The age and height structure of red maple (Acerrubrum) populations in northern Michigan bigtooth aspen (Populusgrandidentata) forests

1992 ◽  
Vol 22 (10) ◽  
pp. 1449-1462 ◽  
Author(s):  
Brian J. Palik ◽  
Kurt S. Pregitzer
Keyword(s):  
Growth Rate ◽  
Resource Availability ◽  
Growth Rates ◽  
Population Level ◽  
Growth Increment ◽  
Height Growth ◽  
Height Increment ◽  
Red Maple ◽  
Age Cohorts ◽  
A Minor

Red maple (Acerrubrum L.) is often the most abundant later successional tree species recruiting in the understories of aspen and oak dominated forests on dry–mesic sites in eastern North America. Limited evidence suggests that this species is capable of recruiting to dominant canopy positions on these sites. Given the potential for increasing overstory importance of red maple in these forests, detailed population-level examinations are warranted. In this study we examined the age and height structures of red maple populations in a bigtooth aspen (Populusgrandidentata Michx.) dominated landscape in northern lower Michigan, United States. Stem analysis was used to examine relationships between establishment times, heights, and height growth rates for overstory and understory red maple from 20 replicate plots in five stands located within a 18-km2 area. Red maple was a minor overstory component in the forests of the study area. The understories of all stands were overwhelmingly dominated by red maple. The populations were composed of two clearly defined age cohorts. The first cohort contained mostly sprout-origin individuals that established concurrently with bigtooth aspen within a 10-year period, beginning 70 years prior to the time of sampling. Mean age of the sprout-origin red maple cohort was not significantly different among stands, nor did it differ from the mean age of bigtooth aspen. Mean height of the red maple sprout-origin cohort was not significantly different among stands. Within each stand, height growth rates of these individuals were highly variable. The variability was not related to differences in stem age. Recent height growth increment of the sprout-origin stems was weakly related to position of an individual in the overstory, suggesting that most red maple were competitively suppressed by taller bigtooth aspen. Some sprout-origin red maple in all stands did approach the dominant bigtooth aspen in height growth rate. These were likely stems that were never competitively suppressed. The second red maple cohort contained seedling-origin individuals that began establishing 30–35 years after stand initiation, immediately after culmination of height increment in dominant overstory bigtooth aspen and red maple. This suggests that increasing resource availability, as a result of declining overstory vigor and canopy closure, may be a factor triggering understory reinitiation in these even-aged forests. In general, heights of seedling-origin red maple were more dependent on stem age compared with sprout-origin individuals. However, height growth rates for similar-aged individuals within the seedling cohort were still highly variable. The tallest individuals generally had the greatest rates of recent height increment, and thus were at a competitive advantage within the understory environment, but these were not always the oldest stems. There was, in fact, a trend of increasing initial height growth rate over time for the fastest growing seedling-origin individuals, again suggesting that resource availability in the understory was increasing over the course of stand development. Red maple's overwhelming understory dominance and ability to reach dominant canopy positions in the stands examined suggests a potential for increasing overstory importance on dry–mesic sites. Life history attributes, including shade tolerance, vigorous resprouting potential, and the ability to respond with increased growth upon release, may foster the development and maintenance of a red maple dominated cover type in the Great Lakes region.

scholarly journals Observations on the increase in size at moulting in the lobster (Homarus vulgaris M.-Edw.)

1958 ◽  
Vol 37 (3) ◽  
pp. 603-606 ◽  
Author(s):  
H. J. Thomas
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Growth Increment ◽  
American Lobster ◽  
Limited Data ◽  
Preliminary Results ◽  
Home Department ◽  
The Individual ◽  
Marine Laboratory

A knowledge of growth rates is a pre-requisite in estimating the effect of fishing upon the available stocks. In Crustacea, where there is no known means of establishing accurately the age of the individual, the importance of measuring the growth rate is increased whilst its determination is made more difficult. In Homarus vulgaris some experiments were undertaken by Dannevig (1936), and Wilder (1953) gives considerable data for the American lobster. Results suggest that the growth increment is not uniform in all latitudes. Experiments to augment the limited data available for H. vulgaris and to establish the increase in size at moulting in local lobster stocks were therefore undertaken by the Marine Laboratory of the Scottish Home Department at Aberdeen. A statement of some preliminary results was given in Report on the Fisheries of Scotland (Lucas, 1957, p. 58).

Height growth of planted black spruce seedlings in response to interspecific vegetation competition: a comparison of four competition measures at two measuring positions

2000 ◽  
Vol 30 (4) ◽  
pp. 573-579 ◽  
Author(s):  
G G Wang ◽  
J Su ◽  
J R Wang
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Picea Mariana ◽  
Black Spruce ◽  
Height Growth ◽  
Percent Cover ◽  
Relative Height ◽  
Full Sunlight ◽  
Significant Relationships ◽  
Hemispherical Photographs

Four simple measures of interspecific competition (percent cover visually estimated in the field, percent cover derived from hemispherical photographs, percent full sunlight measured by a ceptometer, and gap light index derived from hemispherical photographs) obtained at two reference positions (the top and the middle of crop seedlings) were evaluated in relation to two growth variables (relative height growth rates in 1998 and during 1996 to 1998) of black spruce (Picea mariana (Mill.) BSP) seedlings planted on boreal mixedwood sites in southeastern Manitoba. The four competition measures assessed at the two measuring positions explained 57.2-68.0% of the total variation in black spruce height growth rate. Significant relationships were found among the four measures, and between the two measuring positions for each measure. The measuring position was not critical for all competition measures except the percent full sunlight measured by the ceptometer, for which the middle position was much better. When assessed at their preferred positions, the four competition measures ranked as follows: (i) percent cover derived from hemispherical photographs or percent full sunlight measured by the ceptometer; (ii) gap light index derived from hemispherical photographs; and (iii) visually estimated percent cover of vegetation.

scholarly journals Estimating effects of physical distancing on the COVID-19 pandemic using an urban mobility index

2020 ◽  
Author(s):  
Jean-Paul R. Soucy ◽  
Shelby L. Sturrock ◽  
Isha Berry ◽  
Duncan J. Westwood ◽  
Nick Daneman ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Population Level ◽  
Credible Interval ◽  
Reproductive Number ◽  
Urban Mobility ◽  
Daily Growth Rate ◽  
Daily Growth ◽  
Mobility Index

AbstractGovernments have implemented population-wide physical distancing measures to control COVID-19, but metrics evaluating their effectiveness are not readily available. We used a publicly available mobility index from a popular transit application to evaluate the effect of physical distancing on infection growth rates and reproductive numbers in 40 jurisdictions between March 23 and April 12, 2020. A 10% decrease in mobility was associated with a 14.6% decrease (exp(β) = 0.854; 95% credible interval: 0.835, 0.873) in the average daily growth rate and a −0.061 (95% CI: −0.071, −0.052) change in the instantaneous reproductive number 2 weeks later. Our analysis demonstrates that decreases in urban mobility were predictive of declines in epidemic growth. Mobility metrics offer an appealing method to calibrate population-level physical distancing policy and implementation.One sentence summaryAn urban mobility index may be used as a proximal measure of COVID-19 case growth and reproductive number 2 weeks later.

Frequent Irrigation Increases Growth of Pot-in-Pot Sugar and Red Maple

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 474
Author(s):  
Robert K. Witmer ◽  
Roger Harris ◽  
Alex X. Niemiera
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Sugar Maple ◽  
Stem Diameter ◽  
Production Cycle ◽  
Diameter Growth ◽  
Red Maple ◽  
Irrigation Regime ◽  
Moderate Growth ◽  
Stem Diameter Growth

In Virginia, pot-in-pot production of shade trees is normally accomplished by growing bareroot whips in 56-L containers for two complete growing seasons (production cycles). This study monitored the growth of Acer saccharum L. `Green Mountain' (sugar maple), a species with moderate growth rate, and Acer rubrum L. `Franksred' (red maple), a species with a fast growth rate, under standard once-a-day irrigation regime (1X) and a cyclic three-times-a-day regime (3X). Equal daily volumes of water were applied under each regime. Height growth rate increased for sugar maples but decreased for red maples in production cycle two compared to production cycle one. Stem diameter growth rates remained steady for red maple, but increased slightly for sugar maple. A 3X irrigation regime increased stem diameter of red maples, but had no other effect on either species in year one. Height and stem diameter growth of both species were increased by the 3X treatment during production cycle two. This study indicates that the standard production period results in decreased growth in the second production cycle for red maple, but not for sugar maple. Growth rates can be enhanced with a 3X irrigation regime for both species in production cycle two. The 3X irrigation regime only increases the stem diameter growth of red maple in the first production cycle.

Age structure and growth of understory white spruce under aspen

1996 ◽  
Vol 26 (6) ◽  
pp. 1002-1007 ◽  
Author(s):  
Victor J. Lieffers ◽  
Kenneth J. Stadt ◽  
Stan Navratil
Keyword(s):  
Growth Rates ◽  
Tree Height ◽  
Ground Level ◽  
White Spruce ◽  
Height Growth ◽  
Height Increment ◽  
Stem Analysis ◽  
Diameter Increment ◽  
Understory Trees ◽  
Normal Forest

Juvenile white spruce (Piceaglauca (Moench) Voss) under an aspen (Populustremuloides Michx.) overstory were studied in nine boreal mixedwood stands in west-central Alberta. In each stand, 50 understory white spruce were cut for stem analysis at ground level, 30, 70, 130 cm, and every 100 cm to tree height. In four stands, recruitment of these understory spruce occurred immediately after the disturbance, while in others the recruitment was delayed several decades. The period of recruitment was as short as 15–20 years or continued for decades, producing an uneven-aged understory. Trees initiated on rotten logs had a slightly lower initial annual diameter increment but did not differ in height growth compared with those initiated on normal forest floor. The annual height increment increased as the trees grew in height, presumably as they overtopped successive layers of shading vegetation. When seedlings were less than 30 cm tall they grew less than 10 cm per year, but attained growth rates of 30 cm per year or more when they were taller than 230 cm. Height growth rates for these understory trees were comparable to reported growth rates of white spruce of similar size and age from clearcut areas.

Red maple dynamics in Appalachian hardwood stands in West Virginia

1999 ◽  
Vol 29 (2) ◽  
pp. 157-165 ◽  
Author(s):  
Brian D Tift ◽  
Mary Ann Fajvan
Keyword(s):  
West Virginia ◽  
Growth Rates ◽  
Acer Rubrum ◽  
Basal Area ◽  
Height Growth ◽  
Growth Strategies ◽  
Red Maple ◽  
Understory Species ◽  
Partial Harvesting ◽  
The Future

The growth strategies red maple (Acer rubrum L.) used to attain current overstory canopy positions were investigated in two West Virginia Appalachian hardwood stands. In both stands, red maple comprised a small percentage of overstory basal area but was the most abundant understory species. The stands originated after a stand-replacing disturbance around 1930. During stand initiation, red maple invaded the sites for 10-15 years longer than most other species; however, all of the codominant red maples sampled were similar in age to other codominant species. Twenty-seven percent of stem-analysed codominant maples were 1-4 years older than the disturbance and may have originated as advanced reproduction. One sampled codominant maple had been overtopped for 20 years. Other codominant maples had height growth rates similar to codominant oaks (Quercus sp.). Even at advanced ages, understory maples showed increased height growth rates in response to small canopy disturbances. Red maple's understory persistence suggests that partial harvesting may release these individuals and promote greater proportions of overstory maples in the future.

scholarly journals Trophic interactions and population growth rates: describing patterns and identifying mechanisms

2002 ◽  
Vol 357 (1425) ◽  
pp. 1259-1271 ◽  
Author(s):  
Peter J. Hudson ◽  
Andy P. Dobson ◽  
Isabella M. Cattadori ◽  
David Newborn ◽  
Dan T. Haydon ◽  
...  
Keyword(s):  
Growth Rate ◽  
Time Series ◽  
Population Dynamics ◽  
Population Growth ◽  
Growth Rates ◽  
Population Growth Rate ◽  
Empirical Studies ◽  
Population Level ◽  
Model Framework ◽  
Negative Growth

While the concept of population growth rate has been of central importance in the development of the theory of population dynamics, few empirical studies consider the intrinsic growth rate in detail, let alone how it may vary within and between populations of the same species. In an attempt to link theory with data we take two approaches. First, we address the question 'what growth rate patterns does theory predict we should see in time–series?' The models make a number of predictions, which in general are supported by a comparative study between time–series of harvesting data from 352 red grouse populations. Variations in growth rate between grouse populations were associated with factors that reflected the quality and availability of the main food plant of the grouse. However, while these results support predictions from theory, they provide no clear insight into the mechanisms influencing reductions in population growth rate and regulation. In the second part of the paper, we consider the results of experiments, first at the individual level and then at the population level, to identify the important mechanisms influencing changes in individual productivity and population growth rate. The parasitic nematode Trichostrongylus tenuis is found to have an important influence on productivity, and when incorporated into models with their patterns of distribution between individuals has a destabilizing effect and generates negative growth rates. The hypothesis that negative growth rates at the population level were caused by parasites was demonstrated by a replicated population level experiment. With a sound and tested model framework we then explore the interaction with other natural enemies and show that in general they tend to stabilize variations in growth rate. Interestingly, the models show selective predators that remove heavily infected individuals can release the grouse from parasite–induced regulation and allow equilibrium populations to rise. By contrast, a tick–borne virus that killed chicks simply leads to a reduction in the equilibrium. When humans take grouse they do not appear to stabilize populations and this may be because many of the infective stages are available for infection before harvesting commences. In our opinion, an understanding of growth rates and population dynamics is best achieved through a mechanistic approach that includes a sound experimental approach with the development of models. Models can be tested further to explore how the community of predators and others interact with their prey.

scholarly journals Growth rate and body size differences in Rangifer, a study of causes and effects

Rangifer ◽  
1983 ◽  
Vol 3 (1) ◽  
pp. 3 ◽  
Author(s):  
Eigil Reimers
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Growth Rates ◽  
Maximum Growth ◽  
The Body ◽  
Reproductive Age ◽  
Minor Effect ◽  
Reduced Body ◽  
Body Weights ◽  
A Minor

<p>The paper discusses growth rate- and body size differences in Rangifer; their causes and effects. Growth rates and autumn body weights vary considerably both within and between Rangifer subspecies. The variation measured is within limits found in animals of same genetical stock subjected to different environments. Reproductive age, pregnancy rate, calving time and mortality either are or may be functionally related to autumn body weights. The differences in growth rates and body size among Rangifer in different areas are caused primarily by differences in environmental factors during the summer, including stress. The quality of the winter pastures has a minor effect on the body size in areas where the summer conditions allow the animals to grow at their maximum rate. In areas where maximum growth rates for various reasons are counteracted, severely overgrazed winter pastures will contribute to reduced body size. Stress in the terms of human disturbance, insects and predators and the effect on Rangifer activity pattern and hence on growth rates and body size need to be more thoroughly dealt with.</p><p>Forskjeller i vekst og st&oslash;rrelse hos Rangifer, en studie over &aring;rsaker og virkninger.</p><p>Abstract in Norwegian / Sammendrag: Arbeidet diskuterer &aring;rsaker til og virkninger av vekst- og st&oslash;rrelsesforskjeller hos Rangifer. Vekst og h&oslash;stvekter varierer betydelig b&aring;de innen og mellom de enkelte &AElig;angj/er-underartene. Variasjonene er imidlertid ikke st&oslash;rre enn de som er beskrevet i bestander med samme genetiske utgangspunkt og utsatt for ulike milj&oslash;forhold. Alder ved kj&oslash;nnsmodning, drektighetsfrekvens, kalvingstid og d&oslash;delighet er eller synes &aring; v&aelig;re relatert til h&oslash;stvektene. Vekst-og st&oslash;rrelsesforskjeller hos rein og caribou i ulike omr&aring;der skyldes i f&oslash;rste rekke forskjeller i milj&oslash;faktorene om sommeren, stress inkludert. Kvaliteten av vinterbeitene har liten effekt p&aring; kroppsst&oslash;rrelse i omr&aring;der hvor forholdene sommerstid tillater maksimal veksthastighet. I omr&aring;der hvor dette av forskjellige grunner ikke skjer, vil sterkt overbeitede vinterbeiter bidra til reduserte kroppsvekter. Stress i form av menneskelige forstyrrelser, insekter og rovdyr og effekten p&aring; reinens/caribouens aktivitetsbudsjett og derigjennom p&aring; vekst og kroppsvekt har krav p&aring; st&oslash;rre forskningsinteresse.</p><p>Rangiferin kasvun ja suuruuden eroavaisuuksia. Tutkielma syist&aring; ja vaikutuksista.</p><p>Abstract in Finnish / Yhteenveto: Tyo k&aring;sittelee syit&aring; ja vaikutuksia Rangiferin kasvu - ja suuruuseroavaisuuksista. Kasvu ja syyspainot vaihtelevat huomattavasti sek&aring; yksitt&aring;isiss&aring; Rangifer - alalajeissa ett&aring; lajien kesken. Vaihtelu ei ole kuitenkaan suurempi kuin se mit&aring; on kerrottu laumoista, joilla on sama perinnollinen l&aring;htokohta ja jotka ovat joutuneet erilaisten ymparistotekijoiden vaikuttamiksi. Sukukypsyysik&aring;, tiinehtyvyystaajuus, vasonta-aika ja kuolleisuus on tai n&aring;ytt&aring;&aring; olevan suhteessa syyspainoihin. Syy kasvu - ja suuruuseroavaisuuksiin poroilla ja karibulla eri seuduilla n&aring;ytt&aring;&aring; ensi sijassa olevan ymp&aring;ristotekijoiden eroavaisuudet kes&aring;ll&aring;, stressi mukaanluettuna. Talvilaitumien laadulla on pieni vaikutus ruumiin suuruuteen seuduilla, joissa olosuhteet kes&aring;aikaan sallivat enimm&aring;iskasvunopeuden. Seuduilla, joissa t&aring;ta ei tapahdu - eri syist&aring; johtuen, voimakkaasti ylirasitetut talvilaitumet vaikuttavat alentuneisiin ruumiinpainoihin. Stressi, inhimillisten h&aring;irioden muodossa, hyonteiset ja petoel&aring;imet ja poron/karibun vaikutus toimintaan sek&aring; siten kasvuun ja ruumiinpainoon ovat seikkoja, jotka vaativat suurempaa tutkimuskiinnostusta.</p>

Modeling tree regeneration height growth after an experimental hurricane

2006 ◽  
Vol 36 (8) ◽  
pp. 2003-2014 ◽  
Author(s):  
Mary Ann Fajvan ◽  
Audrey Barker Plotkin ◽  
David R Foster
Keyword(s):  
Growth Rates ◽  
Height Growth ◽  
Growth Patterns ◽  
Tree Regeneration ◽  
Tree Seedlings ◽  
Red Maple ◽  
Yellow Birch ◽  
White Ash ◽  
Advance Regeneration ◽  
Species Specific

Annual height growth rates for six species of tree seedlings were modeled during the first 10 years of cohort initiation following an experimental hurricane in central Massachusetts. Selected canopy trees in a second-growth, transition oak – northern hardwoods forest were pulled over with a winch in a 50 m × 160 m area. Regeneration height growth did not follow the species-specific patterns anticipated if the disturbance had been stand replacing. Instead, the temporal increase in shade from crown expansion and sprouting of residual trees slowed cohort development and resulted in a variety of annual height growth patterns among species. Height development was followed separately for advance regeneration and new seedlings of red maple white ash, black cherry, black and yellow birch, paper birch, and red oak. All species had increasing height growth rates for 3 years followed by either decreasing or unchanged (flat) rates except red maple and ash advance regeneration, which had increasing rates throughout the measurement period. After 10 years, black and yellow birch, and red maple are the most numerous species and compose the majority of the tallest regeneration. Red oaks, which dominated the original stand, are few and unlikely to emerge to the canopy of the new cohort.

The impact of overstory density on sapling height growth in the Missouri Ozarks: implications for interspecific differentiation during canopy recruitment

2014 ◽  
Vol 44 (11) ◽  
pp. 1320-1330 ◽  
Author(s):  
Lance A. Vickers ◽  
David R. Larsen ◽  
Benjamin O. Knapp ◽  
John M. Kabrick ◽  
Daniel C. Dey
Keyword(s):  
Growth Rates ◽  
Maximum Growth ◽  
Height Growth ◽  
Red Maple ◽  
Forestry Practices ◽  
Interspecific Differences ◽  
Red Oaks ◽  
Sapling Growth ◽  
Quercus Spp ◽  
The Impact

Successful canopy recruitment is one of the most important components of sustainable forestry practices. For many desirable species in oak-dominated forests, insufficient sapling growth is a common limitation to successful recruitment. The objectives of this study were to (i) examine the impact of overstory density on sapling growth in the Missouri Ozarks, (ii) investigate the potential for overstory retention to promote compositional shifts via interspecific differences in sapling height growth, and (iii) compare the use of mean and near-maximum growth rates to quantify the impact of overstory density on sapling growth and height differentiation among species. We found that the periodic annual height increment of saplings decreased with increasing overstory density for all species groups in this study (red oaks (Quercus spp.), white oaks (Quercus spp.), hickories (Carya spp.), sassafras (Sassafras spp.), blackgum (Nyssa spp.), dogwood (Cornus spp.), red maple (Acer spp.), ashes (Fraxinus spp.), and elms (Ulmus spp.)). There was evidence of interspecific differentiation in growth rates during the sapling stage, and the observed differences were more pronounced at low overstory densities. Increasing overstory densities either reduced or eliminated the differences in growth among species. Although red oaks displayed the greatest maximum growth rates of all species under low overstory densities (<5 m2·ha−1), the growth advantage of red oaks was reduced with increasing overstory density. This may provide opportunities to shift species composition toward white oaks using partial harvesting regimes in the Missouri Ozarks. However, white oaks had little to no advantage in height growth over many competing species when overstory density exceeded about 10 m2·ha−1. This implies that the probability of recruitment under overstory densities greater than about 10 m2·ha−1is likely to decline for all oaks in the Missouri Ozarks. We found that using the 90th quantile of height growth rates to evaluate the impact of overstory density on sapling growth had two potential advantages over using the mean growth rate: (i) it provided better models of the limiting effects of overstory density on sapling height growth, and (ii) the focus was on the growth rates of stems that were most likely to recruit into the canopy.

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