Sequoia Sempervirens Research Articles

Fog interception by Sequoia sempervirens (D. Don) crowns decouples physiology from soil water deficit

Although crown wetting events can increase plant water status, leaf wetting is thought to negatively affect plant carbon balance by depressing photosynthesis and growth. We investigated the influence of crown fog interception on the water and carbon relations of juvenile and mature Sequoia sempervirens trees. Field observations of mature trees indicated that fog interception increased leaf water potential above that of leaves sheltered from fog. Furthermore, observed increases in leaf water potential exceeded the maximum water potential predicted if soil water was the only available water source. Because field observations were limited to two mature trees, we conducted a greenhouse experiment to investigate how fog interception influences plant water status and photosynthesis. Pre-dawn and midday branchlet water potential, leaf gas exchange and chlorophyll fluorescence were measured on S. sempervirens saplings exposed to increasing soil water deficit, with and without overnight canopy fog interception. Sapling fog interception increased leaf water potential and photosynthesis above the control and soil water deficit treatments despite similar dark-acclimated leaf chlorophyll fluorescence. The field observations and greenhouse experiment show that fog interception represents an overlooked flux into the soil-plant-atmosphere continuum that temporarily, but significantly, decouples leaf-level water and carbon relations from soil water availability.

Physiological consequences of height-related morphological variation in Sequoia sempervirens foliage

This study examined relationships between foliar morphology and gas exchange characteristics as they vary with height within and among crowns of Sequoia sempervirens D. Don trees ranging from 29 to 113 m in height. Shoot mass:area (SMA) ratio increased with height and was less responsive to changes in light availability as height increased, suggesting a transition from light to water relations as the primary determinant of morphology with increasing height. Mass-based rates of maximum photosynthesis (A(max,m)), standardized photosynthesis (A(std,m)) and internal CO(2) conductance (g(i,m)) decreased with height and SMA, while the light compensation point, light saturation point, and mass and area-based rates of dark respiration (R(m)) increased with height and SMA. Among foliage from different heights, much of the variation in standardized photosynthesis was explained by variation in g(i,) consistent with increasing limitation of photosynthesis by internal conductance in foliage with higher SMA. The syndrome of lower internal and stomatal conductance to CO(2) and higher respiration may contribute to reductions in upper crown growth efficiency with increasing height in S. sempervirens trees.

Water-use responses of 'living fossil' conifers to CO2 enrichment in a simulated Cretaceous polar environment.

During the Mesozoic, the polar regions supported coniferous forests that experienced warm climates, a CO(2)-rich atmosphere and extreme seasonal variations in daylight. How the interaction between the last two factors might have influenced water use of these conifers was investigated. An experimental approach was used to test the following hypotheses: (1) the expected beneficial effects of elevated [CO(2)] on water-use efficiency (WUE) are reduced or lost during the 24-h light of the high-latitude summer; and (2) elevated [CO(2)] reduces plant water use over the growing season. Measurements of leaf and whole-plant gas exchange, and leaf-stable carbon isotope composition were made on one evergreen (Sequoia sempervirens) and two deciduous (Metasequoia glyptostroboides and Taxodium distichum) 'living fossil' coniferous species after 3 years' growth in controlled-environment simulated Cretaceous Arctic (69 degrees N) conditions at either ambient (400 micromol mol(-1)) or elevated (800 micromol mol(-1)) [CO(2)]. Stimulation of whole-plant WUE (WUE(P)) by CO(2) enrichment was maintained over the growing season for the three studied species but this pattern was not reflected in patterns of WUE inferred from leaf-scale gas exchange measurements (iWUE(L)) and delta(13)C of foliage (tWUE(L)). This response was driven largely by increased rates of carbon uptake, because there was no overall CO(2) effect on daily whole-plant transpiration or whole-plant water loss integrated over the study period. Seasonal patterns of tWUE(L) differed from those measured for iWUE(L). The results suggest caution against over simplistic interpretations of WUE(P) based on leaf isotopic composition. The data suggest that the efficiency of whole-tree water use may be improved by CO(2) enrichment in a simulated high-latitude environment, but that transpiration is relatively insensitive to atmospheric CO(2) in the living fossil species investigated.

Pre-EuroAmerican settlement forests in Redwood National Park, California, USA: a reconstruction using line summaries in historic land surveys

Extensive logging in the twentieth century destroyed much of the coniferous forests in the lower Redwood Creek basin of Redwood National Park. Restoration of cutover lands requires the identification of historical, pre-logging reference conditions. Field notes from the original Public Land Surveys were used to reconstruct the pre-EuroAmerican settlement forests. Most reconstructive studies based on historic surveys rely on bearing tree evidence over large areas to determine vegetation patterns over several hundreds to thousands of square kilometers. Due to the small size of the study area (approximately 200 km2), bearing tree evidence could not accurately reconstruct the vegetation at this scale. Instead, lists of the overstory and understory vegetation for each surveyed mile (line summaries) were employed. Analysis of line summaries evidence identified the historical importance, geographical range, and environmental influences on woody species and vegetation communities. Topography, especially elevation, and soil texture were significantly correlated with plot-scale ordination scores derived from non-metric multidimensional scaling. The influence of topography and distance to ocean coast on the historical distribution of dominant woody species concurs with findings from present-day field studies of local and regional old-growth forest. A comparison with present-day vegetation maps revealed that coast redwood (Sequoia sempervirens), Douglas fir (Pseudotsuga menziesii), Sitka spruce (Picea sitchensis), and red alder (Alnus rubra) experienced the most substantive changes in the vegetation as a result of twentieth century land use activities.

The Effects of Revetment on Streamside Vegetation in Sequoia sempervirens (Taxodiaceae) Forests

Stream-bank stabilization structures, or revetment, can impact riparian systems by confining watercourses to the point where natural functions are limited. Removal of existing revetment may have considerable impacts to stream-bank stability however. The effects of revetment and revetment removal on vegetation and stream-bank morphology were measured on three streams in forests dominated by Sequoia sempervirens (Coast Redwood) in northern California. Data were collected using randomly located transects on three treatments; “no-revetment,” “revetment-intact,” and “revetment removed.” Results were compared between treatments using ANOVA at a 0.05 level of significance. On all three sites, species richness, vegetation cover, and tree seedling density were found to be highest where no revetment existed compared to where revetment was intact. Stream depth and stream-bank slope were highest where revetment was intact. Recovery of vegetation following removal of revetment was more site specific being most pronounced where recovery time was greatest and stream-bank restoration efforts were highest.

Influence of microstructured carbon materials on Sequoia sempervirens (D. Don.) Endl. in vitro culture

The present experimental research has been mainly focused on Sequoia sempervirens (D. Don.) Endl. as woody plant model system, for testing the influence of some microstructured carbon materials (CCM) comparing with the activated charcoal action, on the in vitro growth. The work hypothesis was that CCM can induce effects on the plant culture, similar to those induced by activated charcoal, due to their high absorption capacity. The influence of two types CCM and activated charcoal introduced in the medium culture was evaluated on the fresh weight and on the length of the in vitro regenerants, after 30 and 60 days of cultivation. Our data revealed that the CCM is not toxic and does not inhibit plant growth. We also remarked that S. sempervirens (D. Don.) Endl. was more reactive to the activated charcoal into the nutritive medium than the CCM compounds. The use of these new microstructured compounds is an important step both in the study of materials science and in the field of plant biotechnologies.

Intra-annual variation in the stable oxygen and carbon isotope ratios of cellulose in tree rings of coast redwood (Sequoia sempervirens)

Fog is a seasonally variable hydrologic input to coast redwood ( Sequoia sempervirens, D. Don) ecosystems with a stable isotopic composition (δ 18O, δ2H) that is distinct from rainfall. The intra-annual variation in tree ring cellulose δ18O of coast redwood was measured to determine what portion of the tree ring should be sampled to best target fog signals. Ten years of rings were subdivided into ten equal units for three trees at two sites in northern California. Intra-annual variation in cellulose δ18O was as high as 3‰ with a consistent pattern of enriched (in 18O) values from the annual ring boundary and depleted values from the central portion of the ring. These patterns show a strong coherence between replicate trees at the same site as well as significant correlations between individuals at sites over 250 km apart. Intra-annual variation in stable carbon isotope ratios (δ13C) was as high as 2‰ and produced a pattern with depleted (in 13C) values from the ring boundary and enriched values from the central portion of the ring. Although these δ13C patterns were not as strongly correlated between replicate trees as the patterns in δ18O variation, they did produce significant correlations with the variation in fog frequencies recorded at local airports. This study highlights the importance of quantifying intra-annual variation in tree ring stable isotope signals as a guide to further investigations on historic variability from long chronologies especially if the signal of interest is seasonally variable (eg, fog).

Historical Visions From the Redwood Coast

Between 1870 and 1930, an era of voracious old-growth redwood consumption, several Americans wrote texts positioning California's coastal redwoods at a crossroads of nature and history. Authors wit...

Fog Water and Ecosystem Function: Heterogeneity in a California Redwood Forest

Fog is thought to influence ecological function in coastal forests worldwide, yet few data are available that illuminate the mechanisms underlying this influence. In a California redwood forest we measured water and nitrogen (N) fluxes from horizontally moving fog and vertically delivered rain as well as redwood tree function. The spatial heterogeneity of water and N fluxes, water availability, tree water use, and canopy N processing varied greatly across seasons. Water and N fluxes to soil (annual average of 98% and 89%, respectively) across the whole forest occurred primarily in the rain season and was relatively even across the whole forest. In contrast, below-canopy flux of fog water and N declined exponentially from the windward edge to the forest interior. Following large fog events, soil moisture was greater at the windward edge than anywhere else in the forest. Physiological activity in redwoods reflected these differences in inputs across seasons: tree physiological responses did not vary spatially in the rain season, but in the fog season, water use was greater, yet water stress was less, in trees at the windward edge of the forest versus the interior. In both seasons, vertical passage through the forest changed the amount of water and form and concentration of N, revealing the role of the tree canopy in processing atmospheric inputs. Although total fog water inputs were comparatively small, they may have important ecosystem functions, including relief of canopy water stress and, where there is fog drip, functional coupling of above- and belowground processes.

A response to: Limitations within “The Limits to Tree Height”

Here we respond to the communication in American Journal of Botany (96: 542-544 in this issue) by Netting, who proposes several ways in which our paper "The Limits to Tree Height" (Nature 428: 851-854) may have erred in estimating the biophysical limits to height growth in Sequoia sempervirens. We first explain that because embolism repair requires long time periods and is generally incomplete, xylem vulnerability characteristics offer a sound basis for estimating performance limits in woody plants. We reaffirm our earlier use of vertical gradients of foliar carbon isotope composition with new data for S. sempervirens. We support these arguments with reference to studies in other tree species. We take exception with Netting's view that the turgor pressure-cell expansion relationship for Zea mays is applicable to S. sempervirens. Finally, we second Netting's call for more work on carbon allocation vis a vis height growth limits.

Clones identification of Sequoia sempervirens (D. Don) Endl. in Chile by using PCR-RAPDs technique

A protocol of polymerase chain reaction-random amplified polymorphic DNAs (PCR-RAPDs) was established to analyse the gene diversity and genotype identification for clones of Sequoia sempervirens (D. Don) Endl. in Chile. Ten (out of 34) clones from introduction trial located in Voipir-Villarrica, Chile, were studied. The PCR-RAPDs technique and a modified hexadecyltrimethylammonium bromide (CTAB) protocol were used for genomic DNA extraction. The PCR tests were carried out employing 10-mer random primers. The amplification products were detected by electrophoresis in agarose gels. Forty nine polymorphic bands were obtained with the selected primers (BG04, BF07, BF12, BF13, and BF14) and were ordered according to their molecular size. The genetic similarity between samples was calculated by the Jaccard index and a dendrogram was constructed using a cluster analysis of unweighted pair group method using arithmetic averages (UPGMA). Of the primers tested, 5 (out of 60) RAPD primers were selected for their reproducibility and high polymorphism. A total of 49 polymorphic RAPD bands were detected out of 252 bands. The genetic similarity analysis demonstrates an extensive genetic variability between the tested clones and the dendrogram depicts the genetic relationships among the clones, suggesting a geographic relationship. The results indicate that the RAPD markers permitted the identification of the assayed clones, although they are derived from the same geographic origin.

Limitations within “The Limits to Tree Height”1

Koch et al. (Nature 428: 851-854) measured various parameters that were thought to limit the height of Sequoia sempervirens from northern California and concluded that the maximum height for this species is 122-130 m because within this range: (1) Irreversible embolism formation was proposed to occur when the xylem pressure was less than -1.9 MPa. (2) The leaf mass to area ratio exponentially approached 833 g×m(-2). (3) The discrimination against (13)CO(2) exponentially approached -20. (4) Light-saturated photosynthesis per unit leaf mass decreased to zero, indicating no net gain in leaf biomass. These conclusions are questioned here by reassessing the assumed limits to the biophysical parameters and by reexamining the proposed linear and exponential relationships between these parameters and tree height. It is concluded that: (1) Embolism repair mechanisms could have occurred at -2.7 MPa. (2) The leaf mass to area ratio could be a result of, rather than a determinant of, the large differential between cellular turgor and the xylem pressure. (3) The discrimination against (13)CO(2) may show two populations of foliage with apparent linear relationships with height rather than one exponential relationship. (4) The light-saturated photosynthesis per unit leaf mass as a measure of biomass investment in leaf expansion excludes investment in branch and trunk wood. As a result, tree height may be limited by a long-term balance between dieback and continued growth.

The influence of timber harvest on the structure and composition of riparian forests in the Coastal Redwood region

The composition and structure of riparian forests in the coast redwood region were analyzed in relation to the length of time since timber harvest, and the width of riparian buffer zone. Ten sites were sampled in the central range of the coast redwood forest type within a variety of post-harvest age groups and riparian buffer zone widths. Data was collected using randomly selected sample plots adjacent to perennial coastal steams. Correlation Fisher's r to z tests and two-tailed t-test were used to examine the relationship between the sample variables and the experimental parameters “years since harvest”, and “width of buffer.” Results indicate that canopy cover was negatively correlated to “years since harvest” with the highest level of canopy cover found on the youngest sites and the lowest level found on the old-growth sites. The hardwood to conifer dominance ratio and the basal area of Alnus rubra (red alder) were correlated negatively to both “years since harvest” and “buffer width” indicating that timber harvest favored hardwood species. Late seral associates such as Oxalis oregana (redwood sorrel), Anthyrium filix- femina (lady fern), and Vaccinium parviflorum (billberry) were found preferentially in older forests and sites with wider buffer zones, while non-native species such as Hedera helix (English ivy), Pampas cortedaria (pampas grass), and Myosotis latifolia (forget-me-not) were found preferentially in younger forests and areas with smaller buffer zones.

Ex-Vitro Acclimation of some Horticultural Species in Hydroculture

At the Fruit Research Station of Cluj a simple and efficient ex-vitro acclimation method for in vitro-rooted plantlets was set up for various horticultural species. This method consists of transferring the rooted plantlets into uncapped glass or plastic vessels containing a layer of 1-3 cm of water that should not reach above root level. The water should have an optimal pH for each species for which this acclimation method is applied. Acclimation is accomplished in 3-4 weeks, during which the plantlets grow faster than in the case of the classical acclimation on solid substrate and they generate new roots, being suitable for planting into pots. This technique was successfully applied for a large number of species: raspberry, blackberry (Rubus sp), black currant (Ribes nigrum), highbush blueberry (Vaccinium corymbosum), plum tree (Prunus domestica), cherry rootstock Prunus cerasus), rose (Rosa sp.), Kalanchoe blossfeldiana, Iresine sp., Exacum affine, geranium (Chrysanthemum sp.) ornamental tomato (Lycopersicon esculentum), cornichon cucumber (Cucumis sativus), watermelon (Citrullus vulgaris), Luffa cylindrica, Sequoia sempervirens, Drosera rotundifolia and Cymbidium.

Simulating Multiaged Coast Redwood Stand Development: Interactions between Regeneration, Structure, and Productivity

Abstract Multiaged management regimes and harvesting scenarios were simulated in coast redwood (Sequoia sempervirens [D. Don.] Endl.) stands using models of stand growth and yield (CRYPTOS) and stocking assessment (redwood MASAM). Various stocking and age-class combinations were modeled on site index 100 and 130 ft (50 years). Results demonstrated how the number of cohorts, upper limit of stocking, and cohort densities affected growth and yield. Board foot volume increment reached a plateau in stands with a prescribed upper limit of stocking above leaf area index 7.2 to 8.6. Productivity did not differ between stands with two to five cohorts producing the same tree size at harvest. It was affected by stand structure when a cutting cycle of 20 years was prescribed in stands with three to five cohorts. Stands with the same density returned to the upper limit of stocking much sooner on better sites. Prolonging the cutting cycle by reducing stand density resulted in larger tree sizes at harvest and greater productivity. The growth of trees remaining after cutting 10–50% of stand basal area and growth of new stump sprouts were also simulated. Stands quickly returned to preharvest stocking after light cutting, implying that heavy or frequent light cutting is needed to sustain growth and vigor of regeneration in multiaged coast redwood stands.

Développement de rejets épicormiques sur des séquoias californiens : intensité de l’élagage, génotype, caractéristiques des rejets

• Young coast redwood (Sequoia sempervirens (D. Don.) Endl.) trees were pruned to various heights to examine the effect of pruning severity on epicormic sprouting. Seven separate stands were used with as many as six treatments per stand in coastal Humboldt County, California, USA. • Epicormic sprout development was affected by pruning severity but primarily at the most severe pruning treatments that removed all but the branches in the top 15% of tree height. Less severe treatments produced sprouts but the number and size of these sprouts were comparable to unpruned trees. • Natural clonal patterns were also used to explore patterns of sprouting between genotypes. Linear mixed-effects models were developed to predict sprouting frequency as a function of pruning severity while accounting for the nested data structure (i.e., stem sections sampled nested within genotypes within treatments within sites). • Comparing variances attributed to each of these random effects indicated that at any level of pruning severity, differences in epicormic sprouting between genotypes and sites expressed soon after pruning had disappeared after six growing seasons. Epicormic branches were more common two years after pruning than six years indicating many branches were dying. Branches were more common in the middle of the pruned bole, possibly because of competition from basal sprouts and the expanding tree crown.

FT-Raman study of the (sub)picosecond dynamics in genomic DNA from plant tissues

In this paper the Raman total half bandwidths of eight genomic DNAs from leaf tissues (potato (Solanum tubero- sum L.), sword fern (Nephrolepis exaltata L.), scopolia (Scopolia carniolica Jacq.), redwood (Sequoia sempervirens D. Don. Endl.), orchids (Cymbidium × hybrida), chrysanthemum (Dendranthema grandiflora Ramat.) and common sundew (Drosera rotundifolia L.)) have been measured. The dependencies of the total half bandwidths and of the global relaxation times, on DNA molecular subgroup structure and on the type of genomic plant DNA, are reported. It is shown that changes in the (sub)picosecond dynamics of molecular subgroups in genomic DNAs from leaf tissues can be monitored with Raman spec- troscopy. Particularly, the Raman band parameters for the vibrations at 879 cm −1 (deoxyribose, dA), 1047 cm −1 (CO stretching C-O- P-O-C, dG), 1089 cm −1 (P-O symmetric stretching of PO2 − ), 1124 cm −1 (dA), 1272 cm −1 (dC, dG, dT), 1276 cm −1 (dC), 1455 cm −1 (deoxyribose, dA, dC, dT) and 1482 cm −1 (dG, dA) of genomic leaf tissues DNAs are presented. In our study, the full widths at half-maximum (FWHM) of the bands in genomic DNAs from leaf tissues are typically in the wavenumber range from 7.8 to 23.1 cm −1 . It can be observed that the molecular relaxation processes studied in this work, have a global relaxation time smaller than 1.36 ps and larger than 0.46 ps. The fastest and the slowest relaxation processes of different DNA structural subgroups, for several types of genomic DNA ex- tracted from leaf tissue, have been analyzed. Particularly, the slowest dynamics corresponding to the vibration near 1272 cm −1 takes place in the case of DNA extracted from common sundew (global relaxation time 1.36 ps). A comparison between different time scales of the vibrational energy transfer processes, characterizing several DNA com- plexes, has been given. We have found that the bands at 879 cm −1 (deoxyribose, phosphodiester, dA) and 1455 cm −1 (deoxyribose, dA, dC, dT) are suitable for the study of dynamical behavior of molecular subgroups in genomic DNA extracted from leaf tissues. Specific molecular relaxation processes, depending on the type of genomic DNA extracted from leaf tissues has been ob- served.

Stem Biomass and Structure of a Mature Sequoia sempervirens Stand on the Pacific Coast of Northern California

Stem Biomass and Structure of a Mature Sequoia sempervirens Stand on the Pacific Coast of Northern California

Genetic constitution and diversity in four narrow endemic redwoods from the family Cupressaceae

The genetic constitution and diversity of four relictual redwoods are discussed in this review. These include monotypic genera of the family Cupressaceae: coast redwood (Sequoia sempervirens), giant sequoia (Sequoiadendron giganteum), dawn redwood (Metasequoia glyptostroboides), and alerce (Fitzroya cupressoides). All four species are narrow endemics, share a number of common phenotypic traits, including red wood, and are threatened species. Fossil history suggests that the ancestors of redwoods probably originated during the Cretaceous and Tertiary periods and flourished thereafter for millions of years. Towards the end of the Tertiary period began their decline and struggle for existence that continued during the subsequent geologic upheavals and climate changes, until the survival of the present-day redwoods in the current restricted locations in the world (USA, China, and South America). Although two species, Sequoiadendron and Metasequoia, are diploids (2n = 22), and the other two are polyploids: Fitzroya a tetraploid (2n = 4x = 44), and Sequoia a hexaploid (2n = 6x = 66); they all share the same basic chromosome number x = 11. The genome size in the hexaploid Sequoia is one of the largest (31,500 MB) in the conifers, while the genome sizes of diploid Metasequoia and Sequoiadendron are about one-third (~10,000 MB) of Sequoia. Genetic diversity in the redwoods is lower than most other gymnosperms, except in Sequoia, which seems to rank near the upper quarter of the coniferous forest trees. Genomic research is sparse in the redwoods, and should be pursued for a better understanding of their genome structure, function, and adaptive genetic diversity.

Sources of Inoculum for Phytophthora ramorum in a Redwood Forest

ABSTRACT Sources of inoculum were investigated for dominant hosts of Phytophthora ramorum in a redwood forest. Infected trunks, twigs, and/or leaves of bay laurel (Umbellularia californica), tanoak (Lithocarpus densiflorus), and redwood (Sequoia sempervirens) were tested in the laboratory for sporangia production. Sporangia occurred on all plant tissues with the highest percentage on bay laurel leaves and tanoak twigs. To further compare these two species, field measurements of inoculum production and infection were conducted during the rainy seasons of 2003-04 and 2004-05. Inoculum levels in throughfall rainwater and from individual infections were significantly higher for bay laurel as opposed to tanoak for both seasons. Both measurements of inoculum production from bay laurel were significantly greater during 2004-05 when rainfall extended longer into the spring, while inoculum quantities for tanoak were not significantly different between the 2 years. Tanoak twigs were more likely to be infected than bay laurel leaves in 2003-04, and equally likely to be infected in 2004-05. These results indicate that the majority of P. ramorum inoculum in redwood forest is produced from infections on bay laurel leaves. Years with extended rains pose an elevated risk for tanoak because inoculum levels are higher and infectious periods continue into late spring.