Response of understory vegetation of Adirondack forests to nitrogen additions

1998 ◽  
Vol 28 (6) ◽  
pp. 799-807 ◽  
Author(s):  
T M Hurd ◽  
A R Brach ◽  
D J Raynal
Keyword(s):  
Hardwood Forests ◽  
Fagus Grandifolia ◽  
N Addition ◽  
Nutrient Response ◽  
Woods Lake ◽  
Adirondack Mountain ◽  
A Site ◽  
Atmospheric Inputs ◽  
Nitrogen Additions ◽  
Foliar N Concentration

The influence of N pulses in the form of experimental additions of HNO3 at two times ambient and (NH4)2SO4 at two and four times ambient on the herbaceous and woody understory plants in three Adirondack Mountain hardwood forests was evaluated. Addition of (NH4)2SO4 decreased cover of dominant herbs and woody seedlings at Woods Lake, a site in the western Adirondacks. Tissue N concentrations of combined herbs and ferns at Woods Lake increased with addition of roman NH sub 4 sup + at both levels (9% at two times ambient; 13% at four times ambient) and increased with all three N treatments at Huntington Forest, a central Adirondack site (14% with roman NO sub 3 sup - and roman NH sub 4 sup + at two times ambient; 22% with roman NH sub 4 sup + at four times ambient). Seedlings of American beech (Fagus grandifolia Ehrh.) increased foliar N concentration 7-8% with addition of roman NH sub 4 sup + treatments at Huntington Forest, but did not respond to N addition at Woods Lake and Pancake Hall Creek, a western Adirondack site. In general, greatest plant nutrient response to N addition occurred at Huntington Forest, where atmospheric inputs of N are lower than at Woods Lake and Pancake Hall Creek.

Present-day expansion of American beech in northeastern hardwood forests: Does soil base status matter?

2009 ◽  
Vol 39 (12) ◽  
pp. 2273-2282 ◽  
Author(s):  
Louis Duchesne ◽  
Rock Ouimet
Keyword(s):  
Acer Saccharum ◽  
Sugar Maple ◽  
Basal Area ◽  
Base Cation ◽  
Hardwood Forests ◽  
Fagus Grandifolia ◽  
Soil Base ◽  
Large Area ◽  
American Beech ◽  
Permanent Sample Plots

Recently, sugar maple ( Acer saccharum Marsh.) decline in northeastern North America has been regarded as a major factor structuring hardwood forests by favouring American beech ( Fagus grandifolia Ehrh.) in the understory of maple-dominated stands. To determine whether soil fertility differences associated with sugar maple decline may have promoted the expansion of American beech, we explored the relationships between the soil base status and the sapling and tree strata density and composition, using data from 426 permanent sample plots distributed throughout Quebec. Our results indicate that American beech is currently expanding in the sugar maple range of Quebec. The abundance and proportion of American beech in the sapling stratum are mainly associated with the proportion of American beech in the tree stratum, the relative basal area of dead sugar maple trees, and the base status of soils. In accordance with the many studies reporting on the high sensitivity of sugar maple to the acid–base status of soils and the decline of the sugar maple population, this study supports the hypothesis that soil base cation depletion, caused in part by atmospheric acid deposition, is among the main factors involved in the present-day expansion of American beech over a large area in Quebec.

Survival, Growth, Reproduction, and Diet of Brook Trout (Salvelinus fontinalis) Stocked into Lakes after Liming to Mitigate Acidity

1989 ◽  
Vol 46 (2) ◽  
pp. 277-286 ◽  
Author(s):  
Steven P. Gloss ◽  
Carl L. Schofield ◽  
Robert L. Spateholts ◽  
Barbara A. Plonski
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Acid Tolerance ◽  
Mountain Lakes ◽  
Low Velocity ◽  
Growth And Survival ◽  
Population Loss ◽  
Natural Reproduction ◽  
Woods Lake ◽  
Adirondack Mountain

Brook trout (Salvelinus fontinalis) were stocked into two previously acidic (pH 4.5–5.2) Adirondack Mountain lakes, Woods Lake and Cranberry Pond, following liming in June, 1985. Age 0+ Temiscamie × Domestic hybrid brook trout were stocked at 200∙ha−1 with one-half of the fish selected for presumed acid tolerance. Age 1+ Temiscamie strain brook trout were also stocked at 50∙ha−1. Liming increased pH to well above 7 and alkalinity to over 200 μeq∙L−1. Growth and condition of stocked fish were good while water quality conditions remained suitable. However, in Cranberry Pond, which reacidified 6 mo after liming, both growth and survival declined dramatically. Much of the population loss was due to emigration. Annual survival in Woods Lake averaged 35 and 25% for the age 0+ and 1+ fish, respectively. Initially large invertebrates made up most of the diet for stocked fish. These taxa were replaced by zooplankton within a few months. Limited natural reproduction was associated with low velocity groundwater inflows and high acidity in tributary streams. Fry emergence from artificial spawning substrates placed in Woods Lake peaked well after snowmelt inflows which produced toxic conditions in littoral areas.

scholarly journals The Impact of Long-Term Nitrogen Addition on Microbial Community Composition in Three Hawaiian Forest Soils

2001 ◽  
Vol 1 ◽  
pp. 500-504 ◽  
Author(s):  
Teri C. Balser
Keyword(s):  
Microbial Community ◽  
Community Composition ◽  
Forest Soils ◽  
Microbial Community Composition ◽  
Natural Fertility ◽  
Soil Parameters ◽  
N Addition ◽  
A Site ◽  
The Impact

We evaluated the microbial communities in three Hawaiian forest soils along a natural fertility gradient and compared their distinct responses to long-term nitrogen (N) additions. The sites studied have the same elevation, climate, and dominant vegetation, but vary in age of development, and thus in soil nutrient availability and nutrient limitation to plant growth. Fertilized plots at each site have received 100 kg ha year-1N addition for at least 8 years. Soil parameters, water content, pH, and ammonium and nitrate availability differed by site, but not between control and N-addition treatments within a site at the time of sampling. Microbial biomass also varied by site, but was not affected by N addition. In contrast, microbial community composition (measured by phospholipid analysis) varied among sites and between control and N-addition plots within a site. These data suggest that microbial community composition responds to N addition even when plant net primary productivity is limited by nutrients other than N. This may have implications for the behavior of forests impacted by atmospheric N deposition that are considered to be “nitrogen saturated,” yet still retain N in the soil.

scholarly journals Interference to Hardwood Regeneration in Northeastern North America: Ecological Characteristics of American Beech, Striped Maple, and Hobblebush

2006 ◽  
Vol 23 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Ralph D. Nyland ◽  
Amy L. Bashant ◽  
Kimberly K. Bohn ◽  
Jane M. Verostek
Keyword(s):  
North America ◽  
Woody Species ◽  
Ground Level ◽  
Fagus Grandifolia ◽  
Limited Information ◽  
Beech Bark Disease ◽  
American Beech ◽  
Northeastern North America ◽  
A Site ◽  
Palatable Species

Abstract Several woody species may inhibit regeneration of desirable northern hardwoods. This includes a dense understory of American beech (Fagus grandifolia Ehrh.) that commonly occurs in stands infected with beech bark disease. Root injuries during logging and by natural causes alsopromote new suckers that, along with some stump sprouts, often maintain or increase the abundance of beech saplings. Additionally, browsing deer primarily bypass beech in favor of more palatable species. Where any of these factors has resulted in a dense understory of small beech, overstorycutting will promote its development, increase ground-level shading, and lead to a site conversion to beech. Similarly, striped maple (Acer pensylvanicum L.) often interferes with hardwood regeneration after overstory cutting. This species persists in heavy shade, grows rapidly afterrelease, and produces abundant seed. When dense, striped maple may interfere with the regeneration of other species. Hobblebush (Viburnum alnifolium Marsh.), a shrub, reproduces by rhizomes to form thickets when damaged during overstory cutting. Heavy shade by these thickets may preventregeneration of trees. This review summarizes characteristics of these three species with respect to their interference with desirable hardwoods in northeastern North America. It highlights the limited information about striped maple and hobblebush, and the abundance of sources that deal withAmerican beech.

REPRODUCTION OF FAGUS GRANDIFOLIA EHRH. BY SEED IN WISCONSIN

1965 ◽  
Vol 43 (6) ◽  
pp. 757-763 ◽  
Author(s):  
R. L. Dix ◽  
R. F. Skrentny Jr.
Keyword(s):  
Forest Type ◽  
Seedling Survival ◽  
Survival Rates ◽  
Seed Viability ◽  
Geographic Location ◽  
Hardwood Forests ◽  
Fagus Grandifolia ◽  
In Vitro Tests ◽  
Favorable Conditions

An investigation was carried out to determine the factor or factors causing the paucity of reproduction by seeds of Fagus grandifolia in southern Wisconsin, as contrasted with the relatively abundant reproduction by seed in the northern part of the state. A greater percentage of viable seed was found to occur in northern conifer–hardwood forests than in southern hardwood forests. The results of in vitro tests suggested that pollen from trees in northern conifer–hardwood forests has a higher percentage germination and produces longer pollen tubes than that from trees found in southern hardwood forests. Parthenocarpic development was observed but the seeds from such fruits were not viable. Quantitative studies on seedling survival showed higher survival rates in the mor humus of northern conifer–hardwood stands than in the mul humus of southern hardwood stands. The study suggests that the relatively high success of beech reproduction by seeds in northern conifer–hardwood forests is related to both higher seed viability and more favorable conditions for seed germination and seedling survival. Geographic location of stands appears less important than forest type to the success of beech reproduction by seed.

The contribution of beech bark disease-induced mortality to coarse woody debris loads in northern hardwood stands of Adirondack Park, New York, U.S.A.

2000 ◽  
Vol 30 (9) ◽  
pp. 1453-1462 ◽  
Author(s):  
Gregory G McGee
Keyword(s):  
Coarse Woody Debris ◽  
Sugar Maple ◽  
Woody Debris ◽  
Hardwood Forests ◽  
Fagus Grandifolia ◽  
Beech Bark Disease ◽  
Old Growth ◽  
Northern Hardwood Forests ◽  
Northern Hardwood ◽  
Live Tree

The objective of this study was to adjust previously published estimates of coarse woody debris (CWD) volume and basal areas in northern hardwood forests to account for elevated CWD inputs due to beech bark disease (a disease complex of the scale insect, Cryptococcus fagisuga Lindinger, and a fungus, Nectria spp., on American beech, Fagus grandifolia Ehrh.). Ratios of snags/live tree densities and downed CWD volume/live tree basal area were compared between beech and the codominant, shade-tolerant sugar maple (Acer saccharum Marsh.). The differences between the beech and the sugar maple ratios were used to define the elevated mortality from beech bark disease. Estimated volumes of downed CWD (stumps [Formula: see text] 1.0 m tall and logs), adjusted for effects of beech bark disease, were 108 ± 18 and 48 ± 11 m3·ha-1in old-growth and even-aged, 90- to 100-year-old maturing stands, respectively, representing reductions of 22 and 21%, respectively, compared with observed volumes. Similarly, snag densities were adjusted from 59.7 ± 21.7 to 41.1 ± 26.3 per hectare in the old-growth stands and from 96.3 ± 48.0 to 87.3 ± 46.5 per hectare in the maturing stands. Snag basal areas were reduced 21 and 17% from their observed values to 6.8 ± 3.5 and 3.5 ± 0.6 m2·ha-1in the old-growth and maturing stands, respectively. The adjusted CWD estimates presented here are more historically accurate and ecologically meaningful than previous observations made in diseased northern hardwood forests and, therefore, provide more appropriate target levels for managing CWD in these forest types.

scholarly journals Comment on “Present-day expansion of American beech in northeastern hardwood forests: Does soil base status matter?”Appears in Can. J. For. Res. 39: 2273–2282 (2009).

2011 ◽  
Vol 41 (3) ◽  
pp. 649-653 ◽  
Author(s):  
Christian Messier ◽  
Nicolas Bélanger ◽  
Jacques Brisson ◽  
Martin J. Lechowicz ◽  
Dominique Gravel
Keyword(s):  
Acer Saccharum ◽  
Sugar Maple ◽  
Complex Dynamics ◽  
Base Cations ◽  
Base Cation ◽  
Hardwood Forests ◽  
Fagus Grandifolia ◽  
Soil Base ◽  
American Beech ◽  
Atmospheric Acid Deposition

In a recent rapid communication, Duchesne and Ouimet (2009. Can. J. For. Res. 39: 2273–2282) reported that the current expansion of American beech ( Fagus grandifolia Ehrh.) in Quebec is mainly caused by soil base cation depletion due to atmospheric acid deposition. They based their conclusions on an examination of the relationships between stem densities in the sapling and tree strata compared against canopy composition and the availability of base cations in 426 sample plots. Here in this comment, we raise some shortcomings with their study and provide a more prudent and complete perspective on the complex dynamics associated with fluctuations in American beech and sugar maple ( Acer saccharum Marsh.).

Eels Under Standing Wave Conditions

1982 ◽  
Vol 40 ◽  
pp. 492-495
Author(s):  
O.L. Krivanek ◽  
J. TaftØ
Keyword(s):  
Standing Wave ◽  
Wave Conditions ◽  
Set Up ◽  
A Site ◽  
Complex Crystal

It is well known that a standing electron wavefield can be set up in a crystal such that its intensity peaks at the atomic sites or between the sites or in the case of more complex crystal, at one or another type of a site. The effect is usually referred to as channelling but this term is not entirely appropriate; by analogy with the more established particle channelling, electrons would have to be described as channelling either through the channels or through the channel walls, depending on the diffraction conditions.

Head Size and DNA Content in Bacteriophage T4

1972 ◽  
Vol 30 ◽  
pp. 200-201
Author(s):  
Fred Eiserling ◽  
A. H. Doermann ◽  
Linde Boehner
Keyword(s):  
Electron Microscopy ◽  
Dna Content ◽  
Bacteriophage T4 ◽  
Head Size ◽  
Virus Particles ◽  
Altered Protein ◽  
A Cell ◽  
Bacterial Viruses ◽  
A Site ◽  
Protein Shell

The control of form or shape inheritance can be approached by studying the morphogenesis of bacterial viruses. Shape variants of bacteriophage T4 with altered protein shell (capsid) size and nucleic acid (DNA) content have been found by electron microscopy, and a mutant (E920g in gene 66) controlling head size has been described. This mutant produces short-headed particles which contain 2/3 the normal DNA content and which are non-viable when only one particle infects a cell (Fig. 1).We report here the isolation of a new mutant (191c) which also appears to be in gene 66 but at a site distinct from E920g. The most striking phenotype of the mutant is the production of about 10% of the phage yield as “giant” virus particles, from 3 to 8 times longer than normal phage (Fig. 2).

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