A neighborhood analysis of canopy tree competition: effects of shading versus crowding

2004 ◽  
Vol 34 (4) ◽  
pp. 778-787 ◽  
Author(s):  
Charles D Canham ◽  
Philip T LePage ◽  
K Dave Coates
Keyword(s):  
Radial Growth ◽  
Regression Models ◽  
Spatial Competition ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Competitive Effects ◽  
Canopy Tree ◽  
Per Capita ◽  
Using Data ◽  
Thuja Plicata Donn

We have developed extensions of traditional distance-dependent, spatial competition analyses that estimate the magnitude of the competitive effects of neighboring trees on target tree growth as a function of the species, size, and distance to neighboring trees. Our analyses also estimate inter- and intra-specific competition coefficients and explicitly partition the competitive effects of neighbors into the effects of shading versus crowding. We tested the method using data from forests of northern, interior British Columbia dominated by western hemlock (Tsuga heterophylla (Raf.) Sarg.) and western redcedar (Thuja plicata Donn ex D. Don). For both species, the most parsimonious regression models included terms for the effects of tree size, crowding, and shading and separate competitive effects of four different groups of competing species. The models explained 33%–59% of the variation in radial growth of the two species. For both species, growth declined more steeply as a function of crowding than shading. There was striking asymmetry in the strength of interspecific competition between hemlock and redcedar, with crowding by hemlock having a strong per capita effect on redcedar, while crowding by redcedar had relatively little effect on the radial growth of hemlock.

Factors limiting the early survivorship of Thuja plicata on northern Vancouver Island, British Columbia

2003 ◽  
Vol 33 (5) ◽  
pp. 854-861 ◽  
Author(s):  
Adrian Weber ◽  
Benjamin Gilbert ◽  
JP (Hamish) Kimmins ◽  
C E Prescott
Keyword(s):  
Forest Floor ◽  
Seedling Survival ◽  
Forest Edge ◽  
Vancouver Island ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Local Soil ◽  
Early Seedling ◽  
Successional Species ◽  
Thuja Plicata Donn

Western redcedar (Thuja plicata Donn ex D. Don), a late successional species on northern Vancouver Island, has a low seedling survival in mature hemlock (Tsuga heterophylla (Raf.) Sarg.) – amabilis fir (Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes) (HA) stands. Shade, moss competition, and substrate were tested as causes of low cedar establishment. Cedar seeds were sown on reference and local soils isolated from surrounding soil, on nonisolated local soil, and on forest floor with moss removed. Western hemlock, amabilis fir, and cedar seeded on forest floor acted as controls. Treatments were implemented in the HA interior and the HA–clearcut edge, with soil treatments also implemented in clearcuts. Germinants and very young seedlings of cedar have a low leaf area of needle-like primary foliage. Cedar development of secondary foliage (the scale foliage normally associated with this species) was correlated with greater vigour and growth. Secondary foliage developed in the rankings forest edge and clearcut > forest interior, and reference isolated soil > local isolated soil > nonisolated local soil. Seedling survival rankings were edge > interior, and amabilis fir > hemlock > cedar on soil and with moss removed > cedar on forest floor. Cedar and amabilis fir showed a smaller growth response to light than hemlock. The results indicate that cedar, normally considered a late successional species, needs disturbance for early seedling establishment and survival and thus has some characteristics of an early seral species.

scholarly journals Height prediction equations using diameter and stand density measures

2000 ◽  
Vol 76 (2) ◽  
pp. 303-309 ◽  
Author(s):  
Christie Staudhammer ◽  
Valerie LeMay
Keyword(s):  
Weibull Distribution ◽  
Predictor Variable ◽  
Stand Density ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Thuja Plicata ◽  
Red Cedar ◽  
Non Linear Equation ◽  
Height Prediction ◽  
Thuja Plicata Donn

Height equations for western hemlock (Tsuga heterophylla (Raf.) Sarg.), western red cedar (Thuja plicata Donn), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and alder (Alnus rubra Bong. and Alnus tenuifolia Nutt.) were fitted using dbh as the predictor variable. A simple, non-linear equation gave very similar results to the Weibull distribution, except for hemlock, which was better modelled using the more flexible Weibull distribution function. Introducing stand density variables into the base equations resulted in increased accuracy for predicting heights of alder. Smaller improvements were found for Douglas-fir, cedar, and hemlock. Key words: estimating height, Coastal BC, Weibull estimation, stand density measures

Rates of non-suberized impervious tissue development after wounding at different times of the year in three conifer species

1976 ◽  
Vol 54 (9) ◽  
pp. 881-892 ◽  
Author(s):  
D. B. Mullick ◽  
G. D. Jensen
Keyword(s):  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Conifer Species ◽  
Intraspecific Variations ◽  
Cyclical Pattern ◽  
Woolly Aphid ◽  
Periderm Formation ◽  
Thuja Plicata Donn ◽  
Season Variations ◽  
Host Component

Rates of development of a non-suberized impervious tissue (NIT), which is a prerequisite to necrophylactic periderm formation, vary on the same tree with the changing environment at different times of the year. In Abies amabilis (Dougl.) Forbes, rates varied from 14 days in June, slowing gradually to 35 days in fall, virtually ceasing in winter, and resuming slowly (70 days) in spring. This cyclical pattern in rates of NIT formation was also found in Tsuga heterophylla (Raf.) Sarg. and Thuja plicata Donn. Fluctuations in the environment occasioned by year-to-year within-season variations appear to affect the physiology of NIT formation; in July, NIT developed after 21 days in 1968 and after 16 days in 1969, on the same A. amabilis. Preliminary observations indicate presence of intraspecific variations in the rates. Rates were consistently faster on the resistant than on the susceptible A. amabilis heavily infested with balsam woolly aphid, Adelges piceae Ratz. Possible causes of these variations and implications of the findings, in relation to process of NIT formation as a basic physiological host component in pathogenic interactions of bark, are discussed.

Sphagnum invasion after clear-cutting and excavator mounding in a hypermaritime forest of British Columbia

2004 ◽  
Vol 34 (8) ◽  
pp. 1730-1746 ◽  
Author(s):  
Taro Asada ◽  
Barry G Warner ◽  
Allen Banner
Keyword(s):  
British Columbia ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
North Coast ◽  
Clear Cut ◽  
Clear Cutting ◽  
Lower Productivity ◽  
Sphagnum Girgensohnii ◽  
Thuja Plicata Donn

Sphagnum invasion 8 years after an experimental clear-cut and mounding field trial was examined in a mesic western redcedar (Thuja plicata Donn ex D. Don) – western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest on the outer north coast of British Columbia. Sphagnum invasion was prominent in wet hollows in the mounded blocks. Pioneer species, Sphagnum pacificum Flatb. and Sphagnum angustifolium (C. Jens. ex Russ.) C. Jens., were common despite being minor components in the precut forest. Sphagnum girgensohnii Russ., a species of forests, showed expanding colonies and contained some Sphagnum capillifolium (Ehrh.) Hedw. Comparisons of vertical growth and decomposition rates of Sphagnum in the experimental field site and in a nearby natural peatland suggest that peat accumulation potential in the Sphagnum colonies in the mounded blocks is similar to that in the natural peatland. These observations suggest that open peatland-type plant communities become established and paludification processes are beginning. Mounding may be an effective strategy for silvicultural management to improve tree growth in the short term but may initiate paludification and negatively impact forest productivity in the long term in hypermaritime lower productivity forests.

Short-term population dynamics of Glaucomys sabrinus and Tamiasciurus douglasii in commercially thinned and unthinned stands of coastal coniferous forest

2002 ◽  
Vol 32 (11) ◽  
pp. 2043-2050 ◽  
Author(s):  
Douglas B Ransome ◽  
Thomas P Sullivan
Keyword(s):  
Population Dynamics ◽  
Coniferous Forest ◽  
Tsuga Heterophylla ◽  
Survival Duration ◽  
Thuja Plicata ◽  
Glaucomys Sabrinus ◽  
Short Term ◽  
Commercial Thinning ◽  
Thuja Plicata Donn ◽  
Short Term Effects

Population dynamics of Glaucomys sabrinus (Shaw) and Tamiasciurus douglasii (Audubon and Bachman) were examined in commercially thinned and unthinned stands in British Columbia, Canada. We tested the hypothesis that commercial thinning would have negative short-term effects on the population dynamics of these species. Populations were monitored using mark–recapture techniques in two commercially thinned and two unthinned stands dominated by 60- to 70-year-old western hemlock (Tsuga heterophylla (Raf.) Sarg.) and western redcedar (Thuja plicata Donn. ex D. Don). Populations were sampled intensively from August 1995 to May 1999 at Chehalis Lake and from May 1997 to March 2000 in the Malcolm Knapp Research Forest (MKRF). There were no differences among stands thinned and unthinned in movement, abundance, recruitment, survival, duration individuals remained in stands, percentage of males breeding, and mass of males for G. sabrinus or T. douglasii. Mean density of G. sabrinus in thinned and unthinned stands were 0.65 and 0.89 individuals/ha, respectively, at Chehalis and 0.09 and 0.51 individuals/ha, respectively, at MKRF. Mean density of T. douglasii in thinned and unthinned stands were 1.18 and 0.87 individuals/ha, respectively, at Chehalis and 1.08 and 1.00 individuals/ha, respectively, at MKRF. We concluded that commercial thinning had no negative short-term effects on the population dynamics of these species.

Histology of resin vesicles and oleoresin terpene composition of conifer seeds

2018 ◽  
Vol 48 (9) ◽  
pp. 1073-1084 ◽  
Author(s):  
Kristina Kshatriya ◽  
Justin G.A. Whitehill ◽  
Lina Madilao ◽  
Hannah Henderson ◽  
Allison Kermode ◽  
...  
Keyword(s):  
Abies Balsamea ◽  
Seed Storage ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Abies Lasiocarpa ◽  
Thuja Occidentalis ◽  
Future Studies ◽  
Conifer Seeds ◽  
Seed Coats ◽  
Thuja Plicata Donn

The seed coats of several conifers contain terpene-filled resin vesicles, which may be involved in the protection of the dormant embryo and the seed storage tissue against herbivores or pathogens. We analyzed the terpenoid composition of seeds from four Abies species (Abies amabilis Douglas ex J. Forbes, Abies balsamea (L.) Mill., Abies grandis (Douglas ex D. Don) Lindl., and Abies lasiocarpa (Hook.) Nutt.), two Thuja species (Thuja plicata Donn ex D. Don and Thuja occidentalis L.), and three Tsuga species (Tsuga canadensis (L.) Carrière, Tsuga mertensiana (Bong.) Carrière, and Tsuga heterophylla (Raf.) Sarg.) and examined histological features of resin vesicles in seeds from one species from each genus. Resin vesicle morphology was generally similar among the species analyzed. The composition of the seed terpenes varied largely between species. The described seed terpene profiles of the nine species will serve as a foundation for future studies into the function of seed terpenes and resin vesicles in the seed coat.

New concepts and terminology of coniferous periderms: necrophylactic and exophylactic periderms

1973 ◽  
Vol 51 (8) ◽  
pp. 1459-1470 ◽  
Author(s):  
D. B. Mullick ◽  
G. D. Jensen
Keyword(s):  
External Environment ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Chemical Characteristics ◽  
Main Function ◽  
Field Observations ◽  
New Concepts ◽  
Living Tissues ◽  
Second Category ◽  
Thuja Plicata Donn

Field observations were made on wound and pathological periderms, regardless of the causal agent, and periderms formed at abscission zones, old resin blisters and rhytidomes in Abies amabilis (Dougl.) Forbes, Abies grandis (Dougl.) Lindl., Tsuga heterophylla (Raf.) Sarg., and Thuja plicata Donn. It was established that these periderms were of reddish-purple sequent periderm (rsp) type, rather than either the brown first periderm (bfp), or brown sequent periderm (bsp) types. These reddish-purple pigmented periderms, like the rsp (the usual sequent periderm) were found abutting necrotic tissues and were moreover identical with rsp in 15 newly demonstrated cryofixation and chemical characteristics. Because of this equivalence, it is proposed that all these reddish-purple periderms, including the usual sequent periderm (rsp), constitute one category, the necrophylactic periderms. These periderms arise whenever regeneration of a periderm after death of cells is required, and their main function seems to be protection of living tissues from the adverse effects associated with cell death. Because of the equivalence of bfp and bsp, they constitute another category, the exophylactic periderms. This second category of periderms has a common function of protecting living tissues against the external environment.

Studies on periderm. II. Anthocyanidins in secondary periderm tissue of amabilis fir, grand fir, western hemlock, and western red cedar

1969 ◽  
Vol 47 (9) ◽  
pp. 1419-1422 ◽  
Author(s):  
D. B. Mullick
Keyword(s):  
Tsuga Heterophylla ◽  
Free State ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
Abies Grandis ◽  
Abies Amabilis ◽  
Red Cedar ◽  
Western Red Cedar ◽  
Thuja Plicata Donn

By using a mild method, which precludes the possibility of pigment hydrolysis during extraction and processing, the occurrence of anthocyanidins in the free state has been detected in the normal secondary periderm tissues (rhytidomal region) of amabilis fir (Abies amabilis (Dougl.) Forbes), grand fir (Abies grandis (Dougl.) Lindl.), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and western red cedar (Thuja plicata Donn.). Cyanidin was present in all species. Pelargonidin was present in western hemlock and most likely also in western red cedar.

Natural pigment differences distinguish first and sequent periderms of conifers through a cryofixation and chemical techniques

1971 ◽  
Vol 49 (9) ◽  
pp. 1703-1711 ◽  
Author(s):  
D. B. Mullick
Keyword(s):  
Microscopic Observation ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Field Observations ◽  
Natural Pigment ◽  
Abies Grandis ◽  
Chemical Techniques ◽  
Frozen State ◽  
Cryostat Sections ◽  
Thuja Plicata Donn

Field observations revealed distinctness of the first and sequent periderm pigmentation in each of 40 species from 13 genera of conifers. These distinctions in Abies amabilis (Dougl.) Forbes, Abies grandis (Dougl.) Lindl., Thuja plicata (Donn), and Tsuga heterophylla (Raf.) Sarg. were confirmed by a cryofixation and chemical techniques. The former technique depends upon fixation of tissues by freezing, and microscopic observation of cryostat sections in a frozen state, thus revealing the natural color of the pigments. The first periderm of the aforementioned four species is dark brown. It is replaced invariably by a reddish sequent periderm which always abuts the rhytidome. Additional reddish sequent periderms may continue to arise producing an ever-thickening rhytidomal zone. A second type of sequent periderm, dark brown in color, was found in three of the four species studied. This periderm, whenever present, was found abutting a reddish periderm and never abutting the rhytidome. The pigments are localized exclusively in phellem. The significance of the brownish sequent periderm in rhytidomal scaling and en masse sloughing, and its similarities to the first periderm are discussed.

Conversion of total to projected leaf area index in conifers

2000 ◽  
Vol 78 (4) ◽  
pp. 447-454 ◽  
Author(s):  
Hugh J Barclay ◽  
Doug Goodman
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Pinus Contorta ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
Thuja Plicata ◽  
Area Index ◽  
Conversion Factors ◽  
Horizontal Orientation ◽  
Thuja Plicata Donn

Several definitions of leaf area index (LAI) presently exist in the literature but the relationships among them are not clear. To compare the results of various studies, there is a need to convert from one definition to another. Factors for converting among four definitions of LAI are presented for six conifer species: Abies grandis (Dougl. ex D. Don) Lindl., Thuja plicata Donn ex D. Don., Tsuga heterophylla (Raf.) Sarg., Picea sitchensis (Bong.) Carr.), Pinus contorta Dougl., and Pseudotsuga menziesii (Mirb) Franco). Among the four definitions of LAI, the two extremes involve (i) the total area of the leaf and (ii) the projected area of nonhorizontal leaves, as they occur on the tree. If leaves are randomly oriented in space, then the conversion factor between definitions i and ii should be 0.25. Four of the six species have conversion factors very close to this value, and three of these four are relatively shade-intolerant,. The remaining two species, A. grandis and Thuja plicata, have conversion factors of approximately 0.35, owing to the approximately horizontal orientation of their leaves. These two species are both relatively shade-tolerant, and the trend toward horizontal leaves might be an adaptation to assist in shade tolerance. A sensitivity analysis indicated that the foliage of most of the species maximized the amount of light gathered when the light was coming from almost straight overhead, as is the case with many shaded forest trees.Key words: leaf area index, conifers, leaf area index conversion.

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