Coast Redwood Trees Research Articles

Characterizing lift, drag, and pressure differences across wandering salamanders (Aneides vagrans) with computational fluid dynamics to investigate aerodynamics.

Wandering salamanders (Aneides vagrans), known to occupy the crowns of old growth coast redwood trees, have recently been found to decelerate and engage in controlled, nonvertical descent while falling. Closely related, nonarboreal species with seemingly minor morphological differences exhibit far less behavioral control while falling; however, the influence of salamander morphology on aerodynamics remains to be tested. Here, we examine differences in morphology and aerodynamics of two salamander species, A. vagrans and the nonarboreal ensatina salamander (Ensatina eschscholtzii), using a combination of traditional and contemporary techniques. Specifically, we compare morphometrics statistically, then use computational fluid dynamics (CFD) to characterize predicted airflow and pressure over digitally reconstructed models of the salamanders. While similar in body and tail lengths, A. vagrans are more dorsoventrally flattened with longer limbs and greater surface area of the foot relative to body size than the nonarboreal E. eschscholtzii. CFD results show dorsoventral pressure gradients differ between the two digitally reconstructed salamanders resulting in lift coefficients of approximately 0.02 and 0.00, and lift:drag ratios of approximately 0.40 and 0.00 for A. vagrans and E. eschscholtzii, respectively. We conclude that the morphology of A. vagrans is better suited for controlled descent than that of the closely related E. eschscholtzii and highlight the importance of subtle morphological features, such as dorsoventral flatness, foot size, and limb length, for aerial control. That our simulation reports align with real-world performance data underscores the benefits of CFD for studying the link between morphology and aerodynamics in other taxa.

Genetic structure of coast redwood (Sequoia sempervirens [D. Don] Endl.) populations in and outside of the natural distribution range based on nuclear and chloroplast microsatellite markers.

Coast redwood (Sequoia sempervirens) naturally growing in southern Oregon and northern California is one of the few conifer tree species that are polyploid. Despite its unique ecological and economic importance, its population genetic structure is still insufficiently studied. To obtain additional data on its population genetic structure we genotyped 317 samples collected from populations in California (data set C) and 144 trees growing in a provenance trial in France (data set F) using 12 nuclear (five random nuclear genomic nSSRs and seven expressed sequence tag EST-SSRs) and six chloroplast (cpSSRs) microsatellite or simple sequence repeat (SSR) markers, respectively. These data sets were also used as reference to infer the origin of 147 coast redwood trees growing in Germany (data set G). Coast redwood was introduced to Europe, including Germany as an ornamental species, decades ago. Due to its fast growth and high timber quality, it could be considered as a potential commercial timber species, especially in perspective to climate warming that makes more regions in Germany suitable for its growing. The well performing trees in colder Germany could be potential frost resistant genotypes, but their genetic properties and origin are mostly unknown. Within the natural range in southern Oregon and northern California, only two relatively weak clusters were identified, one northern and one southern, separated by the San Francisco Bay. High genetic diversity, but low differentiation was found based on the 12 nuclear SSR markers for all three data sets F, C and G. We found that investigated 147 German trees represented only 37 different genotypes. They showed genetic diversity at the level less than diversity observed within the natural range in the northern or southern cluster, but more similar to the diversity observed in the southern cluster. It was difficult to assign German trees to the original single native populations using the six cpSSR markers, but rather to either the northern or southern cluster. The high number of haplotypes found in the data sets based on six cpSSR markers and low genetic differentiation based on 12 nuclear SSRs found in this study helps us study and better understand population genetic structure of this complex polyploid tree and supports the selection of potential genotypes for German forestry.

Characterization and Pathogenicity of Botryosphaeriaceae Fungi Associated with Declining Urban Stands of Coast Redwood in California.

Coast redwood (Sequoia sempervirens) is among the most widely planted landscape trees in California (CA) but is in decline outside its natural range due to factors including prolonged drought and plant pathogens. We investigated associations of Botryosphaeriaceae fungi with declining coast redwood trees throughout CA. More than 100 samples were collected from 11 coastal and inland locations in CA. Fifty-nine Botryosphaeria-like fungal strains were isolated and 18 were selected for further study. Phylogenetic analysis of ITS and EF-1α sequence data confirmed the presence of Botryosphaeria dothidea, Neofusicoccum australe, N. luteum, N. mediterraneum, and N. parvum. Pathogenicity testing showed that although the Neofusicoccum species vary in virulence, all are more virulent that B. dothidea. N. australe caused the largest lesions, followed by N. luteum, N. parvum, and N. mediterraneum. Of the species recovered, only B. dothidea has been previously confirmed as a pathogen of coast redwood in CA. These results confirm that multiple Botryosphaeriaceae species are associated with branch decline and dieback on coast redwood in CA, which agrees with similar studies on woody agricultural crops. Accurate diagnosis of fungal pathogens of coast redwood is important for the development of disease management strategies and may help improve horticultural practices in maintenance of urban stands.

Managed Migration of Coast Redwoods: Subjectivity of Stakeholders in Oregon’s Land Use Planning Community

The Earth’s climate is changing at a faster pace than the slow natural adjustment rates of most species to their rapidly shifting habitat conditions, especially for long-lived tree species, such as the iconic coast redwood Sequoia sempersqvirens. This may leave some species stranded in less than optimal environments, resulting in population extinctions and/or the need for human-assisted migration. However, the implementation of assisted migration does not come without economic, legal, political, ecological, and ethical issues. One of the most important and complex social questions regarding assisted migration is that of the land use planning community in the area being considered. This article explores the subjective beliefs among these stakeholders regarding managed migration of coast redwood trees into suitable habitats in Oregon. Q-methodology was used to structure the complexity of participants’ subjective beliefs into a few manageable themes to reveal broader socio-economic and environmental perspectives and shared ways of perceiving and valuing the relationship between social, economic, and environmental concerns. The findings of this study suggest two main factors 1) positively ranked values that align on new perspectives of utilitarian ecological values, and 2) positively ranked values that align on a land based communitarian perspective. This convergence suggests an ecologically aware land management ethos as opposed to the view of favoring human’s dominion over nature, and therefore bolsters the potential for the future success of managed migration of coast redwoods into suitable habitats in Oregon given the state’s existing land use policy.

Variation in the wood properties of coast redwood trees in New Zealand

There is wide variation in the wood properties of plantation-grown coast redwood (Sequoia sempervirens (D.Don) Endl.) in New Zealand. Contributing factors are the seed source, silviculture, growth rate and age of the trees in the plantation forests. Little is known about how these factors affect the variation of wood properties among and within the trees of New Zealand’s coast redwood forests. The wood of plantation-grown coast redwood trees from three forests in the North Island, New Zealand, was evaluated using butt log and breast height discs and cores, and in vitro decay tests with brown- and white-rot fungal cultures, to determine the variation in the heartwood content, basic density, and red colour and natural durability of the heartwood. The heartwood content of the coast redwood trees was strongly influenced by the age and size of the trees. The basic density of the wood varied widely among the trees in the forests. There were strong radial trends of heartwood colour and natural durability within the stems of trees, with differences among trees at the same growth rings. The heartwood showed a wide range of natural durability, with trees from the older forest stands having a higher proportion of durable heartwood. The diameter growth and age of the coast redwood trees, and the variation among and within the stems of trees will affect the wood properties. Faster diameter growth is likely to increase the heartwood content, and longer rotations will increase the quantity of durable heartwood. The variation among trees suggests there is potential for genetic improvement.

Survival and Recovery Following Wildfire in the Southern Range of the Coast Redwood Forest

AbstractFire plays a central role in determining structure, composition, and recruitment in many forest types. In coast redwood forests, the role of fire is not well understood and scant literature exists on post-fire response, particularly in the southern part of the range. In order to better understand patterns of survival and recruitment following fire for coast redwood (Sequoia sempervirens [lamb. ex D. Don] Endl.) and associated tree species, three sites in the Santa Cruz Mountains, California, USA, were sampled following wildfire. Randomly selected 10 m diameter plots were used to collect data on survivorship and post fire regeneration in order to analyze short-term responses including mortality, crown retention, basal sprouting, canopy regeneration, and seedling production. Results indicated that coast redwood had the lowest percent mortality (11.98 %) and highest mean canopy retention (43.10 %) of all species sampled, followed by Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) (25.54 %), tanoak (Notholithocarpus densiflorus [Hook. & Arn.] Manos) (23.27 %), combined oak species (Quercus sp.) (6.67 %), and Pacific madrone (Arbutus menziesii Pursh) (4.13 %). In addition, associated species experienced higher survival rates when proximate to coast redwoods. Coast redwood trees also exhibited the highest canopy regeneration (53 %), the highest average density of basal sprouts (3.54 × 104 ha), and the greatest average number of seedlings, ranging from zero to 2.09 × 105 seedlings ha−1. Overall, coast redwood appeared to have a balance of fire adaptive features, exceeding all associated species, which allow individual trees to withstand fire, while at the same time promoting recruitment following fire.

Natural Durability of the Heartwood of Coast Redwood [Sequoia Sempervirens (D.Don) Endl.] and its Prediction Using near Infrared Spectroscopy

The heartwood of plantation-grown coast redwood trees from three forests in the North Island, New Zealand, was evaluated using in vitro decay tests with fungal cultures to determine variation in natural durability and its prediction using near infrared (NIR) spectroscopy. The NIR spectra were acquired from the solid wood surface, prior to decay testing, using a fibre-optic probe attached to a Bruker MPA FT-NIR spectrometer and an imaging spectrograph coupled to a NIR line camera. The partial least squares (PLS) regression models of mass loss with fungal decay testing, based on spectra collected with the FT-NIR spectrometer, had better predictive performance than the NIR line camera, as evidenced by fewer latent variables and slightly better R2. The ratios of prediction to deviation ( RPD) were 1.3 to 1.4 for both the spectrometer and camera system, which suggests the PLS regression models could be used to segregate the heartwood of coast redwood for high- and low values of natural durability.

Fire History in Coast Redwood Stands in the Northeastern Santa Cruz Mountains, California

Fire regimes in coast redwood forests in the northeastern Santa Cruz Mountains were determined by ring counts from 48 coast redwood stumps, downed logs, and live trees. Degradation of remnant materials from post-harvest fires severely limited available fire scars in this region. The earliest recorded fire was recorded in approximately 1615 and the last fire recorded was in 1884. The Ohlone and early immigrants were probably the primary source of ignitions in this region. For all sites combined, the mean fire return interval (FRI) was 12.0 years; the median FRI was 10 years. There was no significant difference in FRI’s between plot aspects but there was a significant difference in MFI between the four sampled sites. The grand mean FRI for single trees (point) was 16.3 years. Past fire scars occurred most frequently in the latewood portion of the annual ring or during the dormant period. It is probable that the number of fires recorded in coast redwood trees is a subset of those fires that burned in adjacent grasslands and oak savannahs. Continued development of old-growth and young-growth coast redwood forests toward prehistoric conditions may be dependent of a fire regime where prescribed burning substitutes for the now-absent aboriginal ignitions.

A cross-dated fire history from coast redwood near Redwood National Park, California

Cross sections from coast redwood trees (Sequoiasempervirens (D.Don.)Endl.) in and near Redwood National Park were dendrochronologically cross-dated and used to develop a fire history from 1714 to 1985. A master chronology for the study area was first developed from old-growth trees and provided dating control for fire-scarred samples. Redwood offers a challenge for dendrochronology owing to partially absent rings (ring wedging) and uniform ring widths (complacency). Cross dating was successful in portions of 12 of 24 fire-scarred trees. Fire events were dated by noting the position of fire scars and other fire-associated ring structures (resin ducts, double latewood, growth releases, and ring separations) in the cross-dated ring series. Using only dates of fire scars, the mean fire interval (MFI) was 9.9 years from the first recorded fire in 1714 to the last in 1962. The MFI was 8.0 years for the best represented (greatest sample depth) presettlement period from 1714 to 1881. Using dates for all fire-associated ring features, the MFI from 1714 to 1962 was 7.0 years and from 1714 to 1881 was 6.0 years. Use of all fire-associated ring characteristics is argued to be a more complete representation of past fire frequency due to possible under-representation of fire-scar records from stump-top samples. Based upon scar positions within annual rings, fires occurred predominately late in the growing season or after growth ceased for the year. The mean fire intervals determined are shorter than those reported in all except one other fire history study from coast redwood and suggest that fire frequency in redwood may have been underestimated in many past studies.

Modeling effects of prescribed fire on young-growth coast redwood trees

The study was designed to produce data for modeling effects of prescribed fire treatments on top killing and basal sprouting of coast redwood trees (Sequoiasempervirens (D. Don) Endl.) at the plot and individual-tree level. Prescribed fire treatments included two levels of fireline intensity and surface fuel consumption crossed in randomized blocks. Burning was conducted on 32 plots each containing approximately 150 to 250 redwoods. Binary responses of individual trees were modeled using logistic regression analysis. Percent response of trees on each plot by 5-cm diameter classes was modeled using logistic and nonlinear regression analysis. Tree diameter, surface fuel consumption, flame length, and crown scorch were significant predictors in all models of top killing and basal sprouting. Models relating heights of crown scorch and bark charring to fire and tree characteristics were also developed. The ability of coast redwood to sprout along branches following foliar damage from fire is unusual among conifers and contributes to a low incidence of top killing.

Dark metabolic heat rates and integrated growth rates of coast redwood clones are correlated

The metabolic heat rate per gram of apical meristem tissue of coast redwood ( Sequoia sempervirens) is measured to examine the variation of dark respiration rate among clones. Metabolic heat rates are found to be linearly related to integrated growth rates of both 60-day-old unrooted clones and 25-year-old trees. The correlation suggests that metabolic heat rate measurements may provide a means for rapid selection of coast redwood trees with high genetic potential for rapid growth.