variability of various forest types (Churchill et al, , 2014Fry et al, 2014;Harrod et al, 1999;Hopkins et al, 2014;Kaufmann et al, 2007;Knapp et al, 2013;Larson and Churchill, 2012;Lydersen and North, 2012;Lydersen et al, 2013;Stephens et al, 2008;Taylor, 2010;Clyatt et al, 2016). Within patches, tree patterns are defined by uneven-aged and irregularly patchy mosaics of individual trees, tree clumps ranging from 2 to 20 or more trees, comparably sized tree gaps, and even larger openings.…”

Section: Re-creating Fine-scale Heterogeneitymentioning

confidence: 99%

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Tamm Review: Management of mixed-severity fire regime forests in Oregon, Washington, and Northern California

Hessburg

Spies

Perry

et al. 2016

Forest Ecology and Management

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175

190

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a b s t r a c tIncreasingly, objectives for forests with moderate-or mixed-severity fire regimes are to restore successionally diverse landscapes that are resistant and resilient to current and future stressors. Maintaining native species and characteristic processes requires this successional diversity, but methods to achieve it are poorly explained in the literature. In the Inland Pacific US, large, old, early seral trees were a key historical feature of many young and old forest successional patches, especially where fires frequently occurred. Large, old trees are naturally fire-tolerant, but today are often threatened by dense understory cohorts that create fuel ladders that alter likely post-fire successional pathways. Reducing these understories can contribute to resistance by creating conditions where canopy trees will survive disturbances and climatic stressors; these survivors are important seed sources, soil protectors, and critical habitat elements. Historical timber harvesting has skewed tree size and age class distributions, created hard edges, and altered native patch sizes. Manipulating these altered forests to promote development of larger patches of older, larger, and more widely-spaced trees with diverse understories will increase landscape resistance to severe fires, and enhance wildlife habitat for underrepresented conditions.Closed-canopy, multi-layered patches that develop in hot, dry summer environments are vulnerable to droughts, and they increase landscape vulnerability to insect outbreaks and severe wildfires. These same patches provide habitat for species such as the northern spotted owl, which has benefited from increased habitat area. Regional and local planning will be critical for gauging risks, evaluating trade-offs, and restoring dynamics that can support these and other species. The goal will be to manage for heterogeneous landscapes that include variably-sized patches of (1) young, middle-aged, and old, closedcanopy forests growing in upper montane, northerly aspect, and valley bottom settings, (2) a similar diversity of open-canopy, fire-tolerant patches growing on ridgetops, southerly aspects, and lower montane settings, and (3) significant montane chaparral and grassland areas. Tools to achieve this goal http://dx

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Section: Strategy 6: Creating and Maintaining Successional Heterogeneitymentioning

confidence: 99%

Section: Re-creating Fine-scale Heterogeneitymentioning

confidence: 99%

Tamm Review: Management of mixed-severity fire regime forests in Oregon, Washington, and Northern California

Hessburg

Spies

Perry

et al. 2016

Forest Ecology and Management

Self Cite

175

190

View full text Add to dashboard Cite

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“…During exceptional winters, snow accumulations up to 3 m deep can result in a shortened growing season from mid-May to the end of September. The soils were loam to gravelly loam of the Wintoner-Inville families complex, formed primarily from granite, contributing to high site productivity [3]. In Fall 2012, a thinning treatment was applied to approximately 80% of the study area, leaving 20% as untreated controls.…”

Section: Study Areamentioning

confidence: 99%

“…The persistent legacy of fire exclusion practices has substantially increased the stand density in many of these forests [1][2][3], which can cause greater competition for water and other resources [4]. These conditions are potentially exacerbated by a warming climate [5] that can further limit water resources and increase tree stress [6].…”

Section: Introductionmentioning

confidence: 99%

“…Much of California has experienced increasing temperatures over the last few decades, punctuated by an extended and severe drought [40]. Additionally, a century of fire exclusion has allowed shade tolerant species such as white fir (Abies concolor) and incense cedar (Calocedrus decurrens) to establish, resulting in denser stands with greater competition than historical conditions [3,9,41]. Cumulatively, these conditions have likely contributed to the observed decline in sugar pine populations [42] and threaten the persistence of large individuals.…”

Section: Introductionmentioning

confidence: 99%

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Contrasting Impacts of Climate and Competition on Large Sugar Pine Growth and Defense in a Fire-Excluded Forest of the Central Sierra Nevada

Slack

Kane

Knapp

et al. 2017

Forests

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Abstract:Many forest ecosystems with a large pine component in the western United States have experienced environmental stress associated with climate change and increased competition with forest densification in the absence of fire. Information on how changes in climate and competition affect carbon allocation to tree growth and defense is needed to anticipate changes to tree vigor and, ultimately, stand structure. This study retrospectively examined the influence of annual climate and competition measures on the growth and defense of 113 large sugar pines (Pinus lambertiana) in a mixed-conifer forest of the central Sierra Nevada of California. We found that growth in large sugar pine was positively associated with higher January temperatures and lower intraspecific competition. Resin duct size was negatively associated with climatic water deficit and total competition, while resin duct area contrastingly showed a positive relationship with total competition. From 1979 to 2012, the rates of growth increased, while resin duct size decreased. Our results suggest that tree vigor measures can respond differently to climate and competition factors that may lead to separate growth and defense trends over time. Stress associated with warmer temperatures and higher competition may distinctly influence individual tree and stand-level vigor with potential implications for future forest dynamics.

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Impacts of different land management histories on forest change

Collins

Fry

Lydersen

et al. 2017

Ecological Applications

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Many western North American forest types have experienced considerable changes in ecosystem structure, composition, and function as a result of both fire exclusion and timber harvesting. These two influences co-occurred over a large portion of dry forests, making it difficult to know the strength of either one on its own or the potential for an interaction between the two. In this study, we used contemporary remeasurements of a systematic historical forest inventory to investigate forest change in the Sierra Nevada. The historical data opportunistically spanned a significant land management agency boundary, which protected part of the inventory area from timber harvesting. This allowed for a robust comparison of forest change between logged and unlogged areas. In addition, we assessed the effects of recent management activities aimed at forest restoration relative to the same areas historically, and to other areas without recent management. Based on analyses of 22,007 trees (historical, 9,573; contemporary, 12,434), live basal area and tree density significantly increased from 1911 to the early 2000s in both logged and unlogged areas. Both shrub cover and the proportion of live basal area occupied by pine species declined from 1911 to the early 2000s in both areas, but statistical significance was inconsistent. The most notable difference between logged and unlogged areas was in the density of large trees, which declined significantly in logged areas, but was unchanged in unlogged areas. Recent management activities had a varied impact on the forest structure and composition variables analyzed. In general, areas with no recent management activities experienced the greatest change from 1911 to the early 2000s. If approximating historical forest conditions is a land management goal the documented changes in forest structure and composition from 1911 to the early 2000s indicate that active restoration, including fire use and mechanical thinning, is needed in many areas.

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Long-term overstory and understory change following logging and fire exclusion in a Sierra Nevada mixed-conifer forest

Cited by 109 publications

References 60 publications

Tamm Review: Management of mixed-severity fire regime forests in Oregon, Washington, and Northern California

Tamm Review: Management of mixed-severity fire regime forests in Oregon, Washington, and Northern California

Contrasting Impacts of Climate and Competition on Large Sugar Pine Growth and Defense in a Fire-Excluded Forest of the Central Sierra Nevada

Impacts of different land management histories on forest change

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