scholarly journals The evolution and diversification of the red oaks of the California Floristic Province (QuercussectionLobatae, seriesAgrifoliae)

2017 ◽  
Vol 104 (10) ◽  
pp. 1581-1595 ◽  
Author(s):  
Duncan A. Hauser ◽  
Al Keuter ◽  
John D. McVay ◽  
Andrew L. Hipp ◽  
Paul S. Manos
2021 ◽  
Vol 307 (3) ◽  
Author(s):  
Alberto Pérez-Pedraza ◽  
Hernando Rodríguez-Correa ◽  
Susana Valencia-Ávalos ◽  
César Andrés Torres-Miranda ◽  
Maribel Arenas-Navarro ◽  
...  

1981 ◽  
Vol 11 (3) ◽  
pp. 689-695 ◽  
Author(s):  
Craig G. Lorimer

Mortality and growth rates of trees in various crown classes and size classes were analyzed from 40-year permanent plot records of slope and ravine forest dominated by chestnut oak (Quercusprinus L.) and northern red oak (Quercusrubra L.). Average 5-year mortality rates for suppressed trees ≥2.5 cm dbh of chestnut oak and red oak in the slope forest were 26 and 45%, respectively. None of the suppressed red oaks survived the 40-year period, compared with 14% of the chestnut oaks and 33% of the red maples (Acerrubrum L.). Mortality of oak trees in the intermediate crown class was less than half that of suppressed trees, but still much higher than that of maples and birches on the tracts. Survival was reasonably high for oaks as long as the top of the crown was receiving direct sunlight, but the expected 40-year survival rate of red oaks in such a position is only 20%, with an average growth rate of 1.0 mm in diameter per year. Curves and equations expressing average mortality and growth rates at various levels of competition are presented for each species.


Plant Disease ◽  
2019 ◽  
Vol 103 (1) ◽  
pp. 102-109
Author(s):  
Sharon E. Reed ◽  
James T. English ◽  
Rose-Marie Muzika

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.


2021 ◽  
Author(s):  
Scott T O’Donnell ◽  
Sorel T Fitz-Gibbon ◽  
Victoria L Sork

Abstract Ancient introgression can be an important source of genetic variation that shapes the evolution and diversification of many taxa. Here, we estimate the timing, direction and extent of gene flow between two distantly related oak species in the same section (Quercus sect. Quercus). We estimated these demographic events using genotyping by sequencing data (GBS), which generated 25,702 single nucleotide polymorphisms (SNPs) for 24 individuals of California scrub oak (Quercus berberidifolia) and 23 individuals of Engelmann oak (Q. engelmannii). We tested several scenarios involving gene flow between these species using the diffusion approximation-based population genetic inference framework and model-testing approach of the Python package DaDi. We found that the most likely demographic scenario includes a bottleneck in Q. engelmannii that coincides with asymmetric gene flow from Q. berberidifolia into Q. engelmannii. Given that the timing of this gene flow coincides with the advent of a Mediterranean-type climate in the California Floristic Province, we propose that changing precipitation patterns and seasonality may have favored the introgression of climate-associated genes from the endemic into the non-endemic California oak.


2000 ◽  
Vol 24 (1) ◽  
pp. 6-10 ◽  
Author(s):  
Zical Xu ◽  
Theodor D. Leininger ◽  
James G. Williams ◽  
Frank H. Tainter

Abstract The Arborsonic Decay Detector (ADD; Fujikura Europe Limited, Wiltshire, England) was used to measure the time it took an ultrasound wave to cross 280 diameters in red oak trees with varying degrees of bacterial wetwood or heartwood decay. Linear regressions derived from the ADD readings of trees in Mississippi and South Carolina with wetwood and heartwood decay yielded significantly different lines for some combinations and locations. The results of this study suggest that the ADD cannot yet be used to detect wetwood in oak trees with enough certainty to be of practical use to a forester or land manager. However, regression lines describing ADD readings of trees with wetwood at both study sites were located between those of healthy trees and decayed trees suggesting some, albeit limited, ability to differentiate wetwood trees. The use of ultrasound to detect bacterial wetwood in red oaks may be improved by designing a system that allows measurement of signal amplitude and evaluation of waveform patterns. The ability to successfully detect trees with heartwood decay was better, especially for trees with advanced decay. South. J. Appl. For. 24(1):6-10.


1999 ◽  
Vol 23 (3) ◽  
pp. 133-138 ◽  
Author(s):  
Keith L. Belli ◽  
Christopher P. Hart ◽  
John D. Hodges ◽  
John A. Stanturf

Abstract Plots were established to monitor the success of advance regeneration for red oaks and ash on eight high quality sites on minor bottoms in Mississippi. Data were collected pre- and post-harvest, and annually for 3 yr following harvest. Red oak and ash stems were initially categorized by height class, or by diameter class for those stems at least 1 in. in diameter at breast height. Survival and competitive position were monitored to provide estimates of the probability of producing at least one free-to-grow stem 3 growing seasons following stand harvest. Regardless of species, the competitive advantage of larger seedlings and stump sprouts over smaller seedlings (less than 1 ft tall) was clear. Less than 10% of the smaller seedlings were free-to-grow after 3 growing seasons, whereas 26% to 71% of the larger seedlings and stump sprouts were judged free-to-grow after the same amount of time. Results were used to revise an existing regeneration assessment system. A field tally sheet was developed to aid in the application of the revised system. South. J. Appl: For. 23(3): 133-138.


Botany ◽  
2015 ◽  
Vol 93 (10) ◽  
pp. 691-700 ◽  
Author(s):  
Ruhua Zhang ◽  
Andrew L. Hipp ◽  
Oliver Gailing

The North American red oak species Quercus rubra L., Quercus ellipsoidalis E. J. Hill, Quercus velutina Lam., and Quercus coccinea Münchh. are morphologically similar and showed very low interspecific differentiation at most nuclear genetic markers in our earlier analyses (<10%). However, a few genetic markers showed interspecific differentiation values (up to 84%) above neutral expectations, a pattern of genomic divergence consistent with models of ecological speciation in the face of gene flow and strong divergent selection. Accordingly, these interfertile species are predicted to maintain differential adaptations to drought, while neutral regions of the genome appear to be homogenized by interspecific gene flow. According to this model of maintenance of species integrity by divergent selection with gene flow, we expect a sharing of chloroplast haplotypes between interspecific population pairs. We analyzed maternally inherited chloroplast DNA markers for the first time in interspecific populations of the red oaks (section Lobatae) to provide additional evidence for contemporary gene flow between Q. rubra and Q. ellipsoidalis and between Q. velutina and Q. ellipsoidalis. Very low interspecific differentiation (GST = 0.023), but pronounced genetic differentiation among populations from different regions (GST = 0.277) across species, and sharing of regional chloroplast haplotypes between species in sympatric and neighboring populations provided strong evidence for contemporary interspecific gene flow. The pattern of divergence at chloroplast DNA markers in red oaks suggests interspecific gene flow that resulted in a sharing of chloroplast types while the ecological and morphological distinctness of species was maintained.


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