scholarly journals Un arboret cu duglas verde (Pseudotsuga menziesii (Mirbel) Franco) și molid de Sitka (Picea sitchensis (Bong.) Carr.) din Ocolul silvic Obștea Săliște (Vâlcea)

2021 ◽  
Vol 21 (1) ◽  
pp. 73-81
Author(s):  
Valeriu-Norocel Nicolescu ◽  
Gheorghe Mihăilescu ◽  
Ion Andronic ◽  
Roxana-Mihaela Siladi ◽  
Radu Tampa ◽  
...  
Keyword(s):  
Pseudotsuga Menziesii ◽  
Picea Sitchensis

Articolul prezintă rezultatele unui exercițiu de inventariere pe scară mică, realizat într-un arboret (u.a. 34B, U.P. I Săliște, Ocolul silvic Obștea Săliște) care include duglas verde (DF) și molid de Sitka (MOS, specie exotică utilizată foarte rar în România), instalat prin plantare (1,5 x 1,5 m) în anul 1962 în completarea regenerării naturale a fagului. La 60 de ani, duglasul se comportă mai bine decât molidul de Sitka în sens biometric, iar cele mai relevante caracteristici ale celor două specii sunt după cum urmează: - diametrul de bază maxim: 67,1 cm (DU) și 37,7 cm (MOS); - diametrul mediu al suprafeței de bază dg: 41,81 cm (DU) și 27,43 cm (MOS); - înălțimea maximă: 39,5 m (DU) și 30,5 m (MOS); - înălțimea corespunzătoare lui dg: 32,00 m (DU) și 24,95 m (MOS); - indicele de zveltețe mediu: 84 (DU) și 90 (MOS); - diametrul mediu al coroanei: 462 cm (DU) și 361 cm (MOS); - ambele specii prezintă un elagaj natural imperfect, ca și în alte culturi instalate în întreaga Europă. Duglasul verde s-a adaptat la condițiile locale ca și în alte părți din România, unde se întâlnește pe cca 12.700 ha, și prezintă un potențial ridicat de producție de lemn. Molidul de Sitka a fost capabil să supraviețuiască în condiții locale dificile (spre exemplu, altitudine mare, climat temperat-continental, foarte diferit de cel oceanic din arealul natural și de pe coastele nordice și vestice ale Europei), fără a produce la fel de mult lemn ca în alte țări europene gen Marea Britanie și Irlanda.

Distribution of leaf orientations in six conifer species

2001 ◽  
Vol 79 (4) ◽  
pp. 389-397 ◽  
Author(s):  
Hugh J Barclay
Keyword(s):  
Pseudotsuga Menziesii ◽  
Pinus Contorta ◽  
Goodness Of Fit ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
The Other ◽  
Thuja Plicata ◽  
Leaf Angle ◽  
Conifer Species ◽  
Abies Grandis

Leaf angle distributions are important in assessing both the flexibility of a plant's response to differing daily and seasonal sun angles and also the variability in the proportion of total leaf area visible in remotely sensed images. Leaf angle distributions are presented for six conifer species, Abies grandis (Dougl. ex D. Don) Lindl., Thuja plicata Donn. ex D. Don, Tsuga heterophylla (Raf.) Sarg., Pseudotsuga menziesii (Mirb.) Franco, Picea sitchensis (Bong.) Carr. and Pinus contorta Dougl. ex Loud. var. latifolia. The leaf angles were calculated by measuring four foliar quantities, and then the distributions of leaf angles are cast in three forms: distributions of (i) the angle of the long axis of the leaf from the vertical for the range 0–180°; (ii) the angle of the long axis of the leaf for the range 0–90°; and (iii) the angle of the plane of the leaf for the range 0–90°. Each of these are fit to the ellipsoidal distribution to test the hypothesis that leaf angles in conifers are sufficiently random to fit the ellipsoidal distribution. The fit was generally better for planar angles and for longitudinal angles between 0° and 90° than for longitudinal angles between 0° and 180°. The fit was also better for Tsuga heterophylla, Pseudotsuga menziesii, Picea sitchensis, and Pinus contorta than for Abies grandis and Thuja plicata. This is probably because Abies and Thuja are more shade tolerant than the other species, and so the leaves in Abies and Thuja are preferentially oriented near the horizontal and are much less random than for the other species. Comparisons of distributions on individual twigs, whole branches, entire trees, and groups of trees were done to test the hypothesis that angle distributions will depend on scale, and these comparisons indicated that the apparent randomness and goodness-of-fit increased on passing to each larger unit (twigs up to groups of trees).Key words: conifer, leaf angles, ellipsoidal distribution.

scholarly journals A quantitative study of cotyledon positioning in conifer development

Botany ◽  
2016 ◽  
Vol 94 (11) ◽  
pp. 1063-1074 ◽  
Author(s):  
David M. Holloway ◽  
Byron Brook ◽  
JooHyun Kang ◽  
Cameron Wong ◽  
Michael Wu
Keyword(s):  
Pseudotsuga Menziesii ◽  
Quantitative Study ◽  
Growth Regulator ◽  
Auxin Transport ◽  
Picea Sitchensis ◽  
Common Mechanism ◽  
Developmental Patterns ◽  
Second Stage ◽  
Spacing Distance ◽  
Naphthylphthalamic Acid

The number of cotyledons in angiosperm monocots and dicots is tightly constrained. But in the gymnosperm Pinaceae (pine family), which includes many of the conifers, cotyledon number (nc) can vary widely, commonly from 2 to 12. Conifer cotyledons form in whorled rings on a domed embryo geometry. We measured the diameter of embryos and counted the cotyledons to determine the radial positioning of the whorl and the circumferential spacing between cotyledons. Results were similar between Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), Sitka spruce (Picea sitchensis (L.) H.Karst.), and larch (Larix × leptoeuropaea, synonymous with L. × marschlinsii Coaz), indicating a common mechanism for cotyledon positioning in conifers. Disrupting transport of the growth regulator auxin (with 1-N-naphthylphthalamic acid (NPA)) led to cup-shaped embryos, indicating that whorl (ring) formation is separable from cotyledon patterning within the ring. NPA inhibits cotyledon outgrowth, but not the spacing (distance) between cotyledons. The NPA effect is direct; it does not operate indirectly on embryo size. These results support a hierarchical model for cotyledon positioning in conifers, in which a first stage (not requiring auxin transport) sets the whorl position, constraining the second stage (which requires auxin transport) to form cotyledons within this whorl. Similarly, recent studies in Arabidopsis have shown that different components of complex developmental patterns can have different transport properties; this aspect of patterning may be shared across plants.

scholarly journals Dichotomous Keys for Scaling and Grading Merchantable Quality Sawlogs

2003 ◽  
Vol 18 (4) ◽  
pp. 250-258
Author(s):  
Steve Bowers
Keyword(s):  
Pseudotsuga Menziesii ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
Advisory Group ◽  
Time Scaling ◽  
Dichotomous Key ◽  
Second Growth ◽  
Group A ◽  
Length Scaling ◽  
Log Scaling

Abstract This study documented and field-tested a simplified version of the Westside Grading Guidelines as published in the Official Rules Handbook by the Northwest Log Rules Advisory Group. A four-step dichotomous key was documented and field-tested to determine merchantable vs. nonmerchantable logs. The study also documented and field-tested an individual seven-step dichotomous log grading key for evaluating second-growth Douglas-fir (Pseudotsuga menziesii), Sitka spruce (Picea sitchensis), western hemlock (Tsuga heterophylla), and grand fir (Abies grandis) as derived from the Rules For Grading Logs section of the Official Rules Handbook. Results were compared with certified scalers employed by Yamhill Log Scaling & Grading Bureau and Columbia River Log Scaling & Grading Bureau. Eighty-four individuals measured the length, scaling diameter, determined merchantability versus nonmerchantability and assigned log grade for 440 logs. Results showed participants in the study correctly measuring log length 99% of time, scaling diameters were recorded correctly at an 89% rate, and merchantability and log grade at 98 and 97%, respectively. West. J. Appl. For. 18(4):250–258.

Interactive effects of light and stratification on the germination of some British Columbia conifers

1994 ◽  
Vol 72 (11) ◽  
pp. 1635-1646 ◽  
Author(s):  
X. J. Li ◽  
P. J. Burton ◽  
C. L. Leadem
Keyword(s):  
British Columbia ◽  
Seed Germination ◽  
Pseudotsuga Menziesii ◽  
Seed Weight ◽  
Pinus Contorta ◽  
Picea Sitchensis ◽  
Thuja Plicata ◽  
Pinus Monticola ◽  
Larix Occidentalis ◽  
Tree Seed

Pregermination stratification treatment was generally more important than the effects of light on seed germination by 14 conifer species and varieties native to British Columbia. Nevertheless, there were some strong species differences in the response of germination to light. Final germination percentage after 21 days (28 days for Abies spp.) for both stratified and unstratified seeds of Picea glauca, Picea sitchensis, and Tsuga heterophylla showed no response to light during germination. Seed germination by Abies grandis, Pinus contorta var. contorta, Pinus contorta var. latifolia, Pinus ponderosa, Pseudotsuga menziesii var. glauca, and Pseudotsuga menziesii var. menziesii responded positively to light if unstratified but was not significantly affected by light when stratified. For Thuja plicata seeds, germination responded positively to light regardless of stratification pretreatment. Light appeared to reduce germination of stratified seeds of Abies amabilis, Abies lasiocarpa, Larix occidentalis, and Pinus monticola, although stratification conditions for these species were suboptimal. The germination rate of stratified seeds of all species and unstratified seeds of most species was increased by light. Results showed no significant relationship between germination response to light and shade-tolerance ranking or mean seed weight of the species. In six seed lots of Pinus contorta var. latifolia, however, we detected a weak negative correlation between mean seed weight and unstratified light responsivity measured after 1 week but a significant positive correlation when measured after 3 weeks. Very low light levels in closed-canopy forests or in the forest floor may prolong tree seed germination but are unlikely to constrain final germination levels after most seeds have been naturally stratified by moist, cool winter conditions. The importance of differences in the rate and timing of tree seed germination under natural conditions remains to be demonstrated. Key words: conifer biology, forest regeneration, light response, lodgepole pine, Pinus contorta, seed germination, stratification.

scholarly journals COMPARISON OF FAILURE CRITERIA FOR WOOD IN TENSILE-SHEAR STRESS STATE

2017 ◽  
Vol 13 ◽  
pp. 115 ◽  
Author(s):  
Eliška Šmídová ◽  
Petr Kabele
Keyword(s):  
Shear Strength ◽  
Pseudotsuga Menziesii ◽  
Shear Test ◽  
Failure Criteria ◽  
Shear Loading ◽  
Douglas Fir ◽  
Picea Sitchensis ◽  
Tensile Shear ◽  
Hill Criterion ◽  
Maximum Shear Strength

An orthotropic failure criterion enhancing the Lourenco's criterion by a shear strength multiplier and a maximum shear strength upper bound has been recently proposed and validated for timber under tensile and shear loading by the authors. The paper discusses its applicability for predicting strength in comparison with Tsai-Hill criterion, Hankinson's and Hyperbolic formula applying the two above mentioned enhancements of the Lourenco's criterion. Experimental data available in the literature for off-axis tensile and shear test of Sitka spruce (Picea sitchensis Carr.), Katsura (Cercidiphyllurn japonicurn Sieb. and Zucc.), Douglas fir (Pseudotsuga menziesii), Douglas fir laminated veneer and Cupiúba (Goupia glabra) are used for the purpose of this study.

Retention of needles and seeds on logs in Picea sitchensis – Tsuga heterophylla forests of coastal Oregon and Washington

1989 ◽  
Vol 67 (6) ◽  
pp. 1833-1837 ◽  
Author(s):  
Mark E. Harmon
Keyword(s):  
Pseudotsuga Menziesii ◽  
Seedling Survival ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
Tree Recruitment ◽  
Rotten Wood

Logs are a major seedbed in Picea sitchensis – Tsuga heterophylla forests; therefore, the interception and retention of seeds on these surfaces is a potential limitation on tree recruitment. The ability of log surfaces within Picea – Tsuga forests to retain needles and seeds was studied at Cascade Head Experimental Forest, Oregon. Moss- and litter-covered surfaces retained many (48–98%) of the seeds and needles placed on them, but rotten wood, sound wood, and bark of Tsuga heterophylla, Picea sitchensis, and Pseudotsuga menziesii retained few (0–8%). Examination of logs mapped in five Picea sitchensis – Tsuga heterophylla stands in Oregon and Washington indicated a mean projected log cover of 9.9%. Thin (<5 cm) and thick (>5 cm) moss mats were the most abundant log surfaces and covered 59 and 25% of the logs, respectively. Analysis of data on seedbed coverage, retentive characteristics, and seedbed-specific seedling survival indicated approximately 1% of a seed cohort would survive the 1st year on log surfaces.

Studies on the incidence of coniferous needle endophytes in the Pacific Northwest

1978 ◽  
Vol 56 (24) ◽  
pp. 3034-3043 ◽  
Author(s):  
George C. Carroll ◽  
Fanny E. Carroll
Keyword(s):  
Pacific Northwest ◽  
Pseudotsuga Menziesii ◽  
Fungal Infections ◽  
Distribution Patterns ◽  
Picea Sitchensis ◽  
Similarity Coefficients ◽  
Species Dominance ◽  
Morphological Criteria ◽  
Order Of Magnitude ◽  
Coniferous Needles

The incidence of internal fungal infections has been scored in coniferous needles from 19 hosts sampled in over 200 sites dispersed throughout western Oregon and southern Washington. Abies grandis, A. magnifica, Picea sitchensis, Pseudotsuga menziesii, and Sequoia sempervirens have proved congenial hosts for needle blade endophytes; petiole fungi are common in all species of Picea and Tsuga sampled. An undescribed taxon in the Hemiphacidiaceae, Chloroscypha spp., Cryptocline spp., Leptostroma spp., Naemacyclus spp., Phomopsis spp., Phyllosticta sp., and several unidentified Coelomycetes with Phoma-like spores were the dominant fungal taxa in the coniferous hosts sampled. The observed patterns of species dominance and diversity suggest that the true population of endophytes has been inadequately sampled in the present study and that an order of magnitude more intensive sampling might be required for real patterns of dominance and diversity to emerge. Many endophytes are restricted to a single coniferous host or to a restricted group of hosts. When similarity coefficients between coniferous species are computed on the basis of their internal needle microfloras, the resultant taxonomic groupings appear similar to those derived from consideration of conventional morphological criteria. Comparison of endophyte incidence with host distribution patterns for Pseudotsuga menziesii reveals that infection rates decrease at high elevations and dry sites.

Contribution à l'étude des carences en cuivre chez les Abiétacées

1978 ◽  
Vol 56 (21) ◽  
pp. 2648-2659 ◽  
Author(s):  
D. G. Strullu ◽  
M. Bonneau
Keyword(s):  
Pseudotsuga Menziesii ◽  
Copper Sulphate ◽  
Copper Content ◽  
Copper Deficiency ◽  
Experimental Studies ◽  
Douglas Fir ◽  
Picea Sitchensis ◽  
The State

The authors have described the morphological deformations owing to copper deficiency in Pseudotsuga menziesii and Picea sitchensis. The experimental studies entered upon have enabled us to determine the copper deficiency level for both species. With Douglas fir, the deficiencies occur under 4 ppm in the leaves; with spruce, the level is set at 2.5 ppm. Treatment of the plantations with 20 g of copper sulphate per tree increases the copper content in the leaves. This treatment also brings about the straightening of the distorted axes; the recorded effects depend upon the state of the saplings before treatment.

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