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.

Response of Gaultheria shallon and Epilobium angustifolium to large additions of nitrogen and phosphorus fertilizer

2004 ◽  
Vol 34 (2) ◽  
pp. 502-506 ◽  
Author(s):  
Jennifer N Bennett ◽  
Brent M Lapthorne ◽  
Leandra L Blevins ◽  
Cindy E Prescott
Keyword(s):  
Seedling Survival ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Ground Vegetation ◽  
N Availability ◽  
Gaultheria Shallon ◽  
Nitrogen And Phosphorus ◽  
N Application ◽  
Epilobium Angustifolium ◽  
Conifer Seedling

A study was established in coastal British Columbia to determine if repeated nitrogen (N) and phosphorus (P) fertilization negatively influences the reestablishment of salal (Gaultheria shallon Pursh) on cleared and burned cedar–hemlock (Thuja plicata Donn ex D. Don – Tsuga heterophylla (Raf.) Sarg.) forests. Fertilizers were applied for 3 years, and the biomass of ground vegetation and conifer seedling survival and growth were measured. Salal biomass decreased with high levels of N application (1000 kg N/ha), but not when 400 kg P/ha was added with 1000 kg N/ha. The addition of 500 kg N/ha, with or without P, stimulated salal growth. The biomass of fireweed (Epilobium angusti folium L.) increased with the addition of N + P but not with N alone. In the high N and N + P treatments, conifer seedling survival and heights were reduced. These results confirm earlier reports that salal responds negatively to high N applications and that this negative response can be alleviated with simultaneous additions of P. The response of fireweed to N + P, but not to N alone, suggests that the abundance of this species is more indicative of P than N availability.

scholarly journals Multiple-pathway succession in coastal Tsuga heterophylla, Thuja plicata, and Abies amabilis forests on northeastern Vancouver Island, British Columbia

2014 ◽  
Vol 44 (10) ◽  
pp. 1145-1155 ◽  
Author(s):  
Adrian Weber ◽  
J.P. (Hamish) Kimmins ◽  
Benjamin Gilbert ◽  
Yueh-Hsin Lo ◽  
Juan A. Blanco
Keyword(s):  
Natural Disturbance ◽  
Vancouver Island ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Silver Fir ◽  
Frequency Distributions ◽  
Abies Amabilis ◽  
Forest Practices ◽  
Adult Trees ◽  
Disturbance Hypothesis

Sustainable forest practices are often designed to mimic natural disturbance and successional processes, yet succession is poorly understood in many ecosystems. On northeastern Vancouver Island, the “disturbance hypothesis” is a widely assumed succession model asserting that shade-tolerant western redcedar (Thuja plicata Donn ex D. Don) and the ericaceous shrub salal (Gaultheria shallon Pursh) invade and colonize highly productive western hemlock (Tsuga heterophylla (Raf.) Sarg.) – Pacific silver fir (Abies amabilis Douglas ex J. Forbes) stands (HA) on zonal sites in the absence of stand-replacing wind disturbance. This leads to the development of low-productivity, low-density, uneven-aged, open-crowned redcedar–hemlock–salal stands (CH). In conflict with this model, old, apparently stable HA stands lacking redcedar can be found on such sites as well. We sought evidence for the predicted transition to CH stands by examining stand composition, crown closure, tree size class frequency distributions, salal cover, and redcedar establishment on young HA (∼90 years old), old HA (>160 years), and CH (>160 years) stands. When adjacent to a redcedar stand, young HA stands had fewer redcedar seedlings but more redcedar adult trees than old HA stands. However, redcedar abundance did not differ between young and old HA stands at distances further than 10 m from adjacent redcedar stands. This could indicate that redcedar recruits into HA stands at stand establishment and that redcedar seedling establishment is low under the thick canopy of young HA stands. The chronosequence data also suggest that both old HA and CH stands are self-replacing stand types in these forests, contrary to the disturbance hypothesis. We develop a new, multipathway model for this ecosystem that is based on the chronosequence data and life-history traits of the focal tree species and suggest that disturbance plays a role opposite to the equilibrium model.

Ten-year postharvest effects of silviculture systems on soil-resource availability and conifer nutrition in a northern temperate forest

2004 ◽  
Vol 34 (4) ◽  
pp. 800-809 ◽  
Author(s):  
J M Kranabetter ◽  
K D Coates
Keyword(s):  
Tree Growth ◽  
Forest Floor ◽  
Light Availability ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
Net N Mineralization ◽  
Mature Trees ◽  
Foliar N

Silviculture systems (clear-cut, partial-cut, and unharvested forest) were compared 9–10 years after harvesting to determine their effects on conifer nutrition and the availability of soil resources, especially nitrogen. These results were used to discuss the effects of silviculture systems on tree growth in relation to the more commonly described effects of light. Differences in soil properties across the silviculture treatments were most apparent in the forest floor. Depth and C/N ratio of the forest floor had decreased slightly in clearcuts, and forest-floor moisture was highest under partial-cut forest. Despite these differences in soil chemistry and soil moisture, no differences were detected in mineralizable N (anaerobic incubation) or in situ net N mineralization among treatments. Height growth and foliar mass were reduced under the low-light conditions of the partial-cut forest, but there were no differences in foliar N concentrations of hybrid white spruce (Picea glauca (Moench) Voss × Picea sitchensis (Bong.) Carrière), western redcedar (Thuja plicata Dougl. ex D. Don), or western hemlock (Tsuga heterophylla (Raf.) Sarg.) saplings. Mature western hemlock trees in partial-cut forest also had concentrations of foliar N equal to that of mature trees in the unharvested forest. Overall, we detected only minor effects of silviculture systems on soils after 10 years, and we conclude that light availability is likely more responsible for the current differences in tree growth.

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.

Origin, development, and dynamics of coastal temperate conifer rainforests of southern Vancouver Island, Canada

2002 ◽  
Vol 32 (2) ◽  
pp. 353-372 ◽  
Author(s):  
K J Brown ◽  
R J Hebda
Keyword(s):  
Late Glacial ◽  
Vancouver Island ◽  
Tsuga Heterophylla ◽  
Fire Disturbance ◽  
Thuja Plicata ◽  
Quercus Garryana ◽  
Mixed Conifer Forests ◽  
Forested Ecosystems ◽  
Increasing Precipitation ◽  
Early Late

Pollen and charcoal from East Sooke Fen, Pixie Lake, and Whyac Lake were used to reconstruct the post glacial vegetation, climate, and fire-disturbance history across a precipitation gradient on southern Vancouver Island, British Columbia. An open Pinus woodland covered the landscape in the early late-glacial interval. Fires were absent under a cool and dry climate. Closed mixed conifer forests of Pinus, Picea, Abies, Tsuga heterophylla (Raf.) Sarg., and Tsuga mertensiana (Bong.) Carrière replaced the Pinus biogeochron in the late late-glacial interval. Fires became more common even though climate was cool and moist. Open Pseudotsuga menziesii (Mirb.) Franco forests expanded westward during the warm dry early Holocene, though closed Picea and Tsuga heterophylla forests grew in the wettest part of the area at Whyac Lake. Modern precipitation gradients likely originated at this time. Fires occurred in forested ecosystems, although East Sooke Fen at the driest end of the gradient experienced less fire. The middle and late Holocene was characterized by increasing precipitation and decreasing temperature, respectively. Quercus garryana Dougl. stands spread westward during the mid-Holocene. Extant closed Tsuga heterophylla and Cupressaceae (Thuja plicata Donn. ex D. Don) forests arose in the wetter part of the gradient, whereas Pseudotsuga forests occupied drier eastern areas. During this interval, fires were rare in wet western regions but apparently more common in dry eastern regions.

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.

scholarly journals Biochar Effects on Two Tropical Tree Species and Its Potential as a Tool for Reforestation

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 678 ◽  
Author(s):  
David Lefebvre ◽  
Francisco Román-Dañobeytia ◽  
Judith Soete ◽  
France Cabanillas ◽  
Ronald Corvera ◽  
...  
Keyword(s):  
Soil Fertility ◽  
Tree Species ◽  
Field Experiments ◽  
Seedling Survival ◽  
Belowground Biomass ◽  
Plant Performance ◽  
Additional Species ◽  
Positive Effects ◽  
Early Seedling ◽  
Successional Species

Research Highlights: We find that biochar plus fertilizer has synergistic and positive effects on seedling growth and robustness, but slightly lowers early seedling survival. Biochar plus fertilizer has the potential to greatly decrease costs associated with afforestation as compared to traditional fertilization and gives better results. Background and Objectives: Biochar can improve soil fertility and plant yield in crops. However, there is little information regarding the effects of biochar on trees, even though reforestation/afforestation projects are increasing and are often unsuccessful due to soil fertility limitations. This study aims to increase knowledge of biochar use as a reforestation tool. Materials and Methods: We measured survival and growth in an early ((Guazuma crinita Mart. [n = 240])) and a late (Terminalia amazonia (J.F. Gmel.) Exell. [n = 240]) successional species under 6 different biochar treatments in a 6-month nursery experiment. Results: (i) Survival was highest in the 1 t/ha biochar treatment, while treatments containing fertilizers or biochar at 5 t/ha lowered the survival rate of both species compared to the control; (ii) simultaneous addition of biochar and fertilizer lead to significant increases in height, diameter, total number of leaves, and aboveground and belowground biomass of both species as compared to other treatments; (iii) biochar treatment containing 1 t/ha with and without fertilizer showed significantly better results than applications of 5 t/ha; and (iv) Guazuma crinita responded more strongly to treatments containing biochar and fertilizers compared to Terminalia amazonia, which is suggestive of greater synergetic effects of biochar and fertilizer addition on early successional tree species. Conclusions: Applying biochar and fertilizer is synergistic and outperforms any single treatment, as well as the control, in terms of plant performance. This case study suggests that biochar can greatly improve reforestation/afforestation projects by increasing plant performance while substantially reducing fertilizer and labor maintenance costs. Field experiments and testing of additional species is needed to generalize the findings.

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.

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