Populations Of Pinus Sylvestris Research Articles

Differential Above- and Below-ground Biomass Accumulation of European Pinus sylvestris Populations in a 12-year-old Provenance Experiment

Differential Above- and Below-ground Biomass Accumulation of European Pinus sylvestris Populations in a 12-year-old Provenance Experiment

Differentiation in adaptive traits between neighbouring bog and mineral soil populations of Scots pine Pinus sylvestris

I used a reciprocal sowing experiment in the field to reveal differentiation in adaptive traits between two neighbouring northern populations of Scots pine Pinus sylvestris. 1 compared a peat bog population with a mineral soil population. Seedling survival was monitored during seven growing seasons and the plants were then harvested to obtain data on pine traits associated with growth and resource allocation, i.e. height, needle length, total dry weight, relative growth, proportion root and proportion needles. Seeds from the peat bog populations had lower germination capacity and were smaller than those from the mineral soil population. Despite their smaller size, the seeds from the bog population were superior for establishment of pines on the bog. On the mineral soil, the traits were strikingly similar in the two pine populations. In contrast, the traits were more variable and differentiated on the bog. Here, the native bog pines grew faster and had a larger proportion root than those originating from the population on the adjacent mineral soil. It is suggested that the differentiation between peat bog populations and mineral soil populations might represent a major direction of differentiation in northern Scots pine populations.

The postglacial history of Scots pine (Pinus sylvestris L.) in western Europe: evidence from mitochondrial DNA variation

The geographical structure of mitochondrial (mt)DNA variants (mitotypes) was investigated in 38 western European populations of Scots pine Pinus sylvestris using restriction fragment length polymorphism (RFLP) analysis of total DNA and a homologous cox1 probe. Three major mitotypes (designated a, b and d) were detected. Within Spain all three major mitotypes were found, gene diversity was high, HT = 0.586, and this diversity was distributed predominantly among rather than within populations (FST(M) = 0.813 for the seven Spanish populations). Mitotype d was present only in the most southerly population from the Sierra Nevada. Elsewhere in Europe, populations showed little or no mtDNA diversity within regions, but there were marked differences between regions. Italian populations were fixed for mitotype b; populations from northern France, Germany, Poland, Russia and southern Sweden were fixed for mitotype a; while populations in northern Fennoscandia were fixed for mitotype b. The isolated Scottish populations were predominantly of mitotype a, but mitotype b was present in three of the 20 populations scored. In Scotland, UK gene diversity (HT = 0.120) and genetic differentiation among populations (FST(M) = 0.37) was much lower than in Spain. When interpreted in the light of complementary data from pollen analysis and nuclear genetic markers, the results suggest that present‐day populations of P. sylvestris in western Europe have been derived from at least three different sources after glaciation.

Analysis of genetic variation for quantitative characters between and within four native populations of scots pine (Pinus sylvestris)

Summary A combined provenance/progeny trial of native Pinus sylvestris populations was established on a site in southern Scotland in 1991. Four provenances (Abernethy, Glen Affric, Loch Maree and Rannoch) were chosen to represent the range-wide geographical variation for this species within Scotland. At three years after outplanting (7 years of age) the quantitative traits of spring vegetative bud burst, height and diameter were measured. Significant genetic variation was detected among provenances for most of the quantitative traits analysed. Glen Affric provenance showed poor height and diameter growth, while Abernethy provenance burst its buds approximately one week later than the remaining provenances. For the morphological traits measured a genetic basis for within provenance variation was demonstrated. The coefficient of genetic variation (CG) and heritability estimates (h2) suggest that the genetic resource for growth traits within populations is still high (CG = 9.3–16.7%). In contrast the populat...

Differential Above- and Below-ground Biomass Accumulation of European Pinus sylvestris Populations in a 12-year-old Provenance Experiment

Growth and the distribution of biomass among above- and below-ground components were measured in 12-year-old Scots pine (Pinus sylvestris L.) from 19 populations grown in a provenance experiment in central Poland (52° N). The populations originated from the northern (>55°N in Russia, Sweden and Latvia), central (54–47° N in Poland, Germany, Belgium, France, Slovakia, Hungary), and southern (<45° N in Bosnia, Montenegro and Turkey) European range of Scots pine. Height, diameter and biomass were all significantly related to latitude of origin. For populations of northern, central and southern origin, above-ground biomass averaged 3.1, 4.7 and 3.3 kg tree−1 and 25, 43 and 12 Mg ha−1. Total root biomass accounted for 22, 19 and 28% of total stand biomass for northern, central and southern populations, respectively. These differences were primarily the result of proportionally higher fine root biomass in the slower-growing northern and southern than central populations. Since the allometric regression equations based on diameter for total aboveground and coarse root biomass did not differ among populations or regions, biomass of Scots pine, excluding fine roots, may be accurately estimated from forest inventory data.

Nutritional Status of Pollen and Needles of Diverse Pinus Sylvestris Populations Grown at Sites with Contrasting Pollution

Pollen may serve as a biological indicator for air pollution stress in plants. However, knowledge of pollen mineral composition and its relationship to environmental and genetic factors is very limited. We studied the concentrations of macro- and micronutrients in pollen and needles for seven European Scots pine (Pinus sylvestris L.) populations grown in two 15-yr-old provenance plantations with contrasting pollution levels. One site was located near a phosphate fertilizer factory, and the other in an area free of acute air pollution. We also tested the relationship between tree age and pollen nutrient composition by sampling 60-yr-old trees of local origin in both sites. No population differences were found in nutrient concentrations in pollen. However, there were significant differences among populations in needle concentrations of K, Mg and Zn, as well as significant site x population interaction for Mn concentration. In pollen, populations at the polluted site had significantly higher concentrations of S, Mn, Al, Na, Cu, Ni and Cd, and lower Zn. Average concentrations of S, P, Mn and Cd was lower in pollen of 60-yr-old than 15-yr-old Scots pine trees. Pollen concentrations of P, K, Ca, Mg, Fe and B were similar between sites and not related to the concentration of these elements in needles. Therefore, by analyzing the chemical composition of pollen it is not possible to detect any nutritional disorders for P, K, Ca and Mg in plants, and it seems unlikely that nutrient analyses of pollen have an advantage over analyses of foliage as a bioindicator of pollution. However, enhanced accumulation by pollen of such elements as Al, S, Mn, Cu, Ni and Cd at the polluted site may adversely affect pollen function.

Relation between genetic structure and susceptibility to air pollution of European Pinus sylvestris populations from a IUFRO-1982 provenance experiment

Results are presented of genetic variation and relation between genetic parameters with growth, survival and needle necroses of 11 European Pinus sylvestris populations growing in a provenance experiment established in 1984 in western Poland. One site was near a phosphate fertilizer factory, and other in an area free of acute air pollution. A significant differences were found between studied sites in number of alleles per locus, expected and observed heterozygosity, genotype polymorphism indices (all p < 0.1) and in tree height ( p < 0.0001). On average all genetic parameters were higher for polluted site than for a control one. Differences in observed heterozygosity were related to height growth decline and plant mortality.

Evolutionary forces influencing variation among populations of Pinus sylvestris

The evolutionary forces influencing genetic differentiation among populations are identified. Natural selection, random genetic drift, and mutations promote differentiation while phenotypic plasticity and gene flow delay or prevent differentiation. Evolution is a dynamic force which leads to instability and absence of any perfection in the adaptive process. Natural selection acts mainly on phenotypes and only indirectly on the components of important breeding traits. In the northern part of the distribution of Scots pine there is a large among- and within-population variation in survival. The high among-population variation occurs in spite of an assumed high gene flow. Biomass is a product of many components and it also shows a high population variation. Many markers are neutral and such markers will not reveal adaptive variation.

Empirical assessment of allozyme and RAPD variation in Pinus sylvestris (L.) using haploid tissue analysis

We analysed 20 allozyme and 22 putative random amplified polymorphic DNA (RAPD) loci in two populations of Pinus sylvestris (L.) from northern Sweden. Genotypes for individual allozyme and RAPD loci were inferred from segregation patterns in haploid macrogametophytes. Therefore, it was possible to distinguish between homo- and heterozygotes carrying a RAPD fragment and to estimate directly the frequencies of RAPD fragments. The percentage of polymorphic loci and the expected and observed heterozygosity were lower for allozymes than for RAPDs. Average fixation indices for both types of markers were negative indicating a heterozygote excess over panmictic expectations. The apportionment of genetic variation within and among the investigated populations was similar for allozymes and RAPDs and showed that most of the variation resided within populations. RAPD genotypes inferred from haploid material were subsequently converted to diploid phenotypes and used to estimate indirectly the frequencies of RAPD fragments. Gene diversity measurements derived from indirectly estimated RAPD frequencies were distinctly lower than those based on directly estimated RAPD frequencies. This result was caused by the absence of the null homozygote at many loci which appeared as monomorphic in the diploid data set. Population differentiation coefficients based on the indirectly estimated RAPD frequencies were not concordant with those based on directly estimated RAPD frequencies. Our present results indicate that when complete genotype information can be obtained, RAPD analysis provides genetic information similar to that revealed by analysis of allozyme variation. On the other hand, our results are concordant with theoretical results suggesting that analysis of RAPD variation in diploid material can produce unreliable estimates of population-genetic parameters.

Spatial Patterning in Young Stands of Pinus sylvestris in Relation to Mortality Caused by the Snow Blight Pathogen Phacidium infestans

In two young (5-10 year old) populations of Pinus sylvestris, severe infection by the pathogen Phacidium infestans led to significant mortality. Previous studies of this interaction have shown some evidence of density-dependence. Analyses of the spatial distribution of surviving individuals was performed using two contrasting methods based on: (1) a dispersion index; and (2) on nearest neighbour distances. In all situations changes in the degree of aggregation were more obvious in analyses based on the frequency of individuals in small areas (dispersion index) than in those based on the distance between nearest neighbours. These methods detected trends both away from aggregated towards more random patterns of distribution (site 1: two plots) and towards greater aggregation (site 2: one plot). In one of the former areas, the distribution of surviving P. sylvestris individuals was still significantly aggregated after four years, while in the other, the pattern approached spatial randomness. Increasing aggregation on the second site probably has resulted from a complicating biotic interaction between the pathogen and other plant species.

Adaptation to climatic changes of the timing of bud burst in populations of Pinus sylvestris L. and Picea abies (L.) Karst.

To assess the long-term effects of the projected climatic change on Scots pine and Norway spruce in Finland, observations were made on the timing of bud burst in provenance experiments established in 1931-1932 and in 1978. Significant differences in the timing of bud burst were found between seed origins. The northernmost origins flushed earlier than origins from southern regions. However, no correlation was found between the effective temperature sum at which bud burst took place and the annual mean temperature sum at the original location, probably because the experiments included origins from southerly high-altitude sites. When the degree days before bud burst in the 1931 and 1978 Norway spruce experiments at Punkaharju were compared, it appeared that, in the older experiment, the populations had adapted to the environment at the new site as a result of selective thinning.

Growth Variation in a Naturally Established Population of Pinus Sylvestris

We studied the variation in growth of individual trees in a population of Pinus sylvestris near Zurich in relation to tree age, size, and local competition. This population established naturally when the drainage pattern in a peat bog was altered after the Second World War. An unusual opportunity to study stand development was afforded when the trees were harvested in 1987 as part of a restoration program. All trees stumps were mapped, and growth since establishment was measured as cross—sectional area of wood in 5—yr intervals, using disks from the base of each tree. The distribution of cross—sectional area was lognormal over most of the period of growth. Size at the beginning of a time interval was the primary determinant of individual growth during that interval, but age and local competition also had significant effects. Younger, smaller trees were better fitted by an exponential growth model, whereas older, larger trees were better fitted by a Gompertz (sigmoidal) model. Some of the result were very different from previous studies: (1) The spatial distribution of trees was not significantly different from random. (2) Size variability decreased during the course of stand development, even though there was no self—thinning. This was because (3) the density of natural establishment was low, and competition, although clearly detectable, was still relatively weak and symmetric after 45 yr of stand development. Thus, there was no initial advantage in competition, and the younger trees, which were still growing exponentially, were able to catch up with the older trees, whose relative growth rates were declining.

Fertility variation in Pinus sylvestris: A TEST OF SEXUAL ALLOCATION THEORY

Sexual allocation theory assumes trade‐offs and negative genetic correlations between male and female allocation in hermaphrodite plants. We tested this assumption by studying variation in male and female fertility in two experimental populations of Pinus sylvestris. In these populations, the genotypes have been vegetatively replicated, which allowed separation of the genetic and environmental components of variation. The genetic components of variation accounted for 36% of the total variation in pollen production in the two populations, and for 54% of cone production. As assumed by sexual allocation theory, the genetic correlation of pollen and cone production was negative in both populations (‐0.59 and ‐0.15). However, positive environmental correlations between these traits (0.43 and 0.45) resulted in no phenotypic correlation in one population and a positive phenotypic correlation in the other.

Geographic origin of Pinus sylvestris populations influences the effects of air pollution on flowering and growth

Flowering and height growth of 20 Scots pine (Pinus sylvestris L.) populations from 10 countries were analyzed at two replicated provenance sites established in 1984 in western Poland. One site was 2 km from a phosphate fertilizer factory that emits SO2 and fluorides, and the other 12 km to the southeast in an area free of acute air pollution levels was treated as a control. Slow-growing populations from the southern (40 to 45°N) and northern (58 to 61°N) part of the species range exhibited relatively smaller air pollutioninduced growth reductions than those from the central part of the range (45 to 58°N). Trees growing in the control area started flowering 4 yrs earlier than those at the polluted site. The percent of trees flowering at the control site differed significantly among provenances in both 1988 and 1990. The mean percent of trees with flowers was three times lower at the polluted site. The least sensitive southern and northern provenances in terms of pollutioninduced reductions in growth exhibited the largest pollution-induced decreases in flowering. These findings indicate that the sensitivity of vegetative organs to air pollution stress is not always paralleled by the sensitivity of reproductive organs.

Growth and survival of spontaneous provenance hybrids of Pinus sylvestris

Survival and growth were assessed for 17 provenance hybrids and three natural populations of Pinus sylvestris (L.) planted in three field trials in central and northern Sweden. Restricted to the high mortality site the 18‐year hybrid survival percentage increased by three units per degree north latitude and one percent per 100 m higher altitude of the mother. The hybrid height was less influenced by the geographical origin than hybrid survival. For both traits the natural populations were better than or equal to hybrids with the same geographical mean origin. The variance component of the mother was mostly 2–3 times larger than the provenance component. The effect of the grandmother was nonsignificant for both traits.

Age and Size Structure of Pinus Sylvestris Populations on Mires in Central and Northern Sweden

(1) The age and size structures of peatland populations of Pinus sylvestris were studied at eight different sites along a latitudinal gradient from central to northernmost Sweden (6 1-67N). (2) Three of the northern populations had age structures with two or several peaks representing periods of successful pine regeneration. The five remaining populations had unimodal age distributions. The youngest age class was the modal class in only three populations. (3) Stem diameter and height were significantly correlated with age, but the variation in size for any given age was large in all populations. (4) Size distributions were skewed towards larger size classes in all populations. (5) The age structures of most populations suggest a wave-like regeneration pattern. Only the age distributions of the two southernmost populations may reflect a more-or-less constant rate of pine recruitment. No signs of major disturbances could be found at the study sites, and it is suggested that the periodic increases of successful regeneration may be the result of interactions between different age and size classes of pine. (6) Periods of abundant regeneration showed a striking coincidence in the three studied populations which had several peaks in their age structures. These periods also coincide with periods of successful regeneration documented by studies in high-altitude pine populations on mineral soil in the same region of northern Sweden. This suggests that a common external factor, like the fluctuating climate, has played an important role in synchronizing these patterns.

Long-Term Dynamics of High-Altitude Populations of Pinus sylvestris in the Swedish Scandes

The age structure of Scots pine (Pinus sylvestris L.) was studied, on a regional basis, in a narrow altitudinal zone well below the altitudinal tree-limit in the Swedish Scandes. The study period covered the last c. 400 years. Regeneration success was related to changes in summer mean temperature and thermal conditions during the late winter and spring. A positive impact of the twentieth-century climatic improvement was found. A marked regeneration gap occurred during the climax (AD 1680-1720) of the Little Ice Age. Possibly the coldness of this period increased mortality rates even of adult pines. The age structure suggests that within the altitudinal and temporal interval studied pine populations are in a dynamic steady-state condition. Regeneration takes place even during climatically unfavourable periods. This differs from both more and slightly less marginal sites where populations are more vulnerable due to climate and climate-fire interactions, respectively. The existence of this zone of relative population stability is an important feature when discussing Holocene biogeographical changes.

Cortical monoterpene variation in natural populations of Pinus sylvestris in Sweden

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...