Sequoia Sempervirens Research Articles

The Right Tree for the Job? Perceptions of Species Suitability for the Provision of Ecosystem Services

Stakeholders in plantation forestry are increasingly aware of the importance of the ecosystem services and non-market values associated with forests. In New Zealand, there is significant interest in establishing species other than Pinus radiata D. Don (the dominant plantation species) in the belief that alternative species are better suited to deliver these services. Significant risk is associated with this position as there is little objective data to support these views. To identify which species were likely to be planted to deliver ecosystem services, a survey was distributed to examine stakeholder perceptions. Stakeholders were asked which of 15 tree attributes contributed to the provision of five ecosystem services (amenity value, bioenergy production, carbon capture, the diversity of native habitat, and erosion control/water quality) and to identify which of 22 candidate tree species possessed those attributes. These data were combined to identify the species perceived most suitable for the delivery of each ecosystem service. Sequoia sempervirens (D.Don) Endl. closely matched the stakeholder derived ideotypes associated with all five ecosystem services. Comparisons to data from growth, physiological and ecological studies demonstrated that many of the opinions held by stakeholders were inaccurate, leading to erroneous assumptions regarding the suitability of most candidate species. Stakeholder perceptions substantially influence tree species selection, and plantations established on the basis of inaccurate opinions are unlikely to deliver the desired outcomes. Attitudinal surveys associated with engagement campaigns are essential to improve stakeholder knowledge, advancing the development of fit-for-purpose forest management that provides the required ecosystem services.

Restoration of Coast Redwood (<i>Sequoia sempervirens</i>) Forests through Natural Recovery

The management of second-growth Sequoia sempervirens (coast redwood) forests for the purpose of restoration and ecological conservation is a growing trend. However, little is known about the long-term regenerative potential of this forest type in the absence of post-harvest management techniques such as thinning and planting. Data on forest composition and structure were collected on a chronosequence (80 - 160 years) of mature recovering stands in the southern coast redwood range using a replicated, randomized, plot design. Results indicated that many stand characteristics including tree density, canopy cover, redwood dominance, species richness, herbaceous cover, and shrub cover reached levels statistically equivalent with old-growth reference sites in recovering stands within the time frame of this chronosequence. The recovery of individual herbaceous understory species was inconsistent however. While the cover of redwood-associated species (Oxalis oregana, Trientalis latifolia, and Disporum hookeri) reached levels statistically equivalent to old-growth reference sites, others (Trillium ovatum and Viola sempervirens) did not. Total basal area and species evenness also trended toward, but did not reach, old-growth conditions. The arboreal aspects of coast redwood forests appear to be remarkably resilient following a single logging event, and recover rapidly in the absence of active restoration techniques. The protracted recovery of certain redwood associated herbaceous understory species will require further study.

An individual-based growth and competition model for coastal redwood forest restoration

Thinning treatments to accelerate coastal redwood forest stand development are in wide application, but managers have yet to identify prescriptions that might best promote Sequoia sempervirens (Lamb. ex D. Don) Endl. (redwood) growth. The creation of successful thinning prescriptions would be aided by identifying the underlying mechanisms governing how individual tree growth responds to competitive environments in coastal redwood forests. We created a spatially explicit individual-based model of tree competition and growth parameterized using surveys of upland redwood forests at Redwood National Park, California. We modeled competition for overstory trees (stems ≥ 20 cm stem diameter at breast height, 1.37 m (dbh)) as growth reductions arising from sizes, distances, and species identity of competitor trees. Our model explained up to half of the variation in individual tree growth, suggesting that neighborhood crowding is an important determinant of growth in this forest type. We used our model to simulate the effects of novel thinning prescriptions (e.g., 40% stand basal area removal) for redwood forest restoration, concluding that these treatments could lead to substantial growth releases, particularly for S. sempervirens. The results of this study, along with continued improvements to our model, will help to determine spacing and species composition that best encourage growth.

Estimating site productivity in irregular stand structures by indexing the basal area or volume increment of the dominant species

Estimating site productivity in irregular structures is complicated by variations in stand density, structure, composition in mixed stands, and suppression experienced by subordinate trees. Our objective was to develop an alternate to site index (SI) and demonstrate its application in models of individual-tree and stand growth. We analyzed coast redwood (Sequoia sempervirens (Lamb. ex D. Don) Endl.) tree and stand growth in a grid of 234 permanent sample plots covering a 110 ha study area in north coastal California. Partial harvesting created a mosaic of densities and openings throughout the 60-year-old redwood-dominated forest. Redwood SI was a poor predictor of volume increment (VI) per hectare among redwood in each plot over two decades after harvest. A new index of redwood basal area increment (BAI) productivity, calculated using inventory data for all stems in even-aged stands and the oldest cohort of multiaged stands, was a stronger predictor of VI. Diameter increment of individual redwood trees correlated strongly with stand density and the new BAI index. Forest managers should expect widely divergent responses following partial harvesting in crowded even-aged stands, with the greatest response coming from dominant redwoods with long crowns retained in areas with low residual stand density and high BAI index.

Potentialités de production de biomasse de quelques essences résineuses en conditions forestières : Douglas, Épicéa commun, Épicéa de Sitka, Cyprès de Leyland, Séquoia toujours vert

In anticipation of the increase in biomass demand, the authors investigate the possibility of increasing woody production on medium- to low-fertility forest soils by choosing appropriate species and silvicultural methods to produce biomass either exclusively (dedicated scenario), or partially (semi-dedicated scenario) for energy. The production of total aerial biomass is documented for six forest conifers on the basis of dendrometric results most of which were acquired through the FCBA test network (Douglas Fir, Common Spruce, Sitka Spruce, Leyland Cypress, Sequoia sempervirens, Japanese Cedar). The Maritime Pine was investigated through a review of the bibliography. For the most frequent species, the effect of some factors (forest capability class, plantation density, genetic level) was examined. The mean observed increases, which vary between 6 and 10 tonnes/ha/yr. towards 20 years for most species, are then compared to those arising from systems already developed for the purpose of producing biomass, e.g. the VSR Poplar or Eucalyptus coppices, but for which the data was mostly acquired under agricultural conditions. Finally, some of the consequences of intensification of woody production are discussed.

On the patterns and processes of wood in northern California streams

Forest management and stream habitat can be improved by clarifying the primary riparian and geomorphic controls on streams. To this end, we evaluated the recruitment, storage, transport, and the function of wood in 95km of streams (most drainage areas<30km2) in northern California, crossing four coastal to inland regions with different histories of forest management (managed, less-managed, unmanaged). The dominant source of variability in stream wood storage and recruitment is driven by local variation in rates of bank erosion, forest mortality, and mass wasting. These processes are controlled by changes in watershed structure, including the location of canyons, floodplains and tributary confluences; types of geology and topography; and forest types and management history. Average wood storage volumes in coastal streams are 5 to 20 times greater than inland sites primarily from higher riparian forest biomass and growth rates (productivity), with some influence by longer residence time of wood in streams and more wood from landsliding and logging sources. Wood recruitment by mortality (windthrow, disease, senescence) was substantial across all sites (mean 50%) followed by bank erosion (43%) and more locally by mass wasting (7%). The distances to sources of stream wood are controlled by recruitment process and tree height. Ninety percent of wood recruitment occurs within 10 to 35m of channels in managed and less-managed forests and upward of 50m in unmanaged Sequoia and coast redwood forests. Local landsliding extends the source distance. The recruitment of large wood pieces that create jams (mean diameter 0.7m) is primarily by bank erosion in managed forests and by mortality in unmanaged forests. Formation of pools by wood is more frequent in streams with low stream power, indicating the further relevance of environmental context and watershed structure. Forest management influences stream wood dynamics, where smaller trees in managed forests often generate shorter distances to sources of stream wood, lower stream wood storage, and smaller diameter stream wood. These findings can be used to improve riparian protection and inform spatially explicit riparian management.

A Paleolimnological Record of Late Holocene Vegetation Change from the Central California Coast

In this paper, we present results of the analysis of the pollen and microscopic charcoal content of a sediment core from Skylark Pond near Point Año Nuevo in Santa Cruz County, California. The core covers approximately the last 3,000 years and is of interest because Skylark Pond is located only 1.8 km from Quiroste Valley State Cultural Preserve, an important ceremonial and habitation location for the historic Quiroste tribe containing numerous late Holocene archaeological sites. The results show an increase in fire activity from the fifteenth century to the present. Peaks in charcoal at ca. AD 1425 along with subsequent high charcoal abundance indicate either small, frequent fires ignited by humans or large natural conflagrations. Significant changes after European colonization include increases in grass, oak, and bracken fern, all of which indicate the opening of the redwood forest by logging and ranching. Historic period charcoal peaks can be attributed to the burning of logging slash.

Oxygen and carbon stable isotopes in coast redwood tree rings respond to spring and summer climate signals

AbstractInterannual variability in the oxygen and carbon isotope composition of tree ring cellulose was investigated in coast redwood (Sequoia sempervirens) from three sites in coastal Northern California. Middle and late wood samples from annual tree rings were compared to regional climate indices and gridded ocean‐atmosphere fields for the years 1952–2003. The strongest climate‐isotope relationship (r = 0.72) was found with summer (June–September) daily maximum temperature and middle wood δ13, which also responds positively to coastal sea surface temperature and negatively to summer low cloud frequency. Late wood δ18O reflects a balance between 18O‐enriched summer fog drip and depleted summer rainwater, while a combined analysis of late wood δ18O and δ13C revealed sensitivity to the sign of summer precipitation anomalies. Empirical orthogonal function analysis of regional summer climate indices and coast redwood stable isotopes identified multivariate isotopic responses to summer fog and drought that correspond to atmospheric circulation anomalies over the NE Pacific and NW U.S. The presence of regional climate signals in coast redwood stable isotope composition, consistent with known mechanistic processes and prior studies, offers the potential for high‐resolution paleoclimate reconstructions of the California current system from this long‐lived tree species.

Holocene and historical vegetation change and fire history on the north-central coast of California, USA

Pollen, non-pollen palynomorphs (NPPs), and charcoal particle stratigraphies are used to determine environmental change at Glenmire, Point Reyes Peninsula, northcentral coastal California, over the last c. 6200 years. Pollen was not preserved in early Holocene sediments when climate was drier than present. However, groundwater tables rose after c. 6200 cal. BP, allowing for greater subsequent preservation of organic matter. Middle and late Holocene environments were a mosaic of vegetation types, including mixed conifer forest with coastal scrub grassland prior to c. 4000 cal. BP. Subsequently, hardwoods such as alder ( Alnus) and coastal scrub (e.g. Artemisia, Baccharis) expanded until c. 2200 cal. BP, followed by tanoak ( Lithocarpus densiflorus), Douglas fir ( Pseudotsuga menziesii), and coast redwood ( Sequoia sempervirens). With increasing amounts of oak ( Quercus), this mosaic of vegetation types continued to dominate until the arrival of Euro-Americans in the early to mid-1800s. The fire history is probably tied closely to human settlement, since natural ignitions are rare. Elevated charcoal amounts coincide with increased sedentism of the native populations by about 3500 cal. BP. Increased sedentism may have caused a more intense and constant use of the coastal environment around Glenmire. For the most recent centuries, we compared historical records of explorations, Spanish Mission establishment, consolidation of the native Coast Miwok population, ranching by Mexican nationals, and dairying by Americans at the height of California’s gold rush with the paleoecological record. The Glenmire record thus documents changing fire use following the ad 1793 fire suppression proclamation; declines in native forest species; introductions of non-native species, including those associated with livestock grazing and land disturbance; and an increase in coprophilous fungi (NPPs) associated with the presence of large numbers of sheep and cattle, among other changes. During the historical period, the sedimentary record of historical fires closely matches the nearby fire-scar tree-ring record.

Unexpected redwood mortality from synergies between wildfire and an emerging infectious disease

An under-examined component of global change is the alteration of disturbance regimes due to warming climates, continued species invasions, and accelerated land-use change. These drivers of global change are themselves novel ecosystem disturbances that may interact with historically occurring disturbances in complex ways. Here we use the natural experiment presented by wildfires in redwood forests impacted by an emerging infectious disease to demonstrate unexpected synergies of novel disturbance interactions. The dominant tree, coast redwood (fire resistant without negative disease impacts), experienced unexpected synergistic increases in mortality when fire and disease co-occurred. The increased mortality risk, more than fourfold at the peak of the effect, was not predictable from impacts of either disturbance alone. Changes in fire behavior associated with changes to forest fuels that occurred through disease progression overwhelmed redwood's usual resilience to wildfire. Our results demonstrate the potential for interacting disturbances to initiate novel successional trajectories and compromise ecosystem resilience.

Light use efficiency of California redwood forest understory plants along a moisture gradient

We investigated photosynthesis of five plant species growing in the understory at three sites (1,170-, 1,600- and 2,100-mm annual moisture inputs), along the geographical range of coastal California redwood forest, to determine whether greater inputs of rain and fog at northern sites enhance photosynthetic utilization of fluctuating light. Measurements of understory light environment and gas exchange were carried out to determine steady state and dynamic photosynthetic responses to light. Leaf area index ranged from 4.84 at the 2,100-mm site to 5.98 at the 1,170-mm site. Maximum rates of net photosynthesis and stomatal conductance (g) did not vary appreciably within species across sites. Photosynthetic induction after a change from low to high light was significantly greater in plants growing in lower light conditions regardless of site. Photosynthetic induction also increased with the rate of g in diffuse light, prior to the increase to saturating light levels. Post-illumination CO2 assimilation was the largest factor contributing to variation in C gain during simulated lightflecks. The duration of post-illumination photosynthetic activity, total CO2 assimilation per light received, and light use efficiency during simulated lightflecks increased significantly with moisture inputs in four out of five species. Increasing leaf N concentration with increasing moisture inputs in three out of five species, coupled with changes in leaf N isotopic composition with the onset of the summer fog season suggest that natural N deposition increases with rain and fog inputs and contributes to greater utilization of fluctuating light availability in coastal California redwood forests.

Histone deacetylases govern heterochromatin in every phase

Deacetylation of histone tails has been shown to play a role during heterochromatin formation, but the precise mechanism of action has not been understood. Complementary results presented in two recent articles in The EMBO Journal (Alper et al , 2013; Buscaino et al , 2013) together reveal how histone deacetylases (HDACs) affect the various phases of heterochromatin formation: establishment, maintenance and spreading. Heterochromatin, condensed chromatin that is transcriptionally inactive, plays important roles in epigenetic regulation of gene expression and other chromosomal functions, such as chromosome segregation and telomere maintenance. Fission yeast is a good model system to analyse heterochromatin because of the similarity of its heterochromatin structure to other eukaryotes and the ease of genetic analysis. In fact, this organism has contributed greatly to our understanding of the importance of RNA interference (RNAi) during heterochromatin formation. Heterochromatin is defined by methylation of lysine 9 of histone H3 (H3K9me) and hypo‐acetylation of histones. H3K9me provides the binding sites for heterochromatin protein 1, HP1 (Swi6 in fission yeast, Nakayama et al , 2001). Since deacetylation of histone tails by HDACs generally correlates with the repression of transcription at euchromatic regions, a similar function of HDACs is expected at heterochromatin. Indeed, the HDAC Clr3 is required for efficient repression of …

A New Species of Mesoptychia (Lindb.) A. Evans from California

AbstractA small, endemic leafy liverwort found in the coastal redwood forests of Santa Cruz and Monterey Counties of California is described as a new species of Mesoptychia (Lindb.) A. Evans, i.e., Mesoptychia polymorpha Stotler, Crand.-Stotl. &amp; Bakalin, sp. nov. This new taxon is morphologically related to the suite of small-leafed species of the genus, including M. badensis (Gottsche ex Rabenh.) L. Söderstr. &amp; Váňa and M. morrisoncola (Horik.) L. Söderstr. &amp; Váňa, but is unique within the genus in having mature vegetative leaves and bracts that are undivided and apically rounded to emarginate, with bilobed to retuse leaves of restricted occurrence. Although this polymorphic species is paroicous, perianths expand without fertilization and sporophytes are unknown.

Mortality and community changes drive sudden oak death impacts on litterfall and soil nitrogen cycling

Few studies have quantified pathogen impacts to ecosystem processes, despite the fact that pathogens cause or contribute to regional-scale tree mortality. We measured litterfall mass, litterfall chemistry, and soil nitrogen (N) cycling associated with multiple hosts along a gradient of mortality caused by Phytophthora ramorum, the cause of sudden oak death. In redwood forests, the epidemiological and ecological characteristics of the major overstory species determine disease patterns and the magnitude and nature of ecosystem change. Bay laurel (Umbellularia californica) has high litterfall N (0.992%), greater soil extractable NO3 -N, and transmits infection without suffering mortality. Tanoak (Notholithocarpus densiflorus) has moderate litterfall N (0.723%) and transmits infection while suffering extensive mortality that leads to higher extractable soil NO3 -N. Redwood (Sequoia sempervirens) has relatively low litterfall N (0.519%), does not suffer mortality or transmit the pathogen, but dominates forest biomass. The strongest impact of pathogen-caused mortality was the potential shift in species composition, which will alter litterfall chemistry, patterns and dynamics of litterfall mass, and increase soil NO3 -N availability. Patterns of P.ramorum spread and consequent mortality are closely associated with bay laurel abundances, suggesting this species will drive both disease emergence and subsequent ecosystem function.

Modeling Young Stand Development towards the Old-Growth Reference Condition in Evergreen Mixed-Conifer Stands at Headwaters Forest Reserve, California

We sought to answer the question: How do we restore characteristics of old-growth evergreen mixed-conifer forests in young even-aged stands on upland terrain at Headwaters Forest Reserve (HFR)? We described the old-growth reference condition for three stands at HFR. In each old-growth stand, trees within a 1-ha plot were inventoried. We found coast Douglas-fir (Pseudotsuga menziesii var. menziesii) and tanoak (Notholithocarpus densiflorus) well represented while coast redwood (Sequoia sempervirens) dominated in terms of size. Numbers of understory and overstory trees ha−1 and average tree sizes were similar among sites, suggesting these were useful goals for restoration. Adjacent to each old-growth stand, we measured recent growth rates of second-growth trees and remnant old trees across a range of tree sizes, stand structures, and densities. The resultant growth models of redwood and Douglas-fir enabled us to project the development of precommercially thinned young stands at HFR forward in time under two silvicultural prescriptions: (i) no further management; and (ii) partial harvesting simulated before trees attained 30 cm dbh. The partial-harvesting prescription reduced stand density and set the young stand on a more rapid trajectory towards the reference condition found at HFR.

Potential Late-Holocene Disjunction ofSequoia sempervirenson the Central Oregon Coast

A large (> 200-cm diameter) coast redwood (Sequoia sempervirens) stump occurring upright on an Oregon beach, 257 km from the northern limit of its native distribution, may be a remnant of an extinct disjunct population or it may be the result of vertical emplacement of a drift log. Holocene tree stumps in situ in paleosols commonly emerge on the shore platform as a result of a complex history of dune activity, subsidence, and erosion. An historical account reported organic soils associated with the stump during the late 1800s; such soils are normally removed quickly by wave action after exposure. We used several methods to corroborate this account. The stump’s in situ origin is supported by 1) a radiocarbon age indicating a death date between 1820 and 1720 years ago, coeval with other paleosols and in situ stumps; 2) its height and upright position, which are only matched by other in situ stumps; and 3) a photograph from 1912 showing uneroded wood inconsistent with a sea-drift history. Other evidence failed to support the in situ origin: 1) ground-penetrating radar did not reveal an associated paleosol, 2) the age of a nearby paleosols and stumps within 3 km were younger than the stump, and 3) three paleosols did not yield redwood pollen or wood. The only support for a sea-drift origin is that its age slightly predates a known tsunami that may have emplaced the stump. The balance of evidence suggests that the redwood stump is a remnant of an extinct late-Holocene disjunct population.

Woodland salamanders as metrics of forest ecosystem recovery: a case study from California's redwoods

Woodland (Plethodontid) salamanders occur in huge numbers in healthy forests in North America where the abundances of many species vary along successional gradients. Their high numbers and trophic role as predators on shredder and decomposer arthropods influence nutrient and carbon pathways at the leaf litter/soil interface. Their extreme niche conservatism and low vagility offer further advantages to the use of these salamanders as metrics of forest ecosystem condition. Mill Creek is a 103 km2 commercially logged redwood forest watershed acquired as parkland where original primary forest is being restored. This study evaluated woodland salamanders as metrics of seral recovery at Mill Creek. Surface counts and body condition were examined in four sets of stands, two early seral, one mature, and one of primary forest (never harvested old‐growth). Later seral sites were closer to the coast where fog increased available moisture; younger sites were further inland at higher elevations where fog was reduced. We distinguished the effects of geography and succession using ANCOVA with a PCA‐derived landscape covariate. Both geography and succession increased counts of California Slender Salamanders (Batrachoseps attenuatus); advancing succession alone indicated increased counts of Ensatina (Ensatina eschscholtzii). Means and variances in body condition of these two species were lower in older stands; for the Del Norte salamander (Plethodon elongatus) only the means were lower. Coastal proximity increased mean body condition in E. eschscholtzii, but with P. elongatus it was the opposite. We modeled surface counts and body condition along environmental gradients associated with succession. The counts and body condition in two of three species when taken together suggested that the increased structural complexity in late‐seral forest stands supported larger populations that appeared to be competing for limited resources and, thus, likely have greater population fitness than those in younger forests. B. attenuatus and E. eschscholtzii proved to be viable metrics of advancing succession with their numbers and body condition providing readily quantifiable measures of ecosystem recovery at Mill Creek.

Do northern spotted owls use harvested areas?

The 2011 Revised Recovery Plan for the northern spotted owl (Strix occidentalis caurina) declared that active forest management is compatible and consistent with recovery goals. The plan indicated that ecologically motivated silvicultural treatments should improve stand conditions, promote forest resiliency, and develop late-successional structural complexity over the long term. Yet most biologists believe that intensive, even-aged silvicultural systems (i.e., clearcut, seed-tree, or shelterwood regeneration methods) degrade habitat for northern spotted owls. Only for the coastal redwood forests of California is it broadly accepted that small-patch clearcut harvest units interspersed within a landscape containing significant large stands of large, old trees can provide adequate habitat. Spotted owls prey upon ground-dwelling prey, such as dusky-footed woodrats (Neotoma fuscipes), in these situations, primarily along edges of 6–30year old clearcuts that contain dense patches of shrubs and hardwoods as well as woody debris. Demographic pressures presumably cause surplus prey to emigrate into adjacent older stands with sparse understories, where they may be more vulnerable to predation by spotted owls. During 5 radio-telemetry studies in both the Klamath and Coastal Redwood Physiographic Provinces, we detected and observed northern spotted owls foraging as far as 600m from forests within harvest-created hardwood/shrub patches that contained scattered conifers and snags. Preferential use of such areas occurred in winter, especially in patches with conifer basal area of 9–18m2/ha that were outside of dense nesting areas. In areas where ground-dwelling small mammals comprise a significant proportion of the owl’s prey base, we hypothesize that use of young harvest units with retained conifers may contribute to spotted owl conservation. Such treatments may promote greater prey biomass, which could assist females to attain a high plane of nutrition prior to nesting. This hypothesis should be tested and refined via adaptive management experiments.

Surface‐enhanced Raman scattering assessment of DNA from leaf tissues adsorbed on silver colloidal nanoparticles

In this work, the surface‐enhanced Raman scattering (SERS) spectra of seven genomic DNAs from leaves of chrysanthemum (Dendranthema grandiflora Ramat.), common sundew (Drosera rotundifolia L.), edelweiss (Leontopodium alpinum Cass), Epilobium hirsutum L., Hypericum richeri ssp. transsilvanicum (Čelak) Ciocârlan, rose (Rosa x hybrida L.) and redwood (Sequoia sempervirens D. Don. Endl.), respectively, have been analyzed in the wavenumber range 200–1800 cm−1. The surface‐enhanced Raman vibrational modes for each of these cases, spectroscopic band assignments and structural interpretations of genomic DNAs are reported. A high molecular structural information content can be found in the SERS spectra of these DNAs from leaf tissues. Based on this work, specific plant DNA–ligand interactions or accurate local structure of DNA might be further investigated using surface‐enhanced Raman spectroscopy. Besides, this study will generate information which is valuable in the development of label‐free DNA detection for chemical probing in living cell. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Using High Resolution Computed Tomography to Visualize the Three Dimensional Structure and Function of Plant Vasculature

High resolution x-ray computed tomography (HRCT) is a non-destructive diagnostic imaging technique with sub-micron resolution capability that is now being used to evaluate the structure and function of plant xylem network in three dimensions (3D) (e.g. Brodersen et al. 2010; 2011; 2012a,b). HRCT imaging is based on the same principles as medical CT systems, but a high intensity synchrotron x-ray source results in higher spatial resolution and decreased image acquisition time. Here, we demonstrate in detail how synchrotron-based HRCT (performed at the Advanced Light Source-LBNL Berkeley, CA, USA) in combination with Avizo software (VSG Inc., Burlington, MA, USA) is being used to explore plant xylem in excised tissue and living plants. This new imaging tool allows users to move beyond traditional static, 2D light or electron micrographs and study samples using virtual serial sections in any plane. An infinite number of slices in any orientation can be made on the same sample, a feature that is physically impossible using traditional microscopy methods. Results demonstrate that HRCT can be applied to both herbaceous and woody plant species, and a range of plant organs (i.e. leaves, petioles, stems, trunks, roots). Figures presented here help demonstrate both a range of representative plant vascular anatomy and the type of detail extracted from HRCT datasets, including scans for coast redwood (Sequoia sempervirens), walnut (Juglans spp.), oak (Quercus spp.), and maple (Acer spp.) tree saplings to sunflowers (Helianthus annuus), grapevines (Vitis spp.), and ferns (Pteridium aquilinum and Woodwardia fimbriata). Excised and dried samples from woody species are easiest to scan and typically yield the best images. However, recent improvements (i.e. more rapid scans and sample stabilization) have made it possible to use this visualization technique on green tissues (e.g. petioles) and in living plants. On occasion some shrinkage of hydrated green plant tissues will cause images to blur and methods to avoid these issues are described. These recent advances with HRCT provide promising new insights into plant vascular function.