Does coring contribute to tree mortality?

2004 ◽  
Vol 34 (11) ◽  
pp. 2394-2398 ◽  
Author(s):  
Phillip J. van Mantgem ◽  
Nathan L Stephenson
Keyword(s):  
Life Span ◽  
Sierra Nevada ◽  
Tree Mortality ◽  
Mortality Rates ◽  
Permanent Plots ◽  
Abies Concolor ◽  
Maximum Life Span ◽  
Coniferous Species ◽  
Abies Magnifica ◽  
White Fir

We assess the potential of increment coring, a common method for measuring tree ages and growth, to contribute to mortality. We used up to 21 years of annual censuses from two cored and two uncored permanent plots in the Sierra Nevada of California, to detect changes in mortality rates 12 years following coring for individuals >5 cm DBH from two coniferous species, Abies concolor (Gordon & Glend.) Lindl. (white fir) and Abies magnifica A. Murr. (red fir). Using a randomized before-after control impact (BACI) design, we found no differences in mortality rates following coring for 825 cored and 525 uncored A. concolor and 104 cored and 66 uncored A. magnifica. These results support the view that collecting tree cores can be considered nondestructive sampling, but we emphasize that our 12-year postcoring records are short compared with the maximum life-span of these trees and that other species in different environments may prove to be more sensitive to coring.

Tree mortality patterns following prescribed fires in a mixed conifer forest

2006 ◽  
Vol 36 (12) ◽  
pp. 3222-3238 ◽  
Author(s):  
Leda Kobziar ◽  
Jason Moghaddas ◽  
Scott L Stephens
Keyword(s):  
Sierra Nevada ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Fire Behavior ◽  
Mortality Rates ◽  
Fire Intensity ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Mixed Conifer Forest ◽  
White Fir

During the late fall of 2002 we administered three burns in mixed conifer forest sites in the north-central Sierra Nevada. Eight months later we measured fire-induced injury and mortality in 1300 trees. Using logistic regression, an array of crown scorch, stem damage, fuels, and fire-behavior variables were examined for their influence on tree mortality. In Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), white fir (Abies concolor (Gord. & Glend.) Lindl.), and incense cedar (Calocedrus decurrens (Torr.) Florin), smaller trees with greater total crown damage had higher mortality rates. Smaller stem diameters and denser canopies predicted mortality best in ponderosa pine (Pinus ponderosa Dougl. ex P. Laws. & C. Laws). Duff consumption and bark char severity increased model discrimination for white fir and incense cedar and California black oak (Quercus kelloggii Newberry), respectively. In tanoak (Lithocarpus densiflorus (Hook. & Arn.) Rehd.), greater total crown damage in shorter trees resulted in higher mortality rates. Along with tree diameter and consumption of large (>7.6 cm diameter at breast height, DBH) rotten downed woody debris, fire intensity was a significant predictor of overall tree mortality for all species. Mortality patterns for white fir in relation to crown damage were similar among sites, while those for incense cedar were not, which suggests that species in replicated sites responded differently to similar burns. Our results demonstrate actual fire-behavior data incorporated into mortality models, and can be used to design prescribed burns for targeted reduction of tree density in mixed conifer forests.

Growth rate predicts mortality of Abies concolor in both burned and unburned stands

2003 ◽  
Vol 33 (6) ◽  
pp. 1029-1038 ◽  
Author(s):  
Phillip J. van Mantgem ◽  
Nathan L Stephenson ◽  
Linda S Mutch ◽  
Veronica G Johnson ◽  
Annie M Esperanza ◽  
...  
Keyword(s):  
Growth Rate ◽  
Sierra Nevada ◽  
Tree Mortality ◽  
Abies Concolor ◽  
Stress Growth ◽  
Short Term ◽  
Crown Scorch ◽  
White Fir ◽  
Probability Of Death

Tree mortality is often the result of both long-term and short-term stress. Growth rate, an indicator of long-term stress, is often used to estimate probability of death in unburned stands. In contrast, probability of death in burned stands is modeled as a function of short-term disturbance severity. We sought to narrow this conceptual gap by determining (i) whether growth rate, in addition to crown scorch, is a predictor of mortality in burned stands and (ii) whether a single, simple model could predict tree death in both burned and unburned stands. Observations of 2622 unburned and 688 burned Abies concolor (Gord. & Glend.) Lindl. (white fir) in the Sierra Nevada of California, U.S.A., indicated that growth rate was a significant predictor of mortality in the unburned stands, while both crown scorch and radial growth were significant predictors of mortality in the burned stands. Applying the burned stand model to unburned stands resulted in an overestimation of the unburned stand mortality rate. While failing to create a general model of tree death for A. concolor, our findings underscore the idea that similar processes may affect mortality in disturbed and undisturbed stands.

scholarly journals Cross-scale interaction of host tree size and climatic water deficit governs bark beetle-induced tree mortality

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michael J. Koontz ◽  
Andrew M. Latimer ◽  
Leif A. Mortenson ◽  
Christopher J. Fettig ◽  
Malcolm P. North
Keyword(s):  
Water Deficit ◽  
Sierra Nevada ◽  
Bark Beetle ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Mortality Rates ◽  
Dendroctonus Brevicomis ◽  
Scale Interactions ◽  
Climatic Water Deficit ◽  
Host Mortality

AbstractThe recent Californian hot drought (2012–2016) precipitated unprecedented ponderosa pine (Pinus ponderosa) mortality, largely attributable to the western pine beetle (Dendroctonus brevicomis; WPB). Broad-scale climate conditions can directly shape tree mortality patterns, but mortality rates respond non-linearly to climate when local-scale forest characteristics influence the behavior of tree-killing bark beetles (e.g., WPB). To test for these cross-scale interactions, we conduct aerial drone surveys at 32 sites along a gradient of climatic water deficit (CWD) spanning 350 km of latitude and 1000 m of elevation in WPB-impacted Sierra Nevada forests. We map, measure, and classify over 450,000 trees within 9 km2, validating measurements with coincident field plots. We find greater size, proportion, and density of ponderosa pine (the WPB host) increase host mortality rates, as does greater CWD. Critically, we find a CWD/host size interaction such that larger trees amplify host mortality rates in hot/dry sites. Management strategies for climate change adaptation should consider how bark beetle disturbances can depend on cross-scale interactions, which challenge our ability to predict and understand patterns of tree mortality.

Life span bias explains live–dead discordance in abundance of two common bivalves

Paleobiology ◽  
2018 ◽  
Vol 44 (4) ◽  
pp. 783-797 ◽  
Author(s):  
Kelly E. Cronin ◽  
Gregory P. Dietl ◽  
Patricia H. Kelley ◽  
Stewart M. Edie
Keyword(s):  
North Carolina ◽  
Life Span ◽  
Field Study ◽  
Species Abundance ◽  
Mercenaria Mercenaria ◽  
Mortality Rates ◽  
Global Maximum ◽  
Bivalve Species ◽  
Maximum Life Span ◽  
Death Assemblages

AbstractLife span bias potentially alters species abundance in death assemblages through the overrepresentation of short-lived organisms compared with their long-lived counterparts. Although previous work found that life span bias did not contribute significantly to live–dead discordance in bivalve assemblages, life span bias better explained discordance in two groups: longer-lived bivalve species and species with known life spans. More studies using local, rather than global, species-wide life spans and mortality rates would help to determine the prevalence of life span bias, especially for long-lived species with known life spans. Here, we conducted a field study at two sites in North Carolina to assess potential life span bias between Mercenaria mercenaria and Chione elevata, two long-lived bivalve species that can be aged directly. We compared the ability of directly measured local life spans with that of regional and global life spans to predict live–dead discordance between these two species. The shorter-lived species (C. elevata) was overrepresented in the death assemblage compared with its live abundance, and local life span data largely predicted the amount of live–dead discordance; local life spans predicted 43% to 88% of discordance. Furthermore, the global maximum life span for M. mercenaria resulted in substantial overpredictions of discordance (1.4 to 1.6 times the observed live–dead discordance). The results of this study suggest that life span bias should be considered as a factor affecting proportional abundances of species in death assemblages and that using life span estimates appropriate to the study locality improves predictions of discordance based on life span compared with using global life span estimates.

Mycorrhizae of Abies concolor in California

1977 ◽  
Vol 55 (10) ◽  
pp. 1345-1350 ◽  
Author(s):  
Isabel F. Alvarez ◽  
Fields W. Cobb Jr.
Keyword(s):  
Sierra Nevada ◽  
Mycorrhizal Fungi ◽  
Abies Concolor ◽  
North Central ◽  
Chemical Reagents ◽  
The North ◽  
Naturally Occurring ◽  
White Fir ◽  
Different Types ◽  
Cenococcum Graniforme

Nine different types of mycorrhizae were observed on naturally occurring white fir seedlings in the north central Sierra Nevada, including one formed by the ubiquitous Cenococcum graniforme. The macro- and micro-scopic characteristics and reactions to different chemical reagents are described for five types. Possible mycorrhizal fungi of white fir are listed. Nursery-grown seedlings examined were ectomycorrhizal; intracellular penetration was not observed. None of the naturally occurring mycorrhizal types were found on nursery seedlings.

scholarly journals Drought Impacts and Compounding Mortality on Forest Trees in the Southern Sierra Nevada

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 237 ◽  
Author(s):  
Lauren Pile ◽  
Marc Meyer ◽  
Ramiro Rojas ◽  
Olivia Roe ◽  
Mark Smith
Keyword(s):  
Sierra Nevada ◽  
Tree Mortality ◽  
Forest Stand ◽  
Abies Concolor ◽  
Forest Trees ◽  
Insect Outbreaks ◽  
Important Species ◽  
Forest Stand Structure ◽  
Tree Survival ◽  
Pine Species

The increase in compounding disturbances, such as “hotter droughts” coupled with insect outbreaks, has significant impacts on the integrity of forested ecosystems and their subsequent management for important ecosystem services and multiple-use objectives. In the Southern Sierra Nevada, years of severe drought have resulted in unprecedented tree mortality across this mountainous landscape. Additionally, past land management practices, including fire suppression, have led to overly stocked, homogenous forest stand structures, dominated by small diameter, shade-tolerant and fire-intolerant tree species. Thus, the current condition of the landscape has further increased the susceptibility of forest trees to multiple stressors. We sought to determine the effects of extreme drought and insect outbreaks on tree mortality and their influence on forest stand structure and composition. To characterize mortality patterns, we monitored the condition of mature forest trees (>25.4 cm diameter at breast height) across 255 monitoring plots with four repeated measurements from 2015 through 2017. Tree mortality varied by species and through time. Reductions in pine species (Pinus lambertiana Douglas and P. ponderosa Lawson & C. Lawson) occurred earlier in the study period than Abies concolor (Gord. & Glend.) Lindl. Ex Hildebr. or Calocedrus decurrens (Torr.) Florin. Across species, larger tree size, most often associated with tree height, was consistently related to increased survival in mature, overstory trees. As expected, sites with greater pine stocking and subsequently more bark beetle (Curculionidae: Scolytinae) host availability had increased pine mortality, especially for P. ponderosa. For Abies concolor, lower overstory basal area increased tree survival for this species. This study highlights the importance of effective forest monitoring, especially during a period of unprecedented ecological change as the compounding disturbance had a disproportional effect on pine species in smaller diameter classes. Proactive forest management may be necessary to maintain and promote these ecologically important species in heterogeneous mixtures across the landscape.

Post-fire epicormic branching in Sierra Nevada Abies concolor (white fir)

2006 ◽  
Vol 15 (1) ◽  
pp. 31 ◽  
Author(s):  
Chad T. Hanson ◽  
Malcolm P. North
Keyword(s):  
Sierra Nevada ◽  
Fire Suppression ◽  
Large Diameter ◽  
Abies Concolor ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Diameter Class ◽  
Mixed Conifer Forest ◽  
White Fir ◽  
Epicormic Branching

In California’s mixed-conifer forest, which historically had a regime of frequent fires, two conifers, Sequoiadendron giganteum and Pseudotsuga menziesii, were previously known to produce epicormic sprouts from branches. We found epicormic branching in a third mixed-conifer species, Abies concolor, 3 and 4 years after a wildfire in the central Sierra Nevada Mountains of California. Sprouting occurred only from the boles. We investigated (1) whether the degree of crown loss and the extent of epicormic branching were independent; and (2) whether epicormic branching differed by tree size. The vertical extent of epicormic foliage increased with increasing severity of crown loss. There was a significantly greater proportion of large diameter-class (>50 cm diameter at breast height [dbh]) trees with epicormic branching than small/medium diameter-class (25–50 cm dbh) trees. These results suggest large diameter Abies concolor may survive high levels of crown loss, aided by crown replacement through epicormic branching, but that reiterative green foliage may not appear for up to 3 years after fire damage. If this response is widespread, it would suggest some ‘dying’ trees logged under current salvage guidelines could survive, and that higher-intensity fire may substantially reduce the density of small post-fire suppression white fir, while retaining many larger overstory trees.

scholarly journals Cross-scale interaction of host tree size and climatic water deficit governs bark beetle-induced tree mortality

2019 ◽  
Author(s):  
Michael J Koontz ◽  
Andrew M. Latimer ◽  
Leif A. Mortenson ◽  
Christopher J. Fettig ◽  
Malcolm P. North
Keyword(s):  
Water Deficit ◽  
Sierra Nevada ◽  
Bark Beetle ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Mortality Rates ◽  
Dendroctonus Brevicomis ◽  
Scale Interactions ◽  
Climatic Water Deficit ◽  
Host Mortality

The recent Californian hot drought (2012-2016) precipitated unprecedented ponderosa pine (Pinus ponderosa) mortality, largely attributable to the western pine beetle (Dendroctonus brevicomis; WPB). Broad-scale climate conditions can directly shape tree mortality patterns, but mortality rates respond non-linearly to climate when local-scale forest characteristics influence the behavior of tree-killing bark beetles (e.g., WPB). To test for these cross-scale interactions, we conduct aerial drone surveys at 32 sites along a gradient of climatic water deficit (CWD) spanning 350 km of latitude and 1000 m of elevation in WPB-impacted Sierra Nevada forests. We map, measure, and classify over 450,000 trees within 9 km2, validating measurements with coincident field plots. We find greater size, proportion, and density of ponderosa pine (the WPB host) increase host mortality rates, as does greater CWD. Critically, we find a CWD/host size interaction such that larger trees amplify host mortality rates in hot/dry sites. Management strategies for climate change adaptation should consider how bark beetle disturbances can depend on cross-scale interactions, which challenge our ability to predict and understand patterns of tree mortality.

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