Effects of selected forest management practices on environmental parameters related to successional development on the Tanana River floodplain, interior Alaska

1993 ◽  
Vol 23 (5) ◽  
pp. 1001-1014 ◽  
Author(s):  
John Yarie

Two mature floodplain white spruce (Piceaglauca (Moench) Voss) ecosystems (stage VIII) located on islands in the Tanana River, approximately 20 km southwest of Fairbanks, Alaska, were clear-cut during the winter of 1985–1986 to quantify the effects of clear-cutting on selected environmental characteristics. Clearings in earlier successional stages (poplar–alder (Populus–Alnus), stage V; and open willow (Salix), stage III) were used to contrast the environmental parameters with the earlier stages found in the primary successional sequence. After clear-cutting, total radiation at the soil surface increased to early successional stage III levels. Potential evaporation from the soil surface increased 5-fold as a result of clearing in the stage VIII sites and was substantially greater than that found in the stage III sites by other researchers. Clearing had relatively little effect on air temperature. The concentration of P and K was significantly lower in the forest floor of both clearcuts, and the concentration of C was significantly higher at VIII-A-T (stage VIII–site A–treated (cleared) plot) when compared with the control stands. There was a decrease in total forest floor biomass at both clear-cut plots. Organic matter, total N, available NH4 and P, and extractable Mg and K all decreased after cutting, whereas pH increased. Decomposition of spruce foliage on the forest floor surface was slower in the clearcuts. Nitrogen immobilization occurred during the first 2 years of decomposition. During the third year it appeared that some mineralization was beginning to occur but the levels were very low, averaging only 3 mg N per bag in the clear-cut areas. Plant growth analysis indicated that growth was limited by high mineral soil salt content in the early successional stages (III) and that this limitation was species specific. Balsam poplar (Populusbalsamifera L.) appears to be more tolerant of the high cation content of the stage III sites compared with trembling aspen (Populustremuloides Michx.). By the time successional development has progressed to stage V, the soil has been sufficiently augmented by the inclusion of organic matter from the developing vegetation and the fixation of N by alder to result in higher seedling growth rates in the cleared areas.

1983 ◽  
Vol 29 (6) ◽  
pp. 644-648 ◽  
Author(s):  
Thu Kauri

A beech forest after clear-cutting was replanted with spruce. To study how this perturbation affected soil bacteria and their physiological capabilities, an investigation was undertaken 4 years after the change of forest type. Compared with an earlier study in the beech forest, from 1972 to 1975, conducted immediately before clear-cutting, bacterial numbers in the young spruce plantation had increased; an exception was the upper layer (A00), where the numbers decreased. The population densities of bacteria decomposing xylan, pectin, starch, cellulose, and chitin were estimated by a direct multipoint method. The numbers of bacteria in all the physiological groups studied were higher in 1979–1980, with the same exception as before (A00). The greatest changes occurred in the upper horizons. There were considerable changes in the soil environment after the former beech litter fall ceased; the forest floor became more exposed, and the ground vegetation changed. Changes took place in soil properties, such as organic matter and pH. A slight increase in pH was observed in all horizons except in A00, and organic matter increased in two of the horizons (A01/A1; A1).


1984 ◽  
Vol 14 (6) ◽  
pp. 763-767 ◽  
Author(s):  
C. Anthony Federer

Organic content of the forest floor decreases for several years after clear-cutting, and then slowly recovers. Thickness, bulk density, organic matter, and nitrogen content of forest floors were measured for 13 northern hardwood stands in the White Mountains of New Hampshire. Stands ranged from 1 to about 100 years in age. Forest-floor thickness varied significantly with stand age, but bulk density, organic fraction, and nitrogen fraction were independent of age. Total organic content of the forest floor agreed very well with data from Covington's (W. W. Covington 1981. Ecology, 62: 41–48) study of the same area. Both studies indicated that mature forest floors have about 80 Mg organic matter•ha−1 and 1.9 Mg nitrogen•ha−1. Within 10 or 15 years after cutting, the organic matter content of the floor decreases to 50 Mg•ha−1, and its nitrogen content to 1.1 Mg•ha−1. The question whether the decrease is rapid and the minimum broad and flat, or if the decrease is gradual and the minimum sharp, cannot be answered. The subsequent increase to levels reached in mature forest requires about 50 years. Some of the initial decrease in organic matter and nitrogen content of the forest floor may be caused by organic decomposition and nitrogen leaching, but mechanical and chemical mixing of floor into mineral soil, during and after the harvest operation, may also be important. The difference is vital with respect to maintenance of long-term productivity.


1984 ◽  
Vol 14 (6) ◽  
pp. 839-843 ◽  
Author(s):  
J. W. Fitzgerald ◽  
T. L. Andrew ◽  
W. T. Swank

The capacities of soil from hardwood, clear-cut, and pine forests of the Coweeta basin to mineralize, adsorb; and incorporate into Organic matter carbon-bonded sulfur in the form of L-methionine was investigated. These soils adsorbed and incorporated between 40 and 66% of this amino acid within a 0.5-h incubation period, but much of the immobilized sulfur was mineralized after 48 h incubation. Ah additional hardwood forest (watershed 18) was chosen for further study of the incorporation process in both litter and mineral horizons. The O2 forest floor layer exhibited the highest levels of activity in samples taken along a transect of this watershed. Incorporation of methionine into the organic matter of these samples was complete within about 12 h of incubation and was inhibited by pretreatment of the samples with sodium azide; a general inhibitor of cell respiration. The capacities for methionine incorporation determined invitro complement observations of the high levels of carbon bonded sulfur found insitu in forest litter and soil.


2000 ◽  
Vol 30 (11) ◽  
pp. 1726-1741 ◽  
Author(s):  
Barbara J Cade-Menun ◽  
Shannon M Berch ◽  
Caroline M Preston ◽  
L M Lavkulich

When cedar-hemlock (CH) forests of northern Vancouver Island are clear-cut and replanted, growth of replanted trees is often poor. This growth check can be overcome with nitrogen (N) and phosphorus (P) fertilization, suggesting that it may be because of deficiencies of these elements. A widely used site-preparation tool in these forests is slash burning. Because fire is known to alter nutrient cycling in forests, this burning may be contributing to the problem of poor seedling growth. Thus, the objective of this study was to compare P in forest floor and soils from clear-cut CH stands 10 years, 5 years, and immediately after burning to P concentrations and forms in undisturbed old growth CH stands. Analytical methods included extraction and digestion procedures, fractionation and 31P nuclear magnetic resonance spectroscopy. Soon after burning, an "ashbed effect" was noted, with increased pH and higher concentrations of available P in surface soil horizons. Available P concentrations and pH returned to preburn levels within 10 years. However, destruction of organic matter appeared to disrupt illuviation processes throughout the soil profile, producing long-term changes in organic matter, organic P, and organically complexed Fe and Al in lower mineral horizons. Total P concentrations were unchanged, but there was a shift from organic to inorganic P forms and changes in P forms with time at depth in the profile. These changes in P distribution and movement in the soil may contribute to the growth check observed in these forests.


1987 ◽  
Vol 67 (4) ◽  
pp. 943-952 ◽  
Author(s):  
H. H. KRAUSE ◽  
D. RAMLAL

Anion and cation resins were tested as sinks for nutrient ions under variable forest soil conditions. The resins, contained in nylon bags, were placed for periods of 4 wk below the forest floor of a softwood stand, and at approximately 7.5 cm depth on an adjacent clearcut with two different types of site preparation for tree planting. The soil was an Orthic Humo-ferric Podzol. Ion sorption below the forest floor, especially the sorption of ammonium, nitrate and phosphate, was strongly increased after clear-cutting of the forest. Sorption rates were generally lower in the mineral soil than immediately below the forest floor, except for nitrate and sulphate. Mixing of forest floor materials and fine logging debris into the mineral surface horizons generally increased resin sorption if compared to sorption in soil from which the forest floor had been removed. Resin sorption also revealed strong seasonal effects which may have been caused by changes in soil temperature and moisture. Key words: Ion exchange resin, forest soil fertility, seasonal nutrient fluctuation, site preparation


1995 ◽  
Vol 25 (8) ◽  
pp. 1346-1355 ◽  
Author(s):  
Chris E. Johnson

Previous research on chronosequences of even-aged northern hardwood stands has suggested that forest clearing is accompanied by large losses of nitrogen from the forest floor. The timing of the losses and the fate of a large fraction of the lost nitrogen are unclear. The purpose of this investigation was to study these questions through direct measurement of soil nitrogen concentrations and pools through time on an experimental catchment cleared in a whole-tree harvest in 1983–1984. Nitrogen losses from the forest floor at the site, the Hubbard Brook Experimental Forest, New Hampshire, were lower than predictions based on previous research. The mean forest floor nitrogen pool was 17% lower 8 years after clear-cutting of the site (P = 0.18). Predictions based on chronosequence studies suggest that 25–40% of the forest floor nitrogen would be lost after 8 years. Mechanical disturbance during logging may play a role in limiting short-term nitrogen losses. The steep midsection of the catchment experienced the greatest losses of nitrogen and carbon, while pools in the relatively flat spruce-fir zone at the upper elevations were unchanged. Carbon was preferentially lost from soil organic matter, relative to nitrogen, resulting in significant decreases in the C/N and C/organic matter ratios in the soil. The N/organic matter ratio was generally unchanged. Nitrogen losses can be limited after clear-cutting by minimizing organic matter losses and promoting rapid regrowth.


1989 ◽  
Vol 19 (2) ◽  
pp. 204-214 ◽  
Author(s):  
Xiwei Yin ◽  
James A. Perry ◽  
Robert K. Dixon

We compared leaf and forest floor mass loss rates over 2 years on undisturbed (NC), shelterwood-cut (SC0), and clear-cut (CC) sites in a Quercus forest at the Hardie's Creek Forest, Wisconsin, U.S.A. Litterbag techniques and a budgetary approach based on forest floor surveys and litterfall estimations were used. SC0 and NC variables did not differ until final harvest on SC0 (creating SC1). Over a 6-month period, 19% of initial cellulose (filter disk) mass was lost from litterbags placed on SC1 compared with 71% on NC. Leaf mass loss from litterbags was consistently slower on CC than on NC. Rates of mass loss to the upper (01) and lower (02) forest floor horizons in 1985 and total forest floor mass loss rate in both years did not differ among sites; mass loss rate for 01 was lower on CC than on NC, but higher for 02 in 1986. Differences in mass loss rates between CC and NC were attributed to changes in environment (ambient temperature and water content of the soil and forest floor) that were induced by clear-cutting. We suggest that the effects of canopy removal on mass loss from leaf litter appear to vary with regional climatic variables, while the effects on overall forest floor mass loss rate may be buffered by compensation among various forest floor horizons in most areas.


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