scholarly journals Effects of Sitka spruce masting on phenology and demography of siskins Spinus spinus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Euan N. Furness ◽  
Robert W. Furness
Keyword(s):  
Native Species ◽  
Late Summer ◽  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Food Sources ◽  
Breeding Ecology ◽  
Cone Production ◽  
Forestry Practices ◽  
Age Ratio ◽  
Alternative Food Sources

AbstractMasting behaviour of Sitka spruce Picea sitchensis may influence Eurasian siskin Spinus spinus breeding ecology as breeding siskins specialize on spruce seeds. We caught siskins and other small passerines over 16 years using mist nets adjacent to large plantations of mature Sitka spruce. We sexed, aged, measured and weighed the birds and collected feather samples from fledglings to measure nitrogen and carbon stable isotope ratios. Siskins departed in late summer, and returned, and bred earlier in years of higher cone abundance. Nitrogen and carbon isotopes indicated that siskins fed their chicks on Sitka spruce seeds in most years, and more so in years of high cone production. More siskins were caught following heavy rainfall, when the cones had closed, encouraging the birds to seek alternative food sources. Fledglings were not heavier or larger in years with higher cone crops but were more numerous. However, the age ratio of siskins caught the following year was unaffected by cone crop. Given their reliance on Sitka spruce seeds, climate change may have a major impact on siskin numbers by altering the availability of Sitka spruce seeds, either through changes in masting patterns or cone opening, or due to climate-related changes in forestry practices. Siskins represent a valuable study system to conservation ecology, where a native species is ecologically reliant on introduced taxa.

scholarly journals Do linden trees kill bees? Reviewing the causes of bee deaths on silver linden ( Tilia tomentosa )

2017 ◽  
Vol 13 (9) ◽  
pp. 20170484 ◽  
Author(s):  
Hauke Koch ◽  
Philip C. Stevenson
Keyword(s):  
Optimal Foraging ◽  
Late Summer ◽  
Secondary Compounds ◽  
Food Sources ◽  
Flowering Period ◽  
Behavioural Effects ◽  
Foraging Decisions ◽  
Pollen Chemistry ◽  
Alternative Food Sources ◽  
Tilia Tomentosa

For decades, linden trees (basswoods or lime trees), and particularly silver linden ( Tilia tomentosa ), have been linked to mass bee deaths. This phenomenon is often attributed to the purported occurrence of the carbohydrate mannose, which is toxic to bees, in Tilia nectar. In this review, however, we conclude that from existing literature there is no experimental evidence for toxicity to bees in linden nectar. Bee deaths on Tilia probably result from starvation, owing to insufficient nectar resources late in the tree's flowering period. We recommend ensuring sufficient alternative food sources in cities during late summer to reduce bee deaths on silver linden. Silver linden metabolites such as floral volatiles, pollen chemistry and nectar secondary compounds remain underexplored, particularly their toxic or behavioural effects on bees. Some evidence for the presence of caffeine in linden nectar may mean that linden trees can chemically deceive foraging bees to make sub-optimal foraging decisions, in some cases leading to their starvation.

A review of coning and seed production in Picea sitchensis

1987 ◽  
Vol 93 (1-2) ◽  
pp. 183-195 ◽  
Author(s):  
J. J. Philipson
Keyword(s):  
Seed Production ◽  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Breeding Programme ◽  
Mature Trees ◽  
Physiological Mechanisms ◽  
Male And Female ◽  
Cone Production ◽  
Juvenile Phase ◽  
Similar Quantity

SynopsisSitka spruce grown from seed has a juvenile phase of about twenty years before coning commences; mature trees and grafted scions cone intermittently and produce good cone crops every three–five years. These characteristics have lengthened the breeding programme and reduced seed production in orchards. Production of male and female cones can be enhanced by treatments such as heat and drought and by application of a mixture of gibberellins A4 and A7 (GA4/7) to mature grafts. To enhance flowering consistently in container grown grafts the GA4/7 must be applied together with a cultural treatment, but with larger grafts in the field GA4/7 alone is often effective. Attempts to induce cone production in juvenile trees, however, have been less successful. Female cones initiated on field grown trees in response to inductive treatments yield seed of a similar quantity and quality to that from cones on untreated trees. The physiological mechanisms of coning, and cone induction techniques, are discussed.

Location of cones in the crown and along shoots of Sitka spruce (Picea sitchensis (Bong.) Carr.) and the influence of coning intensity and shoot size

1998 ◽  
Vol 28 (12) ◽  
pp. 1756-1772 ◽  
Author(s):  
G C Clarke ◽  
D C Malcolm
Keyword(s):  
Lower Order ◽  
Significant Relationship ◽  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Second Order ◽  
Third Order ◽  
Rooted Cuttings ◽  
Cone Production ◽  
Shoot Size ◽  
Male Cones

The location of female cones in the crowns of rooted cuttings and mature forest-grown trees of Sitka spruce (Picea sitchensis (Bong.) Carr.) was recorded. When cones were allocated to crown sections there were clear patterns of bearing, with the majority of cones on second-order distal shoots on whorls 2 and 3. As total cone production increased, the bearing zone progressed onto more proximal shoots on upper whorls and distal shoots on lower whorls. On individual branches of clonal grafts, female cones tended to be borne on more distal shoots than male cones. Female cones, on all sample sets, tended to be borne primarily on second-order shoots and male cones, on the clonal grafts, on third-order shoots. On the clonal grafts there was a weak, though significant, relationship between the number of original buds and female, but not male, cones on a shoot. Cones were also described by position on bearing shoots. There was a tendency for the proportion of progressively more proximal cone positions to increase on lower-order shoots and vice versa. Cone position was also influenced by the dimensions of the bearing shoot independent of its position with a distal shift in cone-bearing position as shoot dimensions decreased.

Forestry practices and biodiversity, with particular reference to the Maritime Provinces of eastern Canada

1994 ◽  
Vol 2 (1) ◽  
pp. 33-77 ◽  
Author(s):  
Bill Freedman ◽  
Stephen Woodley ◽  
Judy Loo
Keyword(s):  
Native Species ◽  
Forest Products ◽  
Natural Ecosystems ◽  
Eastern Canada ◽  
Old Growth ◽  
Industrial Facilities ◽  
Levels Of Organization ◽  
Forestry Practices ◽  
Forest Industries ◽  
Ecologically Sustainable

The Canadian forest industries are based on the extensive harvesting and management of forests, with attendant effects on biodiversity at all levels of organization. In large part, conflicts between forestry and biodiversity occur because lands that are harvested and managed are mostly natural and seminatural ecosystems. Prior to being affected by forestry, such lands provided habitat for native species of wild life and their communities. Some of these elements of biodiversity may not find silvicultural habitats, especially plantations, to be suitable to their needs. In addition, the longer term integrity of some natural ecosystems, for example old-growth forests, is not compatible with any but the softest types of exploitation and management. This report discusses interactions of forestry and biodiversity at three levels of organization: (i) genetic variation within populations and species; (ii) the richness of species within communities; and (iii) the richness of community types on the landscape. A broader conclusion of our report is the following: If forestry systems of harvesting and management are to be practised in an ecologically sustainable fashion, then all elements of biodiversity must be accommodated within a landscape comprised of an integration of working lands and ecological reserves. The spatial scale of this integration could be various, ranging from large watersheds, to the "woodsheds" of particular industrial facilities, to provincial and national areas. Therefore, resolution of the substantial conflicts between biodiversity and forestry requires the design of ecologically sustainable landscapes that can provide a flow of timber and other valuated forest products, while still sustaining natural biodiversity resources.Key words: forest management, biodiversity, ecological reserves, eastern Canada, harvesting practices, old growth.

Predicting the longitudinal modulus of elasticity of Sitka spruce from cellulose orientation and abundance

Holzforschung ◽  
2010 ◽  
Vol 64 (4) ◽  
Author(s):  
J. Paul McLean ◽  
Robert Evans ◽  
John R. Moore
Keyword(s):  
Bulk Density ◽  
Modulus Of Elasticity ◽  
Microfibril Angle ◽  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Model Parameters ◽  
Bending Tests ◽  
Wood Stiffness ◽  
Using Data ◽  
Longitudinal Modulus

Abstract Sitka spruce (Picea sitchensis) is the most widely planted commercial tree species in the United Kingdom and Ireland. Because of the increasing use of this species for construction, the ability to predict wood stiffness is becoming more important. In this paper, a number of models are developed using data on cellulose abundance and orientation obtained from the SilviScan-3 system to predict the longitudinal modulus of elasticity (MOE) of small defect-free specimens. Longitudinal MOE was obtained from both bending tests and a sonic resonance technique. Overall, stronger relationships were found between the various measures of cellulose abundance and orientation and the dynamic MOE obtained from the sonic resonance measurements, rather than with the static MOE obtained from bending tests. There was only a moderate relationship between wood bulk density and dynamic MOE (R2=0.423), but this relationship was improved when density was divided by microfibril angle (R2=0.760). The best model for predicting both static and dynamic MOE involved the product of bulk density and the coefficient of variation in the azimuthal intensity profile (R2=0.725 and 0.862, respectively). The model parameters obtained for Sitka spruce differed from those obtained in earlier studies on Pinus radiata and Eucalyptus delegatensis, indicating that the model might require recalibration before it can be applied to different species.

Heritability of height growth in 10-year-old Sitka spruce

1985 ◽  
Vol 27 (6) ◽  
pp. 729-734 ◽  
Author(s):  
Francis C. Yeh ◽  
Sven Rasmussen
Keyword(s):  
Sitka Spruce ◽  
Height Growth ◽  
Picea Sitchensis ◽  
Breeding Program ◽  
Progeny Test ◽  
Northwest Coast ◽  
Phenotypic Variance ◽  
Family Selection ◽  
Sources Of Variation

Ten-year height growth for Picea sitchensis (Bong.) Carr. was studied in a progeny test of 42 wind-pollinated families from seven stands on the northwest coast of Vancouver Island. Although stand and family-within-stand effects were significant sources of variation, 79% of the phenotypic variance in 10-year height was associated with differences among trees within family plots. Estimates of heritability ([Formula: see text], [Formula: see text], and [Formula: see text]) indicate that a combination of stand, family-within-stand, and progeny-within-family selection will be effective for a long-term breeding program to increase tree heights in Sitka spruce.Key words: Picea, heritability, quantitative.

Genetic relationships between wood quality traits and diameter growth of juvenile core wood in Sitka spruce

2013 ◽  
Vol 43 (1) ◽  
pp. 1-6 ◽  
Author(s):  
S.G. Kennedy ◽  
A.D. Cameron ◽  
S.J. Lee
Keyword(s):  
Growth Rate ◽  
Genetic Correlation ◽  
Modulus Of Elasticity ◽  
Genetic Relationships ◽  
Wood Quality ◽  
Wood Properties ◽  
Sitka Spruce ◽  
Acoustic Velocity ◽  
Picea Sitchensis ◽  
Good Growth

The trend towards shorter rotations in planted conifer stands has resulted in a reduction in the proportion of mature wood relative to juvenile core wood, raising concerns that the mechanical performance of sawn battens will be affected. The potential to improve the wood quality of the juvenile core of Sitka spruce (Picea sitchensis (Bong.) Carrière) without compromising growth rate was investigated. Rapid and inexpensive indirect methods of assessing wood properties on standing trees using a Pilodyn gun and acoustic velocity were compared with direct measurements made on wood samples cut from the juvenile core. Strong genetic correlations were observed between Pilodyn gun values and direct measures of density (–0.76) and between the square of acoustic velocity and modulus of elasticity (0.73). The genetic correlation between the square of acoustic velocity and microfibril angle was also strong (–0.84). These results suggest that indirect assessments of wood properties within juvenile core wood are sufficiently reliable for these techniques to be used in the Sitka spruce breeding programme. Although a strong negative genetic correlation between diameter at breast height and density was noted (–0.79), sufficient variation exists within the breeding population to select families with both good growth rate and high modulus of elasticity wood.

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