Genotypic diversity and clone size in old-growth populations of coast redwood (Sequoia sempervirens)

2000 ◽  
Vol 78 (11) ◽  
pp. 1408-1419 ◽  
Author(s):  
Deborah L Rogers
Keyword(s):  
Asexual Reproduction ◽  
Genotypic Diversity ◽  
Visual Assessment ◽  
Sequoia Sempervirens ◽  
Allozyme Diversity ◽  
Old Growth ◽  
Clone Size ◽  
Coast Redwood ◽  
Ring Structures ◽  
Individual Trees

Coast redwood (Sequoia sempervirens (D. Don) Endl.) has long-lived individual trees that can reproduce both sexually and asexually. Allozyme markers indicate that, in old-growth populations in northern California, 15-34% of clones are multistemmed. Of those, they have few stems per clone, and none are very spatially pervasive. There is much variety in the clonal configurations observed, including circular, linear, and (or) disjunct arrangements. Visual assessment is a poor predictor of clonal identity and fairy ring structures more often than not contain multiple genotypes. In this first allozyme study of coast redwood, high levels of genetic variation are observed, higher than those observed for most other western conifers. These levels are perhaps related to the species' hexaploid condition, ancient phylogenetic lineage, and historically broader natural range. There are also generally high levels of genotypic diversity. Upland sites, with more frequent and intense fires, do not differ significantly in genotypic diversity from the more mesic lowland sites. Population structure in coast redwood seems to resemble the classic pattern for many open-pollinated conifers: much diversity within and little among populations. However, this is not a rangewide study. The current levels and structure of genetic and genotypic diversity in old-growth populations suggests episodic recruitment. The long-lived nature of individual stems and the capacity for asexual reproduction may allow clones to exist indefinitely, thus challenging some of the generalizations in evolutionary theory that are based on sexually reproducing species.Key words: clones, asexual reproduction, allozyme diversity, conifer, gymnosperm, polyploid.

scholarly journals Fuel load, stand structure, and understory species composition following prescribed fire in an old-growth coast redwood (Sequoia sempervirens) forest

Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
David Cowman ◽  
Will Russell
Keyword(s):  
Species Composition ◽  
Prescribed Burning ◽  
Sequoia Sempervirens ◽  
Anthropogenic Sources ◽  
Fuel Load ◽  
Old Growth ◽  
Understory Species ◽  
Coast Redwood ◽  
Understory Species Composition ◽  
Redwood Forests

Abstract Background With the prevalence of catastrophic wildfire increasing in response to widespread fire suppression and climate change, land managers have sought methods to increase the resiliency of landscapes to fire. The application of prescribed burning in ecosystems adapted to fire can reduce fuel load and fire potential while minimizing impacts to the ecosystem as a whole. Coast redwood forests have historically experienced fire from both natural and anthropogenic sources, and are likely to respond favorably to its reintroduction. Results Random sampling was conducted in three burned sites and in three unburned sites, in an old-growth coast redwood (Sequoia sempervirens [D. Don] Endl.) forest. Data were collected on fuel, forest structure, and understory species composition and compared between treatments. Downed woody fuel, duff depth, litter depth, and density of live woody fuels were found to be significantly lower on sites treated with fire compared to unburned sites. Density of the dominant overstory canopy species, coast redwood and Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco), remained consistent between treatments, and the abundance of herbaceous understory plant species was not significantly altered by burning. In addition, both downed woody fuel and live fuel measures were positively correlated with time since last burn, with the lowest measures on the most recently burned sites. Conclusions Our results indicated that the use of prescribed burning in old-growth redwood forests can provide beneficial reductions in live and dead surface fuels with minimal impacts to overstory trees and understory herbaceous species.

scholarly journals Initial Floristic Response to High Severity Wildfire in an Old-Growth Coast Redwood (Sequoia sempervirens (D. Don) Endl.) Forest

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1135
Author(s):  
Mojgan Mahdizadeh ◽  
Will Russell
Keyword(s):  
Vegetation Type ◽  
Survival Rates ◽  
Tree Height ◽  
Fire Frequency ◽  
Sequoia Sempervirens ◽  
Type Conversion ◽  
Old Growth ◽  
Fire Event ◽  
Coast Redwood ◽  
High Severity

Climate driven increases in fire frequency and severity are predicted for Mediterranean climatic zones, including the Pacific coast of California. A recent high severity wildfire that burned in the Santa Cruz Mountains affected a variety of vegetation types, including ancient coast redwood (Sequoia sempervirens (D. Don) Endl.) stands. The purpose of this study was to characterize the survival and initial recovery of vegetation approximately six months after the fire. We sampled thirty randomly selected points in an old-growth coast redwood forest to examine and compare survival, crown retention, and post fire regeneration of trees by species, and the recovery of associated understory plant species. Sequoia sempervirens exhibited the highest post-fire survival (95%), with lower survival rates for subcanopy hardwood associates including tanoak (Notholithocarpus densiflorus (Hook. & Arn.) Manos) (88%), coast live oak (Quercus agrifolia Nee.) (93%), Pacific wax myrtle (Myrica californica (Cham. & Schltdl.) Wilbur) (75%), Pacific madrone (Arbutus menziesii Pursh) (71%), and the lowest survival recorded for the canopy codominant Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) (15%). Canopy retention and post fire regeneration were also highest for S. sempervirens and lowest for P. menziesii, indicating that S. sempervirens had a competitive advantage over P. menziesii following high severity crown fire. Both canopy survival and regeneration were greater for larger height and diameter trees; and basal sprouting was positively associated with tree height and diameter for S. sempervirens and N. densiflorus. Observed recovery of understory species was modest but included the reemergence of coast redwood associated herbaceous species. The robust nature of survival and recovery of S. sempervirens following this extreme fire event suggest that the removal of scorched, and the seeding or planting of trees, following this type of fire is contraindicated. The decline of P. menziesii is of concern, however, and suggests that repeated high severity fires driven by climate change could eventually lead to vegetation type conversion.

Clonal and nonclonal genetic structure of subarctic black spruce (Picea mariana) populations in Yukon territory

Botany ◽  
2011 ◽  
Vol 89 (2) ◽  
pp. 133-140 ◽  
Author(s):  
Marios Viktora ◽  
Rodney A. Savidge ◽  
Om P. Rajora
Keyword(s):  
Genetic Structure ◽  
Picea Mariana ◽  
Black Spruce ◽  
A Priori ◽  
Nuclear Genome ◽  
Yukon Territory ◽  
Fire Disturbance ◽  
Clone Size ◽  
Flat Terrain ◽  
Individual Trees

Black spruce (Picea mariana) reproduces sexually from seeds and asexually by layering. There is a prevalent concept that clonal reproduction maintains populations of this species in the subarctic and arctic regions. We used microsatellite DNA markers of the nuclear genome to investigate the genetic structure of montane and subalpine black spruce populations from the Western Yukon Plateau in relation to this concept. Sixty individual trees at a minimum distance of 4 m from each other were sampled from each of four populations and individual trees were genotyped for eight microsatellite loci. Each of the 60 individuals from three montane pure black spruce populations growing on flat terrain at relatively low elevations had unique multilocus genotypes, indicating an absence of clonal structure in those populations. However, in an anthropologically undisturbed climax white spruce-dominated subalpine black spruce population on a northwest slope near Mount Nansen, the majority of the sampled individuals belonged to eight genetically distinct clones (genets). Clone size differed by altitude, the dominant genet being nearest the timberline–tundra ecotone. The results indicate that black spruce reproduction is variable and adaptive, being primarily sexual in flat-terrain montane populations previously subjected to fire disturbance, but mixed vegetative–sexual in the anthropogenically undisturbed subalpine population. This study is the first to employ molecular markers a priori to examine the mode of reproduction in natural black spruce populations.

Calicium sequoiae, a new lichen species from north-western California, USA

2008 ◽  
Vol 40 (3) ◽  
pp. 185-194 ◽  
Author(s):  
Cameron B. WILLIAMS ◽  
Leif TIBELL
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Pacific Northwest ◽  
Its Region ◽  
Sequoia Sempervirens ◽  
Old Growth ◽  
The Pacific ◽  
Secondary Substance ◽  
North Western ◽  
A New Species

Abstract:We describe Calicium sequoiae as a new species of lichenized Ascomycota from north-western California, USA. The species is distinguished morphologically from other known members of Calicium by its stalks that react I+ blue, mature ascospores that are ornamented with spiral ridges, and apothecia that produce prominent white pruina. It is also the only Calicium known to produce thamnolic acid as a major secondary substance. Sequences from the ITS-region showed C. sequoiae to be unique among calicioid Physciaceae, and phylogenetic analysis positioned it close to C. adspersum, C. chlorosporum, C. lenticulare, Cyphelium notarisii, and C. tigillare. Thus far, Calicium sequoiae has been collected only from old-growth redwood (Sequoia sempervirens) forests, where it occurred on thick, fibrous bark of large redwood trees. A key to the 12 species of Calicium known from the Pacific Northwest is provided.

scholarly journals Movement of Genotypes of Ceratocystis fimbriata Within and Among Eucalyptus Plantations in Brazil

2011 ◽  
Vol 101 (8) ◽  
pp. 1005-1012 ◽  
Author(s):  
Maria A. Ferreira ◽  
Thomas C. Harrington ◽  
Acelino C. Alfenas ◽  
Eduardo S. G. Mizubuti
Keyword(s):  
Microsatellite Markers ◽  
Cutting Tools ◽  
Genotypic Diversity ◽  
The State ◽  
Soilborne Pathogen ◽  
Ceratocystis Fimbriata ◽  
Rooted Cuttings ◽  
Ceratocystis Wilt ◽  
Eucalyptus Plantations ◽  
Individual Trees

Ceratocystis wilt on eucalyptus, caused by Ceratocystis fimbriata, was first recognized in 1997 in the state of Bahia, Brazil, but is now known in five other states and in four other countries. C. fimbriata is a native, soilborne pathogen in some parts of Brazil but we hypothesized that genotypes of the pathogen have been moved among plantations in rooted cuttings collected from diseased trees and within plantations on cutting tools. We used six microsatellite markers to identify 78 genotypes of C. fimbriata among 177 isolates from individual trees in 20 eucalyptus plantations. The highest gene and genotypic diversity values were found in plantations on formerly wild Cerrado forest in Minas Gerais, suggesting that the fungus was in the soil prior to planting eucalyptus. In contrast, one or only a few genotypes were found in plantations on previous pastureland (with no woody hosts) in Bahia and São Paulo, and most of these genotypes were found in a Bahian nursery or in one of two Bahian plantations that were sources for rooted cuttings. Sources of cuttings tended to be dominated by one or a few genotypes that may have been spread within the plantation on cutting tools.

scholarly journals Vesicular–Arbuscular Mycorrhizae Colonization of Redwood and Incense Cedar Seedlings following Storage

HortScience ◽  
1994 ◽  
Vol 29 (11) ◽  
pp. 1362-1365 ◽  
Author(s):  
U. Afek ◽  
L.A. Lippet ◽  
D. Adams ◽  
J.A. Menge ◽  
E. Pond
Keyword(s):  
Glomus Mosseae ◽  
Arbuscular Mycorrhizae ◽  
Arbuscular Mycorrhizal ◽  
Sequoia Sempervirens ◽  
Fresh Weight ◽  
Coast Redwood ◽  
Moisture Contents ◽  
Vesicular Arbuscular Mycorrhizae ◽  
Vesicular Arbuscular

Vesicular–arbuscular mycorrhizal inoculum consisting of a mixture of roots of coast redwood [Sequoia sempervirens (D. Don)], soil, and spores of Glomus mosseae (Nicol. and Gerd.) Gerdemann and Trappe was tested for viability and efficacy following storage for 4 or 8 weeks at 4, 9, 15, or 24C and moisture contents of 0%, 6%, 12%, or 17%. Storage regimes did not have any effect on the number of spores of Glomus mosseae recovered after storage. However, germinability of the spores decreased from 35% before storage to 10% to 31% during storage, especially under typical ambient room conditions (17% moisture at 24C). Maximum colonization of coast redwood, sierra redwood [Sequoiadendrom giganteum (Lindl.) Buchh.], and incense cedar (Libocedrous decurrens Torr.) was achieved after inoculation with 1 inoculum: 1 potting mix dilution (w/w). However, plant fresh weight was highest following inoculation with a 1 inoculum: 5 potting mix dilution (w/w). Dried inoculum was effective when stored at 24C, or below 10C when moist.

Estimating relative error in growth ring analyses of second-growth coast redwood (Sequoia sempervirens)

2006 ◽  
Vol 36 (9) ◽  
pp. 2216-2222 ◽  
Author(s):  
Kristen M Waring ◽  
Kevin L O'Hara
Keyword(s):  
Cross Sections ◽  
Growth Ring ◽  
Ring Width ◽  
Sequoia Sempervirens ◽  
North Central ◽  
Coast Redwood ◽  
Central California ◽  
Breast Height ◽  
Second Growth ◽  
Annual Growth Rings

Coast redwood (Sequoia sempervirens (D. Don) Endl.) grows in the coastal zone of north-central California and southern Oregon in pure and mixed-species forests. Redwood has long been recognized to exhibit unusual patterns within the annual growth rings typical of temperate forest trees, including partial and missing rings and ring-width anomalies. However, these patterns have not been quantified beyond a few suppressed trees. This study quantified the variation in ring counts occurring in 22 second-growth redwood trees from different canopy classes. Ring counts from cross sections taken at sample points along each tree bole revealed missing or incomplete rings in all sample trees and 70% of the cross sections. Ring counts along multiple radii were used to calculate probability of obtaining a maximum ring count along one radius. This probability was lowest at the tree base (0.25) and breast height (0.30) and highest near the top of the tree (0.90). Because of the high amount of variation present in ring counts at breast height, care should be taken when drawing conclusions regarding stand ages from increment cores. Increment cores should be taken from the longest axis of the tree and coring at tree base can be abandoned as cores are not likely to have higher ring counts than breast height cores.

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