Developing a Stand Hazard Index for Oak Decline in Upland Oak Forests of the Ozark Highlands, Missouri

Abstract Black oak (Quercus velutina Lam.) and scarlet oak (Quercus coccinea Muenchh.)—two major components (44% of total stand basal area) of upland oak forests—are suffering severe decline and mortality in the Ozark Highlands, Missouri. However, factors influencing their survival (mortality) are not well understood. In this study we quantified how stand and tree-level predisposing factors are associated with survival of black and scarlet oaks. Sixteen-year monitoring data from the Missouri Ozark Forest Ecosystem Project (MOFEP) indicated that overall annual mortality of black and scarlet oaks averaged 2.2 and 1.7%, respectively, three to five times higher than expected (around 0.5%) for white oak, a common associate. For the first 8 years of the study (1990‐1998), survival rates of black and scarlet oaks were similar. Thereafter, the survival rate of black oak declined relative to scarlet oak. Using the classification and regression tree (CART) method we classified black oak and scarlet oak trees into seven and nine risk groups, respectively, that differed significantly in rates of tree mortality. Groups were distinguished based on tree diameter, crown class, and size relative to competitors. An oak decline and mortality hazard index was thus developed as the weighted means of risk group mortality, which can help managers prescribe species-specific silvicultural treatments to help mitigate oak decline and associated mortality.

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Effects of Oak Decline on Species Composition in a Northern Arkansas Forest

Southern Journal of Applied Forestry ◽

10.1093/sjaf/27.4.264 ◽

2003 ◽

Vol 27 (4) ◽

pp. 264-268 ◽

Cited By ~ 15

Author(s):

Eric Heitzman

Keyword(s):

Species Composition ◽

Tree Mortality ◽

Stand Structure ◽

Acer Rubrum ◽

Basal Area ◽

Red Oak ◽

Oak Decline ◽

Northern Red Oak ◽

Red Maple ◽

White Oak

Abstract Since 1999, widespread and locally severe oak decline and mortality have occurred throughout the Ozark Mountains of northern Arkansas and southern Missouri. A contributing factor in the decline and mortality is an outbreak of the red oak borer [Enaphalodes rufulus (Haldeman) (Coleoptera: Cerambycidae)]. In northern Arkansas, a 2,150 ac mature oak forest severely affected by decline was selected as a case study to describe changes in species composition and stand structure and to assess regeneration potential of oaks and non-oak species. Mortality reduced total overstory basal area from 105 to 57 ft2/ac, and overstory density decreased from 156 to 89 trees/ac. Most dead and dying trees were northern red oak (Quercus rubra L.) and black oak (Q. velutina Lam.). Basal area and density of overstory red oaks were reduced from 51 to 11 ft2/ac and from 60 to 11 trees/ac, respectively. These trees died regardless of dbh class. Mortality was less common in white oak (Q. alba L.) and was generally limited to smaller trees. Understory trees and taller seedlings were predominantly red maple (Acer rubrum L.), flowering dogwood (Cornus florida L.), blackgum (Nyssa sylvatica Marsh.), and black cherry (Prunus serotina Ehrh.). Oaks less than 3 ft tall were abundant, but taller oak seedlings and saplings were uncommon. Tree mortality increased the proportion of white oak and hickories (Carya spp.) in the overstory, and stimulated a regeneration response of mostly non-oak species. South. J. Appl. For. 27(4):264–268.

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Tree architecture as a predictor of growth and mortality after an episode of red oak decline in the Ozark Highlands of Missouri, U.S.A.

Canadian Journal of Forest Research ◽

10.1139/cjfr-2014-0067 ◽

2014 ◽

Vol 44 (9) ◽

pp. 1005-1012 ◽

Cited By ~ 5

Author(s):

Christopher A. Lee ◽

Steven Voelker ◽

Ricardo M. Holdo ◽

Rose-Marie Muzika

Keyword(s):

Mortality Rate ◽

Tree Mortality ◽

Carbon Allocation ◽

Basal Area ◽

Red Oak ◽

Oak Decline ◽

Growth Trend ◽

Ozark Highlands ◽

Basal Area Growth ◽

Area Growth

Mixed oak stands in the Ozark Highlands of southern Missouri were revisited eight years after a severe episode of red oak decline to determine which predictor variables, collected in 2003, best predicted subsequent tree growth and mortality patterns. Between 2002 and 2009, the mortality rate was 5% (0.625% annual mortality rate), generally below previously reported background rates. Generalized linear mixed models indicated that dieback (an estimate of branch mortality), age, relative height, and the interaction between the last two were most effective at predicting tree mortality. By contrast, tree vigor index (TVI), a composite variable derived from basic measurements of crown and stem architecture, was unequivocally the best predictor of basal area growth trend from one long-term period to the next. Basal area growth increases linearly with TVI, reinforcing the notion that even in ring-porous oaks (which must build new earlywood vessels each year), sustained growth is a low priority for carbon allocation in chronically stressed trees. The findings validate TVI as a useful metric for predicting growth rates of scarlet oak (Quercus coccinea Münchh.) and black oak (Quercus velutina Lam.).

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Oak Mortality in Eastern Kentucky

Southern Journal of Applied Forestry ◽

10.1093/sjaf/13.2.86 ◽

1989 ◽

Vol 13 (2) ◽

pp. 86-91 ◽

Cited By ~ 21

Author(s):

Jeffrey W. Stringer ◽

Thomas W. Kimmerer ◽

John C. Overstreet ◽

James P. Dunn

Keyword(s):

Tree Mortality ◽

Basal Area ◽

White Oak ◽

Mortality Pattern ◽

Eastern Kentucky ◽

Red Oaks ◽

Management Plans ◽

Oak Mortality ◽

Black Oak ◽

Upper Slope

Abstract Canopy-tree mortality was assessed from 1985 through 1987 at Robinson Forest in eastern Kentucky. Red oaks, predominantly scarlet oak and black oak, experienced the greatest mortality followed by hickories, white oak, and chestnut oak. Mortality was concentrated in mixed red and whiteoak stands on relatively xeric mid- or upper-slope positions. Mortality was not severe in oak-pine stands on extremely xeric sites. The loss of red oaks in mixed oak stands is typical of the current mortality pattern in the southern Appalachians as well as past mortality associated with regionaldroughts. Mortality will probably continue, and these types of losses should be incorporated into management plans. Treatments to alleviate monetary losses include salvage cuts where feasible and treatments aimed at decreasing the basal area of black and scarlet oaks growing in stands whichare considered at risk. South. J. Appl. For. 13(2):86-91.

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Classification and regression tree based survival analysis in oak-dominated forests of Missouri's Ozark highlands

Canadian Journal of Forest Research ◽

10.1139/x06-068 ◽

2006 ◽

Vol 36 (7) ◽

pp. 1740-1748 ◽

Cited By ~ 29

Author(s):

Zhaofei Fan ◽

John M Kabrick ◽

Stephen R Shifley

Keyword(s):

Survival Analysis ◽

Regression Tree ◽

Species Group ◽

Classification And Regression Tree ◽

Tree Age ◽

Oak Forests ◽

Shortleaf Pine ◽

White Oak ◽

Tree Survival ◽

Classification And Regression

Tree survival or mortality is a stochastic process and highly variable over time and space. Many factors contribute to this process, including tree age, tree size, competition, drought, insects, and diseases. Traditional parametric approaches to modeling tree survival or mortality are often unable to capture this variation, especially in natural, mixed-species forests. We analyzed tree survival in Missouri Ozark oak forests using a combination of classification and regression tree (CART) and survival analysis of more than 35 000 trees with DBH >11 cm measured four times between 1992 and 2002. We employed a log-rank test with CART to classify trees into seven disjoint survival groups and used a nonparametric KaplanMeier (product limit) method to estimate tree survival rate and construct confidence intervals for each survival group. We found that tree species, crown class, DBH, and basal area of larger trees were the variables most closely associated with differences in tree survival rates. In these mature oak forests, mortality for the red oak species group was three to six times greater than for the white oak, hickory, or shortleaf pine species group. The results provide practical information to guide development of silvicultural prescriptions to reduce losses to mortality.

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A large database supports the use of simple models of post-fire tree mortality for thick-barked conifers, with less support for other species

Fire Ecology ◽

10.1186/s42408-020-00082-0 ◽

2020 ◽

Vol 16 (1) ◽

Author(s):

C. Alina Cansler ◽

Sharon M. Hood ◽

Phillip J. van Mantgem ◽

J. Morgan Varner

Keyword(s):

Tree Mortality ◽

Characteristic Curve ◽

Small Diameter ◽

Fire Effects ◽

Tree Level ◽

Clear Understanding ◽

Bark Thickness ◽

Mortality Models ◽

Species Specific ◽

Stem Mortality

Abstract Background Predictive models of post-fire tree and stem mortality are vital for management planning and understanding fire effects. Post-fire tree and stem mortality have been traditionally modeled as a simple empirical function of tree defenses (e.g., bark thickness) and fire injury (e.g., crown scorch). We used the Fire and Tree Mortality database (FTM)—which includes observations of tree mortality in obligate seeders and stem mortality in basal resprouting species from across the USA—to evaluate the accuracy of post-fire mortality models used in the First Order Fire Effects Model (FOFEM) software system. The basic model in FOFEM, the Ryan and Amman (R-A) model, uses bark thickness and percentage of crown volume scorched to predict post-fire mortality and can be applied to any species for which bark thickness can be calculated (184 species-level coefficients are included in the program). FOFEM (v6.7) also includes 38 species-specific tree mortality models (26 for gymnosperms, 12 for angiosperms), with unique predictors and coefficients. We assessed accuracy of the R-A model for 44 tree species and accuracy of 24 species-specific models for 13 species, using data from 93 438 tree-level observations and 351 fires that occurred from 1981 to 2016. Results For each model, we calculated performance statistics and provided an assessment of the representativeness of the evaluation data. We identified probability thresholds for which the model performed best, and the best thresholds with either ≥80% sensitivity or specificity. Of the 68 models evaluated, 43 had Area Under the Receiver Operating Characteristic Curve (AUC) values ≥0.80, indicating excellent performance, and 14 had AUCs <0.7, indicating poor performance. The R-A model often over-predicted mortality for angiosperms; 5 of 11 angiosperms had AUCs <0.7. For conifers, R-A over-predicted mortality for thin-barked species and for small diameter trees. The species-specific models had significantly higher AUCs than the R-A models for 10 of the 22 models, and five additional species-specific models had more balanced errors than R-A models, even though their AUCs were not significantly different or were significantly lower. Conclusions Approximately 75% of models tested had acceptable, excellent, or outstanding predictive ability. The models that performed poorly were primarily models predicting stem mortality of angiosperms or tree mortality of thin-barked conifers. This suggests that different approaches—such as different model forms, better estimates of bark thickness, and additional predictors—may be warranted for these taxa. Future data collection and research should target the geographical and taxonomic data gaps and poorly performing models identified in this study. Our evaluation of post-fire tree mortality models is the most comprehensive effort to date and allows users to have a clear understanding of the expected accuracy in predicting tree death from fire for 44 species.

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Phytophthora Species Detected in Two Ozark Forests with Unusual Patterns of White Oak Mortality

Plant Disease ◽

10.1094/pdis-02-18-0253-re ◽

2019 ◽

Vol 103 (1) ◽

pp. 102-109

Author(s):

Sharon E. Reed ◽

James T. English ◽

Rose-Marie Muzika

Keyword(s):

The United States ◽

Phytophthora Species ◽

Quercus Alba ◽

White Oak ◽

Ozark Highlands ◽

Survey Techniques ◽

Red Oaks ◽

Oak Mortality ◽

One Year ◽

Crown Dieback

Widespread decline and mortality of white oaks (Quercus alba) occurred in Missouri Ozark forests between 2011 and 2017. Symptoms included rapid crown death with bronzing of leaves, retention of dead leaves, crown dieback and thinning, and loss of large limbs within one year of death. Decline and mortality were associated with hillside drainages and fit descriptions of European oak forests predisposed to decline by pathogenic Phytophthora species. A survey was performed at two locations in 2014 and 2015 to assess the distribution of dead and declining white oaks, and the occurrence and distribution of Phytophthora species. Multiple Phytophthora species were detected, including P. cinnamomi, P. cactorum, P. europaea, and P. pini. P. cinnamomi was the most common and widely distributed species among plots at both locations. The detection of P. cinnamomi at the base of white oaks was not associated with poor crown vigor. However, more quantitative survey techniques are necessary to clearly evaluate this relationship. P. cinnamomi kills fine roots of white and red oaks in North America and has been associated with the decline of white oaks in the United States (Ohio) and other countries. Further studies are needed to determine the importance of P. cinnamomi in oak decline within the Ozark highlands.

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Nut Selection by Captive Blue Jays: Importance of Availability and Implications for Seed Dispersal

The Condor ◽

10.1093/condor/108.2.377 ◽

2006 ◽

Vol 108 (2) ◽

pp. 377-388 ◽

Cited By ~ 2

Author(s):

Jeffrey E. Moore ◽

Robert K. Swihart

Keyword(s):

Correlation Coefficients ◽

Discrete Choice Models ◽

Red Oak ◽

Quercus Alba ◽

Northern Red Oak ◽

White Oak ◽

Large White ◽

Shagbark Hickory ◽

Black Oak ◽

Blue Jays

Abstract We assessed dietary preference of 14 captive Blue Jays (Cyanocitta cristata) for different food types under different conditions of availability. In four separate feeding trials, we provisioned jays with the following: Trial 1, two nuts each of white oak (Quercus alba), pin oak (Q. palustris), black oak (Q. velutina), northern red oak (Q. rubra), and shagbark hickory (Carya ovata); Trial 2, two small and two large red oak acorns; Trial 3, two germinating and two nongerminating white oak acorns; and Trial 4, one large red oak acorn, one large white oak acorn, and one shagbark hickory nut. We used discrete choice models to describe selection under conditions of changing choice sets. Blue Jays displayed a clear preference for pin oak and strong avoidance of red oak acorns when alternative foods were available. White oak and black oak acorns were selected intermediately. Shagbark hickory nuts were never used. Correlation coefficients suggested that preference was inversely related to seed size and the proportion of seed consisting of hard seed coat. In the absence of alternative food items, small red oak acorns were readily taken, whereas large red oak acorns were mostly avoided but still used by some birds. These results highlight the importance of considering food availability when making conclusions about preference, and lend support to the hypothesis that Blue Jays can be important dispersers of even less-preferred oak species. We discuss the potential as well as the limitations for Blue Jays to act as seed dispersers, with respect to postglacial range expansion of fagaceous tree species, and in the context of present-day dispersal in regions where forests are highly fragmented.

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Early indications of drought impacts on forests in the southeastern United States

The Forestry Chronicle ◽

10.5558/tfc2015-067 ◽

2015 ◽

Vol 91 (04) ◽

pp. 376-383 ◽

Cited By ~ 4

Author(s):

Michael K. Crosby ◽

Zhaofei Fan ◽

Martin A. Spetich ◽

Theodor D. Leininger ◽

Xingang Fan

Keyword(s):

United States ◽

Forest Type ◽

Southeastern United States ◽

Forest Health ◽

Classification And Regression Tree ◽

Future Research ◽

Red Oak ◽

White Oak ◽

Cart Analysis ◽

Crown Dieback

In the southeastern United States, drought can pose a significant threat to forests by reducing the amount of available water, thereby stressing trees. Destructive changes in crown conditions provide the first visible indication of a problem in a forested area, making it a useful indicator for problems within an ecosystem. Forest Health and Monitoring (FHM) and Palmer's Drought Severity Index (PDSI) data from 11 states in the southeastern United States were obtained in an effort to determine the role that drought, forest type, and ecoregion have in indicating differences in crown dieback. Analyses were conducted by species groups using classification and regression tree (CART) analysis. The greatest amount of total relative crown dieback occurred in red oak (18%), followed by other hardwoods (14%), and white oak (11%). Relative crown dieback varied by forest type and ecoregion with a relationship to drought in both red oak and white oak. This information will be useful for focusing future research and modeling efforts to predict forest health conditions affected by changing climate variables.

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First Report of Xylella fastidiosa Associated with Leaf Scorch in Black Oak in Washington, D.C.

Plant Disease ◽

10.1094/pdis.2004.88.2.224c ◽

2004 ◽

Vol 88 (2) ◽

pp. 224-224 ◽

Cited By ~ 2

Author(s):

Q. Huang

Keyword(s):

Xylella Fastidiosa ◽

The United States ◽

Enzyme Linked Immunosorbent Assay ◽

Bacterial Suspension ◽

White Oak ◽

First Report ◽

Leaf Petiole ◽

Leaf Scorch ◽

Pcr Product ◽

Black Oak

Bacterial leaf scorch caused by Xylella fastidiosa has been reported in 17 species of oak including bur, pin, red, scarlet, shingle, and white oaks (3). In September 2002, a leaf scorch symptom characterized by marginal necrosis of leaves bordered by a darker brown band was observed in a mature black oak (Quercus velutina Lam.) at the U.S. National Arboretum in Washington, D.C. The leaf petiole of the black oak was processed in general extraction buffer (Agdia, Inc., Elkhart, IN) contained in a FastDNA lysing matrix tube using the FastPrep FP120 instrument (Qbiogene, Inc., Carlsbad, CA) (1). The leaf petiole extract reacted with an antiserum specific for X. fastidiosa (Agadia, Inc.) in an enzyme-linked immunosorbent assay (ELISA). A slow-growing bacterium was cultured from leaf petioles of the affected black oak tree by soaking the surface-sterilized, finely cut leaf petioles in sterile water for 30 min, followed by spreading the bacterial suspension on periwinkle wilt plates (1). When the cultured bacterium was subjected to polymerase chain reaction (PCR) with primers specific for X. fastidiosa (2), a 472-bp PCR product was detected. The PCR product was confirmed to be the predicted X. fastidiosa product by sequencing and sequence comparison with the reported genomic sequence of X. fastidiosa. ELISA and bacterial isolation from leaf petioles of a nearby symptomless white oak (Q. alba L.) tree were negative. To our knowledge, this is the first report of X. fastidiosa associated with leaf scorch in black oak in the United States, expanding the host range of the bacterium in economically important landscape tree species. References: (1) Q. Huang and J. L. Sherald. Curr. Microbiol. 48:73, 2004. (2) M. R. Pooler and J. S. Hartung. Curr. Microbiol. 31:377, 1995. (3) J. L. Sherald. Xylella fastidiosa, A bacterial pathogen of landscape trees. Page 191 in: Shade Tree Wilt Diseases, C. L. Ash, ed. The American Phytopathological Society, 2001.

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Effect of climate change, drought, and insects on oak-pine forests in the Ozark highlands

10.32469/10355/78121 ◽

2020 ◽

Author(s):

◽

Shengwu Duan

Keyword(s):

Climate Change ◽

Forest Growth ◽

Pine Forests ◽

Spatial And Temporal Variation ◽

Oak Forests ◽

Drought Effect ◽

Ozark Highlands ◽

Disturbance Regimes ◽

Warming Climate ◽

The Impact

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI--COLUMBIA AT REQUEST OF AUTHOR.] Oak-dominated forests in the Ozarks Highlands of Arkansas and Missouri have been suffering severe oak decline and this became a chronic problem since the late 1970s. Such decline became increasingly severe as numerous dense oak forests in this region approaching physiological maturity. Repeated droughts and insect outbreaks in the Ozarks Highlands from 1998 to 2015 accelerate the decline process and resulted in increased mortality of the oaks, particularly those in red oak group. Given these concerns, the overall objective of this dissertation was to conduct a regional scale assessment to evaluate and predict the impact of drought and insects on the oak forests under changing climate. This dissertation contained three main objectives: 1) to evaluate the drought effect on forest growth phenology and productivity by using spatially-explicit drought indices and land surface phenology techniques to capture oak, pine and mixed oak-pine forests' responses to repeated droughts; 2) to develop a climate sensitive biotic disturbance agent (BDA) module in forest landscape modeling framework to quantify the relative importance in determining the insect disturbance regimes under the warming climate; and 3) to predict the effects of insect disturbance, climate change and their interactions on forest composition under alternative climate and insect disturbance scenarios. The dissertation provided a methodology to disassemble the spatial and temporal variation of drought conditions in the Ozark Highlands and provided new insights into improving drought resistance and recovery capacity of forests with different species under climate change. The results from this dissertation also helped to understand the importance of vegetation feedback in predicting inset disturbance regimes under a warming climate as they may mediate or even reverse the expectation of increased insect disturbance in this region. In addition, the projections of how tree species will response to insect disturbance will benefit decision making in silvicultural prescriptions and longterm management plans in the Ozark Highlands.

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