Sulfate sulfur concentrations and pH of precipitation and streamflow, and sulfur concentrations of biomass and soil components, were determined for a 97.5-ha mixed deciduous forest (Walker Branch Watershed) in eastern Tennessee. Amounts of sulfur (S) added precipitation and lost by streamflow were compared to fluxes of S between biomass pools. Approximately 18.1 kg/ha per year entered the watershed from the atmosphere, while only 11.5 kg/ha per year were lost in streamflow. Analysis of biomass and soil concentrations of S indicate that, of the 6.6 kg/ha per year apparent accumulation of S for the watershed as a whole, 8.6 kg accrue to mineral soil while 4.3 kg are lost from organic soil horizons, and 2.3 kg accrue to annual increment of vegetation. Seasonal variations in S input and export from the watershed were closely tied to precipitation events. The weighted mean pH of the rainfall samples collected at five sampling sites on the watershed was pH 4.2. Sulfate accounts for 80% of major anions (millequivalent basis) contributed to the watershed. The behavior of S on Walker Branch Watershed appears to differ significantly from locations in the northeastern U.S., however the data suggest active expansion to the southeastern U.S. of the area impacted by atmospheric sulfate pollution commonly associated with the northeastern region of the U.S.

In the northern hardwood forest, growth of vernal photosynthetic herbs is temporally restricted to the period between spring snowmelt and summer canopy development. This characteristic suggests that several unique adaptations exist which allow the species to complete their life cycles, and that temporal separation of production in the herbaceous layer may add to structural and functional complexity of the ecosystem. Erythronium americanum Ker. (Liliaceae) was examined in central New Hampshire with respect to its natural history, growth characteristics and influence on energy flow and mineral cycling in the deciduous forest ecosystem. Growth leading to the early spring development of photosynthetic tissue begins with fall root growth and continues through a long winter phase during which the shoot elongates from the perennating organ, through the soil and into the snowpack. Following snowmelt, the shoots begin rapid unfurling and maturation of the photosynthetic tissue. The length of the mature leaf phase is controlled by the timing of snowmelt and canopy development, and may be quite variable between successive years. During the short period of production, total biomass increased by 190% in 1972 and 338% in 1973; however, plant weight at the end of the winter period in 1973 had decreased to 28% of the spring 1972 maximum. In the annual energy cycle, biomass losses during the nonphotosynthetic period may amount to more than production during the preceding spring. In comparison with summer green herbs, Erythronium shoot tissue contained significantly higher concentrations of N but lower levels of K, Mg and Ca, suggesting that the spring adaptation may be oriented toward higher N levels of the soil during the spring period as well as higher light levels at the forest floor. Significant correlations of biomass of vernal photosynthetic herbs with summer green species imply that temporally separated species may utilize the same physical site and resources. This adds to the structural complexity and production of the herbaceous layer; however, the vernal photosynthetics account for only 0.5% of total aboveground primary production of the ecosystem. The temporal character of Erythronium's growth and its capacity for rapid biomass accumulation combine to make it a significant factor in nutrient dynamics in the deciduous forest. Uptake of N and K during spring flushing of nutrients from the ecosystem and later release through senescence of shoot tissue appear to reduce gross ecosystem losses of these elements.

CERES is a forest stand growth model which incorporates sugar transport in order to predict both short-term effects and long-term accumulation of trace contaminants and/or nutrients when coupled with the soil chemistry model (SCHEM), and models of solute uptake (DIFMAS and DRYADS) of the Unified Transport Model, UTM. An important feature of CERES is its ability to interface with the soil-plant-atmosphere water model (PROSPER) as a means of both predicting and studying the effects of plant water status on growth and solute transport. CERES considers the biomass dynamics of plants, standing dead and litter with plants divided into leaves, stems, roots, and fruits. The plant parts are divided further into sugar substrate, storage, and in the case of stems and roots, heartwood components. Each ecosystem component is described by a mass balance equation written as a first-order ordinary differential equation.

NZMS 1 S45 map showing locations of the six forest sites used in this study not included in electronic file. See Archive copy held in Library. | Aspects of nutrient cycling in indigenous and pine forests of the Grey Valley, Westland, were followed over a 2-year period. Four sites representing stages in exotic conversion from mature podocarp-hardwood to 10 year-old radiata pine were selected on similar sites. Nutrient flux in litterfall, rainfall, throughfall and soil drainage beneath the organic horizon and rooting zone were determined. A comparison of throughfall and litterfall was made between mature hard beech and closed-canopy 17 year-old radiata pine. Performance of tension and tray lysimeters was compared on a 1 year-old radiata pine site, at two soil depths. The standing crop of nutrients in components of podocarp-hardwood above-ground biomass was determined. Throughfall was the principal pathway for transfer of Na, Cl and K from canopy to forest floor. Ca, Mg and P were returned predominantly by litterfall. Nutrients may be recycled considerably faster by canopy leaching than by litterfall. Hard beech had substantially greater litterfall than podocarp-hardwood (PH 17) or 17 year-old radiata pine due, predominantly, to higher wood-fall. Litterfall in beech and pine was greatest in spring and autumn while in PH 17 a maximum occurred in summer. Litterfall in 10 year-old radiata pine doubled in the second year over the first year after thinning. Nutrient inputs to the forest floor were considerably greater in PH 17 than 10 year-old or younger pine. Of the three closed-canopy forests (hard beech, podocarp-hardwood and 17 year-old radiata pine) hard beech had largest inputs to the forest floor of Ca and P and lowest inputs of Na and Cl; inputs of K were intermediate. The forest floor of radiata pine had considerably lower inputs of Ca and Mg than for indigenous forest floors. In soil drainage, there was a net transfer of K, Ca, Mg and P from organic to mineral soil in 1 and 10 year-old radiata pine, but a net uptake from PH 17 organic soil drainage. Net uptake from mineral soil drainage occurred on all sites. It was greatest on the 10 year-old radiata pine site. Net loss of K from the ecosystem decreased rapidly with increasing biomass. Substantial losses occurred from a 1 year-old radiata pine site. Losses of Ca and Mg were greatest from 10 year-old pine which had recently been thinned. Net losses of P were nil or very low on all sites. Application of superphosphate fertiliser at the rate of 10 c.p.a. to a 10 year-old radiata pine stand caused negligible increases in leaching of Ca and P below the organic soil and rooting zone. For a 3-year study it was considered that 5 raingauges, 15-25 throughfall collectors, 20-30 lysimeters and 12-24 littertraps, depending on the site, were adequate to determine nutrient flux in the forested ecosystems studied.

Resumo Medições da respiração edáfica (método de Walter & Haber) em floresta arenícola, campinarana e campina, na Reserva INPA-SUFRAMA e arredores (02°38'S, 60°01'W). em Manaus, Amazonas, forneceram médias (mg CO2/m2.h) de 60,18; 52,85 e 44,99 e valores de decomposição no solo (ton M.O./ha.ano) de 2,50; 2.20 e 1.87 respectivamente, estatisticamente diferentes. Incluindo a decomposição aérea, a produtividade primária da floresta arenícola é de 5,0 ton M.O./ha.ano, o valor mais baixo encontrado em florestas amazônicas, provavelmente devido à pobreza do solo em nutrientes minerais e à reduzida biomassa da floresta arenícola. Parece ocorrer aporte e/ou lavagem de nutrientes da fitomassa e seu acúmulo na serapilheira e, talvez, sua transferência direta para a biomassa, bem como grande perda de nutrientes do solo por percolação. Complexação, quelação e insolubilização podem reter certos nutrientes na serapilheira, provavelmente com ação de microrganismos, para os quais o ferro e o alumínio parecem ser importantes. Afora o ferro, os nutrientes retidos na serapilheira parecem depender do tipo de cobertura vegetal Exceto a 40 cm sob campina, todas as demais amostras de solo apresentaram concentrações de alumínio consideradas tóxicas a muitas plantas. Os maiores valores de pH foram encontrados no solo da campina e os menores, na campinarana. Diferenças de comportamento das frações granulométricas com o aumento da profundidade sob cada tipo de vegetação parecem indicar ocorrência de processos diferentes em cada solo. Os autores sugerem outros estudos sobre respiração edáfica durante o ano; sobre ciclagem de nutrientes; sobre alumínio e ferro e sua ação na vegetação e nos decompositores; sobre o solo em diferentes profundidades. | Summary Soil respiration measurements (Walter & Haber method) were taken in sand forest, campinarana and campina, in the INPA-SUFRAMA reserve and vicinities (02°38'S,60°01'W), near Manaus, Amazonas, Brazil. Carbon dioxide evolution from soil was measured during 7 periods (6 for campina) of 24 hours duration. Its conversion Into primary productivity has furnished mean values which have shown to be statistically different for each habitat, highly significant through the Willis rank-test. The mean values for soil respiration were 60.18, 52.85 and 44.99 mg CO2/m2.h, and the mean values for decomposition were 2.50, 2.20 and 1.87 tons org. mat./ha.year, respectively for sand forest, campinarana and campina. Considering aerial decomposition, the sand forest primary productivity was estimated at 5,0 tons org.mat./ha.year, the lowest figure reported to date for forests of this region. These results are probably due to the soil nutrient deficiency and to the low biomass of this kind of vegetation. Chemical analyses of leaves, litter and soil at different depths seem to indicate that nutrients may be deposited on and/or washed out of the phytomass by rain water; that they may accumulate in the litter layer; that they may then be transferred to biomass via microrhizae and predation in addition to the normal method of nutrient uptake by plants; and that there is a great loss of nutrients in the soil by water (and solutes) percolation. The accumulation of nutrients in the litter layer seems to be due to their complexation. chelation and insolubilization, processes in which microorganisms should have an Important role. Iron and aluminium should also be important in these processes, as well as for these microorganisms. The accumulation of nutrients in the litter layer seems also to be a direct result of the vegetation cover. An exception is iron, which has been shown to be indifferent to the vegetation cover. Except at 40 cm depth under campina all other soil samples have aluminium concentration considered to be toxic to most plants. The highest pH values were found for campina soil, and the lowest ones for campinarana soil. The different behaviour of the granulomerc fractions with increasing depths seems to indicate occurrence of different soil processes. The authors indicate complementary studies which might help in understanding these vegetation types: on annual soil respiration, on nutrient cycling, on aluminum and iron and their influence upon the vegetation and the decomposers, on the soil at different depths.

Metal distribution in vegetation and soil components, annual inputs, and losses were determined in undisturbed urban and rural ecosystems in northwestern Indiana. The urban area has been exposed to contamination from industrial and other urban sources for about 100 years. The levels of cadmium, zinc, copper, and lead (Cd, Zn, Cu, and Pb) were significantly higher in the soils and vegetation on the urban site compared to a similar system in a rural setting 67 km away. Metal concentration in the top 2.5 cm of soil averaged 10 ppm Cd, 2,456 ppm Zn, 463 ppm Pb, and 119 ppm Cu. This was 20 to 100 times more concentrated than that found on the rural site. The surface litter (O horizon) on the urban site also had four to nine times greater metal concentration and total metal quantities were many times greater in the urban ecosystem than on the rural site. The higher soil levels were reflected in higher concentrations in most plant species, but species differed greatly in metal levels. Greater than 95% of the weight of all four metals was found in the soil (0–25 cm) for both dune and wetland ecosystems. The remaining metal burden is equally distributed between the surface litter and the plant biomass. Slightly more Cd and twice as much Zn entered the urban site than the rural site during 1975–76. Annual input of Pb and Cu was four times greater on the urban site. While pollution control has apparently reduced annual input to the urban site, metal concentrations will remain high due to the low rates of leaching losses measured.

The William L. Hutcheson Memorial Forests is a mixed oak stand located on the New Jersey Piedmont, and is believed to have remained uncut and unburned for >250 yr. Abundant canopy gaps and large fallen boles indicate old—age status. Patterns of detritus distribution appear different from younger or disturbed forests. Consequently, we studied organic matter and element content in 12 distinct detritus components, litter deposition, element ratios, element turnover rates, and latitudinal oak forest detritus affinities. Total detrital organic matter (ash—free) was 27.6 kg/m², with 86% located in the mineral soil horizons. Of the 3.8 kg/m² of detritus lying above the mineral soil, 71% was in fallen boles and large branches. Detrital organic matter exceeds aboveground biomass. In the forest floor and associated decaying wood, N was the abundant element (81 g/m²), followed by Ca (22 g/m²), Mg (11 g/m²), K (10.5 g/m²), and P (4.5 g/m²). The thin humus layer, averaging 0.5 centimetres thick, had a much higher total element content per square metre than older detrital components due to high element concentration values. Concentrations of each element increased as branch diameter decreased, and as leaf, branch, and bole litter decomposed. Organic matter:element ratios exhibited the same trend as carbon:element ratios, a decrease with decreasing branch diameter, increasing forest floor depth, and increasing bole decay. Average annual litter deposition (ash—free) was 616 g/m². Nitrogen, P, and K content of litter deposition was higher in summer than in autumn. Leaves returned the majority of each element followed by small branches and fruits. Forest—floor organic matter and element content increase along a latitudinal gradient of eastern oak forests. Organic matter and element turnover times of southern oak forests, including Hutcheson Forest, are similar, despite differing organic matter and element pools and deposition rates. One interesting aspect of detritus in an old, undisturbed forest is the pronounced role of detrital wood. Large decaying boles represent 10% of aboveground biomass and 9% of total detritus. These boles are a habitat and energy source for detritivores, influence seeding establishment and soil development, and affect hydrologic and biogeochemical cycles. Because of large carbon:element ratios and slow rates of decomposition, boles lying on the forest floor may exhibit a net accumulation and storage of elements until a critical carbon:element ratio is reached and net mineralization occurs. A time delay thus exists for element release which may provide regular elemental supply through time.