Ecological impact of a microburst windstorm in a northern hardwood forest

We quantified damage by a microburst windstorm to a northern hardwood forest (Hubbard Brook Experimental Forest, New Hampshire). These storms may be important in regulating the structure and composition of forests of the northeastern United States, but few studies of damage patterns from microbursts have been reported. In the 600 ha area most heavily impacted by the microburst at Hubbard Brook, 4.6% of the canopy was removed. Although most disturbances were small (<200 m2), much (22%) of the area damaged by the storm was associated with one 5.2 ha blowdown within which 76% of the trees suffered severe damage. Roughly one-half of the damaged trees were uprooted and one-quarter were snapped off, with few differences among tree species. The remaining trees in the blowdown either avoided damage or suffered less severe damage (i.e., leaning but not snapped or uprooted). Regeneration of shade-intolerant (pin cherry (Prunus pensylvanica L. f.)) and mid-tolerant (yellow birch (Betula alleghaniensis Britt.), red maple (Acer rubrum L.)) trees was present in the large canopy gaps. While recruitment opportunities in these large gaps may be important for maintaining populations of pioneer species, the limited spatial extent of microbursts suggests that they play a minor role in the overall dynamics of the northeastern forest.

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Effects of an intense ice storm on the structure of a northern hardwood forest

Canadian Journal of Forest Research ◽

10.1139/x02-089 ◽

2002 ◽

Vol 32 (10) ◽

pp. 1763-1775 ◽

Cited By ~ 111

Author(s):

Anne G Rhoads ◽

Steven P Hamburg ◽

Timothy J Fahey ◽

Thomas G Siccama ◽

Elizabeth N Hane ◽

...

Keyword(s):

Hardwood Forest ◽

Forest Damage ◽

Northern Hardwood Forest ◽

Betula Alleghaniensis ◽

Regression Equations ◽

Ice Storm ◽

Beech Bark Disease ◽

Area Index ◽

Northern Hardwood ◽

Advance Regeneration

A major ice storm in January 1998 provided an opportunity to study the effects of a rare, intense disturbance on the structure of the northern hardwood forest canopy. Canopy damage was assessed using visual damage classes within watersheds of different ages at the Hubbard Brook Experimental Forest (HBEF) and changes in leaf area index in two of these watersheds. Ice thickness was measured, and ice loads of trees were estimated using regression equations. In the 60- to 120-year-old forests (mean basal area 26 m2·ha1), damage was greatest in trees >30 cm diameter at breast height and at elevations above 600 m. Of the dominant tree species, beech (Fagus grandifolia Ehrh.) was the most damaged, sugar maple (Acer saccharum Marsh.) was the most resistant, and yellow birch (Betula alleghaniensis Britt.) was intermediate. Trees with advanced beech bark disease experienced heavier ice damage. Little damage occurred in the 14-year-old forest, while the 24- to 28-year-old forest experienced intense damage. In the young stands of this forest, damage was greatest between 600 and 750 m, in trees on steep slopes and near streams, and among pin cherry (Prunus pensylvanica L.). Recovery of the canopy was tracked over three growing seasons, and root growth was monitored 1 year after the storm. Because of the high density of advance regeneration from beech bark disease and root sprouting potential in ice-damaged beech, HBEF will likely see an increase in beech abundance in older forests as a result of the storm. There will also be a more rapid change from pioneer species to mature northern hardwoods in the younger forests. These predictions illustrate the ability of rare disturbances to increase heterogeneity of forest structure and composition in this ecosystem, especially through interactions with other disturbances.

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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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