Ectomycorrhizal community structure on western hemlock (Tsuga heterophylla) seedlings transplanted from forests into openings

2002 ◽  
Vol 80 (8) ◽  
pp. 861-868 ◽  
Author(s):  
J M Kranabetter ◽  
J Friesen

This study tested whether mature-forest ectomycorrhizal (ECM) communities could be maintained in forest openings on seedlings. Naturally regenerated western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings were transplanted from mature forests into openings and the ECM fungal community was compared after 2 years with similar seedlings planted back into the forests or seedlings from openings planted back into openings. Fewer ECM morphotypes, lower average richness per seedling, and a steeper, less even species distribution curve were found, all of which suggest that the mature-forest ECM fungal community changed after transplanting forest seedlings into the openings. The increased abundance of pioneer fungi such as Thelephora terresteris suggested that many of the mature-forest ECM fungi were unable to maintain or continue root colonization in openings. Results suggest that many mature-forest ECM fungi require further stand development to maintain enough rooting density and hyphal contact to persist.Key words: ectomycorrhizal succession, disturbance, species-importance curves, multistage and late-stage fungi.

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 109 ◽  
Author(s):  
Petra Veselá ◽  
Martina Vašutová ◽  
Magda Edwards-Jonášová ◽  
Pavel Cudlín

Bark beetle infestation is a widespread phenomenon in temperate forests, which are facing significant weather fluctuations accompanying climate change. Fungi play key roles in forest ecosystems as symbionts of ectomycorrhizal trees, decomposers, or parasites, but the effect of severe disturbances on their communities is largely unknown. The responses of soil fungal communities following bark beetle attack were determined using Illumina sequencing of soil samples from 10 microsites in a mature forest not attacked by bark beetle, a forest attacked by bark beetle, a forest destroyed by bark beetle, and a stand where all trees were removed after a windstorm. The proportion of ITS2 sequences assigned to mycorrhizal fungal species decreased with increased intensity of bark beetle attack (from 70 to 15%), whereas the proportion of saprotrophs increased (from 29 to 77%). Differences in the ectomycorrhizal (ECM) fungal community was further characterized by a decrease in the sequence proportion of Elaphomyces sp. and Russula sp. and an increase in Piloderma sp., Wilcoxina sp., and Thelephora terrestris. Interestingly, the species composition of the ECM fungal community in the forest one year after removing the windstorm-damaged trees was similar to that of the mature forest, despite the sequence proportion attributed to ECM fungi decreased.


1998 ◽  
Vol 76 (2) ◽  
pp. 189-196 ◽  
Author(s):  
J M Kranabetter ◽  
T Wylie

We examined the diversity and distribution of ectomycorrhizal morphotypes on naturally regenerated western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings across small forest openings (50-75 m in diameter) in northwest British Columbia. The total and average morphotype richness decreased across the 4-year-old forest openings despite the rapid establishment of western hemlock and lack of soil disturbance. Average fungal richness decreased from 13.1 morphotypes under the forest canopy to 9.6 at the forest edge (27% reduction) and to 7.8 in the forest opening (40% reduction). Cenococcum geophilum, Mycelium radicis atrovirens, and Lactarius I were the most abundant ectomycorrhizae at each gap position, and none of the ectomycorrhizal fungi found in openings were eliminated by "late-stage" fungi in mature stands. This fungal distribution supports the "multistage" concept of ectomycorrhizal succession. Seedlings under the forest canopy had a total of 38 fungal morphotypes in a relatively even distribution pattern that corresponded well to the "random niche boundary" hypothesis. Fungal distributions were progressively less even for seedlings at the forest edge and opening than for seedlings beneath the canopy, perhaps because reduced fungal diversity and hyphal inoculum had affected the competitive balance of the ectomycorrhizal community.Key words: ectomycorrhizal community, diversity, succession, forest gaps.


1997 ◽  
Vol 75 (9) ◽  
pp. 1424-1435 ◽  
Author(s):  
D. Mailly ◽  
J. P. Kimmins

Silvicultural alternatives that differ in the degree of overstory removal may create shady environments that will be problematic for the regeneration of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Gradients of light in the field were used to compare mortality, growth, and leaf morphological acclimation of two conifer species of contrasting shade tolerances: Douglas-fir and western hemlock (Tsuga heterophylla (Raf.) Sarg.). Results after two growing seasons indicated that Douglas-fir mortality occurred mainly at relative light intensity (RLI) below 20%, while western hemlock mortality was evenly distributed along the light gradient. Height, diameter, and biomass of the planted seedlings increased with increasing light for both species but at different rates, and maximum biomass accumulation always occurred in the open. Douglas-fir allocated more resources to stem biomass than western hemlock, which accumulated more foliage biomass. Increases in specific leaf area for Douglas-fir seedlings occurred at RLI ≤ 0.4 and red/far red (R/FR) ratio ≤ 0.6, which appear to be the minimal optimum light levels for growth. Conversely, western hemlock seedlings adjusted their leaf morphology in a more regular pattern, and changes were less pronounced at low light levels. These results, along with early mortality results for Douglas-fir, suggest that the most successful way to artificially regenerate this species may be by allowing at least 20% of RLI for ensuring survival and at least 40% RLI for optimum growth. Key words: light, light quality, leaf morphology, acclimation.


1987 ◽  
Vol 119 (12) ◽  
pp. 1109-1115
Author(s):  
W.P.L. Osborn ◽  
J.H. Borden

AbstractTo mitigate the effects of mosquitoes, settlers in the Revelstoke area of British Columbia reportedly burned the sporophores of the Indian paint fungus, Echinodontium tinctorium (Ell. & Ev.) Ell. & Ev., a pathogen of western hemlock, Tsuga heterophylla (Raf.) Sarg., and true firs, Abies spp. Larval and adult yellowfever mosquitoes, Aedes aegypti (L.), were exposed to aqueous extracts of smoke (smoke-waters) from E. tinctorium sporophores, and from western hemlock sapwood and heartwood. Smoke-waters were of approximately equal toxicity to larvae. Fungus smoke-water, but not sapwood or heartwood smoke-waters, lost 50% of its potency in 5 months. Vapors from fungus smoke-water were significantly more toxic to adult mosquitoes than those from sapwood or heartwood. Thus smoke from E. tinctorium sporophores and T. heterophylla wood apparently contain different water-soluble combustion products toxic to A. aegypti.


2005 ◽  
Vol 35 (6) ◽  
pp. 1496-1501
Author(s):  
G R Johnson ◽  
C Cartwright

Western hemlock (Tsuga heterophylla (Raf.) Sarg.) families were grown under different levels of shade for 2 or 3 years at two nursery sites to determine whether families performed differently relative to one another in the different shade environments. Differences were found both for levels of shade and families, but no family × shade interaction was found. Results suggest that families selected in full-sun environments (clearcuts or farm fields) may be well suited for use in silvicultural systems where seedlings are planted in understory conditions.


2019 ◽  
Vol 433 ◽  
pp. 105-110
Author(s):  
Matthew E. Hane ◽  
Andrew J. Kroll ◽  
Aaron Springford ◽  
Jack Giovanini ◽  
Mike Rochelle ◽  
...  

1990 ◽  
Vol 122 (3) ◽  
pp. 555-562 ◽  
Author(s):  
R.F. Shepherd ◽  
T.G. Gray

AbstractEggs of western blackheaded budworm, Acleris gloverana (Walsingham), are laid on the lower surface of western hemlock, Tsuga heterophylla (Raf.) Sarg., needles. A comparison was made of the following measures of sample branch size as a basis for expressing egg density: fresh branch weight, branch area, total twig length, branch volume, and number of buds. The criteria for selection of these measures were as follows: correlations of branch size with dry needle weight, variances of egg density and their relative contribution to sample size, and ease of measurement. Fresh branch weight was the best choice. A sequential sampling system was developed on this basis and was related to a scale of predicted defoliation. In addition, a transformation was provided for use in data analysis.


1949 ◽  
Vol 27c (6) ◽  
pp. 312-331 ◽  
Author(s):  
D. C. Buckland ◽  
R. E. Foster ◽  
V. J. Nordin

An investigation of decay in western hemlock (Tsuga heterophylla (Raf.) Sarg.) and fir (mainly Abies amabilis (Loud.) Forb.) in the Juan de Fuca forest region of British Columbia has shown that the major organisms causing root and butt rots are the same in both species. These are Poria subacida (Peck) Sacc., Fomes annosus (Fr.) Cke., Armillaria mellea Vahl ex Fr., Polyporus sulphureus Bull. ex Fr., and P. circinatus Fr. Those organisms causing trunk rots of western hemlock, in decreasing order of importance, are Fomes pinicola (Sw.) Cke., F. Pini (Thore) Lloyd, Stereum abietinum Pers., Fomes Hartigii (Allesch.) Sacc. and Trav., and Hydnum sp. (H. abietis). These same organisms causing trunk rots of fir, in decreasing order of importance, are Fomes pinicola, Stereum abietinum, Hydnum sp. (H. abietis), Fomes Pini, and Fomes Hartigii. The logs of 963 western hemlock were analyzed in detail. Maximum periodic volume increment was reached between 225 and 275 years of age. Maximum periodic volume increment was reached between 275 and 325 years of age in the 719 fir that were analyzed. Scars were the most frequent avenue of entrance for infection. In 59% of the cases of infection studied the fungus had entered through wounds.


2002 ◽  
Vol 32 (6) ◽  
pp. 1057-1070 ◽  
Author(s):  
Linda E Winter ◽  
Linda B Brubaker ◽  
Jerry F Franklin ◽  
Eric A Miller ◽  
Donald Q DeWitt

The history of canopy disturbances over the lifetime of an old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stand in the western Cascade Range of southern Washington was reconstructed using tree-ring records of cross-dated samples from a 3.3-ha mapped plot. The reconstruction detected pulses in which many western hemlock (Tsuga heterophylla (Raf.) Sarg.) synchronously experienced abrupt and sustained increases in ringwidth, i.e., "growth-increases", and focused on medium-sized or larger ([Formula: see text]0.8 ha) events. The results show that the stand experienced at least three canopy disturbances that each thinned, but did not clear, the canopy over areas [Formula: see text]0.8 ha, occurring approximately in the late 1500s, the 1760s, and the 1930s. None of these promoted regeneration of the shade-intolerant Douglas-fir, all of which established 1500–1521. The disturbances may have promoted regeneration of western hemlock, but their strongest effect on tree dynamics was to elicit western hemlock growth-increases. Canopy disturbances are known to create patchiness, or horizontal heterogeneity, an important characteristic of old-growth forests. This reconstructed history provides one model for restoration strategies to create horizontal heterogeneity in young Douglas-fir stands, for example, by suggesting sizes of areas to thin in variable-density thinnings.


Sign in / Sign up

Export Citation Format

Share Document