Nutrient stress in young scots pines suffering from needle loss in a dry heath forest

In the early summer of 1987 an untimely needle loss was observed in Scots pine (Pinus sylvestris L.) of different ages growing on oliogotrophic mineral soils in Cladina and Calluna-type heath forests in northern Finland. The first symptoms were observed at the beginning of July when current shoot growth was ending and the young needles were flushing. The older needles first yellowed then later turned brown before falling. Needle loss proceeded from the oldest to the younger needle age classes. The trees lost between one and four age classes of needles from earlier growth and retained only the most recent 1 to 3 yr needles. Foliar analysis indicated nutrient stress as revealed by retranslocation of mobile nutrients such as N and insufficient uptake of immobile nutrients such as Ca. The soil nutrient concentration, however, was normal at poor sites and therefore it appears the primary reason for needle loss is a nutrient stress due to root damage. This damage was caused by unusual weather in the winter of 1986 to 1987, rather than by soluble Al.     

Can Graphical Vector Analysis be Used to Identify Micro Nutrient Deficiency?

Initial analysis of needle nutrient status and visible symptoms suggested that a declining Norway spruce (Picea abies L. Karst.) stand in south Sweden was suffering from B and Cu deficiency. Effects of addition of 1000 kg ha^-1 of a commercial N-free fertilizer containing macro nutrients plus B, Cu, and Zn were investigated. B concentrations and B/N ratios were increased significantly in needles from fertilized trees compared to the control, to levels well above critical levels of deficiency and optimum nutrient ratios. In contrast, the treatment did not change the low needle Cu status and there was no effect on growth measured as needle mass after one growing season. Graphical vector analysis together with the absence of change in needle mass suggested a luxury uptake of B. Application of the concepts for critical levels of deficiency and optimum nutrient ratios in relation to N suggested B and Cu deficiency were contributing factors to the observed forest damage in the area. Graphical vector analysis requires a rapid response in needle mass, in combination with improved needle nutrient status in order to identify nutrient deficiencies. The applicability of the technique appears to be limited to primarily growth-promoting nutrients.     

Effects of nutritional status on the drought resistance in Norway spruce

Many studies have dealt with the links between nutrient supply and tree growth. High N availability usually leads to increased growth but it may also be a stress factor and may affect the ability of the tree to take up both water and nutrients. We measured the nutritional status of the trees and estimated their tolerance to drought by examining the flushing of new shoots and needle loss. The studies were carried out on trees grown under different N and water supply in a field experiment using a 25–30 year old Norway spruce (Picea abies) in SW Sweden. The treatments included in this study were ammonium sulphate (NS) where 100 kg N ha^?1 was applied yearly, N-free fertiliser (V) where P, K, Ca, Mg and S but no N was applied, and also the combinations of ammonium sulphate and drought (ND) and N-free fertiliser and drought (VD). The NS treatment caused increased N but decreasing P/N, K/N and Mg/N ratios in the needles whereas the N-free fertiliser resulted in increased P/N and Ca/N ratios. In ND and VD, nutrient ratios remained relatively unchanged compared with NS and V. Thus, trees keep a stable internal nutrient balance. However, as a response to the drought, ND seemed to stop the flushing of new shoots to a higher degree than VD. In conclusion, this study showed that nutrient status did affect drought resistance which could be seen as differences in the flushing of new shoots rather than changes in nutrient ratios in the needles.     

Nutritional stress in ficea sitchensis plantations in coastal British columbia: The effects of gaultheria shallon and declining site fertility

Examples of nutritional stress in conifer seedlings caused by competing ericaceous species (e.g. Calluna and Kalmia), have been reported in several parts of the world. Nutritional stress (primarily N deficiency) has been reported in Sitka spruce (Picea sitchensis) plantations growing in association with an ericaceous species, salal (Gaultheria shallon), in coastal British Columbia. Nutritional interference by salal was investigated on a chronosequence of sites up to 10 yr after clearcutting and slashburning. No direct evidence for an allelopathic contribution to the N stress was obtained. However, the rapid accumulation of salal fine roots and rhizomes, and the nutrients contained therein, provides a partial explanation for the observed stress symptoms. Soil analyses and seedling bioassays demonstrated a reduction in fertility in the period 8 to 10 yr after clearcutting and slashburning in comparison to the period 2 to 4 yr, which is believed to impose further nutritional stress on Sitka spruce. It is concluded that the nutritional stress in these Sitka spruce plantations is caused by a combination of (1) salal competition for nutrients and their subsequent immobilization in salal biomass, and (2) declining site fertility caused by the termination of the flush of nutrients (the assert period) that occurs in the immediate post-clearcutting and slashburning period. Sustaining good growth of plantations under such circumstances will require site nutrient management as well as vegetation management.     

Needle Structures and Epiphytic Microflora of Scots Pine (Pinus Sylvestris L.) under Heavy Ammonia Deposition from Fur Farming

Scots pine (Pinus sylvestris) needles from forest sites differing in distance from big fur farms emitting large amounts of ammonia and ammonium (=NH_y) were examined by scanning and transmission electron microscopy. Specific features indicating an ammonium-nitrogen overload, such as an abundance of needle surface organisms and modifications in cellular and wax structures, were classified. Throughout the study area (up to 1000 m from the farms), mesophyll cells had thin cytoplasm and folding plasmalemma indicating frost damage. Phloem damage attributable to a possible nutrient imbalance was also observed. Chloroplast membranes were undulating and the occurrence of leaf surface organisms (e.g. aerophilic algae) was more abundant at the closest sites. The changes were related both to the direct effects of dry NH_y deposition on the needles, and to the effects operating via soil acidification. The needle epicuticular waxes proved to be structurally rather inert against the influence of ammonium compounds, since no significant changes due to NH_y were observed.     

Schwermetall- und Nährelementgehalte von Pflanzen und Bodenproben schwermetallhaltiger Halden im Raum Bleiberg in Kärnten (Österreich). II. Holzpflanzen

Heavy metal- and nutrient contents of plants and soil samples from metalliferous waste dumps in Bleiberg (Carinthia, Austria). II. Woody plants Needles, stem- and root-samples from coniferous trees (Norway spruce and Scots pine), taken from a waste dump habitat and an offmine-site in Bleiberg (Carinthia) were analysed on their macronutrient-and heavy metal-contents. No significant age dependent differences in N-and P-content of the two species were observed. The highest potassium levels occured in the youngest needle age group. The needles of the trees from the mining dump site show increasing Ca- and Fe- concentrations with increasing needle age. The Mn-contents of needles collected in offmine-sites were higher than those from the waste dump. The Mg-levels in the needles from both sites are remarkably low, a symptom of undersupplement. High Pb- and Zn-concentrations were determined in older needles of waste-dump-trees. Because of rather high Pb- and Zn-levels in the roots of the trees from this site a physiological transport barrier is assumed, which partly inhibits the upward lead transport; on the other hand lead is partly deposited in stem-wood of the two species. The heavy metal contents of roots from mining dump site are interpreted as an effect of high metal stress in the fine fraction of soil material.     

Foliar symptoms on norway spruce and relationships to magnesium deficiencies

Crown symptoms, foliar and soil nutrient status, disease and insect presence in Norway spruce (Picea abies [L.] Karst.) were evaluated in twelve plantations across West Virginia, Pennsylvania, New York and New Hampshire during 1987 to 1988. The most obvious crown symptoms observed under plantation conditions were thinning and chlorosis. These symptoms were similar to those observed on this species throughout the past decade in central Europe and specifically in the Black Forest of the Federal Republic of Germany. A crown vigor index (CVI) was calculated for each tree to classify health status. Of the 180 trees sampled, 247 were healthy; 517 were intermediate, and 257 had severe crown symptoms. The symptoms varied from state to state, plantation to plantation, and from tree to tree. The most severe symptoms were noted on trees at Plantation 12, near Davis, WV. Severe symptoms were also noted on trees within Plantations 4 and 5 in the Tug Hill Plateau region, NY, and within Plantation 3 near Donegal, PA. Two entire branches were removed from the top crown and mid-live crown, respectively, of each sampled tree. Based on laboratory observations, the most common needle symptom was a uniform chlorosis. Chlorotic spots on needle surfaces were the second most common symptom. Thirteen major and trace foliar nutrient elements were determined. Average foliar Mg concentrations of symptomatic trees within several plantations ranged from 0.022 to 0.0637; levels less than the accepted deficiency threshold value. There were significant (negative) correlations between the mean foliar Mg concentrations for the trees and their corresponding CVI and mean discoloration indices of needles. Corresponding soil pH, available P, exchangeable cations, 7 saturation of K, Mg, and Ca of soils were determined for each tree. Soil pH, exchangeable Mg and 7 saturation of Mg were significantly lower in the more symptomatic Norway spruce.     

Effects of ammonia,ammonium sulphate and sulphur dioxide on the frost sensitivity of scots pine (Pinus sylvestris L.).

The deterioration of forest vitality has been at least partly attributed to air pollution. Especially NH₃, originating from intensive livestock farming and locally deposited in high concentrations, may contribute to forest decline in The Netherlands. Therefore, the effect of NH₃ and SO₂ fumigations on cold stress and water stress of Pinus svlvestris were examined. P. sylvestris trees (3 yr old) were exposed to ambient air supplemented with several NH₃ concentrations, with SO₂ or a combination of NH₃ and SO₂.Tops of branches were then exposed to various subzero temperatures and the effect of air pollution on frost damage was examined. Neither ambient air, NH₃ or SO₂ significantly influenced from sensitivity at –4 or –7°C. Following freezing treatments of –10°C, the influence of NH₃ and SO₂ became apparent. The effect of the combination of these pollutants is synergistic. Exposure to NH₃ alone followed by freezing temperatures lower than –10°C resulted in more severe frost damage in early autumn and spring than in the winter. It also increased the susceptibility of P. sylvestris to water stress. A greater loss of water was observed in NH₃-fumigated needles following drought stress, suggesting increased cuticular transpiration. Bud burst and subsequent shoot growth was also strongly reduced by NH₃ fumigations.     

Element contents of spruce needles (P. abies [L.] Karst.) along an altitudinal gradient in the bavarian alps

One and 3 yr old needles of (Picoa abies [L.] Karst) were analyzed for mineral content and to determine the main nutrients and pollutants. In the Bavarian Alps 70 adult spruce trees were selected along an altitudinal gradient on seven stands from 800 to 1720 m above sea level. The samples, collected at different times of the year, came from the tops of the crowns. The needle analysis showed a severe P and a mild N deficiency. Samples which were washed with chloroform have significantly lower Fe and Ph contents. The low S concentrations of the needles exclude a burden by air pollution caused by SO₂.     

Relationships between Lignin and Nutrients in Picea Abies L. under Alkaline Air Pollution

The influence of alkaline dust pollution (pH of water solution12.3–12.6) from a cement plant (Kunda, Estonia) and alkalizedgrowth substrate on lignin and mineral composition of the needles of 75–90-yr-old Norway spruce was studied on sample plots established at different distances from the emission source. Disbalanced content of nutrients and an increase in thelignin content were found under the high level of air pollution.The contents of K, Ca, S and B in needles were higher, while those of Mn and N were lower in heavily polluted plots. A strongcorrelation was found between lignin and K, N and B concentrations as well as Ca/K in needles and shoots. Stimulation of lignification of needles correlated with the pollution load. Reduction of needle growth was observed and a negative correlation was established between the lignin concentration in tissues and the length of needles under the impact of dust pollution.     

Immobilization of avian excreta-derived nutrients and reduced lignin decomposition in needle and twig litter in a temperate coniferous forest

The possible effects of excreta of the Great Cormorant Phalacrocorax carbo on decomposition processes and dynamics of nutrients (N, P, Ca, K, Mg) and organic chemical components (lignin, total carbohydrates) were investigated in a temperate evergreen coniferous forest near Lake Biwa in central Japan. Two-year decomposition processes of needles and twigs of Chamaecyparis obtusa were examined at two sites, control site never colonized by the cormorants (site C) and colonizing site (site 2). Mass loss was faster in needles than in twigs. Mass loss of these litter types was faster at site C than at site 2, which was ascribed to the decreased mass loss rate of acid-insoluble ‘lignin’ at site 2. Net immobilization of N, P, and Ca occurred in needles and twigs at site 2; whereas at site C, mass of these elements decreased without immobilization during decomposition. Duration of immobilization phase of these nutrients at site 2 was estimated to be 1.6 to 2.5 years in needles and 19.6 to 23.5 years in twigs. Immobilization potential (maximum amount of exogenous nutrient immobilized per gram initial material) was similar between needles and twigs for N and Ca but was about 10 times higher in twigs than in needles for P. δ¹³C in needles was relatively constant during the first year and then increased during the second year, whereas δ¹³C in twigs was variable during decomposition. Acid-insoluble fraction was depleted in ¹³C compared to whole needles (1.6-2.1‰) and twigs (2.0-2.5‰). δ¹⁵N of needles and twigs and their acid-insoluble fractions approached to δ¹⁵N of excreta during decomposition at site 2. This result demonstrated the immobilization of excreta-derived N into litter due to the formation of acid-insoluble lignin-like substances complexed with excreta-derived N. No immobilization occurred in K and Mg and their mass decreased during decomposition at both sites. Based on these results of nutrient immobilization during decomposition and on the data of litter fall and excreta amount at site 2, we tentatively calculated stand-level immobilization potential of litter fall and its contribution to total amount of N and P deposited as excreta. Thus, the potential maximum amount immobilized into litter fall (needles and twigs) was estimated to account for 5-7% of total excreta-derived N and P.     

Nutrient balance in Scots pine (Pinus sylvestris L.) forest. 5. Tree growth in a field plot experiment

A field plot experiment on fertilization with N, Mg and P in Scots pine forest was established. The experiment had a factorial design with three levels of N (0, 30 and 90 kg ha^?1), two levels of Mg (0 and 1.5 kg ha^?1) and two levels of P (0 and 5.3 kg ha^?1). The application was done annually. There was a significant growth increase for the two N treatments. During a period of 5-years the mean increase in volume increment was 2.3 and 4.5 m³ ha^?1 for the 30 N and 90 N kg ha^?1 yr^?1 treatments, respectively. This represents a percentage increase in volume increment of 53 and 102% compared to the untreated control plots. No significant growth effect of P and Mg application was detected, either alone or in combination with N. The needle nutrient concentrations have been followed along with the annual measurements. An increase in N-concentration was detected after the first growing season in the N treated trees. After five years the Mg concentrations in the needles are lower in these treatments. The one year old needles have concentrations as low as 0.05% Mg. No visible deficiency symptoms have been observed. The field experiment effects demonstrates that N is still the most limiting nutrient under these conditions and that there is a relative large potential for N accumulation in these forest types without negative effects.     

Perturbation of nutrient source–sink relationships by post‐anthesis stresses results in differential accumulation of nutrients in wheat grain

Mineral nutrients in grains act as a source of nutrients in human diets, in which deficiencies of key minerals including calcium, magnesium, copper, iron, and zinc have prompted efforts to increase their concentrations in the edible portions of staple grain crops. Wheat (Triticum aestivum L.) crops in many regions often suffer abiotic stresses such as drought, extreme heat or frost during grain filling, which affect mineral source–sink relationships. We hypothesized that these stresses would have nutrient‐specific impacts on grain nutrient concentrations due to differences among nutrients in phloem mobility, post‐anthesis uptake and grain loading patterns. Nutrient loading patterns into wheat grains were investigated in two wheat cultivars in the field by sequentially harvesting tagged ears and analyzing tissues for key nutrients. In addition, the impact of perturbed source–sink relations during grain filling on nutrient loading was investigated by inducing post‐anthesis drought /floret abortion in a glasshouse study. Over 90% of Ca and around 70% of Na, K, and Mg accumulated in both wheat cultivars in the field during the first 14 d of grain development. The concentrations of micronutrients (Mn, Fe, Cu and Zn), Mg and P in grains generally increased when florets were aborted, and were unchanged under drought stress, while concentrations of Ca and K were highest under drought stress and lowest under the 66% floret abortion treatment. The observed changes in grain nutrient concentrations from post‐anthesis drought/floret abortion could not be fully explained by nutrient‐specific differences in phloem mobility, post‐anthesis uptake and grain loading patterns. This study will inform future research to define the precise roles of individual nutrients within developing grains and to fully understand the observed variations in grain nutrient concentrations due to source/sink modifications.     

Montezuma pine nutrient status as affected by alder densities nitrogen fertilization

Literature reports both positive and negative effects of N‐fixing alders on conifer growth in alder‐conifer stands. Such divergent effects probably result from poorly understood species interactions. The aim of this work was to examine how varying alder‐to‐pine ratios (APRs) and N fertilization affect pine nutrient status. A pseudo‐experiment was installed in each of two areas of regeneration (AR) with different amounts of radiation reaching alder. The experimental approach consisted of a series of pseudoreplicated plots with five APRs within each AR. Half of each plot received 200 kg N ha^–1. Data were interpreted by vector analysis. Alders in the AR 1987 induced needle‐biomass reductions, K deficiency, and P accumulation in pine needles. However, nutrient availability increased with the proportion of alders in the AR 1989, where alders received high sunlight due to a less dense pine stand. Nitrogen fertilization increased needle biomass and N in three out of five alder proportions where alders were sunlight‐limited. In the other stand, with the exception of the no‐alder and A4 plots, positive effects of N fertilization increased with decreasing alder density. We conclude that sunlight‐limited alders may not positively affect associated‐species growth even in N‐limited sites.     

Effects of reduced atmospheric deposition on soil solution chemistry and elemental contents of spruce needles in NE—Bavaria,Germany

The decrease in anthropogenic deposition, namely SO₄^2— and SO₂, in European forest ecosystems during the last 20 years has raised questions concerning the recovery of forest ecosystems. The aim of this study was to evaluate if the long term data of element concentrations at the Fichtelgebirge (NE‐Bavaria, Germany) monitoring site indicates a relationship between the nutrient content of needles and the state of soil solution acidity. The soil at the site is very acidic and has relatively small pools of exchangeable Ca and Mg. The trees show medium to severe nutrient deficiency symptoms such as needle loss and needle yellowing. The Ca and Mg concentrations in throughfall decreased significantly during the last 12 years parallel to the significant decline in the throughfall of H⁺ and SO₄^2— concentrations. Soil solution concentrations of SO₄^2—, Ca and Mg generally decreased while the pH value remained stable. Aluminum concentrations decreased slightly, but only at a depth of 90 cm. Simultaneously a decrease in the molar Ca/Al and Mg/Al ratios in the soil solution was observed. Ca and Mg contents in the spruce needles decreased, emphasizing the relevance of soil solution changes for tree nutrition. The reasons for the delay in ecosystem recovery are due to a combination of the following two factors: (1) the continued high concentrations of NO₃^— and SO₄^2— in the soil solution leading to high Al concentrations and low pH values and, (2) the decreased rates of Ca and Mg deposition cause a correlated decrease in the concentration of Ca and Mg in the soil solution, since little Ca and Mg is present in the soil's exchangeable cation pools. It is our conclusion that detrimental soil conditions with respect to Mg and Ca nutrition as well as to Al stress are not easily reversed by the decreasing deposition of H⁺ and SO₄^2—. Thus, forest management is still confronted with the necessity of frequent liming to counteract the nutrient depletion in soils and subsequent nutrient deficiencies in trees.     

Decomposition of organic matter and nutrient mineralisation in wood ant (<Emphasis Type="Italic">Formica rufa</Emphasis> group) mounds in boreal coniferous forests of different age

Wood ants (Formica rufa group) are dominating ecosystem elements of the boreal region due to their wide and abundant occurrence. They collect and concentrate organic material from the surrounding forest floor by building large above-ground mounds. These mounds have higher temperature and lower water content than the surrounding forest floor. We studied how these peculiar environmental conditions affected mass loss and carbon (C), nitrogen (N), phosphorus (P) and potassium (K) mineralisation of organic matter in boreal Norway spruce (Picea abies L. Karst.)-dominated mixed forest stands of four different age classes (5-, 30-, 60-, and 100-year-old) situated in eastern Finland using the litter bag technique. Norway spruce needle litter was incubated in inhabited and abandoned wood ant mounds as well as on the surrounding forest floor. We expected decomposition to be extremely slow due to the dryness of the mounds. Mass losses inside inhabited mounds were lower compared to the surrounding forest floor (on average 30 vs 50% after 2 years) but not as low as we expected, which might be a result of ant and microbial activity in the mounds. Decomposition in the abandoned mounds proceeded similarly as on the forest floor. Nutrient mineralisation proceeded more slowly in the ant mounds than on the surrounding forest floor. Mineralisation occurred for all studied nutrients in the ant mounds, except for N, which net amount remained stable during the years of the experiment. When wood ant mounds are abandoned and their porous and dry structure is no longer maintained by the ants, their decomposition is accelerated, and nutrients may be available for uptake by plants, although the nutrient mineralisation seems still to remain lower compared to the surrounding forest floor. However, eventually the mound material will be decomposed and nutrients mineralised, thus providing a nutrient hot spot increasing the heterogeneity of forest floor nutrient availability.     

Foliage Age and Pollution Alter Content of Phenolic Compounds and Chemical Elements in Pinus nigra Needles

Changes of phenolics and chemical elements [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), iron (Fe), boron (B), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), chromium (Cr), nickel (Ni) and cobalt (Co)] content in needles of black pine ( Pinus nigra) as dependent on age of needles (5–6 classes) and pollution were examined. The content of ortho-diphenols (o-dPh) and total phenols (TPh) was significantly higher at a polluted site than at a control one. It increased with age of needles at both sites. At the polluted site contents of N, K, Mg in black pine needles were lower and of Fe, Ni and F were higher than at the control site. An increase of content with age of needles at both sites was detected for Ca, Fe, B and F, and a decrease for N, P, K, Cu and Ni. The content of elements in different age classes of needles is connected with their mobility. The content of phenolics is negatively correlated with main nutrients and positively with some toxic elements.     

Silicon concentration in spruce needles

The Si concentration in 1 year old needles from Norway spruce (P. abies) was determined at 39 sites within an area of 150 km². The sites had uniform elevation, precipitation and immission characteristics. The mean value was 1423 μg Si g^?1, and the coefficient of variation between sites was 29 %. There was no correlation of Si concentration in needles with soil pH in the range of pH 3.5 to 7.6, but significant negative correlations with soil organic matter concentration and with the effective cation exchange capacity were found. Silicon in needles correlated positively with Al, La, and Fe in needles, but showed no correlation with 20 other elements. The seasonal variation of Si concentration in needles showed a nonuniform increase with time. The seasonal changes of Si were similar to those of Ca. The investigation of 4 successive needle age classes, however, showed a strictly linear increase of the Si concentrations.     

Effects of mixing radiata pine needles and understory litters on decomposition and nutrients release

A microcosm experiment was conducted to understand the impacts of mixing radiata pine (Pinus radiata D. Don) needle litter and understory (gorse—Ulex europaeus L., broom—Cytisus scoparius L., bracken—Pteridium aquilinum L., and lotus—Lotus pedunculatus L.) litter materials on decomposition and nutrient release dynamics. Mixing of pine needle litter with understory litter material had significant impacts on both the rate of decomposition and nutrient release patterns of pine litter as well as that of the understory species. Incubation in microcosms over 10 months resulted in significantly lower mass loss of radiata pine needle litter mixed with broom and lotus litters (35.8±8.4 and 41.3±0.8%, respectively) than pure pine needle litter (63.5±2.3%). Mixing with pine needle litter significantly increased the mass loss of broom (53.1±6.1%) compared to that of pure broom (30.2±1.0%). Significant transfers of nutrients, especially of magnesium and potassium, were observed in litter mixture treatments. Concentration of K in litter materials was found to be the most limiting factor for the decomposing microorganisms in the present study. The findings of this study suggest that management of understory litter composition via weed control could be used to manipulate carbon turnover and nutrient release in the forest floor. Also, initial selection of understory species will be important and could be managed.     

Pine Needle Chemistry Near a Large Point SO2 Source in Northern Fennoscandia

Air pollution induced changes in pine needle chemistry were observed at sample sites in the surroundings of the Pechenganikel smelter. Close to the smelter, elevated concentrations of Ni, Cu and S were found (Ni: 0.7–1 mmol/kg, Cu: 0.4–0.5, and S 40–60 mmol/kg). Close to the pollution source, needles were enriched in Ni and Cu by needle age. Correlation and principal component analyses show that changes in the element composition of pine needles depended on air pollution and on natural factors as well. The contribution from air pollution increased with needle age. Besides direct input of pollutants from atmosphere, soil contamination and nutritional disturbance contributed significantly to the observed changes.