Spatial models of competition and gap dynamics in old-growth Tsuga heterophylla/Thuja plicata forests

1997 ◽  
Vol 94 (1-3) ◽  
pp. 175-186 ◽  
Author(s):  
Melinda Moeur
Keyword(s):  
Spatial Models ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Gap Dynamics ◽  
Old Growth

Canopy openness and leaf area in chronosequences of coastal temperate rainforests

2000 ◽  
Vol 30 (2) ◽  
pp. 239-256 ◽  
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.

Vertical and seasonal variation in canopy arthropod communities in an old-growth conifer forest in southwestern Washington, USA

1998 ◽  
Vol 88 (6) ◽  
pp. 633-640 ◽  
Author(s):  
T.D. Schowalter ◽  
L.M. Ganio
Keyword(s):  
Pacific Northwest ◽  
Pseudotsuga Menziesii ◽  
Tree Species ◽  
Community Organization ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Conifer Forest ◽  
Old Growth ◽  
Arthropod Species ◽  
Arthropod Fauna

AbstractVariation in canopy arthropod abundances and community structure were evaluated in an old-growth (500-year-old) forest at the Wind River Canopy Crane Research Facility in southwestern Washington, USA. Arthropods were sampled at three canopy levels and two seasons in each of four tree species (Pseudotsuga menziesii, Tsuga heterophylla, Abies grandis, and Thuja plicata). The four tree species had distinguishable arthropod species compositions and community organization. Thuja plicata (Cupressaceae) had a particularly distinctive canopy fauna dominated by several mite taxa which did not occur on the other tree species (all Pinaceae). Pseudotsuga menziesii hosted a relatively diverse arthropod fauna with greatest richness of taxa and functional groups. Distinct arthropod assemblages were not observed among canopy levels and sampling dates, but these factors significantly influenced abundances of 63% of the arthropod taxa, either individually or interactively with other factors. These data indicate that forests managed for fewer tree species eliminate important components of arthropod diversity in Pacific Northwest forests and that sampling for biodiversity assessment also should represent season and canopy level.

scholarly journals Height growth and vertical development of an old-growth Pseudotsuga-Tsuga forest in southwestern Washington State, U.S.A.

2000 ◽  
Vol 30 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Hiroaki Ishii ◽  
Joel H Reynolds ◽  
E David Ford ◽  
David C Shaw
Keyword(s):  
Future Development ◽  
Growth Rates ◽  
Forest Canopy ◽  
Size Structure ◽  
Tree Height ◽  
Tsuga Heterophylla ◽  
Height Growth ◽  
Washington State ◽  
Thuja Plicata ◽  
Old Growth

A detailed analysis of diameter-height relationships was applied to an old-growth Pseudotsuga menziesii (Mirb.) Franco var. menziesii - Tsuga heterophylla (Raf.) Sarg. forest in southwestern Washington State, U.S.A., to predict future development of vertical stratification among tree species. Differences among species in relative abundance and size structure resulted in diameter-height regressions of varying certainty and stability. Damage and shading had negative impacts on predicted heights and estimates of maximum attainable height (Hmax) in all species. However, species varied as to the main causes and size dependency of damage in relation to tree height. Current height-growth rates of the upper canopy species declined with increasing tree height, reaching minimum values near the predicted Hmax. The future development of the forest canopy would involve a slow invasion of the upper canopy by Tsuga heterophylla and Thuja plicata Donn ex D. Don, as P. menziesii are near their maximum attainable height, and Abies amabilis Dougl. ex Forbes and Taxus brevifolia Nutt. are restricted to the middle to lower canopy. However, if current height-growth rates continue, P. menziesii should maintain its dominant status in the upper canopy for at least another century.

Old-Growth Douglas-Fir and Western Hemlock: A 36-Year Record of Growth and Mortality

1987 ◽  
Vol 2 (4) ◽  
pp. 111-114 ◽  
Author(s):  
Dean S. DeBell ◽  
Jerry F. Franklin
Keyword(s):  
Volume Growth ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
Silver Fir ◽  
Pinus Monticola ◽  
White Pine ◽  
Old Growth ◽  
Stand Volume

Abstract Growth and mortality were measured at 6-year intervals in a 1,180-acre old-growth stand in southwestern Washington. Principal tree species were Douglas-fir (Pseudotsuga menziesii), western hemlock (Tsuga heterophylla), Pacific silver fir (Abies amabilis), western redcedar (Thuja plicata), and western white pine (Pinus monticola). They composed 59, 27, 6, 6, and 1%, respectively, of the total cubic volume (13,290 ft³) in 1947. Gross volume growth averaged 94 ft³ per acre per year, and mortality averaged 86 ft³ per acre per year. Net growth was therefore minimal, and total stand volume remained nearly constant for 36 years. Douglas-fir, which accounted for only one-third of the gross growth and nearly one-half of the mortality, is losing dominance to western hemlock, which provided nearly one-half the gross growth and only 28% of the mortality. Pacific silver fir increased in importance in the lower canopy and composed 60% of the in-growth. Thus, although net gain in timber volume was nil, substantial changes occurred in stand characteristics during the 1947-1983 period. West. J. Appl. For. 2(4):111-114, October 1987.

Understory species composition and production in old-growth western hemlock – Sitka spruce forests of southeastern Alaska

1997 ◽  
Vol 75 (4) ◽  
pp. 574-580 ◽  
Author(s):  
Thomas A. Hanley ◽  
Ward W. Brady
Keyword(s):  
Species Composition ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
Thuja Plicata ◽  
Stand Age ◽  
Soil Drainage ◽  
Site Factors ◽  
Old Growth ◽  
Understory Species ◽  
Understory Species Composition

Vascular understory species composition and production were studied in 36 stands in both northern and southern portions of southeastern Alaska, United States. Understory composition and production were related to site factors of soil drainage and slope and overstory factors of species composition, stand age, canopy coverage, and mass (net wood volume). Principal floristic gradients were dominated by differences in production of Alaska blueberry (Vaccinium alaskaense How.), skunk-cabbage (Lysichiton americanum Huit. & St. John), and lady fern (Athyrium filix-femina (L.) Roth). Soil drainage was the principal environmental factor determining understory species composition. Soil drainage also determined overstory mass and, consequently, total understory production, presumably through effects of overstory mass on light interception. Well-drained sites were more productive of trees and less productive of understory than were poorly drained sites. Relations between windthrow, soil drainage, overstory mass, and understory species composition and production are interactive in these excessively wet, old-growth forests. Key words: plant communities, biomass, forest overstory, temperate rain forest, Tsuga heterophylla, Picea sitchensis, Thuja plicata, western red cedar.

scholarly journals Alternatives to clearcutting in BC Coastal Montane Forests

1997 ◽  
Vol 73 (6) ◽  
pp. 670-678 ◽  
Author(s):  
J. T. Arnott ◽  
W. J. Beese
Keyword(s):  
Organic Matter ◽  
High Elevation ◽  
Tsuga Heterophylla ◽  
Organic Matter Decomposition ◽  
Nutrient Loss ◽  
Thuja Plicata ◽  
Old Growth ◽  
Available Nitrogen ◽  
Early Results ◽  
Harvesting Costs

The Montane Alternative Silvicultural Systems (MASS) partnership was formed in 1992 to test new approaches to harvesting high-elevation old-growth forests of Vancouver Island, British Columbia. Uniform Shelterwood (SW), Green Tree Retention (GT) and Patch Cuttings (PC) were tested as alternatives to Clearcutting (CC). All systems were compared to an Old Growth (OG) control. Harvesting was completed in 1993. This paper summarizes the conclusions from the operational aspects of the study and reviews some early results from studies of the biological impacts. Harvesting costs to roadside were about 12% greater for the PC and GT and 49% greater for the SW. Cumulative losses to windthrow after three years were 25% in the GT and 5% in the SW. Site disturbance, soil compaction and rates of organic matter decomposition were low across all harvested treatments. Rates of organic matter decomposition and N mineralization on SW, GT and PC were intermediate between CC and OG. Nutrient loss in soil solution was reduced with partial harvesting but lack of available nitrogen is limiting the early growth of coniferous regeneration among all systems. During spring and summer, SW and CC treatments were generally cooler than PC or GT. Damage to understory vegetation and advanced conifer regeneration was least in the SW, which also provided the greatest amounts of seedfall among all harvested treatments. Key words: Abies amabilis, Tsuga heterophylla, Thuja plicata, Chamaecyparis nootkatensis, harvesting costs, site impacts, silvicultural systems, shelterwood

Distribution of leaf orientations in six conifer species

2001 ◽  
Vol 79 (4) ◽  
pp. 389-397 ◽  
Author(s):  
Hugh J Barclay
Keyword(s):  
Pseudotsuga Menziesii ◽  
Pinus Contorta ◽  
Goodness Of Fit ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
The Other ◽  
Thuja Plicata ◽  
Leaf Angle ◽  
Conifer Species ◽  
Abies Grandis

Leaf angle distributions are important in assessing both the flexibility of a plant's response to differing daily and seasonal sun angles and also the variability in the proportion of total leaf area visible in remotely sensed images. Leaf angle distributions are presented for six conifer species, Abies grandis (Dougl. ex D. Don) Lindl., Thuja plicata Donn. ex D. Don, Tsuga heterophylla (Raf.) Sarg., Pseudotsuga menziesii (Mirb.) Franco, Picea sitchensis (Bong.) Carr. and Pinus contorta Dougl. ex Loud. var. latifolia. The leaf angles were calculated by measuring four foliar quantities, and then the distributions of leaf angles are cast in three forms: distributions of (i) the angle of the long axis of the leaf from the vertical for the range 0–180°; (ii) the angle of the long axis of the leaf for the range 0–90°; and (iii) the angle of the plane of the leaf for the range 0–90°. Each of these are fit to the ellipsoidal distribution to test the hypothesis that leaf angles in conifers are sufficiently random to fit the ellipsoidal distribution. The fit was generally better for planar angles and for longitudinal angles between 0° and 90° than for longitudinal angles between 0° and 180°. The fit was also better for Tsuga heterophylla, Pseudotsuga menziesii, Picea sitchensis, and Pinus contorta than for Abies grandis and Thuja plicata. This is probably because Abies and Thuja are more shade tolerant than the other species, and so the leaves in Abies and Thuja are preferentially oriented near the horizontal and are much less random than for the other species. Comparisons of distributions on individual twigs, whole branches, entire trees, and groups of trees were done to test the hypothesis that angle distributions will depend on scale, and these comparisons indicated that the apparent randomness and goodness-of-fit increased on passing to each larger unit (twigs up to groups of trees).Key words: conifer, leaf angles, ellipsoidal distribution.

Tekstura drzewostanów naturalnych w polskich parkach narodowych na tle teorii dynamiki lasu

2021 ◽  
Author(s):  
Leszek Bartkowicz ◽  
Keyword(s):  
Tree Species ◽  
Stand Structure ◽  
Basal Area ◽  
Site Conditions ◽  
Gap Dynamics ◽  
Old Growth ◽  
Mosaic Pattern ◽  
Spruce Forests ◽  
Old Growth Forest ◽  
Patch Mosaic

The aim of the study was to compare a patch-mosaic pattern in the old-growth forest stands developed in various climate and soil conditions occurring in different regions of Poland. Based on the assumption, that the patch-mosaic pattern in the forest reflect the dynamic processes taking place in it, and that each type of forest ecosystem is characterized by a specific regime of natural disturbances, the following hypotheses were formulated: (i) the patches with a complex structure in stands composed of latesuccessional, shade-tolerant tree species are more common than those composed of early-successional, light-demanding ones, (ii) the patch-mosaic pattern is more heterogeneous in optimal forest site conditions than in extreme ones, (iii) in similar site conditions differentiation of the stand structure in distinguished patches is determined by the successional status of the tree species forming a given patch, (iv) the successional trends leading to changes of species composition foster diversification of the patch structure, (v) differentiation of the stand structure is negatively related to their local basal area, especially in patches with a high level of its accumulation. Among the best-preserved old-growth forest remaining under strict protection in the Polish national parks, nineteen research plots of around 10 ha each were selected. In each plot, a grid (50 × 50 m) of circular sample subplots (with radius 12,62 m) was established. In the sample subplots, species and diameter at breast height of living trees (dbh ≥ 7 cm) were determined. Subsequently, for each sample subplot, several numerical indices were calculated: local basal area (G), dbh structure differentiation index (STR), climax index (CL) and successional index (MS). Statistical tests of Kruskal- Wallis, Levene and Generalized Additive Models (GAM) were used to verify the hypotheses. All examined forests were characterized by a large diversity of stand structure. A particularly high frequency of highly differentiated patches (STR > 0,6) was recorded in the alder swamp forest. The patch mosaic in the examined plots was different – apart from the stands with a strongly pronounced mosaic character (especially subalpine spruce forests), there were also stands with high spatial homogeneity (mainly fir forests). The stand structure in the distinguished patches was generally poorly related to the other studied features. Consequently, all hypotheses were rejected. These results indicate a very complex, mixed pattern of forest natural dynamics regardless of site conditions. In beech forests and lowland multi-species deciduous forests, small-scale disturbances of the gap dynamics type dominate, which are overlapped with less frequent medium-scale disturbances. In more difficult site conditions, large-scale catastrophic disturbances, which occasionally appear in communities formed under the influence of gap dynamics (mainly spruce forests) or cohort dynamics (mainly pine forests), gain importance.

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

2002 ◽  
Vol 32 (6) ◽  
pp. 1057-1070 ◽  
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 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.

Black Bear Damage to Thinned Timber Stands in Northwest Montana

1989 ◽  
Vol 4 (1) ◽  
pp. 10-13 ◽  
Author(s):  
Andrew C. Mason ◽  
David L. Adams
Keyword(s):  
Pinus Contorta ◽  
Black Bear ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Abies Lasiocarpa ◽  
Pinus Monticola ◽  
Larix Occidentalis ◽  
Western Larch ◽  
Engelmann Spruce ◽  
Northwest Montana

Abstract Bear damage was at least five times higher in thinned blocks than in adjacent unthinned blocks of western larch (Larix occidentalis), lodgepole pine (Pinus contorta), and Engelmann spruce (Picea engelmannii) on the Kootenai National Forest in northwest Montana. Western larch suffered the greatest damage (63% of all trees damaged and 92% of the trees killed). Damaged larch ranged from 4 to 13 in. dbh; the 4 to 8-in. dbh class accounted for 85% of the damage. Douglas-fir (Pseudotsuga menziesii), western redcedar (Thuja plicata), subalpine fir (Abies lasiocarpa), western white pine (Pinus monticola), and western hemlock (Tsuga heterophylla) were not damaged. Stand projections showed up to a 17% reduction in board-foot yield from bear damage, after 50 years, compared with hypothetical undamaged stands. West. J. Appl. For. 4(1):10-13, January 1989.

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