Converting larch plantations to mixed stands: Effects of canopy treatment on the survival and growth of planted seedlings with contrasting shade tolerance

Shrubs in the genus Dirca are rarely used in landscaping despite their shade tolerance and aesthetic qualities. A trial of 81 plants, 27 of each of three species, was established in 2007 in USDA hardiness zone 5a to evaluate survival and growth. After four winters, survival of Dirca mexicana (89%) was greater than survival of Dirca palustris from Florida (44%) and Dirca occidentalis (41%). Survival of Dirca palustris from Ontario, Canada, was intermediate (56%), but annual stem extension was only 60% that of Dirca mexicana and Dirca palustris from Florida. Surviving plants of Dirca mexicana and Dirca palustris from Ontario showed minimal winter injury, but tips of some stems of Dirca palustris from Florida and Dirca occidentalis were killed. Our data on survival, winter injury, plant health, and stem extension of the California-endemic Dirca occidentalis suggest it will be especially challenging to identify genotypes adapted for use in the Upper Midwest. In contrast, we conclude that another narrowly endemic species, Dirca mexicana, has potential as a new shrub for horticulture. Additionally, our results provide evidence for variation in cold-hardiness and annual stem extension of Dirca palustris. Although over half of plants from Florida had died after the first two winters, no additional mortality occurred over remaining years, and survivors were more vigorous than plants from Ontario. This suggests that exploitable variation in cold-hardiness and vigor exists among and within populations of this broadly distributed species.

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Early vegetation control for the regeneration of a single-cohort, intimate mixture of white spruce and trembling aspen on upland boreal sites

Canadian Journal of Forest Research ◽

10.1139/x10-012 ◽

2010 ◽

Vol 40 (3) ◽

pp. 549-564 ◽

Cited By ~ 22

Author(s):

Douglas G. Pitt ◽

Philip G. Comeau ◽

William C. Parker ◽

Daniel MacIsaac ◽

Scott McPherson ◽

...

Keyword(s):

White Spruce ◽

Stem Volume ◽

Woody Vegetation ◽

Trembling Aspen ◽

Mixed Stands ◽

Vegetation Control ◽

Tree Survival ◽

Intimate Mixture ◽

Survival And Growth ◽

Single Cohort

In Canada’s boreal forest region, there is increasing demand for practical regeneration strategies that will recreate mixed stands of white spruce ( Picea glauca (Moench) Voss) and trembling aspen ( Populus tremuloides Michx.). In 2002, we implemented an experiment in both west-central Alberta and northeastern Ontario to better understand the effects of herbaceous and woody vegetation control on crop tree survival and growth, within the context of prescription development for the regeneration of a single-cohort, intimate mixture of spruce and aspen. After five growing seasons, good spruce growth, health, and survival were observed with 2 m radial treatments consisting of herbaceous and woody (i.e., complete) vegetation control centred on trees planted at 5 m spacing. These spruce were 4%–64% taller and 68%–178% larger in stem diameter than untended trees, leading to 167%–1166% gains in stem volume, and were at least equivalent to the same stock grown at 2.5 m spacing and provided with complete, continuous relief from competition. Removing only the woody vegetation within treated radii stimulated herbaceous competition, resulting in reduced survival and growth of spruce and reduced height of surrounding aspen. Early results suggest that spot treatments that provide 2–4 years of relief from herbaceous and woody competition may offer a practical strategy for growing spruce with aspen.

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Survival and growth as measures of shade tolerance of planted western redcedar, western hemlock and amabilis fir seedlings in hemlock-fir forests of northern Vancouver Island

Forest Ecology and Management ◽

10.1016/j.foreco.2016.11.019 ◽

2017 ◽

Vol 386 ◽

pp. 13-21 ◽

Cited By ~ 3

Author(s):

Adrian Weber ◽

Sara Leckie ◽

J.P. (Hamish) Kimmins ◽

Benjamin Gilbert ◽

Juan A. Blanco ◽

...

Keyword(s):

Shade Tolerance ◽

Vancouver Island ◽

Western Hemlock ◽

Western Redcedar ◽

Survival And Growth

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Efficiency of Biostimulants for Alleviating Shade Effects on Forage Grass

Journal of Agricultural Studies ◽

10.5296/jas.v9i3.18833 ◽

2021 ◽

Vol 9 (3) ◽

pp. 14

Author(s):

Monyck Jeane dos Santos Lopes ◽

Moacyr Bernardino Dias-Filho ◽

Thomaz Henrique dos Reis Castro ◽

Ely Simone Cajueiro Gurgel ◽

Gisele Barata da Silva

Keyword(s):

Biochemical Parameters ◽

Shade Tolerance ◽

Normal Growth ◽

Primary Metabolism ◽

Forage Grass ◽

Inhibitory Effects ◽

Brachiaria Brizantha ◽

Primary Metabolites ◽

Tropical Forage ◽

Survival And Growth

Shade is considered an abiotic stress factor which reduce the primary metabolism and restricts normal growth in forage grass in integrated systems. Biostimulants are beneficial in promoting growth and protecting plants against environmental stresses. This is the first study that links biostimulants and the primary metabolism of plants grown under contrasting light intensities. We investigated how the use of biostimulants modifies the primary metabolism, reducing the deleterious effects of shading in the development of tropical forage grass Brachiaria brizantha cv. BRS Piatã. The association of Pseudomonas fluorescens and Burkholderia pyrrocinia, inoculated by soil drench, were used as biostimulants. We measured leaf anatomy, plant growth, and biochemical parameters. The use of biostimulants increased the shade tolerance on B. brizantha by modifying leaf structure, increasing the chlorophyll content, and inducing the production of osmoregulants, such as carbohydrates and proteins. In turn, increasing the accumulation of primary metabolites, promoted root development, plant height, and leaf area, resulting in more vigorous plants with greater biomass production. These results suggested that forage grass can be protected from inhibitory effects of the shade stress by the biostimulants, and this would improve its survival and growth in integrated crop-livestock-forestry systems.

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Canopy stratification, age structure, and development of multicohort stands of eastern white pine, eastern hemlock, and red spruce

Canadian Journal of Forest Research ◽

10.1139/x93-228 ◽

1993 ◽

Vol 23 (9) ◽

pp. 1799-1809 ◽

Cited By ~ 26

Author(s):

Mary Ann Fajvan ◽

Robert S. Seymour

Keyword(s):

Shade Tolerance ◽

Height Growth ◽

Red Spruce ◽

Eastern Hemlock ◽

Spatial And Temporal Variability ◽

Cohort Model ◽

White Pine ◽

Mixed Stands ◽

Interspecific Differences ◽

Partial Harvesting

The causes of canopy stratification were investigated in five mixed stands of red spruce (Picearubens Sarg.), hemlock (Tsugacanadensis (L.) Carr.), and white pine (Pinusstrobus L.) in eastern Maine. All species were present in all crown classes; however, there was a clear pattern of pine dominance and eventual emergence. Red spruce was prevalent in the middle stratum, and hemlock most common in the lower strata. Canopy stratification was caused by interspecific differences in shade tolerance and height growth, and by multicohort structures. The multicohort structures developed as a result of episodic partial disturbances such as spruce budworm (Choristoneurafumiferana Clemens) outbreaks and partial harvesting that both initiated regeneration and released previously suppressed trees of older, surviving cohorts. Spatial and temporal variability in disturbances created extremely variable patterns of competition among cohorts, resulting in a more complex developmental pattern than would be found in a single-cohort model involving stand-replacing disturbances.

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A test of the accuracy of shade-tolerance classifications based on physiognomic and reproductive traits

Canadian Journal of Botany ◽

10.1139/b83-172 ◽

1983 ◽

Vol 61 (6) ◽

pp. 1595-1598 ◽

Cited By ~ 25

Author(s):

Craig G. Lorimer

Keyword(s):

Growth Rates ◽

Tree Species ◽

Shade Tolerance ◽

Reproductive Traits ◽

Permanent Plot ◽

Oak Forest ◽

Tolerance Index ◽

Stem Density ◽

Survival And Growth ◽

Tolerance Indices

Traits such as live crown ratio and understory stem density are often used subjectively as a guide to grouping tree species into shade tolerance classes. The accuracy of this approach was tested on nine species in an upland oak forest by comparing a tolerance index based on measurements of live crown ratio and understory stem density with observed survival and growth rates of suppressed trees obtained from 19-year permanent plot records. A high correlation (r = 0.93) was found between predicted and observed tolerance indices. The observed tolerance of several species differs from traditional classifications but was correctly predicted by the tolerance index.

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Coral husbandry for ocean futures: leveraging abiotic factors to increase survivorship, growth, and resilience in juvenile Montipora capitata

Marine Ecology Progress Series ◽

10.3354/meps13534 ◽

2021 ◽

Vol 657 ◽

pp. 123-133

Author(s):

JR Hancock ◽

AR Barrows ◽

TC Roome ◽

AS Huffmyer ◽

SB Matsuda ◽

...

Keyword(s):

Abiotic Factors ◽

Larval Rearing ◽

Abiotic Conditions ◽

Montipora Capitata ◽

Reef Restoration ◽

Juvenile Corals ◽

Bleaching Response ◽

The Face ◽

Survival And Growth ◽

Global And Local

Reef restoration via direct outplanting of sexually propagated juvenile corals is a key strategy in preserving coral reef ecosystem function in the face of global and local stressors (e.g. ocean warming). To advance our capacity to scale and maximize the efficiency of restoration initiatives, we examined how abiotic conditions (i.e. larval rearing temperature, substrate condition, light intensity, and flow rate) interact to enhance post-settlement survival and growth of sexually propagated juvenile Montipora capitata. Larvae were reared at 3 temperatures (high: 28.9°C, ambient: 27.2°C, low: 24.5°C) for 72 h during larval development, and were subsequently settled on aragonite plugs conditioned in seawater (1 or 10 wk) and raised in different light and flow regimes. These juvenile corals underwent a natural bleaching event in Kāne‘ohe Bay, O‘ahu, Hawai‘i (USA), in summer 2019, allowing us to opportunistically measure bleaching response in addition to survivorship and growth. This study demonstrates how leveraging light and flow can increase the survivorship and growth of juvenile M. capitata. In contrast, larval preconditioning and substrate conditioning had little overall effect on survivorship, growth, or bleaching response. Importantly, there was no optimal combination of abiotic conditions that maximized survival and growth in addition to bleaching tolerances. This study highlights the ability to tailor sexual reproduction for specific restoration goals by addressing knowledge gaps and incorporating practices that could improve resilience in propagated stocks.

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Mechanisms leading to recruitment inhibition of giant kelp Macrocystis pyrifera by an understory alga

Marine Ecology Progress Series ◽

10.3354/meps13550 ◽

2021 ◽

Vol 657 ◽

pp. 59-71

Author(s):

BA Beckley ◽

MS Edwards

Keyword(s):

Field Experiments ◽

Local Community ◽

Kelp Forest ◽

Macrocystis Pyrifera ◽

Forest Recovery ◽

Kelp Forests ◽

Giant Kelp ◽

Combined Effects ◽

Life Stages ◽

Survival And Growth

The forest-forming giant kelp Macrocystis pyrifera and the communities it supports have been decreasing across their native ranges in many parts of the world. The sudden removal of giant kelp canopies by storms increases space and light for the colonization by understory macroalgae, such as Desmarestia herbacea, which can inhibit M. pyrifera recovery and alter local community composition. Understanding the mechanisms by which algae such as D. herbacea interact with M. pyrifera can provide insight into patterns of kelp forest recovery following these disturbances and can aid in predicting future community structure. This study experimentally tested the independent and combined effects of two likely competitive mechanisms by which D. herbacea might inhibit recovery of M. pyrifera in the Point Loma kelp forest in San Diego, California (USA). Specifically, we conducted field experiments to study the individual and combined effects of shade and scour by D. herbacea on the survival of M. pyrifera microscopic life stages, and the recruitment, survival, and growth of its young sporophytes. Our results show that scour had the strongest negative effect on the survival of M. pyrifera microscopic life stages and recruitment, but shade and scour both adversely affected survival and growth of these sporophytes as they grew larger. Canopy-removing storms are increasing in frequency and intensity, and this change could facilitate the rise of understory species, like D. herbacea, which might alter community succession and recovery of kelp forests.

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