Water In Forests Research Articles

Candida phangngensis sp. nov., an anamorphic yeast species in the Yarrowia clade, isolated from water in mangrove forests in Phang-Nga Province, Thailand

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Candida phangngensis sp. nov., an anamorphic yeast species in the Yarrowia clade, isolated from water in mangrove forests in Phang-Nga Province, Thailand

Two yeast strains (TM2-16 and PT1-17(T)) were isolated by membrane filtration from samples of estuarine water collected from two mangrove forests, in Khao Lumpee-Haad Thaimueang National Park and Mu Ko Ra-Ko Prathong National Park, Phang-Nga Province, Thailand. Analysis of the D1/D2 domain of the large-subunit rDNA sequences revealed that the sequences of the two strains were identical. The closest species in terms of pairwise sequence similarity was Candida galli, but the level of nucleotide substitutions (13.2 %) was sufficient to justify the description of a separate species. Phylogenetic analysis demonstrated that the two strains occupy a basal position with respect to Yarrowia lipolytica and C. galli of the Yarrowia clade, supported by a high bootstrap value. The two strains showed identical phenotypic characteristics, including proliferation by multilateral budding, absence of ascospores and ballistoconidia and negative Diazonium blue B and urease reactions. The major ubiquinone was Q-9. On the basis of the above findings, these two strains were assigned to a single novel species of the genus Candida, for which the name Candida phangngensis sp. nov. is proposed. The type strain is PT1-17(T) (=BCC 21306(T) =NBRC 101970(T) [corrected] =CBS 10407(T)).

Canopy snow influence on water and energy balances in a coniferous forest plantation in northern Japan

Summary Snowfall captured by the forest canopy is an important component of the water and energy balances in forests that are seasonally covered with snow. In the present study, we examined the influence of canopy snow on water and energy balances above a coniferous forest in the Hitsujigaoka Experimental Forest of Japan during winter 1997–1998. Measured data comprised eddy covariance fluxes above the forest, micrometeorological data, and canopy-snow monitoring data obtained from photographs and by weighing a cut tree. The maximum daily canopy snow storage was around 6.9 mm water equivalent. The snow-covered area of the canopy affected the partitioning of the energy balance above the canopy. The quantity of canopy snow strongly influenced canopy surface albedo, canopy surface temperature, and aerodynamic resistance between forest and atmosphere. About 26% of the accumulated snowfall from 1 January 1998 to 31 March 1998 was intercepted by the forest canopy.

Cloud water in windward and leeward mountain forests: The stable isotope signature of orographic cloud water

Cloud water can be a significant hydrologic input to mountain forests. Because it is a precipitation source that is vulnerable to climate change, it is important to quantify amounts of cloud water input at watershed and regional scales. During this study, cloud water and rain samples were collected monthly for 2 years at sites on windward and leeward East Maui. The difference in isotopic composition between volume‐weighted average cloud water and rain samples was 1.4‰ δ18O and 12‰ δ2H for the windward site and 2.8‰ δ18O and 25‰ δ2H for the leeward site, with the cloud water samples enriched in 18O and 2H relative to the rain samples. A summary of previous literature shows that fog and/or cloud water is enriched in 18O and 2H compared to rain at many locations around the world; this study documents cloud water and rain isotopic composition resulting from weather patterns common to montane environments in the trade wind latitudes. An end‐member isotopic composition for cloud water was identified for each site and was used in an isotopic mixing model to estimate the proportion of precipitation input from orographic clouds. Orographic cloud water input was 37% of the total precipitation at the windward site and 46% at the leeward site. This represents an estimate of water input to the forest that could be altered by changes in cloud base altitude resulting from global climate change or deforestation.

Moss beneath a leafless larch canopy: influence on water and energy balances in the southern mountainous taiga of eastern Siberia

AbstractThe southern mountainous taiga of eastern Siberia has a sparse larch canopy and an understory dominated by a thick moss layer. The physiology of moss is very different from that of other plants, as mosses lack roots and vascular systems and take up water directly. During May 2002, we conducted hydrological and meteorological measurements in the taiga of eastern Siberia to investigate the role of understory moss on water and energy balances within a leafless larch forest. We found that below‐leafless canopy net all‐wave radiation partitions into 39% latent heat flux and 39% sensible heat flux, while the mean daily Bowen ratio is about 1. Ground heat flux on the moss surface is also an important factor, as it comprises 22% of net all‐wave radiation. Evaporation from moss beneath the leafless canopy was 24 mm during the 1‐month observation period, representing 23% of the water flux into the larch forest. This finding implies that moss intercepted 23% of the water flux into the larch forest. In addition, evaporation from the moss understory during May 2002 comprised 22% of total evapotranspiration previously estimated above the canopy (April–October 2001). We conclude that moss is an important component of the water and energy balance in larch forests in the taiga region. Copyright © 2007 John Wiley & Sons, Ltd.

Sulphate and Nitrate in Precipitation and Soil Water in Pine Forests in Latvia

The SO4–S and NO3–N concentrations and pH in bulk precipitation, throughfall, stemflow and soil water for the 1994–2004 period were studied in pine forests in Latvia (Rucava and Taurene Integrated Monitoring stations). The SO4–S and NO3–N concentrations decreased over the study period, simultaneously with a decrease of acidity in precipitation. The changes were more evident in the western part of Latvia, probably due to declining long-range air pollution from West Europe. The trend of decreasing sulphate concentrations and increasing pH in precipitation were not followed by respective changes in soil water. In the upper soil horizon sulphate ion concentrations and acidity increased in soil water. Over the observation period, nitrate concentrations also showed an increasing trend in soil water at Rucava and Taurene, but these changes were not statistically significant.

Constraining rooting depths in tropical rainforests using satellite data and ecosystem modeling for accurate simulation of gross primary production seasonality

AbstractAccurate parameterization of rooting depth is difficult but important for capturing the spatio‐temporal dynamics of carbon, water and energy cycles in tropical forests. In this study, we adopted a new approach to constrain rooting depth in terrestrial ecosystem models over the Amazon using satellite data [moderate resolution imaging spectroradiometer (MODIS) enhanced vegetation index (EVI)] and Biome‐BGC terrestrial ecosystem model. We simulated seasonal variations in gross primary production (GPP) using different rooting depths (1, 3, 5, and 10 m) at point and spatial scales to investigate how rooting depth affects modeled seasonal GPP variations and to determine which rooting depth simulates GPP consistent with satellite‐based observations. First, we confirmed that rooting depth strongly controls modeled GPP seasonal variations and that only deep rooting systems can successfully track flux‐based GPP seasonality at the Tapajos km67 flux site. Second, spatial analysis showed that the model can reproduce the seasonal variations in satellite‐based EVI seasonality, however, with required rooting depths strongly dependent on precipitation and the dry season length. For example, a shallow rooting depth (1–3 m) is sufficient in regions with a short dry season (e.g. 0–2 months), and deeper roots are required in regions with a longer dry season (e.g. 3–5 and 5–10 m for the regions with 3–4 and 5–6 months dry season, respectively). Our analysis suggests that setting of proper rooting depths is important to simulating GPP seasonality in tropical forests, and the use of satellite data can help to constrain the spatial variability of rooting depth.

Net Ecosystem Exchanges of Carbon, Water, and Energy in Young and Old-growth Douglas-Fir Forests

To be able to estimate the cumulative carbon budget at broader scales, it is essential to understand net ecosystem exchanges (NEE) of carbon and water in various ages and types of ecosystems. Using eddy-covariance (EC) in Douglas-fir dominated forests in the Wind River Valley, Washington, USA, we measured NEE of carbon, water, and energy from July through September in a 40-year-old stand (40YR) in 1998, a 20-year-old stand (20YR) in 1999, and a 450-year-old stand (450YR) during both years. All three stands were net carbon sinks during the dry, warm summers, with mean net daily accumulation of –0.30 g C m−2 d−1, –2.76 g C m−2 d−1, and –0.38 g C m−2 d−1, respectively, in the 20YR, 40YR, and 450YR (average of 1998, 1999) stands; but for individual years, the 450YR stand was a carbon source in 1998 (0.51 g C m−2 d−1) and a sink in 1999 (–1.26 g C m−2 d−1). The interannual differences for the summer months were apparent for cumulative carbon exchange at the 450YR stand, which had 46.9 g C m−2 loss in 1998 and 115.9 g C m−2 gain in 1999. As predicted, the 40YR stand assimilated the most carbon and lost the least amount of water to the atmosphere through evapotranspiration.

Water shortage affects the water and nitrogen balance in Central European beech forests.

Whilst forest policy promotes cultivation and regeneration of beech dominated forest ecosystems, beech itself is a highly drought sensitive tree species likely to suffer from the climatic conditions prognosticated for the current century. Taking advantage of model ecosystems with cool-moist and warm-dry local climate, the latter assumed to be representative for future climatic conditions, the effects of climate and silvicultural treatment (different thinning regimes) on water status, nitrogen balance and growth parameters of adult beech trees and beech regeneration in the understorey were assessed. In addition, validation experiments with beech seedlings were carried out under controlled conditions, mainly in order to assess the effect of drought on the competitive abilities of beech. As measures of water availability xylem flow, shoot water potential, stomatal conductance as well as delta (13)C and delta (18)O in different tissues (leaves, phloem, wood) were analysed. For the assessment of nitrogen balance we determined the uptake of inorganic nitrogen by the roots as well as total N content and soluble N compounds in different tissues of adult and young trees. Retrospective and current analysis of delta (13)C, growth and meteorological parameters revealed that beech growing under warm-dry climatic conditions were impaired in growth and water balance during periods with low rain-fall. Thinning affected water, N balance and growth mostly of young beech, but in a different way under different local climatic conditions. Under cool, moist conditions, representative for the current climatic and edaphic conditions in beech forests of Central Europe, thinning improves nutrient and water status consistent to published literature and long-term experience of forest practitioners. However, beech regeneration was impaired as a result of thinning at higher temperatures and under reduced water availability, as expected in future climate.

Potential effects of climate change on canopy communities in a tropical cloud forest: an experimental approach.

Global climate change models predict reduced cloud water in tropical montane forests. To test the effects of reduced cloud water on epiphytes, plants that are tightly coupled to atmospheric inputs, we transplanted epiphytes and their arboreal soil from upper cloud forest trees to trees at slightly lower elevations that are naturally exposed to less cloud water. Control plants moved between trees within the upper site showed no transplantation effects, but experimental plants at lower sites had significantly higher leaf mortality, lower leaf production, and reduced longevity. After the epiphytes died, seedlings of terrestrial gap-colonizing tree species grew from the seed banks within the residual mats of arboreal soil. Greenhouse experiments confirmed that the death of epiphytes can result in radical compositional changes of canopy communities. Thus, tropical montane epiphyte communities constitute both a potentially powerful tool for detecting climate changes and a rich arena to study plant/soil/seed interactions under natural and manipulated conditions. This study also provides experimental evidence that the potential effects of global climate change on canopy and terrestrial communities can be significant for cloud forest biota. Results suggest there will be negative effects on the productivity and longevity of particular epiphytes and a subsequent emergence of an emerging terrestrial component into the canopy community from a previously suppressed seed bank.

Seasonal variation in the energy and water exchanges above and below a larch forest in eastern Siberia

AbstractThe water and energy exchanges in forests form one of the most important hydro‐meteorological systems. There have been far fewer investigations of the water and heat exchange in high latitude forests than of those in warm, humid regions. There have been few observations of this system in Siberia for an entire growing season, including the snowmelt and leaf‐fall seasons. In this study, the characteristics of the energy and water budgets in an eastern Siberian larch forest were investigated from the snowmelt season to the leaf‐fall season. The latent heat flux was strongly affected by the transpiration activity of the larch trees and increased quickly as the larch stand began to foliate. The sensible heat dropped at that time, although the net all‐wave radiation increased. Consequently, the seasonal variation in the Bowen ratio was clearly ‘U’‐shaped, and the minimum value (1·0) occurred in June and July. The Bowen ratio was very high (10–25) in early spring, just before leaf opening. The canopy resistance for a big leaf model far exceeded the aerodynamic resistance and fluctuated over a much wider range. The canopy resistance was strongly restricted by the saturation deficit, and its minimum value was 100 s m−1 (10 mm s−1 in conductance). This minimum canopy resistance is higher than values obtained for forests in warm, humid regions, but is similar to those measured in other boreal conifer forests. It has been suggested that the senescence of leaves also affects the canopy resistance, which was higher in the leaf‐fall season than in the foliated season. The mean evapotranspiration rate from 21 April 1998 to 7 September 1998 was 1·16 mm day−1, and the maximum rate, 2·9 mm day−1, occurred at the beginning of July. For the growing season from 1 June to 31 August, this rate was 1·5 mm day−1. The total evapotranspiration from the forest (151 mm) exceeded the amount of precipitation (106 mm) and was equal to 73% of the total water input (211 mm), including the snow water equivalent. The understory evapotranspiration reached 35% of the total evapotranspiration, and the interception evaporation was 15% of the gross precipitation. The understory evapotranspiration was high and the interception evaporation was low because the canopy was sparse and the leaf area index was low. Copyright © 2001 John Wiley & Sons, Ltd.

Evaporation of intercepted precipitation based on an energy balance in unlogged and logged forest areas of central Kalimantan, Indonesia

The effect of logging practices on rainfall interception loss has been investigated in a humid tropical rainforest of central Kalimantan. The traditional volume balance method was used to measure throughfall, stemflow and interception loss. The evaporation rate during and after rainfall has ceased in canopy-saturated conditions was calculated by an energy balance method, which relied on the modified Penman equation using directly determined microclimatic and canopy structure variables as inputs. The results obtained showed that the evaporation from wet canopies in this research area is driven more by advected energy than by radiative energy. In the unlogged plot, advective energy accounted for 0.38 mm h −1 of the 0.51 mm h −1 of evaporation, whereas radiative energy accounted for only 0.13 mm h −1. A similar relationship between the major driving variables and the rate of evaporation was also found in the logged plot and this implies that logging activities did not change the proportion of energy used for interception loss. The Priestley–Taylor equation was found to be a poor model for evaporation of intercepted water in tropical forests because advected energy is very important at the canopy scale.

Use of objective criteria for the assessment of biogeochemical ecosystem models

Ecosystem modeling is confronted with complex biological systems and changing environmental conditions. A model which describes ecosystem behavior under all conditions has not been found yet and there does not exist one `true' model for a specific ecosystem. Often ecosystem models describe the measured data more or less well, but most judging criteria for model performance are rather subjective. Furthermore, from a mathematical view point the calibrations of ecosystem models are hardly ever unique. The aim of this study was to develop and use criteria which permit an objective comparison of different models to the observed field data and to each other. A given model which describes a specific system significantly better will be declared the `valid' model while the other will be rejected. The term `valid' is used here in a sense that any model that could not be proven invalid would be a valid model for the system. We used the biogeochemical soil models MAGIC (Cosby, B.J., Hornberger, G.M., Wright, R.F., 1985. Modelling the effects of acid deposition: assessment of a lumped-parameter model of soil water and stream water chemistry. Water Resour. Res. 21, 51–63) and the SO-Model (derived from the Batch Equilibrium Model (BEM; Prenzel, J., 1991. Introduction to BEM (Batch Equilibrium Model), vol 28. Berichte des Forschungszentrums Waldökosysteme/Waldsterben, Göttingen, 51 pp.). The data set used was the soil solution chemistry in a forest ecosystem of the Solling area (North-West Germany). To test the performance of the models four criteria were used: the efficiency (Martinec, J., Rango, A., 1989. Merits of statistical criteria for the performance of hydrologic models. Water Resour. Bull. 25 (2), 421–432; Hinzman, L.D., Kane, D.L., 1991. Snow hydrology of a headwater artic basin; 2. Conceptual analysis and computer modelling. Water Resour. Res. 27, 1111–1121), the Normalized Mean Absolute Error ( NMAE, given by Janssen, P.H.M., Heuberger, P.S.C., 1995. Calibration of process orientated models. In: van Grinvsen, J.J.M. (Ed.), Modelling Water, Carbon and Nutrient Cycles in Forests: Application of 16 Simulation Models to a Spruce Stand at Solling, Germany. Ecological Modelling, vol. 83, pp. 55–66), the confidence interval test ( CIT, developed in this study) and the model rejection criteria (Sun, N.Z., 1994. Inverse Problems in Groundwater Modelling. Dordrecht, 337 pp.). Whereas the efficiency and NMAE are related to the averaged data, the CIT and the model rejection criteria include the spatial heterogeneity at every time step. When evaluated visually, both model results might be accepted. From the application of the model performance criteria we selected the MAGIC model as the `valid' model for our system.

Estimating regional forest productivity and water yield using an ecosystem model linked to a GIS

We used the PnET-II model of forest carbon and water balances to estimate regional forest productivity and runoff for the northeastern United States. The model was run at 30 arc sec resolution (approximately 1 km) in conjunction with a Geographic Information System that contained monthly climate data and a satellite-derived land cover map. Predicted net primary production (NPP) ranged from 700 to 1450 g m2 yr1 with a regional mean of 1084 g m2 yr1. Validation at a number of locations within the region showed close agreement between predicted and observed values. Disagreement at two sites was proportional to differences between measured foliar N concentrations and values used in the model. Predicted runoff ranged from 24 to 150 cm yr1with a regional mean of 63 cm yr1. Predictions agreed well with observed values from U.S. Geologic Survey watersheds across the region although there was a slight bias towards overprediction at high elevations and underprediction at lower elevations. Spatial patterns in NPP followed patterns of precipitation and growing degree days, depending on the degree of predicted water versus energy limitation within each forest type. Randomized sensitivity analyses indicated that NPP within hardwood and pine forests was limited by variables controlling water availability (precipitation and soil water holding capacity) to a greater extent than foliar nitrogen, suggesting greater limitations by water than nitrogen for these forest types. In contrast, spruce-fir NPP was not sensitive to water availability and was highly sensitivity to foliar N, indicating greater limitation by available nitrogen. Although more work is needed to fully understand the relative importance of water versus nitrogen limitation in northeastern forests, these results suggests that spatial patterns of NPP for hardwoods and pines can be largely captured using currently available data sets, while substantial uncertainties exist for spruce-fir.

Temporal and spatial patterns in vegetation and atmospheric properties from AVIRIS

Little research has focused on the use o f intaging spectrometry for change detection. In this paper, we apply Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data to the monitoring of seasonal changes in atinospheric water vapor, liquid water, and surface cover in the vicinity of the Jasper Ridge, CA, for three dates in 1992. Apparent surface reflectance was retrieved and water vapor and liquid water mapped by using a radiativetransfer-based inversion that accounts for spatially variable atmospheres. Spectral mixture analysis (SMA) was used to model reflectance data as mixtures of green vegetation (GV), nonphotosynthetic vegetation (NPV), .soil, and shade. Temporal and spatial patterns in endineinber fractions and liquid water were compared to the normalized difference vegetation index (NDVI). The reflectance retrieval algorithm was tested by using a temporally invariant target. Atmospheric analysis showed a strongly negative linear relation between water vapor and elevation with significant seasonal variation in water vapor. Comparison of AVIRIS estimates of specific humidity to ground-based measures showed good correspondence for all three dates. Analysis of .surface properties showed that GV, NDVI, and liquid water varied in. response to green vegetation and were highly correlated. However, whereas the NDVI peaked between 0.7 and 0.85 in forests, liquid water continued to vary by as much as a factor of two. Seasonal patterns included senescence in herbaceous and nonconiferous vegetation, potential leaf growth in cortiferous forests, and a general increase in shadows. This resulted in seasonal declines in NDVI, GV, and liquid water for non forested vegetation and increases in NPV. Nonconiferous forests showed similar declines in liquid water rend GV and increases in shade and NPV, but they showed an. increase in NDVI. In coniferouns forests, liquid water and NDVI increased seasonally, matching an interpretation of continued growth, but GV decreased owing to increased .shade. The combination of retrieved surface reflectance, atmospheric modeling, and mapping of liquid water demonstrates the utility of imaging spectrometry for change detection. SMA with the use of reference endmembers is an c effective method for monitoring surficial changes. Temporal patterns in NDVI that contradict trends of GV and liquid water in nonconiferous forests raise additional questions about the NDVI. Liquid water may be more appropriate for analysis of high-leaf-area, shadowed forests because it overcomes the problem of saturation with NDVI.

Does atmospheric deposition of nitrogen threaten Swedish forests?

The health and productivity of forests is fundamentally important to many societies, and the culture and economy of Sweden are intimately linked with Sweden's forests. Are the health and productivity of Sweden's forests at risk from too much nitrogen from acid deposition? We evaluated this question by posing a number of specific questions, and synthesized information from the extensive research in Sweden on N deposition, fertilization and forest growth. We addressed the questions: Have Swedish forest soils acidified in recent decades? Are Swedish forest saturated with N, or do they have an excess of N? Will excessive N lead to forest decline? Will liming or vitalisation fertilization improve forest nutrition and health? We examined the ideas behind these questions, the available evidence, and whether the evidence supported or refuted the ideas. Several studies have documented reductions in soil pH (measured in water) in Swedish forests over periods of several decades. This acidification has been accompanied by increases in ionic strength of soil solutions, reduced base saturation and increased soil organic matter. The importance of each of these acidifying processes has not been investigated directly, but evidence supports a substantial role for each mechanism in at least some cases. Current expectations about rates of mineral weathering are not consistent with the evidence; rates of weathering appear to be greater than expected, and to differ depending on tree species. Swedish forests are not saturated with N; only a few stands near the southwest coast (with the highest deposition rates) show leaching losses of N that rival N deposition rates. Across all regions of Sweden, inadequate supplies of N limit forest growth. Within each region, some stands fail to respond to N fertilization (or respond with a decrease in growth), which is common for other forest types in other countries. Stands that have received heavy fertilization with N may become responsive to further fertilization with phosphorus (P) or base cations, and fertilization with trace amounts of boron (B) may be important on some soils. No evidence supports any widespread responsiveness of the forests to fertilization with other elements unless N is also added. Vitalisation fertilization (with non-N nutrients) has not demonstrated substantial improvements in tree growth, although most experiments have focused on N-limited sites rather than N-excess sites. Liming studies from Sweden and around Scandinavia indicate that forest health typically suffers after liming, including growth losses of 5 to 10% lasting one or more decades. The forests of Sweden averaged about 30% greater growth per hectare in the 1990s than in the 1950s, and extensive forest inventories show no indication of abnormal forest declines within this overall picture of improving growth. Hypotheses of declining forest growth as a function of the ratio of base cations to aluminum in soil solution can be tested with N fertilization experiments. The cation ratios uniformly declined with N fertilization, but growth typically increased, refuting the idea that cation ratios can represent changes in forest productivity. We conclude that no evidence supports the hypothesis of past or current deposition of N has reduced the health or productivity of Sweden's forests; the opposite may have occurred. We also stress that several important questions cannot be addressed satisfactorily with current information. In particular, we recommend additional research on sites where N leaching rivals N deposition, elucidating mechanisms controlling N leaching and responses of trees to excessive levels of soil N.

Soil water dynamics of the Solling spruce stand, calculated with the forhyd simulation package

The forhyd simulation package was applied to the Solling spruce stand to calculate the water balance and soil water dynamics in the context of a comparison of 16 models which simulate water, carbon and nutrient cycles in forests. The simulated results appeared to fit the measurements of pressure heads and time-integrated chloride concentrations when only throughfall parameters were calibrated. However, the applicability of pressure head and chloride concentration measurements for validating the simulation results is very limited. Objective criteria to select specific statistical fit-measures are lacking and measures are sometimes contradicting when using either pressure heads or pF-values. The water holding capacity and the capillary redistribution of water to the root zone appear to be sufficient to fulfil the transpiration demand in most years although the spruce has a very shallow rooting depth. Therefore, the calculated transpiration is almost entirely determined by the calculated potential transpiration. Any error in parametrisation of the root profile or the physical soil characteristics only causes changes in the calculated profiles of water uptake or vertical fluxes, but not in the total water balance components.

Experimental manipulations of the water and nutrient cycles in forest ecosystems (patch-scale roof experiments: EXMAN)

EXMAN is a joint project funded by the Commission of the European Communities (CEC) Directorate XII, Science and Research (DG XII), with research partners in five European countries. The aim of EXMAN is experimental manipulations of the water and nutrient cycles in forests. These experiments are aimed at testing hypotheses on ecosystem reactions to altered inputs and boundary conditions. EXMAN developed along with the ‘roof method’ as a means for the manipulation of water and solute fluxes into the forest soil on an ecosystem scale. Large roofs are built underneath the forest canopy to collect the throughfall. This amount of water is then, by means of technical equipment, altered in its chemical composition and/or its quantity and/or its temporal flux distribution and reapplied by sprinkler systems to the soil. The reactions of the soil chemical and hydrological parameters, as well as the physiological reactions of the forest stand and the soil fauna and microflora, are investigated in an integrated manner. Such patch-scale roof studies are running in Denmark, the Netherlands, Ireland and Germany (EXMAN sites), as well as in Norway and Sweden. Concerted planning and evaluation of results is secured by periodic contacts between the groups. Results from the manipulation studies may contribute considerably to the progress of the projects GCTE (Global Change and Terrestrial Ecosystems) and BAHC (Biological Aspects of the Hydrological Cycle, e.g. the soil-vegetation-atmosphere transfer (SVAT) models). Relevant BAHC Foci are Focus 1, Activity 1, Tasks 1.1.2, 1.1.3 and 1.1.5.

Long-Term Changes in Water and Soil Chemistry in Spruce and Beech Forests, Solling, Germany

With declining sulfur emissions in western Europe, the degree and time scales of reversibility of soil and freshwater acidification are of major interest. We analyzed long-term changes (1969-1991) in the chemistry of bulk precipitation, throughfall water, soil water, and exchangeable base cations in a beech and a spruce forest in Solling, Germany. Time trends in dissolved and exchangeable pools of base cations in the soils were compared with simulations from a simple mechanistic soil chemistry model to identify the processes controlling long-term changes in soil chemistry. In the early 1970s, profound acidification occurred in the spruce and beech soils due to increasing concentrations of dissolved SO 4

Relationships between water, nutrients and productivity in Australian forests: Application to wood production and quality

Relationships between water, nutrients and productivity in Australian forests: Application to wood production and quality