Growth and survivorship of American beech (Fagus grandifolia Ehrh.) seedlings in a northern hardwood forest following a mast event1

The response of trace gas fluxes (CO2, CH4, and N2O) and litter decomposition to increased soil temperature was evaluated in a northern hardwood forest. Four experimental plots (10 × 10 m) had heating cables installed within the forest floor. Temperatures at 5 cm were increased 2.5, 5.0, or 7.5°C in individual heated plots during the field season in 1993 and 1994. The fourth plot was a cabled, nonheated reference. Trace gas fluxes were monitored using closed chambers. Soil moisture was monitored using tensiometers and time domain reflectometry. Changes in leaf litter decomposition were quantified using litter bags for American beech (Fagus grandifolia Ehrh.) and sugar maple (Acer saccharum Marsh.) litter. Fluxes of CO2 increased exponentially with increased soil temperatures within treatments and were higher in heated plots than in the reference plot. Temperature coefficients (Q10) and mass remaining of American beech leaf litter decreased with the level of heating, suggesting a nonlinear microbial response to elevated temperatures. Soil water content exhibited the most influence on CH4 and N2O flux in the second season. The experimental manipulations showed the importance of evaluating the influence of soil temperature coupled with effects of N and moisture availability.

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Calcium and magnesium in wood of northern hardwood forest species: relations to site characteristics

Canadian Journal of Forest Research ◽

10.1139/x98-210 ◽

1999 ◽

Vol 29 (3) ◽

pp. 339-346 ◽

Cited By ~ 16

Author(s):

M A Arthur ◽

T G Siccama ◽

R D Yanai

Keyword(s):

Sugar Maple ◽

Abies Balsamea ◽

Fagus Grandifolia ◽

Hardwood Forest ◽

Northern Hardwood Forest ◽

Betula Alleghaniensis ◽

Forest Species ◽

White Birch ◽

Yellow Birch ◽

Northern Hardwood

Improving estimates of the nutrient content of boles in forest ecosystems requires more information on how the chemistry of wood varies with characteristics of the tree and site. We examined Ca and Mg concentrations in wood at the Hubbard Brook Experimental Forest. Species examined were the dominant tree species of the northern hardwood forest and the spruce-fir forest. The concentrations of Ca and Mg, respectively, in lightwood of these species, mass weighted by elevation, were 661 and 145 µg/g for sugar maple (Acer saccharum Marsh.), 664 and 140 µg/g for American beech (Fagus grandifolia Ehrh.), 515 and 93 µg/g for yellow birch (Betula alleghaniensis Britt.), 525 and 70 µg/g for red spruce (Picea rubens Sarg.), 555 and 118 µg/g for balsam fir (Abies balsamea (L.) Mill.), and 393 and 101 µg/g for white birch (Betula papyrifera Marsh.). There were significant patterns in Ca and Mg concentrations with wood age. The size of the tree was not an important source of variation. Beech showed significantly greater concentrations of both Ca (30%) and Mg (33%) in trees growing in moist sites relative to drier sites; sugar maple and yellow birch were less sensitive to mesotopography. In addition to species differences in lightwood chemistry, Ca and Mg concentrations in wood decreased with increasing elevation, coinciding with a pattern of decreasing Ca and Mg in the forest floor. Differences in Ca and Mg concentration in lightwood accounted for by elevation ranged from 12 to 23% for Ca and 16 to 30% for Mg for the three northern hardwood species. At the ecosystem scale, the magnitude of the elevational effect on lightwood chemistry, weighted by species, amounts to 18% of lightwood Ca in the watershed and 24% of lightwood Mg but only 2% of aboveground biomass Ca and 7% of aboveground Mg.

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Validation and refinement of allometric equations for roots of northern hardwoods

Canadian Journal of Forest Research ◽

10.1139/x07-032 ◽

2007 ◽

Vol 37 (9) ◽

pp. 1777-1783 ◽

Cited By ~ 16

Author(s):

Matthew A. Vadeboncoeur ◽

Steven P. Hamburg ◽

Ruth D. Yanai

Keyword(s):

Sugar Maple ◽

Lateral Roots ◽

Fagus Grandifolia ◽

Allometric Equations ◽

Hardwood Forest ◽

Northern Hardwood Forest ◽

Sampling Effort ◽

Betula Alleghaniensis ◽

Northern Hardwood ◽

Mean Error

The allometric equations developed by Whittaker et al. (1974. Ecol. Monogr. 44: 233–252) at the Hubbard Brook Experimental Forest have been used to estimate biomass and productivity in northern hardwood forest systems for over three decades. Few other species-specific allometric estimates of belowground biomass are available because of the difficulty in collecting the data, and such equations are rarely validated. Using previously unpublished data from Whittaker’s sampling effort, we extended the equations to predict the root crown and lateral root components for the three dominant species of the northern hardwood forest: American beech ( Fagus grandifolia Ehrh.), yellow birch ( Betula alleghaniensis Britt), and sugar maple ( Acer saccharum Marsh.). We also refined the allometric models by eliminating the use of very small trees for which the original data were unreliable. We validated these new models of the relationship of tree diameter to the mass of root crowns and lateral roots using root mass data collected from 12 northern hardwood stands of varying age in central New Hampshire. These models provide accurate estimates of lateral roots (<10 cm diameter) in northern hardwood stands >20 years old (mean error 24%–32%). For the younger stands that we studied, allometric equations substantially underestimated observed root biomass (mean error >60%), presumably due to remnant mature root systems from harvested trees supporting young root-sprouted trees.

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