Crown structure of a codominant Douglas-fir

1983 ◽  
Vol 13 (2) ◽  
pp. 264-269 ◽  
Author(s):  
Edward C. Jensen ◽  
James N. Long
Keyword(s):  
Photosynthetic Efficiency ◽  
Photosynthetic Capacity ◽  
Basic Structure ◽  
Douglas Fir ◽  
Intensive Study ◽  
Crown Structure

Results are presented from an intensive study of crown structure in a 39-year-old codominant Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco). The patterns of crown development observed may represent a species adaptation for maximizing photosynthetic efficiency. While branches originating at nodes provide the basic structure of the crown, short-lived nonnodal branches provide much of the photosynthetic capacity. In addition, nonnodal branches support nearly half of the young needles near the top and outside edges of the crown.

Influence of Swiss needle cast on foliage age-class structure and vertical foliage distribution in Douglas-fir plantations in north coastal Oregon

2006 ◽  
Vol 36 (6) ◽  
pp. 1497-1508 ◽  
Author(s):  
Aaron R Weiskittel ◽  
Douglas A Maguire ◽  
Sean M Garber ◽  
Alan Kanaskie
Keyword(s):  
Vertical Distribution ◽  
Douglas Fir ◽  
Parameter Estimates ◽  
Class Structure ◽  
Needle Cast ◽  
Age Class ◽  
Relative Contribution ◽  
Crown Structure ◽  
Growth Decline ◽  
Swiss Needle Cast

Swiss needle cast (SNC) causes premature loss of foliage and subsequent growth decline in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Although the mechanisms leading to this growth decline include loss of photosynthetic surface area and physiological disruption of surviving foliage, estimating the relative contribution of these two primary sources requires precise quantification of SNC effects on total foliage mass, foliage age-class structure, and vertical foliage distribution. The effect of SNC severity on these crown structural attributes was tested across a range of stand densities and site qualities in 10- to 60-year-old plantations in north coastal Oregon. Foliage mass in each age-class was sampled at the branch level, and the resulting equations were applied to all live branches on intensively measured sample trees. Vertical distribution of each foliage age-class was described by a beta distribution fitted to each sample tree, and sources of variation in vertical distribution were tested by regressing beta parameter estimates on SNC intensity and other covariates representing tree, stand, and site attributes. Distribution of foliage mass by age-class and by relative height in the crown was significantly affected by SNC severity, in addition to other covariates such as crown size and tree social position. SNC caused a reduction in the amount of foliage in each age-class and greater relative representation of younger needles. SNC also shifted the mode of relative vertical distribution toward the top of the tree for the three youngest foliage age-classes, but toward the base of the crown for 4- and 5-year-old foliage. Quantification of foliage age-class structure and vertical distribution across a range of SNC severity has helped to establish diagnostic criteria for assessing changes in crown structure that precede declines in growth and vigor. The induced changes in crown structure will also help to identify the relative contribution of several mechanisms causing growth losses in diseased trees.

The Effect of Nano-ZnO on the Photosynthetic Capacity and Survival of Anabaena sp. and M. aeruginosa

2014 ◽  
Vol 1073-1076 ◽  
pp. 77-80
Author(s):  
Jian Fen Du ◽  
Yu Lin Tang ◽  
Qian Li
Keyword(s):  
Photosynthetic Efficiency ◽  
Photosynthetic Capacity ◽  
Electron Transport Rate ◽  
Pulse Amplitude ◽  
Maximal Effect ◽  
Effective Quantum Yield ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Malondialdehyde Content ◽  
Anabaena Sp

Anabaena sp. and M. aeruginosa were used to examine the toxic mechanism of nanoZnO to them, as well as the toxicity. Typical chlorophyll fluorescence parameters, including effective quantum yield, photosynthetic efficiency and maximum electron transport rate, were measured by a pulse amplitude modulated fluorometer. Results showed that nanoZnO could inhibit Anabaena sp. and M.aeruginosa growth with the EC50 (concentration for 50% of maximal effect) of 0.74±0.01 and 1.68±0.01 mg/L respectively. The toxicity of nanoZnO to Anabaena sp. is higher than that to M.aeruginosa, which can be proved by the malondialdehyde content in Anabaena sp. and M.aeruginosa cells.

Crown structure in western hemlock, Douglas-fir, and grand fir in western Washington: trends in branch-level mass and leaf area

1995 ◽  
Vol 25 (12) ◽  
pp. 1897-1912 ◽  
Author(s):  
John A. Kershaw Jr. ◽  
Douglas A. Maguire
Keyword(s):  
Branch Length ◽  
Allometric Equation ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Crown Structure ◽  
Indicator Variables ◽  
Western Washington ◽  
Modified Likelihood ◽  
Individual Trees ◽  
Fertilization Effects

Extensions of a basic allometric equation applied in predicting total foliage of individual trees were developed to estimate foliage and woody components of individual branches in western hemlock (Tsugaheterophylla (Raf.) Sarg.), Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), and grand fir (Abiesgrandis (Dougl. ex D. Don) Lindl.). Nine initial equations were fitted on both nonlinear and log-transformed scales to data collected in the western Cascade Mountains of Washington. In all cases, the logarithmic form of each equation provided the best fit to the data based on a modified likelihood criterion and residual patterns. Branch diameter was the overall best predictor of branch foliage and woody mass; however, significant (p = 0.05) improvements in fit were obtained when other structural and positional variables were included in the equations (e.g., foliated branch length and depth into crown). The effects of fertilization and site (locality) differences were explored using indicator variables for western hemlock branches. Significant site effects were observed for intercept terms for all three branch components (total foliage area, total foliage mass, and total woody mass), while fertilization effects were observed in interaction with relative height above crown base for both foliage components.

scholarly journals Differences in isoprenoid-mediated energy dissipation pathways between coastal and interior Douglas-fir seedlings in response to drought

2019 ◽  
Vol 39 (10) ◽  
pp. 1750-1766 ◽  
Author(s):  
Laura Verena Junker-Frohn ◽  
Anita Kleiber ◽  
Kirstin Jansen ◽  
Arthur Gessler ◽  
Jürgen Kreuzwieser ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Intraspecific Variation ◽  
Photosynthetic Capacity ◽  
Photosynthetic Apparatus ◽  
Douglas Fir ◽  
Future Climate ◽  
Photochemical Quenching ◽  
Negative Effects ◽  
Climate Conditions ◽  
Pool Sizes

ABSTRACT Plants have evolved energy dissipation pathways to reduce photooxidative damage under drought when photosynthesis is hampered. Non-volatile and volatile isoprenoids are involved in non-photochemical quenching of excess light energy and scavenging of reactive oxygen species. A better understanding of trees’ ability to cope with and withstand drought stress will contribute to mitigate the negative effects of prolonged drought periods expected under future climate conditions. Therefore we investigated if Douglas-fir (Pseudotsuga menziesii(Mirb.)) provenances from habitats with contrasting water availability reveal intraspecific variation in isoprenoid-mediated energy dissipation pathways. In a controlled drought experiment with 1-year-old seedlings of an interior and a coastal Douglas-fir provenance, we assessed the photosynthetic capacity, pool sizes of non-volatile isoprenoids associated with the photosynthetic apparatus, as well as pool sizes and emission of volatile isoprenoids. We observed variation in the amount and composition of non-volatile and volatile isoprenoids among provenances, which could be linked to variation in photosynthetic capacity under drought. The coastal provenance exhibited an enhanced biosynthesis and emission of volatile isoprenoids, which is likely sustained by generally higher assimilation rates under drought. In contrast, the interior provenance showed an enhanced photoprotection of the photosynthetic apparatus by generally higher amounts of non-volatile isoprenoids and increased amounts of xanthophyll cycle pigments under drought. Our results demonstrate that there is intraspecific variation in isoprenoid-mediated energy dissipation pathways among Douglas-fir provenances, which may be important traits when selecting provenances suitable to grow under future climate conditions.

Vegetation competition effects on aboveground biomass and macronutrients, leaf area, and crown structure in 5-year old Douglas-fir

New Forests ◽  
2007 ◽  
Vol 35 (3) ◽  
pp. 299-311 ◽  
Author(s):  
Kyle S. Petersen ◽  
Adrian Ares ◽  
Thomas A. Terry ◽  
Robert B. Harrison
Keyword(s):  
Leaf Area ◽  
Aboveground Biomass ◽  
Douglas Fir ◽  
Crown Structure ◽  
Competition Effects

Crown structure of old-growth Douglas-fir in the western Cascade Range, Washington

2001 ◽  
Vol 31 (7) ◽  
pp. 1250-1261 ◽  
Author(s):  
Hiroaki Ishii ◽  
Megan E Wilson
Keyword(s):  
Structural Complexity ◽  
Douglas Fir ◽  
Cascade Range ◽  
Old Growth ◽  
Crown Structure ◽  
Branch Biomass ◽  
Size Variability ◽  
Branch Density ◽  
Branch Size ◽  
Epicormic Branches

Crown structure of old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) is characterized by low live-branch density, numerous dead branches and epicormic branches, high branch-size variability, and large gaps in the crown. These features define structural complexity of the crown and create variable crown microenvironments. For the 60 m tall, 400-year-old Douglas-fir trees measured in this study, number of live branches decreased and dead branches increased from the upper to lower crown. Dead branches were found below the lowest live branch indicating that crown recession had occurred. Live-branch biomass culminated at 45 m and decreased markedly below 35 m. Numerous vertical gaps between branches occurred below 40 m. Epicormic branches accounted for 14.6–47.5% of the total number of live branches per tree and contributed to increased crown depth. Epicormic branches filled inner regions of the crown, and contributed to increased branch-size variability. A model of crown structure developed for young trees could be fit to the upper crown of the study trees but could not be applied to the middle to lower crown because of increased branch-size variability. Relative levels of photosynthetically active radiation in the crown decreased with decreasing height, but a local peak occurred around 35–40 m, coinciding with the height of marked decrease in live-branch biomass.

The Photosynthetic Capacity of the Phytoplankton in the Waters of a Coral Reef

1976 ◽  
Vol 3 (1) ◽  
pp. 53 ◽  
Author(s):  
DJ Griffiths
Keyword(s):  
Surface Waters ◽  
Photosynthetic Efficiency ◽  
Co2 Fixation ◽  
Photosynthetic Capacity ◽  
High Rate ◽  
Total Carbon ◽  
Soluble Form ◽  
Barrier Reef ◽  
Photosynthetic Productivity ◽  
Lizard Island

Phytoplankton are relatively scarce in surface waters in a region of the Great Barrier Reef near Lizard Island. The phytoplankton sampled have a high rate of photosynthetic efficiency (1.2 millimoles CO2 fixed per milligram chlorophyll a per hour), although between 30 and 50% of the total carbon fixed may be excreted in soluble form. The rate of photosynthetic CO2 fixation into the particulate fraction is sensitive to varying levels of oxygen, suggesting the existence of a photorespiratory mechanism, a factor which might significantly influence the photosynthetic productivity of the algae in these tropical waters.

REPRESSION OF SPRUCE BEETLE (COLEOPTERA) ATTRACTION BY METHYLCYCLOHEXENONE IN IDAHO

1974 ◽  
Vol 106 (5) ◽  
pp. 485-491 ◽  
Author(s):  
L. N. Kline ◽  
R. F. Schmitz ◽  
J. A. Rudinsky ◽  
M. M. Furniss
Keyword(s):  
Rare Species ◽  
Douglas Fir ◽  
Intensive Study ◽  
Dendroctonus Rufipennis ◽  
Spruce Beetle ◽  
Synthetic Attractant ◽  
Natural And Synthetic

AbstractAttraction of the spruce beetle, Dendroctonus rufipennis (Kirby), to beetle-infested logs was reduced 99% by addition of 3-methyl-2-cyclohexen-1-one (MCH), the natural antiaggregative pheromone of the Douglas-fir beetle, D. pseudotsugae Hopkins. The synthetic attractant frontalin and α-pinene attracted few spruce beetles and its nominal attraction was nearly nullified by addition of MCH. Male spruce beetles responded to the natural and synthetic attractants in greater numbers than females. When MCH was added to these treatments, females predominated among the few beetles caught. The clerid Thanasimus undatulus Say was strongly attracted to treatments containing frontalin, whether or not MCH was added, but MCH alone was not attractive to this predator. Among 13 other species of scolytids caught, the most abundant were Scierus annectens Leconte and Hylastes nigrinus (Mann.). Two relatively rare species, Scierus pubescens Sw. and Xylechinus montanus Blkm., were attracted in unusual numbers to natural spruce beetle attractant. Intensive study is recommended of the possible use of MCH to prevent increase of spruce beetle populations.

Impact of competitor species composition on predicting diameter growth and survival rates of Douglas-fir trees in southwestern Oregon

2001 ◽  
Vol 31 (12) ◽  
pp. 2237-2247 ◽  
Author(s):  
Felipe Bravo ◽  
David W Hann ◽  
Douglas A Maguire
Keyword(s):  
Species Composition ◽  
Survival Rates ◽  
Basal Area ◽  
Douglas Fir ◽  
Diameter Growth ◽  
Individual Tree ◽  
Growth And Survival ◽  
Probability Of Survival ◽  
Hardwood Species ◽  
Crown Structure

Mixed conifer and hardwood stands in southwestern Oregon were studied to explore the hypothesis that competition effects on individual-tree growth and survival will differ according to the species comprising the competition measure. Likewise, it was hypothesized that competition measures should extrapolate best if crown-based surrogates are given preference over diameter-based (basal area based) surrogates. Diameter growth and probability of survival were modeled for individual Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees growing in pure stands. Alternative models expressing one-sided and two-sided competition as a function of either basal area or crown structure were then applied to other plots in which Douglas-fir was mixed with other conifers and (or) hardwood species. Crown-based variables outperformed basal area based variables as surrogates for one-sided competition in both diameter growth and survival probability, regardless of species composition. In contrast, two-sided competition was best represented by total basal area of competing trees. Surrogates reflecting differences in crown morphology among species relate more closely to the mechanics of competition for light and, hence, facilitate extrapolation to species combinations for which no observations are available.

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