Spatial distribution and succession of epiphytes on Tsuga heterophylla (western hemlock) in an old-growth Douglas-fir forest

We examined the distribution and abundance of nonvascular epiphytes on western hemlock trees in an old-growth coniferous forest focusing on patterns of epiphyte distribution at different spatial scales, epiphyte abundance amongst trees differing in size, and crown structures associated with epiphyte abundance. Total epiphyte cover was greatest in four canopy microhabitats: the upper canopy strata, crowns of large trees, lower crown branches, and inner branch plots. Epiphyte functional groups were stratified vertically within the stand and horizontally within branches. Alectorioid and "other" lichens were most abundant in the upper canopy and outer branch plots. Cyanolichens and Sphaerophorus globosus (Huds.) Vain. were most abundant in the lower to mid canopy. Although cyanolichens were most abundant in middle branch plots, Sphaerophorus was most abundant in inner branch plots. Bryophytes were most abundant in the lower canopy and inner branch plots. At the stand level, canopy height and tree size were the main influences on epiphytes. Within trees, plots closer to the tree trunk and lower in the crown had the greatest abundance of epiphytes. In this forest, understory trees were colonized first by bryophytes, not by alectorioid and "other" lichens as is common for small trees in young stands.Key words: epiphyte succession, lichens, western hemlock, old growth, forest canopy, crown structure.

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Basal area growth impacts of dwarf mistletoe on western hemlock in an old-growth forest

Canadian Journal of Forest Research ◽

10.1139/x07-174 ◽

2008 ◽

Vol 38 (3) ◽

pp. 576-583 ◽

Cited By ~ 13

Author(s):

David C. Shaw ◽

Manuela Huso ◽

Howard Bruner

Keyword(s):

Basal Area ◽

Analysis Of Covariance ◽

Western Hemlock ◽

Dwarf Mistletoe ◽

Old Growth ◽

Old Growth Forest ◽

Basal Area Growth ◽

Initial Diameter ◽

Large Trees ◽

Area Growth

We investigated the effect of western hemlock dwarf mistletoe ( Arceuthobium tsugense (Rosend.) G.N. Jones ssp. tsugense ) on the 13 year basal area growth of large (>45.7 cm diameter at breast height) western hemlock ( Tsuga heterophylla (Raf.) Sarg.) trees in an old-growth forest in southwestern Washington state. We controlled for spatial effects on tree growth by utilizing twenty-seven 0.4 ha plots that had uninfected, lightly, moderately, and severely infected classes of trees present on each plot. Basal area growth was analyzed using analysis of covariance of a randomized block design that was a balanced design with four treatments (infection classes) and 27 replicates (blocks or 0.4 ha plots), with initial diameter as the covariate. Basal area growth was found to be significantly different among the infection classes (F[3,77] = 10.09 and p < 0.0001). Growth of the light and moderate infection classes was not detectably different from growth of uninfected trees. However, severely infected trees grew from 16% to 46% (mean = 36%) less than uninfected trees of the same initial diameter over the period of study (1991–2004). The large trees in this stand did not show growth impacts until they were severely infected.

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Canopy disturbances over the five-century lifetime of an old-growth Douglas-fir stand in the Pacific Northwest

Canadian Journal of Forest Research ◽

10.1139/x02-030 ◽

2002 ◽

Vol 32 (6) ◽

pp. 1057-1070 ◽

Cited By ~ 29

Author(s):

Linda E Winter ◽

Linda B Brubaker ◽

Jerry F Franklin ◽

Eric A Miller ◽

Donald Q DeWitt

Keyword(s):

Pacific Northwest ◽

Variable Density ◽

Tsuga Heterophylla ◽

Douglas Fir ◽

Western Hemlock ◽

Old Growth ◽

The Pacific ◽

History Of ◽

Horizontal Heterogeneity ◽

Restoration Strategies

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 15001521. 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.

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Understory conifer seedling response to a gradient of root and ectomycorrhizal fungal contact

Canadian Journal of Botany ◽

10.1139/b05-035 ◽

2005 ◽

Vol 83 (6) ◽

pp. 638-646 ◽

Cited By ~ 9

Author(s):

J M Kranabetter

Keyword(s):

Picea Glauca ◽

Tsuga Heterophylla ◽

Picea Sitchensis ◽

Forest Understory ◽

Western Hemlock ◽

Scarce Resources ◽

Full Contact ◽

Mycorrhizal Network ◽

Mycorrhizal Networks ◽

Common Mycorrhizal Network

The possible benefit of common mycorrhizal network linkages to seedling growth was tested in a low light partial-cut forest understory. Naturally regenerated western hemlock (Tsuga heterophylla Raf.) and hybrid spruce (Picea glauca × Picea sitchensis [Moench] Voss) seedlings were transplanted directly into soil or within bags of different pore sizes to restrict the amounts of root and ectomycorrhizal contact. The 5-year study included "full contact" (no bag), "moderate contact" (250-µm openings), and "low contact" (4-µm openings) treatments. Height increment was lowest for full contact seedlings over most of the experiment, and highest for low contact seedlings by years 4 and 5. Full contact seedlings also had slightly lower foliar N content than moderate and low contact seedlings. There were no significant interactions in growth detected between tree species and treatments, despite the higher potential for common mycorrhizal network linkages between a western hemlock understory and canopy. Fifty-eight ectomycorrhizal fungal morphotypes were identified on the seedlings, including many with smooth mantles or with only sparse emanating hyphae, which likely reduced the potential for common mycorrhizal network linkages. These results would support the more traditional concepts of competition for scarce resources by isolated seedlings as the primary interaction for the understory of these mature forests.Key words: common mycorrhizal networks, facilitation, shade tolerance, competition.

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Canopy openness and leaf area in chronosequences of coastal temperate rainforests

Canadian Journal of Forest Research ◽

10.1139/x99-201 ◽

2000 ◽

Vol 30 (2) ◽

pp. 239-256 ◽

Cited By ~ 62

Author(s):

Gordon W Frazer ◽

J A Trofymow ◽

Kenneth P Lertzman

Keyword(s):

Leaf Area ◽

Tsuga Heterophylla ◽

Thuja Plicata ◽

Canopy Openness ◽

East Side ◽

The West ◽

Old Growth ◽

Regional Patterns ◽

Forest Canopies ◽

Old Growth Forest

We examined spatial and temporal differences in canopy openness and effective leaf area (Le) in a series of eight forest chronosequences located on southern Vancouver Island, British Columbia. Structural attributes were measured on the west and east side of the island in immature, mature, and old-growth stands using hemispherical photography and the LAI-2000 plant canopy analyzer (PCA). Old-growth forest canopies were distinct from those of younger stands: they were more open, more heterogeneous in their openness, and maintained a lower stand Le. Although the overall developmental trajectories of forests were similar across the study sites, site-to-site differences in the rate and magnitude of these temporal changes indicated that site-specific factors also play a significant role in determining the character of forest canopies and their development. The most significant changes in canopy structure did not emerge until the later stages of stand development (150-200 years). Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) dominated east-side forests were, on average, more open, more heterogeneous, and had a lower stand Le than the stands dominated by western hemlock (Tsuga heterophylla (Raf.) Sarg.) and western redcedar (Thuja plicata Donn.) forming the west-side chronosequences. Shoot clumping, along with other evidence, suggested that species-related differences in leaf display and the geometry of branching structure might have contributed significantly to these regional patterns.

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Older eastern white pine trees and stands sequester carbon for many decades and maximize cumulative carbon

10.1101/2020.10.27.358044 ◽

2020 ◽

Author(s):

Robert T. Leverett ◽

Susan A. Masino ◽

William R. Moomaw

Keyword(s):

New England ◽

Carbon Storage ◽

Safety Net ◽

White Pine ◽

Eastern White Pine ◽

Old Growth ◽

Old Growth Forest ◽

Large Trees ◽

Natural Climate

AbstractPre-settlement New England was heavily forested, with some trees exceeding 2 m in diameter. New England’s forests have regrown since farm abandonment and represent what is arguably the most successful regional reforestation on record; the region has recently been identified as part of the “Global Safety Net.” Remnants and groves of primary “old-growth” forest demonstrate that native tree species can live for hundreds of years and continue to add to the biomass and structural and ecological complexity of forests. Forests are an essential natural climate solution for accumulating and storing atmospheric CO2, and some studies emphasize young, fast-growing trees and forests whereas others highlight high carbon storage and accumulation rates in old trees and intact forests. To address this question directly within New England we leveraged long-term, accurate field measurements along with volume modeling of individual trees and intact stands of eastern white pines (Pinus strobus) and compared our results to models developed by the U.S. Forest Service. Our major findings complement, extend, and clarify previous findings and are three-fold: 1) intact eastern white pine forests continue to sequester carbon and store high cumulative carbon above ground; 2) large trees dominate above-ground carbon storage and can sequester significant amounts of carbon for hundreds of years; 3) productive pine stands can continue to sequester high amounts of carbon for well over 150 years. Because the next decades are critical in addressing the climate crisis, and the vast majority of New England forests are less than 100 years old, and can at least double their cumulative carbon, a major implication of this work is that maintaining and accumulating maximal carbon in existing forests – proforestation - is a powerful near-term regional climate solution. Furthermore, old and old-growth forests are rare, complex and highly dynamic and biodiverse, and dedication of some forests to proforestation will also protect natural selection, ecosystem integrity and full native biodiversity long-term. In sum, strategic policies that grow and protect existing forests in New England will optimize a proven, low cost, natural climate solution for meeting climate and biodiversity goals now and in the critical coming decades.

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Secondary disturbance following a deposit of volcanic tephra: A 30 year record from old-growth forest understory

Canadian Journal of Forest Research ◽

10.1139/cjfr-2020-0473 ◽

2021 ◽

Author(s):

Donald B Zobel ◽

Joseph A. Antos ◽

Dylan Grey Fischer

Keyword(s):

Vegetation Change ◽

Forest Disturbance ◽

Canopy Cover ◽

Soil Disturbance ◽

Tree Canopy ◽

Forest Understory ◽

Old Growth ◽

Old Growth Forest ◽

Volcanic Ejecta ◽

Woody Litter

Forest disturbance is usually described by effects on trees, and small disturbances to forest understory are seldom studied. Nevertheless, effective analyses of succession need to consider both stand-replacing and subsequent “secondary” disturbances in both canopy and understory. We estimated characteristics of 13 types of secondary disturbance in old-growth forest understory, and of canopy cover, after the 1980 tephra (aerially transported volcanic ejecta) deposition from Mount St. Helens, Washington. We sampled 100 1-m2 plots at each of four sites for vegetation change and types of disturbance at ten times from 1980-2010; we sampled tree canopy above each plot in 1980 and 2016. The number of canopy gaps increased 23 % and mean gap dimension 68 % during 36 years, mostly from loss of Abies amabilis. Secondary disturbance in understory affected 1.4 % of stand area per year. The areas affected by soil disturbance and effects of woody litter were similar. Erosion, greater in deep than in shallow tephra, peaked in 1981, whereas most litter-caused disturbances increased after 2000. Less frequent litter-based disturbances covered greater area. Our results differ from conclusions about non-volcanic understory disturbances. Secondary disturbances are variable, need more study, and are likely to affect many other systems.

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Leaf area index of an old-growth Douglas-fir forest estimated from direct structural measurements in the canopy

Canadian Journal of Forest Research ◽

10.1139/x00-121 ◽

2000 ◽

Vol 30 (12) ◽

pp. 1922-1930 ◽

Cited By ~ 58

Author(s):

Sean C Thomas ◽

William E Winner

Keyword(s):

Leaf Area Index ◽

Leaf Area ◽

Tsuga Heterophylla ◽

Douglas Fir ◽

Understory Vegetation ◽

Western Hemlock ◽

Old Growth ◽

Area Index ◽

Contact Frequency ◽

Canopy Access

Leaf area index (LAI) in old-growth Douglas-fir (Pseudotsuga menziesii var menziesii (Mirb.) Franco) forests exceeds that of any other forest ecosystem by some estimates; however, LAI determinations in coniferous forests have generally been indirect, involving extrapolations of patterns observed in younger stands. Aided by a 75-m construction crane for canopy access, we used a vertical line-intercept method to estimate LAI for a [Formula: see text]450-year-old Douglas-fir - western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest in southwestern Washington state. LAI was calculated as the product of foliage contact frequency and an "extinction coefficient" accounting for foliage angular distribution, geometry, and the ratio of "interceptable" to total leaf area. LAI estimates were 9.3 ± 2.1 (estimate ± 95% confidence interval), 8.5 ± 2.2, and 8.2 ± 1.8 in 1997, 1998, and 1999, respectively, or 8.6 ± 1.1 pooled across years. Understory vegetation, including foliage of woody stems <5 cm diameter, represented 20% of this total. Sample points in which Douglas-fir was dominant had a higher total LAI than points dominated by western hemlock, including a higher LAI of understory vegetation. Our results do not support the contention that old-growth Douglas-fir - western hemlock forests maintain an appreciably higher LAI than do other forest ecosystems. Moreover, LAI in very old stands may decline as western hemlock replaces Douglas-fir through the course of succession.

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Population densities of understorey birds across a habitat gradient in Palawan, Philippines: implications for conservation

Oryx ◽

10.1017/s0030605310001031 ◽

2011 ◽

Vol 45 (2) ◽

pp. 234-242 ◽

Cited By ~ 13

Author(s):

N.A.D. Mallari ◽

N.J. Collar ◽

D.C. Lee ◽

P.J.K. McGowan ◽

R. Wilkinson ◽

...

Keyword(s):

Threatened Species ◽

Bird Species ◽

The Philippines ◽

Area Network ◽

Old Growth ◽

Density Estimates ◽

Old Growth Forest ◽

Habitat Gradient ◽

Key Species ◽

Large Trees

AbstractThere is widespread concern for many understorey and ground-dwelling bird species in the Philippines that appear intolerant of forest alteration. We present density estimates for 18 key bird species in old growth forest, advanced and early secondary growth and active cultivation within the Puerto Princesa Subterranean River National Park in Palawan. Six species were not recorded in cultivation and the abundance of these and several others increased along the successional gradient from cultivation to old growth forest. Eleven species, including five endemics and three of four threatened species, had highest density estimates in old growth forest. However, several species had high density estimates in the heavily disturbed habitats and every habitat type held highest densities of at least one of the bird species. The commonest habitat association across the bird community was a preference for areas containing large trees, indicating the importance of retention of such trees in allowing suitable ground and understorey microhabitats to persist. Old growth forests have the highest conservation value for Palawan’s endemic birds and, while some species thrive in the anthropogenic habitats that occur within the Park, the present extent of cultivation and associated successional stages within its boundaries should not be increased. We caution against extrapolation of the abundance figures from the Park to the whole island but we suggest that population sizes for the threatened species are likely to be much greater than previously thought. We urge authorities to strengthen management within the protected area network in Palawan to ensure survival of key species.

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STUDIES IN FOREST PATHOLOGY: VIII. DECAY OF WESTERN HEMLOCK ON THE QUEEN CHARLOTTE ISLANDS, BRITISH COLUMBIA

Canadian Journal of Botany ◽

10.1139/b51-044 ◽

1951 ◽

Vol 29 (5) ◽

pp. 479-521 ◽

Cited By ~ 5

Author(s):

R. E. Foster ◽

A. T. Foster

Keyword(s):

British Columbia ◽

Tsuga Heterophylla ◽

Total Loss ◽

Western Hemlock ◽

Site Quality ◽

Forest Pathology ◽

Old Growth ◽

Queen Charlotte Islands ◽

Dead Trees ◽

Understory Trees

An investigation of western hemlock (Tsuga heterophylla (Raf.) Sarg.) on the Queen Charlotte Islands, British Columbia, has shown that decay losses in old-growth stands are appreciable, amounting to 13.9, 8.0, and 10.7% of the gross volume of Grades 1, 2, and 3 logs respectively. Total loss, including dead trees, amounted to 25.5% of the gross volume. Twenty-seven decay-producing fungi have been isolated. The most important of these are Fomes pinicola (Sw.) Cke., F. pini (Thore) Lloyd, F. annosus (Fr.) Cke., and Polyporus sulphureus Bull. ex Fr. Echinodontium tinctorium E. & E. apparently does not occur in the region. Scars provided the most frequent, and roots the most important, avenue of entrance for decay. The logs of 2318 western hemlock were analyzed in detail. Decay was found to increase progressively with diameter, age, and decreasing site quality. Maximum net periodic increment was reached between 350 and 400 years of age and between 35 and 40 in. in diameter. Color of bark was found to provide an added indication of tree maturity. Understory trees were found to give a substantial yield of sound wood.

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