Young Spruce Trees Research Articles

Effects of ambient ozone concentrations on contents of non-structural carbohydrates in young Picea abies and Fagus sylvatica.

Young spruce (Pirea abies [L.] Karst; 2-yr) and beech trees (Fagus sylvatica L.; current-year and 1-yr-old seedlings) were grown under field conditions at a rural site near the city of Base] (Schonenbuch; 400 m above sea level) and 2-yr-old spruce trees at an elevated montainous site (Wengernalp; 1890 m above sea level). The plants were exposed in open-top-chambers (OTC) either to charcoal-filtered air or ambient air with ozone being the predominant air pollutant at both sites. The exposures lasted up to 1 yr. At the end of the growth period the plants were harvested and the pool sizes of the major non-structural carbohydrates were determined. Exposure to ambient air compared with filtered air controls caused an increase of glucose, fructose, pinitol, starch and, in some cases, sucrose in needles whereas carbohydrate contents in roots and twigs of spruce were reduced, in particular at Wengernalp. In beech saplings at Schönenbuch, a significant rise of sucrose and, in some cases, of raffinose, together with a significant reduction of glucose and fructose was observed in buds, leaves, twigs, and roots in ambient air compared with filtered air. In phloem exudates of current year beech seedlings, a 54-160 higher content of carhohydrates was found in ambient air than in filtered air. In roots of the beech saplings, the amount of soluble carbohydrates increased and starch contents mostly decreased. In general, starch storage in roots and stems was more abundant in beech trees. Spruce, especially at the mountainous site, accumulated high amounts of soluble carbohydrates in needles, in particular glucose.

Dissipation kinetics of azadirachtin in some forest matrices and its systemic translocation in conifers for spruce budworm control

Field microcosm studies were conducted to investigate the deposition, persistence, translocation and bioactivity of the botanical insecticide azadirachtin‐A (AZ‐A) in young spruce trees. The deposition and persistence of AZ‐A in aspen foliage, forest soil and litter were also studied. AZ‐A residues in the different matrices were monitored at intervals of time after spray application of Neemix® 4.5 formulation at 100 g AZ‐A in 2.3 L/ha. The dissipation half‐lives in the matrices ranged from 16.9 to 33.6 h. AZ‐A was translocated and concentrated in the growing parts (especially the shoots) of spruce trees, after treatment by trunk injection (Tl), basal bark painting (BBP) and foliar painting (FP) of the Neemix 4.5 formulation. Systemically translocated and accumulated AZ‐A residues in the shoots after Tl and FP were found to be effective against spruce budworm (Choristoneura fumiferana Clemens.) larvae. Results suggest that Tl may be a useful way of using neem insecticide to protect high value trees from insect pests.

Leaf and shoot formation of young spruce and beech exposed to elevated CO 2

Sixteen open-top chambers (divided into two halves each containing either calcareous or acidic soil) were supplied in four combinations with either 366 or 550 μl CO 2 L −1, and either 2.5 or 25 kg N ha −1 y −1) (ammonium nitrate by irrigation). The development of young spruce ( Picea abies) and beech ( Fagus sylvatica) trees planted in the chambers together with understory plants will be studied over four years. The presented data are preliminary results from the first year of this experiment and refer to 64 spruce and 64 beech trees from two different Swiss spruce and beech provenances; two trees each per soil type, sampled in July and September in each chamber. Specific current-year spruce needle length (length/dry mass) was reduced by elevated CO 2 due to an increase in dry mass. Beech specific leaf area was only temporarily reduced in July. Elevated CO 2 induced an earlier autumnal leaf discoloration. Total current-year shoot length per spruce and total number of leaves per beech tree were not influenced by the first year treatment with elevated CO 2. N deposition had no effect on these parameters, but soil type influenced spruce needle colour. Spruce, in contrast to beech, may therefore profit from elevated CO 2 (when other resources are unlimited) by increasing shoot and needle dry mass.

Root uptake, translocation, accumulation and dissipation of the botanical insecticide, azadirachtin, in young spruce trees

Abstract A formulation containing the biopesticide azadirachtin‐A (AZ‐A), extracted from the seeds of neem tree, Azadirachta indica A. Juss, was applied (10 μg/mL) in a nutrient solution (200 mL) to the roots of young spruce trees [Picea glauca (Moench) Voss]. The uptake, translocation, persistence and dissipation of AZ‐A in spruce were studied. The insecticide was taken up by the root system, translocated via xylem vessels and accumulated in the photosynthate sinks (areas of new growth, especially shoots), confirming that AZ‐A is systemic. The peak AZ‐A concentrations (μg/g, fresh weight) in the shoots (5.16 ± 0.73) and needles (2.56 ± 0.31) occurred at 8 and 15 d after treatment, respectively. The AZ‐A concentrations in bark and wood during this period were very low, however they were high in the root samples. The dissipation of AZ‐A from the shoots was rapid compared to other matrices. The initial (0‐d) and final (20‐d) AZ‐A concentrations (μg/mL) in the nutrient solution were 8.99 ± 1.24 and 3.24 + 0....

Long-term exposure of young spruce and beech trees to 2450-MHz microwave radiation

Young spruce and beech trees were planted in field plots and exposed to 2450-MHz microwave radiation generated by a 600-W magnetron source. Power flux densities (PFD) ranged from 0.007 to 300 W/m 2, depending on the location within the plots. Microwave exposure was permanent during 3.5 years. Heating effects of the microwave radiation were estimated by measuring the hydrolysis rate of exposed sucrose solutions. This method revealed a temperature increase of ∼4°C at the highest PFDs. During the whole exposure period, the microwave radiation caused no visual symptoms of damage. PFD had no effect on crown transparency, a parameter commonly estimated in forest condition inventories. Height growth was similar at all PFDs for both species, as was photosynthesis in beech leaves, determined by chlorophyll fluorescence measurements. A negative relationship existed between foliar concentrations of calcium and sulfur in beech and PFD during the first 2 years of exposure. However, the concentrations of both nutrients remained within the sufficiency range. In the third year of exposure, the effect was absent. The microwave effect on calcium is discussed in connection with literature data.

Continuous monitoring of gas exchange in open‐top chambers in pollution experiments: methodological aspects

summaryAs part of an experiment on effects of atmospheric pollution on the physiology of spruce trees (Picea abies (L.) Karsten), a method for continuous monitoring of gas exchange of young trees grown in Open Top Chambers (OTC) was developed. The basic principles and feasibility of this method are first presented in detail. The installation of a fine perforated polyethylene net over the top of the OTC, in order to reduce ingress of outer air, made it possible satisfactorily to monitor the gas exchange of the trees over long periods. Examples are given of typical measurements of net assimilation and transpiration fluxes for an experimental canopy of 15 young spruce trees to show diurnal and seasonal variation.

Distribution of Cd and Zn in annual xylem rings of young spruce trees [Picea abies (L.) Karst.] grown in contaminated soil

Concentrations and total amounts of Cd and Zn in individual annual xylem increments of 5-year-old spruce trees (Picea abies) were investigated after one growing season in contaminated soils. The plants had been potted in soils amended with different concentrations of Cd and Zn and kept in open air conditions. In the outer xylem rings formed during the treatment period lowest concentrations of Cd and Zn were found. In inner rings concentrations of both elements increased and were highest at the pith. Total amounts of both elements showed reversed distribution patterns with highest values in the outermost rings. The observed increase of total dry matter of the rings from pith towards the outer rings was stronger than the parallel increase in total element amounts in the rings. Thus, concentrations dropped in younger rings. The time of the soil contamination event cannot be inferred from element concentrations in annual rings. The results challenge the concept of monitoring historical trends in trace element pollution using analytical data of tree rings of conifers.

Influence of air pollutants and nutrient deficiency on D-1 protein content and photosynthesis in young spruce trees

Influence of air pollutants and nutrient deficiency on D-1 protein content and photosynthesis in young spruce trees

Influence of air pollutants and nutrient deficiency on D‐1 protein content and photosynthesis in young spruce trees

Long‐term fumigation with different mixtures of air pollutants, such as O3, NO2 and SO2, in combination with potassium deficiency in 4‐year‐old spruce trees shows clearly that the photosynthetic apparatus reacts very sensitively to environmental stress. Even when no change in photosynthetic oxygen evolution of the leaves was measurable, the content of D‐1 protein in the reaction center of photosystem II already increased significantly at low stress conditions. With increasing concentrations of pollutants, the content of D‐1 protein decreased considerably. This pattern was observed with all combinations of gases, although they differed in effectiveness. The most potent effect on the content of D‐1 protein was found with a combined fumigation of SO2 plus NO2. Obviously, the ratio between synthesis and degradation of the D‐1 protein is influenced by stress factors. However, the content of D‐1 protein was not strongly correlated with photosynthetic oxygen evolution in whole needles nor with electron transport rate in isolated thylakoids. Under controlled potassium deficiency, effects similar to those observed upon ozone fumigation developed. The results suggest unspecific stress answers for the D‐1 content and the photosynthetic reactions rather than specific responses.

The Sensitivity of Young White Spruce to Spruce Budworm Defoliation

Abstract Relationships between defoliation and volume growth were determined for 68 young white spruce trees in a 20-year-old plantation defoliated over a 2-year period by the spruce budworm. In the first year of defoliation, intensities ranging from 7 to 89% of the current foliage did not influence volume growth significantly. Two consecutive years of defoliation, averaging over the 2-year period from 0-33, 34-66, and 67-100% of the current foliage, reduced average volume growth by about 6, 11, and 27%, respectively. White spruce is much less sensitive to defoliation than balsam fir. This is partly due to white spruce's ability to compensate for even moderate defoliation intensities by a prolific shoot production. North. J. Appl. For. 8(4):168-171.

Infektionsversuche mit Rhizosphaera kalkhoffii und Lophodermium piceae an unterschiedlich gestreßten Jungfichten (Picea abies [L.] Karst.)

Young spruce trees [Picea abies (L.) Karst.] artificially inoculated with Rhizosphaera kalkhoffii B. and Lophodermium piceae (F.) v. H. were exposed to fumigations with O3 and SO2 and drought. These treatments showed no influence on the infection-rates of the fungi. R. kalkhoffii proved to be a saprophyte living for a long period as an epiphyte on the needle surfaces.

Effect of simulated acidic fog on carbohydrate leaching, CO 2 assimilation and development of damage symptoms in young spruce trees ( Picea abies L. Karst)

The effect of acidic fog on carbohydrate leaching, CO 2 assimilation, carbohydrate status, and cuticle development of young spruce trees was studied in a greenhouse experiment. Over a period of 9 weeks the plants were subjected to fog application on 27 occasions. In one treatment trees were exposed to a fog of pH 2.75 (acidic fog) and in one treatment to a fog of pH 5.00 (control treatment). Leaching rates for carbohydrates (sucrose, glucose, fructose) were significantly higher in the acidic fog treatment than in the control treatment. The total amount of carbohydrates leached out of the trees by acidic fog, however, was low and amounted to less than 1% of the non-structural carbohydrates in the needles. Trees which had been exposed to acidic fog were not affected in photosynthesis and in the distribution of photosynthates to various plant parts. In the younger needles significantly lower concentrations of starch, glucose, and fructose were found in the treatment with acidic fog as compared with the control plants. Also the starch concentration in the roots of the control plants was significantly higher than that in the plants exposed to acidic fog. These findings are suggestive of a stress situation with a high energy demand. Application of acidic fog resulted in a disintegration of the epicuticular wax layer and of the epistomatal wax props. In the treatment with acidic fog some needles of the current year turned reddish-brown and some older needles became chlorotic and later brown. These needles were shed to a large degree. Needle loss of the trees exposed to acidic fog was significantly higher than that of the control trees.

Effect of acidic fog on needle surface and water relations of Picea abies

Young spruce trees [Picea abies (L.) Karst.) exposed to acidic fog (pH 3) showed a disintegration of the epicuticular waxes of the current year's needles as compared with trees treated with a fog of pH 5. The fog treatment was followed by a period in which the trees received different water supply. Under water stress conditions, trees that had been exposed to the acidic fog showed significantly higher transpiration rates than control trees that were treated with a fog of pH 5. The water loss of the controls was 0 at the middle of the photoperiod, while the trees pretreated with acidic fog still showed a substantial transpiration rate at this time. Water loss of excised twigs measured in the dry atmosphere of a desiccator also provided evidence that the water holding capacity of needles pretreated with acidic fog was affected. There is evidence that particularly the cuticular transpiration was increased by pretreatment with acidic fog. The xylem water potential of twigs pretreated with acidic fog was significantly lower than that of twigs pretreated with a fog of pH 5, while the osmotic potential was not affected by the different fog treatments. It is suggested that in draught years trees with a damaged cuticle caused by acidic fog will be affected in their resistance against water stress. In this way acidic fog could be involved in forest decline now widely spread in Central Europe.

Development of Vascular Cambium and Compression Wood Formation in the Shoot of Young Spruce (Picea Jezoensis Var. Hondoensis)

In the course of the righting movement in young spruce trees (Picea jezoensis Carr. var. hondoensis Rehd.) inclined at 45°, the occurrence of compression wood associated with the development of vascular cambium in the shoot was observed. In shoots, the recovery first took place at the mid point, a few days after inclination. The observations of serial cross sections taken from the apex downward revealed no appreciable difference in the development of the procambium-cambium continuum between the upper- and underside of the shoot. The formation and structure of primary tracheary elements were similar, irrespective of the site of the procambium in the shoot. No compression wood cells occurred before the vascular cambium cylinder was complete. The stimulus of compression wood formation is received only by the differentiating secondary xylem tissues derived from the cambium cylinder.

Leaf injury on wheat plants exposed in the field in winter to SO2

The combined stresses of air pollution and low temperatures have been suspected as a cause of difficulty in establishing grasses1 and trees2 in upland areas of northern England. Davison and Bailey3 recently showed in controlled environment studies that exposure to SO2 predisposed grasses to frost injury, and Keller4 has established that exposure to SO2 of young spruce trees kept in cabinets outdoors over winter enhanced their sensitivity to frost injury the following spring. We report here the first observations of injury of winter wheat exposed in the field to controlled concentrations of SO2 during the severe winter weather of December 1981 to January 1982. We conclude that the injury was probably caused by cold-stress after SO2 exposure had rendered the plants cold-sensitive.

The Spruce Bud Midge, Rhabdophaga swainei Felt (Cecidomyiidae: Diptera)

In May, 1948, numerous malformed buds were collected from young spruce trees at Fredericton, N.B. These enlarged buds were about 7 mm. long and 4 mm. in diameter, with lateral scales reflexed and their rosette-like apices loose and open. Dipterous adults emerged in a few days and their identification as Rhabdophaga swainei Felt was confirmed by G. E. Shewell, Systematic Unit, Division of Entomology, Ottawa.The only references in the literature are Felt's (1) original description of the adults and a mention of the gall by the same author (2).The following notes are based on field observations made at intervals through 1948 and early 1949 near Fredericton, N.B.