Showing papers in "Scandinavian Journal of Forest Research in 1986"
TL;DR: In northern coniferous forests nutrient release from litter occurs primarily in late stages of decomposition when mainly extensively lignified parts remain An important regulating factor in these as discussed by the authors, however, this is not the case in most of the other parts of the world.
Abstract: In northern coniferous forests nutrient release from litter occurs primarily in late stages of decomposition when mainly extensively lignified parts remain An important regulating factor in these
394 citations
TL;DR: High accuracy in the control of nutrition and growth has been obtained in solution culture experiments in which the relative addition rate was applied as the treatment variable, when all necessary nutrients were accounted for, when the additions were made very often, and when the culture solution was in darkness and in good physical contact with the roots.
Abstract: The experimental use of the relative addition rate as the driving variable for plant nutrition and growth is reviewed with special attention to the theoretical background and the technical and methodological problems. In this technique the culture solution is not a “nutrient solution” in the classical sense, i.e. a solution with a specified initial concentration of nutrient salts. Instead the solution is a carrier of repeatedly added nutrients to the roots. The nutrients are added quantitatively for a specified growth rate and period of time, to permit a steady state relative uptake rate. High accuracy in the control of nutrition and growth has been obtained in solution culture experiments in which the relative addition rate was applied as the treatment variable, when all necessary nutrients were accounted for, when the additions were made very often, and when the culture solution was in darkness and in good physical contact with the roots.
370 citations
TL;DR: In this paper, 90 soil profiles sampled for pH measurements in 1927 revealed a general decrease in pH with 0.3-0.9 units (measured electrometrically on field-moist samples in water with the same ratio soil/water on both occasions).
Abstract: Reinvestigation of 90 soil profiles sampled for pH measurements in 1927 revealed a general decrease in pH with 0.3–0.9 units (measured electrometrically on field‐moist samples in water with the same ratio soil/water on both occasions). All soil horizons (A0, A2, B and the subsoil, C, at 70 cm depth) had become more acid beneath all types of canopy (beech, oak, spruce planted during different periods), but the spruce stands were on average more acid than the hardwoods. In the upper soil horizons (A0 and A2), old spruce stands were more acid than the young ones at both samplings, but this effect was small in the B horizon and absent in the C horizon. While the tree species effect and age effect in the spruce stands may be called biological acidification, the acidification of deeper horizons, now often below pH 4.5 and in the aluminium buffer range, seems difficult to explain without assuming an influence of acid deposition.
263 citations
TL;DR: In this article, a simple model was made on the influence of both climate and nutrient concentrations (nitrogen and phosphorus) on mass loss rate, and about 90% of the first-year mass loss could be explained by this approach.
Abstract: The climatic influence on plant litter decomposition has been successfully correlated on a regional level by using estimated actual evapotranspiration (AET) and annual mass loss. This approach was applied to decomposition studies carried out in a transect along Sweden with litter incubated in four different forest types. A unified needle litter was used and among 14 Scots pine sites about 80% of the mass‐loss rate could be explained. A simple model was made on the influence of both climate and nutrient concentrations (nitrogen and phosphorus) on mass‐loss rate. About 90% of the first‐year mass loss could be explained by this approach. As early decomposition stages were studied (<40%) no influence of lignin was observed.
121 citations
TL;DR: In this article, the probability of achieving an anatomically mature seed crop of Scots pine (Pinus sylvestris L.) in Northern Finland has been studied on the basis of earlier data and meteorological observations.
Abstract: The probability of achieving an anatomically mature seed crop of Scots pine (Pinus sylvestris L.) in Northern Finland has been studied on the basis of earlier data and meteorological observations. The meteorological data over the period of 1951–1980 was used to calculate the probability of having a mature seed crop in various parts of Northern Finland. The climatic variables used were: (a) June‐August mean temperature (b) June—September mean temperature, and (c) annual temperature sum (+5°C base temperature). A non‐linear relationship between the percentage of mature seeds in a seed crop and the annual temperature sum was detected, indicating that 50% mature seed crop was achieved at appr. 890 degree days. The results suggest that the probability of having 50% mature seed crop is approximately 0.02–0.03 near the polar timber line. The probability of the occurrence of such years is, however, considerably higher in lowlands and lake districts even near the timber line.
94 citations
TL;DR: The likelihood of detecting decay present in Norway spruce trees when taking bore core samples at breast height or at stump height was analyzed in two stands and misjudgements occurred mainly where either decay was present at stump Height but not at Breast height or when the decay column had a lateral position.
Abstract: The likelihood of detecting decay present in Norway spruce trees when taking bore core samples at breast height or at stump height was analyzed in two stands. The actual numbers of decayed trees were obtained after the trees were felled. More than 80% of the decay extending to breast height level was detected by taking core samples at that level. However, these core samples revealed only 40–70% of the actual amount of decay present at stump height. At stump height a higher portion of the total amount of decay present was revealed. Heterobasidion annosum was detected in 69 and 77% of the decayed trees in the two stands. Misjudgements occurred mainly where either (i) decay was present at stump height but not at breast height or (ii) when the decay column had a lateral position. At breast height the probability of finding lateral rot columns was higher than at stump height.
83 citations
TL;DR: Some species can adapt to soil anaerobiosis by producing hypertrophied lenticels which assist in aeration of the stem and release of toxic compounds, and growing new roots to replace loss of original roots under anaerobic conditions.
Abstract: Many forest trees exhibit reduced growth or are killed when the soil is low in oxygen. Anaerobic soil conditions are associated with flooding or compaction of soil but also occur commonly in soils of heavy texture. Reductions in height growth, leaf growth, cambial growth and reproductive growth of trees growing on poorly aerated soils are well documented. The amount of growth reduction varies widely among species and duration of anaerobic soil conditions during the growing season. Inhibition of growth is preceded by changes in physiological processes, including food, water, hormone, and mineral relations. Some species can adapt to soil anaerobiosis by (1) producing hypertrophied lenticels which assist in aeration of the stem and release of toxic compounds, and (2) growing new roots to replace loss of original roots under anaerobic conditions. The replacement roots assist in absorption of water and mineral nutrients and in oxidizing the rhizosphere and detoxifying soil toxins. Ethylene, together with other...
68 citations
TL;DR: The present knowledge on birch genetics is reviewed as regards the fields of cytology, crossability within and between species, flowering, plant growth rhythm, tree growth and quality, and hybridization.
Abstract: The present knowledge on birch genetics is reviewed as regards the fields of cytology, crossability within and between species, flowering, plant growth rhythm, tree growth and quality, and hybridization. Incompatibility occurs but can be partly overcome by crossing at low temperature. Species hybridization was more successful when the female parent was of low ploidy. Crosses within one subsection are not more successful than crosses between subsections. Earliness of male and female flowering can be improved by selection. Flowering is probably polygenically inherited. Clinal variation in north‐south direction occurs for growth rhythm characters, the northern provenances show the earliest growth cessation. Long‐distance transfers northwards or southwards result in reduced growth. The ratio between the family and the population variance components varies with type of character studied and the geographic range of the material studied. Long‐distance crosses within a species or between species do not seem to le...
58 citations
TL;DR: Root growth capacity (RGC) in Scots pine seedlings was studied from the time of sowing and during the following two growing seasons to establish a method for measuring RGC.
Abstract: Root growth capacity (RGC) in Scots pine seedlings was studied from the time of sowing and during the following two growing seasons. The method used for measuring RGC is also described. In the firs...
47 citations
TL;DR: The carbohydrate reserve of bareroot Scots pine seedlings was evaluated as means of describing seedling quality and capacity to withstand stress during nursery lifting, outplanting and acclimatization at the planting site.
Abstract: The carbohydrate reserve of bareroot Scots pine (Pinus sylvestris L.) seedlings was evaluated as means of describing seedling quality and capacity to withstand stress during nursery lifting, outplanting and acclimatization at the planting site. Carbohydrate concentrations in needles were followed through four spring storage treatments and the postplanting success and growth of seedlings monitored at two sites. The reduction in total glucose concentration in needles was affected by storage time and temperature. Depletion of carbohydrate reserves decreased needle growth, reduced the number of terminal buds, disturbed leader shoot formation, and consequently reduced shoot length. The depletion of reserves below a threshold concentration of ∼2 % total glucose during storage resulted in significant seedling mortality. A simple model for estimating the depletion of carbohydrate reserves based on dark respiration was evaluated as a measure of the accumulated strain during the storage. The application of carbohyd...
46 citations
TL;DR: Significant differences in frost resistance between one‐year‐old open pollinated families were found within all populations except the most northern one and the correlations within populations between frost resistance and field mortality varied considerably.
Abstract: Six short‐term freezing experiments were carried out on 24 one‐year‐old single‐tree open pollinated families of Pinus sylvestris (L.) representing four populations in northerly Sweden (latitude 62°10'N to 66°50'N). Two experiments were conducted in a climate chamber, two in a greenhouse and two outdoors. For freeze testing the plants were exposed to ‐10°C for three hours in a freezing chamber. A freezing experiment in a climate chamber of 28 one‐year‐old full‐sib families (half diallel with two parents from each population) was also carried out. The results were related to the mortality of the same open pollinated families over the first 18 years in the field. The ranking of the populations was the same in all six freezing experiments as in the field. Significant differences in frost resistance between one‐year‐old open pollinated families were found within all populations except the most northern one. The correlations within populations between frost resistance and field mortality varied considerably bet...
TL;DR: Root and shoot growth of Scots pine and Norway spruce were reduced after exposure to the lowest test temperatures (‐16°C and ‐20°C) and the length of exposure, ranging between 1 and 8 hours had no effect on subsequent growth.
Abstract: Roots of 1‐year‐old containerized seedlings of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) were experimentally frozen in December. The seedlings were then grown for 3 weeks in a growth chamber and evaluated with regard to root growth capacity (RGC) and shoot elongation. The subsequent RGC of Scots pine declined as root zone temperatures were lowered from ‐6°C to ‐11°C and from ‐11°C to ‐16°C. Almost no root growth was observed after exposure to ‐20°C. Shoot growth was also negatively affected by low root temperatures but less than root growth. Low root temperatures did not affect Norway spruce as much as Scots pine, although root and shoot growth of Norway spruce were reduced after exposure to the lowest test temperatures (‐16°C and ‐20°C). The length of exposure, ranging between 1 and 8 hours had no effect on subsequent growth.
TL;DR: In this article, the authors used the Weibull distribution to predict stem frequencies in different diameter classes before and after a specified thinning of Norway spruce stands in Denmark, using the Chi-square and Kolmogoroff-Smirnow tests.
Abstract: The three‐parameter Weibull function met specified statistical standards for goodness of fit as a model for the diameter distribution of moderately thinned Norway spruce stands in Denmark. Weibull distributions estimated by percentile estimators fit the majority of 522 observed diameter distributions (material made available by the Danish Forest Experiment Station) at the 10% level of significance in the Chi‐square and Kolmogoroff‐Smirnow tests. The Weibull distribution was less suited to describe the diameter distribution in unthinned stands and heavily thinned stands. Weibull parameter predictions were developed and used in connection with a Danish yield table for Norway spruce on clay‐rich coastal soils. The use of the Weibull distribution to predict stem frequencies in different diameter classes before and after a specified thinning of stands is demonstrated.
TL;DR: The effectiveness of a plastic collar designed to protect planted seedlings against damage caused by Hylobius abietis (L.) (Col., Curculionidae) was evaluated at 63 planting sites in southern Sweden during 1979 and 1980.
Abstract: The effectiveness of a plastic collar designed to protect planted seedlings against damage caused by Hylobius abietis (L.) (Col., Curculionidae) was evaluated at 63 planting sites in southern Sweden during 1979 and 1980. Nearly 10 000 collar‐protected pine and spruce plants and 10 000 controls were carefully examined for Hylobius‐damage and other injuries. In addition, the impact of some microsite factors on weevil damage and collar performance was evaluated, and the height growth was measured. The protective effect of the collar for two seasons after planting was comparable to that of insecticides and was best at sites with sparse vegetation and high weevil pressure. Proper application of the collar was crucial for good control. Collars were not observed to affect plant growth. Soil scarification reduced mortality in both collared plants and controls.
TL;DR: It was found that high proportions of limonene occurred in greater percentages in trees of northern origins, while high sabinene was frequently found in southern trees, and variation coefficients as a measure of variability within populations appeared to be clinal with latitude.
Abstract: Cortical oleoresins were obtained from 10 natural populations of Pinus sylvestris L. from different geographical localities. Gas chromatography was used to determine quantities of individual monoterpenes. Considerable variation was found in monoterpene composition among different populations. High proportions of limonene occurred in greater percentages in trees of northern origins, while high sabinene was frequently found in southern trees. Mean proportions of limonene and sabinene in the populations were clinal with latitude. For some monoterpenes, variation coefficients as a measure of variability within populations appeared to be clinal with latitude. 85.4% of the variance in monoterpene composition was found within populations and 14.6 between populations. Discriminant analysis differentiates populations from different geographical localities into different groups. The differences in monoterpene patterns between adjacent populations were statistically nonsignificant. It is recommended that monoterpene...
TL;DR: In this article, the above-ground biomass of peatland stands was measured using two statistically coupled linear models with squared diameter at breast height as independent variable, and all fractions except reproductive structures of pine and dead branches of spruce were estimated at high precision levels.
Abstract: Above‐ground biomass has been measured on fertilized and control plots up to stand age 31 years. Each biomass fraction was estimated by two statistically coupled linear models with squared diameter at breast height as independent variable. All fractions except reproductive structures of pine and dead branches of spruce were estimated at high precision levels, R. between 0.93 and 0.99. The above‐ground biomass fractions per hectare could be precisely described by stem volume with bark. Application of the models for prognostic purposes is discussed. Annual above‐ground net biomass production in pine increased from 2.05 to 4.34 MT d.m./ha‐yr on control plots over 11 years, while plots given complete fertilizer mixture ranged from 6.75 to 9.09. Spruce stands with a nearly optimum water relationship and fertilizer programmes yielded from 9.50 to 11.86 MT d.m./ha‐yr. The combination of energy and timber production in highly productive peatland stands is discussed.
TL;DR: The time constant of the dehardening of one‐year‐old Scots pine (Pinus sylvestris L.) seedlings was studied in three experiments started at different times of the year on the basis of the temperature response of the specific impedance difference in the shoot.
Abstract: The time constant of the dehardening of one‐year‐old Scots pine (Pinus sylvestris L.) seedlings was studied in three experiments started at different times of the year. The seedlings were transferred from outside to the different controlled conditions in January (Exp. 1), March (Exp. 2) and April (Exp. 3). Changes in the frost resistance of the seedlings were followed on the basis of the temperature response of the specific impedance difference in the shoot. The time constant for dehardening at a temperature of 7.5°C was found to be about 12 days in Exp. 1, about 8 days in Exp. 2, and about 5 days in Exp. 3. the terminal bud burst when the frost resistance of the shoot had risen to about ‐10°C.
TL;DR: In this article, the tarnished plant bug (Lygus rugulipennis) and occasionally L. punctatus were found to feed on pine seedlings in central Finland and both the nymphs and adults of Lygus bugs injured the apical meristem of the seedlings.
Abstract: The tarnished plant bug (Lygus rugulipennis) and occasionally L. punctatus were found to feed on pine seedlings in central Finland. Both the nymphs and adults of Lygus bugs injured the apical meristem of the seedlings. This led to the death of the apex, and the opening of the lateral buds, resulting in a seedling with multiple leaders. L. rugulipennis may also oviposit on pine seedlings and the development from egg to adult on pine alone is possible. In laboratory experiments it was shown that the main factor in the apical meristem injury is the mechanical damage caused by the bug's stylet. The feeding damage and artificial mechanical damage caused by needles to the apical meristem of pine seedlings resulted in increased numbers of multiple‐leader seedlings and reduced shoot length and dry weight of the shoot and root.
TL;DR: Tumours from both species induced by the wild‐type strain grew in vitro on medium without added phytohormones, with large tumours formed on A. nordmanniana and Picea abies.
Abstract: Abies nordmanniana and Picea abies seedlings were inoculated with a wild‐type (C 58) or an attenuated strain (rooter or shooter mutants) of Agrobacterium tumefaciens Large tumours were formed on A nordmanniana in response to the wild‐type and rooter strains, 60–65 % of the seedlings being susceptible Smaller tumours were formed on Picea abies in response to the wild‐type strain, at least 12% of the seedlings being susceptible Tumours from both species induced by the wild‐type strain grew in vitro on medium without added phytohormones
TL;DR: In this paper, the authors investigated the relationship between crown damage and the development of the volume increment of Norway spruce trees and found that stem and crown dimensions, growing space as well as the competition of neighboring stems can substantially outweigh the influence of crown damage on volume increment.
Abstract: Although a good correlation has been found between the mean degree of damage and the increment trend of larger Norway spruce collectives, individual spruce trees often betray no relationship between crown damage and the development of the volume increment. Detailed investigations show that stem and crown dimensions, growing space as well as the competition of neighboring stems can substantially outweigh the influence of crown damage on the volume increment. Furthermore, current methods to determine crown parameters and needle loss are in many cases quite error‐prone. Use of more accurate techniques for measuring spruce trees produced a stronger relation between the volume increment per square meter crown surface area and the degree of crown damage (needle loss).
TL;DR: The number of sprouting stumps was correlated with light intensity and temperature and the mean height of suckers was higher the higher the tempera...
Abstract: Two‐year‐old seedlings of Betula pendula Roth of three provenances were cut to stump heights of 0 and 10 cm. The birch stumps were exposed to different light levels (25–400 μEm−2s−1) and temperatures (6–24°C) for 100 days in climate chambers. Birches were also cut down to seven stump heights (0, 2, 5, 10, 15, 20 and 25 cm) and exposed to light intensity 25 and 200 μEm−2s−1 at 12/6°C for 100 days in climate chambers. In the third experiment 10 cm stumps of birch were exposed to different light intensities (10–400 μEm−2s−1) for 30 days in a greenhouse at 20°C. Starch content in root systems was analyzed before and after treatment. Ten stumps per treatment were used in the experiments except the third experiment where 15 stumps were used. The number of sprouting stumps was correlated with light intensity and temperature. None of the stumps exposed to 6 or 9°C produced suckers. At stump height 0 cm fewer sprouting stumps were produced than at 10 cm. The mean height of suckers was higher the higher the tempera...
TL;DR: Seasonal changes in the N and P content of foliage in a young forest of Fagus sylvatica were measured and the most efficient retranslocation of N was recorded in the upper crown and probably resulted from higher leaf temperatures and a longer senescent period in the sun leaves than in the shade leaves.
Abstract: Seasonal changes in the N and P content of foliage in a young forest of Fagus sylvatica were measured. Leaves from branches of the upper and lower crown of dominant trees and from suppressed trees were compared. Nutrient retranslocation rates during senescence differed considerably between trees. This variation appeared not to be related to any differences in environmental factors or tree vigour, and was probably genetically induced. In dominant trees the most efficient retranslocation of N was recorded in the upper crown and probably resulted from higher leaf temperatures and a longer senescent period in the sun leaves than in the shade leaves. Phosphorus retranslocation efficiency was higher in suppressed trees than in dominant ones, but no such tendency was observed with N. The most obvious difference between leaves at different crown levels concerned the time at which P translocation began; an outflow of P from leaves in the lower crown began in June, while in the upper crown this outflow did not begi...
TL;DR: The branch biomass of young Scots pines (Pinus sylvestris L) was inversely related to the branch number per projected crown area giving greater branch density and smaller branch biomass for narrow crowns than for broad crowns as discussed by the authors.
Abstract: The branch biomass of young Scots pines (Pinus sylvestris L) was inversely related to the branch number per projected crown area giving greater branch density and smaller branch biomass for narrow crowns than for broad crowns In particular, in dense stands the small share of branches from the total biomass of narrow‐crowned trees was emphasized The productivity of narrow crowned trees was, however, smaller than that of trees with broad crowns The concept of the tree ideotype has been discussed on the basis of theoretical calculations
TL;DR: In this article, the effect of annual additions for four years to the forest floor of sulfuric acid (64 kg S.ha−1), sulfur powder (64.ha −1), and in the first year l...
Abstract: The effect on litter decomposition rates was studied after annual additions for four years to the forest floor of sulfuric acid (64 kg S.ha−1), sulfur powder (64 kg S.ha−1), and in the first year l...
TL;DR: In this paper, containerized seedlings of Norway spruce (Picea abies (L.) Karst) and Scots pine (Pinus sylvestris L.) were overwintered on the ground and above ground on pallets.
Abstract: Containerized seedlings of Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) were overwintered on the ground and above ground on pallets. Soil temperatures in elevated containers were lower and showed greater fluctuation than containers on the ground. The lowest temperatures (‐15 to ‐16°C) were observed in containers stored on pallets with little or no snow cover during the winter. Temperatures in the edge rows of containers were lower than interior bed soil temperatures. Lower temperatures were also observed in the top than in the bottom of the container. The storage on pallets resulted in reduced shoot and root growth. Although insulation preventing air movements beneath the container units improved soil temperature conditions and subsequent seedling growth, the best result was obtained when seedlings were stored directly on the ground surface.
TL;DR: The aim of the study was to obtain the basic information about nitrogen mobilization needed in carrying out studies on the optimal nitrate and ammonium ratios in the metabolism of Scots pine.
Abstract: Free amino acid and protein levels, and γ‐glutamyltransferase activity in apical buds and shoots of Scots pine during the growing season. The aim of the study was to obtain the basic information about nitrogen mobilization needed in carrying out studies on the optimal nitrate and ammonium ratios in the metabolism of Scots pine (Pinus sylvestris L.). Considerable seasonal changes in the concentrations of free amino acids and other ninhydrin‐positive low molecular‐weight compounds were observed in the buds and shoots of Scots pine. 43 different amino compounds were identified, the concentrations of arginine, glutamine, glutamic acid, γ‐aminobutyric acid, alanine and aspartic acid being highest at the break of dormancy. The amounts of certain amino compounds decreased during the growing season, those of arginine, ethanolamine and various ammonium compounds in particular. The amount of glutamic and aspartic acids, glycine, alanine and γ‐aminobutyric acid, however, remained relatively constant. The protein con...
TL;DR: Children's wood density looks uncertain as a selection criterion for mature wood density and genetic parameters seemed to be equal for all provenances.
Abstract: Seventy‐four half‐sib families of lodgepole pine (Pinus contorta ssp. latifolia Engelm.) plus trees were measured for vigour, height growth, stem diameter, wood density and ring width in two Swedish field trials at age 9. Height growth, wood density and ring width differed between families within provenances with variance components of 3–8 %. Coefficients of variation were highest for height growth and lowest for ring width. Heritabilities were similar for height growth and wood density but lower for ring width. These genetic parameters seemed to be equal for all provenances. Indirect selection for high dry stem biomass was more effective using height growth than wood density, and a correlated response in wood density of 2.1 % of mean by selecting the 15 highest parent trees was indicated. Juvenile wood density looks uncertain as a selection criterion for mature wood density.
TL;DR: Isozyme‐analysis techniques have been applied to test the efficiency of supplemental mass pollination in a seed orchard of Pinus Sylvestris and found it to be high.
Abstract: Isozyme‐analysis techniques have been applied to test the efficiency of supplemental mass pollination in a seed orchard of Pinus Sylvestris. Mass pollination was done on one single occasion before ...
TL;DR: Eight trees were selected at age eight years from seed in each of 52 full‐sib families of Picea abies and were propagated by rooted cuttings and the parents were both of Norwegian and German origin.
Abstract: Eight trees were selected at age eight years from seed in each of 52 full‐sib families of Picea abies and were propagated by rooted cuttings. The parents were both of Norwegian and German origin. Results are presented for the variation in height growth in the progeny test and in the clonal test, for rooting percentages, and for plagiotropic growth. More than 40% of the total variance of rooting percentages is of genetic origin. In the set of crosses between Norwegian and German parents 18% of the clones were classified as plagiotropic, while the same number was 27% in the crosses between Norwegian parents. The plagiotropic growth reduces the correlations between ortets and ramets both at the individual and at the family level. Family information is important in the selection of ortets, and a culling of plagiotropic clones seems necessary to obtain a substantial gain from selection.