Stand structure governs the crown collisions of lodgepole pine

Rudnicki, Mark; Lieffers, Victor J.; Silins, U.

doi:10.1139/x03-055

Cited by 60 publications

(76 citation statements)

References 27 publications

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“…This supports the idea that increased wind exposure and bending may damage the xylem of tree stems, reducing hydraulic conductivity and intensifying moisture stress (Fredericksen et al 1994, Liu et al 2003. Bending and damage to water-conduct- ing tissue is potentially a greater problem for more slender stems due to wider oscillations of the crowns than for trees with stout boles (Rudnicki et al 2003).…”

Section: Discussionsupporting

confidence: 70%

Elevated mortality of residual trees following structural retention harvesting in boreal mixedwoods

Bladon¹,

Lieffers²,

Silins³

et al. 2008

The Forestry Chronicle

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In recent years boreal forests have been harvested to retain a portion of the original canopy, thereby providing forest structure, mostly for biodiversity reasons. Boreal mixedwood cutovers were surveyed at one and five years after harvesting with approximately 10% structural retention, to quantify the mean annual mortality rates of the residual trembling aspen, balsam poplar, paper birch and white spruce trees. For comparison, "natural" mortality rates by species were estimated from permanent sample plots in stands of similar composition. Species ranking of the annual mortality rates of residuals in areas harvested with structural retention were: poplar (10.2%) > birch (8.7%) > aspen (6.1%) > spruce (2.9%). Annual mortality rates were 2.5 to 4 times greater than in the reference stands. The majority of broadleaved species died as snags (~70%-90%), while most spruce died due to windthrow (80%). Mortality rates increased with slenderness coefficient for codominant and understory poplar and for understory birch. For aspen, codominants were most likely to die, while in spruce, dominant trees and trees with the greatest damage to the bole from harvesting operations had the highest mortality.Key words: Alberta, Betula papyrifera, dieback, harvesting damage, mixedwood forests, variable retention, Picea glauca, Populus balsamifera, Populus tremuloides, structural retention, sustainable forest management RÉSUMÉ Au cours des dernières années, les forêts boréales ont été récoltées pour retenir une portion de la canopée originale, fournissant ainsi une structure forestière, surtout pour des raisons de biodiversité. À la suite de la récolte, on a vérifié le parterre de la coupe après un an et après cinq ans en ayant conservé environ 10 % de la structure, afin de quantifier la moyenne des taux annuels de mortalité des peupliers faux-trembles, des peupliers baumiers, des bouleaux à papier et des épinettes blanches. Aux fins de comparaison, les taux de mortalité « naturelle » par les espèces ont été estimés à partir des lotissements permanents représentatifs dans des peuplements de composition semblable. Le classement par espèce des taux de mortalité annuelle des arbres rémanents dans les zones récoltées avec une rétention structurelle étaient : le peuplier (10,2 %) > le bouleau (8,7 %) > le tremble (6,1 %) > l'épinette (2,9 %). Les taux de mortalité annuelle étaient de 2,5 à 4 fois plus élevés que les taux dans les peuplements de référence. La majorité des espèces caducifoliées est morte comme chicot (~70 % -90 %), alors que la plupart des épinettes sont mortes à cause du déracinement par le vent (80 %). Les taux de mortalité ont augmenté avec le coefficient de sveltesse pour le peuplier codominant et dominé et pour le bouleau dominé. Pour le tremble, il était plus probable que les codominants meurent tandis que pour l'épinette, les arbres dominants et les arbres ayant le plus de dommages sur le tronc à cause des opérations de récolte étaient ceux qui avaient le taux le plus élevé de mortalité.

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Section: Discussionsupporting

confidence: 70%

Elevated mortality of residual trees following structural retention harvesting in boreal mixedwoods

Bladon¹,

Lieffers²,

Silins³

et al. 2008

The Forestry Chronicle

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“…Trees growing in a crowded stand or trees with larger crowns may experience more physical interactions with neighboring trees, resulting in increased crown recession (Power et al 2012). Crowns of tall trees are also subject to considerable movement due to wind-blow and resulting collisions may lead to substantial abrasion of branches and foliage (Rudnicki et al 2003). Any change in the HCB may also reflect variability in the epicormic re-sprouting after a canopy loss during a drought period and after snow damages (Taylor et al 2016).…”

Section: Discussionmentioning

confidence: 99%

Modelling tree crown-to-bole diameter ratio for Norway spruce and European beech

Sharma¹,

Vacek²,

Vacek³

2017

Silva Fenn.

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Highlights• Modelled crown-to-bole diameter ratio (CDBDR) using tree and stand-level predictors, and sample plot random effects.• Spatially explicit mixed-effects model described the largest part of CDBDR variation with no significant trend in the residuals.• The CDBDR increased with increasing stand development stage and site quality, but decreased with decreasing proportion of the species of interest, and increasing competition. AbstractCrown dimensions are correlated to growth of other parts of a tree and often used as predictors in growth models. The crown-to-bole diameter ratio (CDBDR), which is a ratio of maximum crown width to diameter at breast height (DBH), was modelled using data from permanent sample plots located on Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.) stands in different parts of the Czech Republic. Among various tree and stand-level measures evaluated, DBH, height to crown base (HCB), dominant height (HDOM), basal area of trees larger in diameter than a subject tree (BAL), basal area proportion of the species of interest (BAPOR), and Hegyi's competition index (CI) were found to be significant predictors in the CDBDR model. Random effects were included using the mixed-effects modelling to describe sample plot-level variation. For each species, the mixed-effects model described a larger part of the variation of the CDBDR than nonlinear ordinary least squares model with no trend in the residuals. The spatially explicit mixed-effects model showed more attractive fit statistics [conditional R 2 ≈ 0.73 (spruce), 0.78 (beech)] than its spatially inexplicit counterpart [conditional R 2 ≈ 0.71 (spruce), 0.76 (beech)]. The model showed that CDBDR increased with increasing HDOM -a measure that combines the stand development stage and site quality -but decreased with increasing HCB and competition (increasing BAL and CI), and decreasing proportions of the species of interest (increasing BAPOR). For both species, the spatially explicit mixed-effects model should be a preferred choice for a precise prediction of the CDBDR. The CDBDR model will have various management implications such as determination of spacing, stand basal area, stocking, and planning of appropriate species mixture.

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“…ex Loud. ), a closely related species with similar stand development that is capable of hybridizing with P. banksiana, have shown that trees collide hundreds of times per hour in moderate winds (Rudnicki et al 2003), that preventing these collisions increases leaf area (Meng et al 2006), and that trees do not compensate for leaf area lost to collisions by maintaining longer crowns (Fish et al 2006). We suggest that the impact of collisions may be asymmetric: smaller trees are disproportionately damaged when they collide with large trees because the upper branches (which are more important for intercepting light) of shorter trees collide with lower branches (which are less important for intercepting light) of the taller trees.…”

Section: Discussionmentioning

confidence: 99%

Patterns of inter-annual variation in the size asymmetry of growth in Pinus banksiana

Metsaranta

Lieffers

2010

Oecologia

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A large body of literature suggests that asymmetric competition, where large individuals suppress the growth of smaller individuals by intercepting a disproportionate share of incoming light, is a dominant process in tree population development. This has not been examined extensively for long-lived tree species that accumulate growth over many years under varying growing conditions. Using dendrochronological techniques, we reconstructed annual growth and mortality rates at ten stands of jack pine (Pinus banksiana Lamb.) in Western Canada. We used these data to calculate an annual index of the size asymmetry of growth for each stand for the last 50 years. Jack pine is a shade-intolerant species found in even-aged monoculture stands, so the simple hypothesis is that large trees should consistently perform relatively better than small trees. Inter-annual variation in the index of size-asymmetric growth was positively associated with interannual variation in stand productivity at eight of ten sites. The size asymmetry of growth also showed a positive trend with age at eight of ten sites, even though all sites were in a period of declining leaf area. This should have reduced the intensity of asymmetric competition for light and reduced the size asymmetry of growth over time. Alternate hypotheses for this trend are (1) that physical collisions between crowns result in asymmetric competition for growing space because they are more damaging to small trees, or (2) that a differential build up of diseases in susceptible trees suppresses their growth, even in the absence of competition.

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Stand structure governs the crown collisions of lodgepole pine

Cited by 60 publications

References 27 publications

Elevated mortality of residual trees following structural retention harvesting in boreal mixedwoods

Elevated mortality of residual trees following structural retention harvesting in boreal mixedwoods

Modelling tree crown-to-bole diameter ratio for Norway spruce and European beech

Patterns of inter-annual variation in the size asymmetry of growth in Pinus banksiana

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