Dudley J. Raynal

Effects of acidic deposition on forest and aquatic ecosystems in New York State.

Acidic deposition is comprised of sulfuric and nitric acids and ammonium derived from atmospheric emissions of sulfur dioxide, nitrogen oxides, and ammonia, respectively. Acidic deposition has altered soil through depletion of labile pools of nutrient cations (i.e. calcium, magnesium), accumulation of sulfur and nitrogen, and the mobilization of elevated concentrations of inorganic monomeric aluminum to soil solutions in acid-sensitive areas. Acidic deposition leaches essential calcium from needles of red spruce, making this species more susceptible to freezing injury. Mortality among sugar maples appears to result from deficiencies of nutrient cations, coupled with other stresses such as insect defoliation or drought. Acidic deposition has impaired surface water quality in the Adirondack and Catskill regions of New York by lowering pH levels, decreasing acid-neutralizing capacity, and increasing aluminum concentrations. Acidification has reduced the diversity and abundance of aquatic species in lakes and streams. There are also linkages between acidic deposition and fish mercury contamination and eutrophication of estuaries.

Biodiversity and conservation of Turkish forests

The rapid human population growth of Turkey and associated demands on natural resources threaten the biodiversity of the nations natural ecosystems, including forests. Though limited to about 26% of the total land area of the country, maintaining healthy forests is vital to support sustainable development in Turkey. The purpose of this paper is to introduce the current status of Turkeys forests, present the national objectives for forest conservation and sustainable use, and describe the actions needed to protect forest biodiversity. While Turkey has numerous laws, regulations, and programmes that seek to promote biodiversity, implementation of these guidelines requires increased commitment and vigilance. Conservation programmes should be increased in number and effectiveness, particularly in light of increasing demand for forest products. Management plans for all conservation programmes require completion and implementation. Creating monitoring programs and building quantitative databases for conservation programs will be essential to assess future success in maintaining biodiversity. Conservation of natural resources requires public education and promoting awareness of the vital role of maintaining a healthy environment for sustainable development. Agroforestry endeavors can provide practical means of meeting both environmental protection and agricultural product production goals.

Long-term trends in the chemistry of precipitation and lake water in the Adirondack Region of New York, USA

Long-term changes in the chemistry of precipitation (1978–94) and 16 lakes (1982–94) were investigated in the Adirondack region of New York, USA. Time-series analysis showed that concentrations of SO42−, NO3−, NH4+ and basic cations have decreased in precipitation, resulting in increases in pH. A relatively uniform rate of decline in SO42− concentrations in lakes across the region (1.81±0.35 μeq L−1 yr−1) suggests that this change was due to decreases in atmospheric deposition. The decrease in lake SO42− was considerably less than the rate of decline anticipated from atmospheric deposition. This discrepancy may be due to release of previously deposited SO42− from soil, thereby delaying the recovery of lake water acidity. Despite the marked declines in concentrations of SO42− in Adirondack lakes, there has been no systematic increase in pH and ANC. The decline in SO42− has corresponded with a near stoichiometric decrease in concentrations of basic cations in low ANC lakes. A pattern of increasing NO3− concentrations that was evident in lakes across the region during the 1980s has been followed by a period of lower concentrations. Currently there are no significant trends in NO3− concentrations in Adirondack lakes.

Effects of aluminum on red spruce seedlings in solution culture

Abstract Red spruce (Picea rubens Sarg.) seedlings were grown in solution culture at pH 4.0 with 250, 500, 1000 and 2000 μM Al. To evaluate the effects of culture medium concentratioms comparisons were made between Al effects in the full strength medium and a 5-fold diluted medium. Overall, the effect of Al on seedling growth and nutrient composition was more severe in the 1/5 strength medium. In both media Al reduced root biomass to a greater degree than shoot biomass. Tap root and shoot elongation were significantly reduced by 250 μM both in the full and 1/5 medium. However, total length of lateral roots was greater in the 1/5 strength medium compared to the full medium. Al tissue content increased with Al solution concentration and was substantially larger in fine roots compared to young needles. Needle Al content was higher in the 1/5 medium. This may explain the greater Al injury observed in 1/5 strength medium. It suggests that ionic strength has a significant effect on Al translocation. With the exception of phosphate, Al reduced the ionic content of plant tissues. The effects were generally more severe in the 1/5 strength medium and were observed at the 250 μM Al concentration. At higher Al levels reduction in tissue Mg and Ca may have been sufficiently severe to induce nutrient deficiences.

MEASUREMENTS OF WET AND DRY DEPOSITION IN A NORTHERN HARDWOOD FOREST

Inputs of wet and dry deposition were monitored at the Huntington Forest in the Adirondack Mountains of New York for two years in the open and beneath the canopy of a northern hardwood forest. In the open, ion flux estimates were similar using wet-only weekly (NADP protocol) and event collections, but bulk collections were higher for all ions except H+, which was much lower. These differences were due to the contribution of dry deposition and possible biotic alterations in bulk collectors. Dry deposition was estimated using air concentrations and ion-specific depositional velocities modeled with meteorological data, and contributed substantially to the input of all ions [H+ (45%), Na+ (24%), K+ (22%), NH4+ (12%), Ca2+ (58%), Mg2+(43%), NO3− (55%), Cl− (27%) and SO4−2 (26%)]. Dry input of base cations was dominated by coarse particles, whereas gaseous inputs were more important for S and NO3−. Atmospheric concentrations of SO2 and inputs of SO42− and H+ were lower at this site than sites closer to point sources of S gas emission. The importance of estimating atmospheric inputs was examined using examples of elemental budgets. For example, different estimates of the contribution of dry deposition of SO42− (9–21 meq m−2 y−1) resulted in conclusions ranging from no net retention to a net loss of this element. Such differences have important implications in assessing the current and future role of atmospheric inputs in affecting elemental cycling.

Aluminum toxicity in forests exposed to acidic deposition: The ALBIOS results

The ALBIOS project was conducted to examine the influence of acidic deposition on aluminum transport and toxicity in forested ecosystems of eastern North America and northern Europe. Patterns of aluminum chemistry were evaluated in 14 representative watersheds exposed to different levels of sulfur deposition. Controlled studies with solution and soil culture methods were used to test interspecific differences in aluminum sensitivity for one indicator species (honeylocust - Gleditsia triacanthos L. ) and six commercial tree species (red spruce - Picea rubens Sarg., red oak - Quercus rubra L., sugar maple - Acer saccharum Marsh., American beech - Fagus grandifolia Ehrh., European beech - Fagus sylvatica, and loblolly pine - Pinus Taeda L. ). Overall, red spruce was the tree species whose growth was most sensitive to soluble aluminum, with significant biomass reductions occurring at Al concentrations of approximately 200–250 umol/L. Analyses of soil solutions from the field sites indicated that the conditions for aluminum toxicity for some species exist at some of the study areas. At these watersheds, aluminum toxicity could act as a contributing stress factor affecting forest growth.

Biogeochemistry of a forested watershed in the central Adirondack Mountains : Temporal changes and mass balances

Information on atmospheric inputs, water chemistry and hydrology were combined to evaluate elemental mass balances and assess temporal changes in elemental transport from 1983 through 1992 for the Arbutus Lake watershed. This watershed is located within a northern hardwood ecosystem at the Huntington Forest within the central Adirondack Mountains of New York (USA). Changes in water chemistry, including increasing NO3− concentrations (1.1 μmolc, L−1 yr-1), have been detected during this study period. Starting in 1991 hydrological flow has been measured from Arbutus Lake and these measurements were compared with predicted flow using the BROOK2 hydrological simulation model. The model adequately (r2=0.79) simulated flow from this catchment and was used to estimate drainage for earlier periods when direct hydrological measurements were not available. Modeled drainage water losses coupled with estimates of wet and dry atmospheric deposition were used to calculate solute budgets. Export of SO42− (831 molc ha−1 yr−1) from the greater Arbutus Lake watershed exceeded estimates of atmospheric deposition in an adjacent hardwood stand suggesting an additional source of S. These large drainage losses of SO42− also contributed to the drainage fluxes of basic cations (Ca2+, Mg2+, K+ and Na+). Most of the atmospheric inputs of inorganic N were retained (average of 74% of wet precipitation and 85% total deposition) in the watershed. There were differences among years (56 to 228 mol ha−1 yr−1) in drainage water losses of N with greatest losses occurring during a warm, wet period (1989–1991).

Root sprouting in American beech (Fagus grandifolia) : Effects of root injury, root exposure, and season

Abstract Superficial woody American beech roots were manipulated and left in situ for three growing seasons to evaluate seasonal influences of injury and exposure on root sprout formation. A total of 648 root segments were arranged in a 32 × 2 split-plot factorial experiment with three injury levels (scrape, cut, and control), two exposure levels (exposed and buried), and three seasons (summer, late fall, and spring). Analysis of variance revealed significant injury, season, exposure and interaction effects. Injured roots developed more callus, adventitious buds and sprouts than did controls. Exposure stimulated bud initiation, and spring injury resulted in higher levels of sprouting compared to late fall or summer injury.

Nitrogen biogeochemistry in the Adirondack Mountains of New York: hardwood ecosystems and associated surface waters

Studies on the nitrogen (N) biogeochemistry in Adirondack northern hardwood ecosystems were summarized. Specific focus was placed on results at the Huntington Forest (HFS), Pancake-Hall Creek (PHC), Woods Lake (WL), Ampersand (AMO), Catlin Lake (CLO) and Hennessy Mountain (HM). Nitrogen deposition generally decreased from west to east in the Adirondacks, and there have been no marked temporal changes in N deposition from 1978 through 1998. Second-growth western sites (WL, PHC) had higher soil solution NO(3-) concentrations and fluxes than the HFS site in the central Adirondacks. Of the two old-growth sites (AMO and CLO), AMO had substantially higher NO(3-) concentrations due to the relative dominance of sugar maple that produced litter with high N mineralization and nitrification rates. The importance of vegetation in affecting N losses was also shown for N-fixing alders in wetlands. The Adirondack Manipulation and Modeling Project (AMMP) included separate experimental N additions of (NH4)2SO4 at WL, PHC and HFS and HNO3 at WL and HFS. Patterns of N loss varied with site and form of N addition and most of the N input was retained. For 16 lake/watersheds no consistent changes in NO(3-) concentrations were found from 1982 to 1997. Simulations suggested that marked NO(3-) loss will only be manifested over extended periods. Studies at the Arbutus Watershed provided information on the role of biogeochemical and hydrological factors in affecting the spatial and temporal patterns of NO(3-) concentrations. The heterogeneous topography in the Adirondacks has generated diverse landscape features and patterns of connectivity that are especially important in regulating the temporal and spatial patterns of NO(3-) concentrations in surface waters.

Response of tree seedlings to acid precipitation— II. Effect of simulated acidified canopy throughfall on sugar maple seedling growth

Abstract Sugar maple seedling radicle growth in a laboratory growth apparatus was significantly reduced after exposure to simulated acidified canopy throughfall at pH 3.0 and below. Seedlings exposed to low pH were susceptible to bacterial infection; survival of seedlings transplanted to soil declined with increasing acidity of simulated canopy throughfall. Extension growth and leaf weight gain of established potted seedlings subjected to acidic throughfall was dependent on soil nutrient supplying capacity. Under nutrient-limited conditions, throughfall of pH 3.0 promoted seedling growth although causing foliar damage. At higher fertility levels, reduction in growth was found only after the pH 2.0 treatment. Evaluation of the findings in relation to natural conditions is complicated by (1) the capacity of vegetation and the forest floor to buffer the seedling environment from extreme pH changes, (2) the direct effects of acidity on pathogenic micro-organisms and the predisposition of seedlings to infection, (3) the episodic nature and varying acidity of precipitation, and (4) differential sensitivity of laboratory and field grown seedlings to acidic deposition. However, these studies indicate that sugar maple seedlings are potentially susceptible to direct and indirect effects of acid precipitation.