Hubbard Brook ecosystem study: forest biomass and production
A small watershed in the White Moutains of New Hampshire bearing mesophytic, cool-temperate, broadleaf-deciduous forests was studied. Acer saccharum, Betula lutea, and Fagus grandifolia are dominant, but toward higher elevations Picea rubens and Abies balsamea also occur and indicate the transition toward subalpine climate. The stands are young (following cutting in 1909-17) but contain older trees; stand composition is thought reasonably representative of the climax. For application of the Brookhaven system of forest dimension analysis, 93 sample trees, of major species were cut and roots excavated. Mean dimensions of sample trees, and the constants for the system of logarithmic regressions relating volume, surface, mass, and growth to diameter at breast height and other independent variables, show decrease in tree sizes and height/diameter ratios toward higher elevations. Stand characteristics, based on application of the regressions to forest samples, show trends of decrease for the elevation belts from low to high. Biomass (and, presumably, production) of root systems is 18 to 21% of that aboveground. Different estimations suggest that a mean climax biomass for the watershed may be around 350 t/ha, aboveground. Net ecosystem production is estimated as 350 g/m/sup 2//yr aboveground and 85 belowground for 1956-60, 238 and 52 g/m/sup 2//yr for 1961-65. Analysis of stem wood volume increments reveals an abrupt and striking (18%) decrease in volume growth and productivity from 1956-60 to 1961-65. Both drought and effects of increasing air pollution (notably increasing acidity of rainfall) may be responsible for the recent decrease in productivity.
- OSTI ID:
- 5547727
- Journal Information:
- Ecol. Monogr.; (United States), Journal Name: Ecol. Monogr.; (United States) Vol. 44; ISSN ECMOA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Density, biomass, productivity, and nutrient-cycling changes during stand development in wave-regenerated balsam fir forests
Vegetation of the Santa Cataline Mountains, Arizona. V. Biomass, production, and diversity along the elevation gradient
Related Subjects
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
560303 -- Chemicals Metabolism & Toxicology-- Plants-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACID RAIN
ACIDIFICATION
ATMOSPHERIC PRECIPITATIONS
BEECH TREES
BIOLOGICAL EFFECTS
BIOLOGICAL STRESS
CONIFERS
CONNECTICUT
FEDERAL REGION I
FORESTS
MAPLES
NORTH AMERICA
PLANTS
PRECIPITATION SCAVENGING
PRODUCTIVITY
RAIN
SEPARATION PROCESSES
TREES
USA