Streamflow Changes after Forest Clearing in New England
TL;DR: In this paper, the authors show that clearing a hardwood forest cover and preventing regrowth with herbicides on a 39-acre watershed in central New England increased annual water yield an average 12.2 area-inches for the first two water years after treatment.
Abstract: Clearing a hardwood forest cover and preventing regrowth with herbicides on a 39-acre watershed in central New England increased annual water yield an average 12.2 area-inches for the first two water years after treatment. Most of this increase occurred during the critical low flow months of June through September, and the amount was governed in large part by rainfall in this period. There was a small advance of snowmelt runoff and a consistent increase in growing season high flow values. Our data agree with others showing that sizeable streamflow increases can result from forest clearing in the uplands of the eastern United States.
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TL;DR: In this paper, a summary and review of 94 catchment experiments shows that accumulated information on the effect of vegetation changes on water yield can be used for practical purposes, since no experiments, with the exception of perhaps one, have resulted in reductions in water yield with reductions in cover, or increases in yield, with increases in cover.
2,455 citations
TL;DR: In this paper, the authors focus on the use of paired catchment studies for determining the changes in water yield at various time scales resulting from permanent changes in vegetation and highlight the potential underestimation of water yield changes if regrowth experiments are used to predict the likely impact of permanent alterations to a catchment's vegetation.
1,384 citations
TL;DR: Large increases in streamwater concentration were observed for all major ions, except NH4+, SO4 = and HCO3—, approximately five months after the deforestation, and an inverse relationship between sulfate and nitrate concentrations in stream water was observed in both undisturbed and deforested situations.
Abstract: All vegetation on Watershed 2 of the Hubbard Brook Experimental Forest was cut during November and December of 1965, and vegetation regrowth was inhibited for two years by periodic application of herbicides. Annual stream—flow was increased 33 cm or 39% the first year and 27 cm or 28% the second year above the values expected if the watershed were not deforested. Large increases in streamwater concentration were observed for all major ions, except NH4+, SO4 = and HCO3—, approximately five months after the deforestation. Nitrate concentrations were 41—fold higher than the undisturbed condition the first year and 56—fold higher the second. The nitrate concentration in stream water has exceeded, almost continuously, the health levels recommended for drinking water. Sulfate was the only major ion in stream water that decreased in concentration after deforestation. An inverse relationship between sulfate and nitrate concentrations in stream water was observed in both undisturbed and deforested situations. Average streamwater concentrations increased by 417% for Ca++, 408% for Mg++, 1558% for K+ and 177% for Na+ during the two years subsequent to deforestation. Budgetary net losses from Watershed 2 in kg/ha—yr were about 142 for NO3—N, 90 for Ca++, 36 for K+, 32 for SiO2—Si, 24 for Al+++, 18 for Mg++, 17 for Na+, 4 for Cl—, and 0 for SO4—S during 1967—68; whereas for an adjacent, undisturbed watershed (W6) net losses were 9.2 for Ca++, 1.6 for K+, 17 for SiO2—Si, 3.1 for A1+++, 2.6 for Mg++, 7.0 for Na+, 0.1 for C1—, and 3.3 for SO4—S. Input of nitrate—nitrogen in precipitation normally exceeds the output in drainage water in the undisturbed ecosystems, and ammonium—nitrogen likewise accumulates in both the undisturbed and deforested ecosystems. Total gross export of dissolved solids, exclusive of organic matter, was about 75 metric tons/km2 in 1966—67, and 97 metric tons/km2 in 1967—68, or about 6 to 8 times greater than would be expected for an undisturbed watershed. The greatly increased export of dissolved nutrients from the deforested ecosystem was due to an alteration of the nitrogen cycle within the ecosystem. The drainage streams tributary to Hubbard Brook are normally acid, and as a result of deforestation the hydrogen ion content increased by 5—fold (from pH 5.1 to 4.3). Streamwater temperatures after deforestation were higher than the undisturbed condition during both summer and winter. Also in contrast to the relatively constant temperature in the undisturbed streams, streamwater temperature after deforestation fluctuated 3—4°C during the day in summer. Electrical conductivity increased about 6—fold in the stream water after deforestation and was much more variable. Increased streamwater turbidity as a result of the deforestation was negligible, however the particulate matter output was increased about 4—fold. Whereas the particulate matter is normally 50% inorganic materials, after deforestation preliminary estimates indicate that the proportion of inorganic materials increased to 76% of the total particulates. Supersaturation of dissolved oxygen in stream water from the experimental watersheds is common in all seasons except summer when stream discharge is low. The percent saturation is dependent upon flow rate in the streams. Sulfate, hydrogen ion and nitrate are major constituents in the precipitation. It is suggested that the increase in average nitrate concentration in precipitation compared to data from 1955—56,as well as the consistent annual increase observed from 1964 to 1968, may be some measure of a general increase in air pollution.
1,188 citations
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01 Jan 2002TL;DR: The third edition of Gordon Bonan's comprehensive textbook introduces an interdisciplinary framework to understand the interaction between terrestrial ecosystems and climate change as discussed by the authors, which is suitable for advanced undergraduate and graduate students studying ecology, environmental science, atmospheric science, and geography.
Abstract: The third edition of Gordon Bonan's comprehensive textbook introduces an interdisciplinary framework to understand the interaction between terrestrial ecosystems and climate change. Ideal for advanced undergraduate and graduate students studying ecology, environmental science, atmospheric science, and geography, it reviews basic meteorological, hydrological, and ecological concepts to examine the physical, chemical, and biological processes by which terrestrial ecosystems affect and are affected by climate. This new edition has been thoroughly updated with new science and references. The scope has been expanded beyond its initial focus on energy, water, and carbon to include reactive gases and aerosols in the atmosphere. The new edition emphasizes the Earth as a system, recognizing interconnections among the planet's physical, chemical, biological, and socioeconomic components, and emphasizing global environmental sustainability. Each chapter contains chapter summaries and review questions, and with over 400 illustrations, including many in color, this textbook will once again be an essential student guide.
758 citations
TL;DR: In this article, the effects of forest cover reduction (or catchment area harvested) of less than 20% could not be determined by hydrometric or streamflow measurement methods.
568 citations
References
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TL;DR: The balance of calcium, magnesium, potassium, and sodium was studied in six watersheds of the Hubbard Brook Experimental Forest at West Thornton, New Hampshire, and the relationship between concentration and discharge was not significant for Ca+ and Mg+ + in any of the watersheds, but was inversely significant for Na+ .
Abstract: Six West Thornton, New Hampshire watersheds are characterized by a near climax, northern hardwoods ecosystem, humid continental climate, and acid metamorphic rock. Concentration of Ca/sup + +/, Mg/sup + +/, K/sup +/, and Na/sup +/ in weekly precipitation samples was variable. The annual weighted average values (mg/liter) were; 1973-74, Ca 0.26, mg. 0.06, K 0.21, Na 0.09; 1964-65, Ca 0.30, Mg 0.12, K 0.19, Na 0.22. Differences were not related to elevation. The contribution of cations from dry fallout was negligible. Cation content of stream water was relatively very low. The weighted average content for the entire area (mg/liter) was Ca 1.18, Mg 0.38, K 0.26, Na 0.87 during 1963-64; and Ca 0.80, Mg 0.38, K 0.22, Na 0.91 during 1964-65. In general, the cationic concentrations in drainage water were constant although discharge of water varied greatly. Statistically, the relationship between concentration and discharge was not significant for Ca/sup + +/ and Mg/sup + +/ in any of the watersheds, but was inversely significant for Na/sup +/, and was possibly direct for K/sup +/ in a few instances. The budget for dissolved cations was calculated from determinations of input (cation concentration times volume of precipitation) and output (cation concentration timesmore » volume of runoff.) During 1963-64 the average inputs in kg/ha were 3.0 Ca/sup + +/, 0.7 Mg/sup + +/, 2.5 K/sup +/, and 1.0 Na/sup +/, while the output averaged 8.0 Ca/sup + +/, 2.6 Mg/sup + +/, 1.8 K/sup +/, and 5.9 Na+. During 1964-65 the values were: input, 2.8 Ca/sup + +/, 1.1 Mg/sup + +/, 1.8 K/sup +/, and 2.1 Na/sup +/; and output, 3.9 Ca/sup + +/, 11.8 Mg/sup + +/, 1.1 K/sup +/, and 4.5 Na/sup +/. Assuming that the vegetation is near synamic equilibrium, the net losses of Ca/sup + +/, Mg/sup + +/, and Na/sup +/ represent conservative measurements of geochemical weathering in the system. The K/sup +/ budget is probably near balance.« less
274 citations
TL;DR: The forest of a small watershed-ecosystem was cut in order to determine the effects of removal of vegetation on nutrient cycles, and the cut ecosystem exhibited accelerated loss of nutrients.
Abstract: The forest of a small watershed-ecosystem was cut in order to determine the effects of removal of vegetation on nutrient cycles. Relative to undisturbed ecosystems, the cut ecosystem exhibited accelerated loss of nutrients: nitrogen lost during the first year after cutting was equivalent to the amount annually turned over in an undisturbed system, and losses of cations were 3 to 20 times greater than from comparable undisturbed systems. Possible causes of the pattern of nutrient loss from the cut ecosystem are discussed.
263 citations
TL;DR: The nitrate concentration (weighted average) in stream water from an experimentally deforested watershed increased from 0.9 milligram per liter before removal of the vegetation to 53 milligrams per liter 2 years later.
Abstract: The nitrate concentration (weighted average) in stream water from an experimentally deforested watershed increased from 0.9 milligram per liter before removal of the vegetation to 53 milligrams per liter 2 years later. This nitrate mobilization, presumably due to increased microbial nitrification, was equivalent to all of the other net cationic increases and anionic decreases observed in tae drainage water.
241 citations
TL;DR: In this article, the balances of input in atmospheric precipitation and discharge in streams have been determined for selected mineral constituents in three small tributaries to Hubbard Brook in the White Mountains of New Hampshire.
Abstract: The balances of input in atmospheric precipitation and discharge in streams have been determined for selected mineral constituents in three small tributaries to Hubbard Brook in the White Mountains of New Hampshire. Inputs and discharge of sulfate, ammonium, and nitrate were calculated from hydrologic data, together with chemical analyses of weekly samples of precipitation and streamwater taken over a 2-year period. The calculations show that precipitation provides most of the 30–50 kilograms of sulfate per hectare carried annually by the streams and that inputs exceed outflows of ammonium and of nitrate. Maximum effluent nitrate concentrations of 2 mg/l (milligrams per liter) are observed in early spring. Measurements of pH indicate that the hydrogen ion is one of the major cations in precipitation over the area. Determinations were made of the discharge of bicarbonate, silica, and aluminum in the streams. Annual stream loads of silica ranged from 20 to 40 kilograms per hectare. Effluent bicarbonate and silica concentrations vary directly with each other and inversely with aluminum.
90 citations
Book•
07 Nov 2017
TL;DR: In this article, the first results of forest watershed management research on the Fernow Experimental Forest in Tucker County, West Virginia were described and compared to the results reported in this paper.
Abstract: This report describes first results of forest watershed management research on the Fernow Experimental Forest in Tucker County, West Virginia.
72 citations