Populations Of Abies Research Articles

Possible Change in Distribution Areas of Abies in Kastamonu due to Global Climate Change

Aim of the study: In the process of global climate change (GCC), the migration mechanism needed especially for forest trees must be provided by humans. For this purpose, contrary to the previous studies, detailed studies to be carried out on small areas are needed. 
 Area of study: In the present study carried out in Kastamonu Regional Directorate of Forestry, which performs the highest level of wood production in Türkiye, it was aimed to specify the actual distribution areas of the Abies and the change in their suitable distribution areas due to GCC. 
 Material and methods: In this study, besides the existing distribution areas and the potential future distribution areas, also the suitable distribution areas were determined by using SSP 126, SSP 370, and SSP 585 scenarios for the years 2040, 2070, and 2100 for Abies at Kastamonu. 
 Main results: The results achieved there showed that, depending on the results of climate change, distribution areas of Abies populations would change in the future and this change would be in form of an increase in general. 
 Research highlights: This species (Abies) seems incapable of keeping up with such changes without human intervention. Thus, considering the study results, it is recommended to make necessary amendments to the forest management plans.

The history of Abies pinsapo during the Holocene in southern Spain, based on pedoanthracological analysis

The aim of this research is to reconstruct the ancient distribution area of Abies pinsapo Boiss. (Spanish fir) in the Serranía de Ronda region, southern Spain, during the Holocene. The main method was pedoanthracological analysis, the study of non-archaeological charcoal found in natural soils. In this research a total of 37 soil excavations were done in several mountain ranges with potentially favourable places for firs to have grown in the past. Specific sites and places such as hillsides, endorheic basins (with no outflow), sinkholes, summits and mountain passes were selected on the basis of evidence from a range of different sources including ancient documents, pollen studies and species distribution models. The soil samples collected from these sites were prepared in the laboratory and the charcoal was identified and radiocarbon dated. Statistical and cartographic analyses were also done. The study revealed evidence of past populations of Abies sp. in places where it is no longer found today. A total of 47 different chronologies were obtained from these sites with ages ranging between 9,931 cal bp and 78 cal bp. In addition, the wide variations in the charcoal values enabled us to make an initial estimate of the importance of ancient forest fires in different places in the Serranía de Ronda. When this information has been considered with all the other available data sources, it will be an essential resource for the efficient management of relict fir woods in southern Spain.

Genogeography of norway spruce (Picea abies (L.) Karst.) according to the analysis of cytoplasmic DNA

Norway spruce (Picea abies (L.) Karst.) is one of the main forest-forming species in Belarus. It plays important economic, ecological and social roles. The spruce forest of the region is characterized by a complex history of the formation of its population genetic structure. The aim of this study was the genogeographic analysis of P. abies populations and the description of regional features of its gene pool in Belarus. Molecular genetic analysis of microsatellite (SSR) loci of chloroplast DNA and mt15-D02 locus of mitochondrial DNA of Norway spruce was carried out for samples from 57 naturally originated forest stands. We identified 19 allelic variants of the Pt63718, Pt26081, Pt71936 cpDNA loci and two allelic variants of mt15-D02 mtDNA. The geographical distribution of the alleles has been described and the regional features of the genogeographic differentiation of the spruce forests have been considered. The southern border of the continuous distribution area of P. abies and its island localities lie in the south of Belarus (Brest and Gomel regions). The frequency of occurrence of individual allelic variants of cpDNA SSR loci has the most pronounced deviations from the average values for the whole country in those regions. Analysis of cpDNA showed the presence of certain regional features of the genogeographic structure of the spruce forest in the “south-north” and “west-east” directions. According to mitochondrial DNA analysis higher concentration of P. abies trees of southern (Carpathian) origin is observed in the southwest of Belarus. On the contrary northern (Boreal) origin dominates in the rest of the country. The results of performed genogeographic analysis of Norway spruce populations can serve as a basis for improving the forest seed zoning of the tree species.

Patterns of genetic diversity vary among shoot and root functional traits in Norway spruce Picea abies along a latitudinal gradient

Roots constitute a major segment of plant biomass, and variation in belowground traits in situ correlates with environmental gradients at large spatial scales. Local adaptation of populations maintains intraspecific genetic variation in various shoot traits, but the contribution of genetic factors to adaptation to soil heterogeneity remains poorly known. I established a common‐garden experiment with three Norway spruce Picea abies populations sampled between 60° and 67° N in Finland, each represented by 13 or 15 maternal families, to determine whether belowground traits are as genetically differentiated among populations as those in the shoot along a collective latitudinal gradient of temperature and soil heterogeneity. Two growing season simulations enabled testing for among‐population differences in phenotypic plasticity. I phenotyped 777 first‐year seedlings from shoot to root to capture functional traits that may influence survival in the wild: autumn phenology, shoot growth, root system size, root architecture, root morphology and growth allocation. All traits exhibited within‐population genetic diversity, but among‐population differentiation ranged from strong in shoot traits to nonexistent in root system architecture and morphology that are scaled to root system size. However, latitudinal trends characterised root‐to‐shoot ratio and root tip‐to‐shoot ratio that account for among‐population differences in aboveground growth. Overall trait variability was multidimensional with variable among‐ versus within‐population trends: for example, phenology and shoot growth covaried across populations, but their association within individual populations was variable. Shoot growth correlated positively with root system size, but not with root architecture or morphology. Finally, the two higher‐latitude populations exhibited greater phenotypic plasticity in shoot traits and growth allocation. The results demonstrate varying patterns of genetic variation in functional traits of Norway spruce in the boreal zone, suggesting simultaneous adaptation to multiple environmental factors. Functional traits that exhibit phenotypic plasticity, genetic diversity and little covariation will promote long‐term survival of populations in fluctuating environments.

Towards new seed orchard designs in Germany – A review

Abstract New first and 1.5 generation seed orchards are to be created in Germany based on recently assembled breeding populations of Acer pseudoplatanus, Larix sp., Picea abies, Pinus sylvestris, Pseudotsuga menziesii, and Quercus sp. To justify the high expenses in time and cost for orchard establishment and maintenance, planning should make use of consolidated knowledge and experience of both the national and international scientific community. Here, we briefly describe advances in genetic gains achieved through tree breeding, and resume population genetic aspects and design considerations to draw conclusions for clonal composition and spatial design of the new orchards. We conclude that to avoid outbreeding depression separate orchards are required for each breeding zone. The zones are species-specific and defined by ecological and climatic aspects. A minimum of 60-80 clones per orchard is recommended for native tree species with high proportions of natural regeneration in forest practice. This would allow future selective thinning based on estimated breeding values from progeny testing. It would also permit the transfer of seed orchard progenies into a naturally regenerating forest stands without the risk of a genetic bottleneck. Lower clone numbers are appropriate for non-native species and hybrids. It is important to strictly avoid inbreeding depression, achieved by using only one clone per progeny or population, from which the plus trees were selected. Further, the spatial layout should promote random mating by optimizing the neighbourhood of each clone. With all of these considerations taken into account, we expect superior quality traits and at least 10-15 % more volume from the new seed orchards.

Tracing human impact on a mountainous plant landscape in Rhodopi Mt (N. Greece) during the last 1100 years

Mediterranean mountain ecosystems have been attractive to human societies due to their valuable resources, but are also susceptible to environmental and climate changes. The Rhodope Mountain Range hosts one of the least disturbed natural forests of Europe and is a conservation priority area in the Southern Balkans. Located in the borderlands of the plain of Macedonia, the forest ecosystem development of Rhodope Mountains was shaped not only by Late Holocene climatic variability, but also by changes in human activities since Byzantine times. Palynological and microscopic charcoal analysis of the Livaditis ombrotrophic bog record offers unique insights into vegetation and landscape evolution under the influence of human land-use practices in the south Rhodope area during the last c.a. 1100 years. The findings show a forested landscape, with well-developed Pinus and Abies forests of in the montane zone and mixed deciduous oak forests below that flourished in the area until 900 AD. The expansion of human activity in mountainous areas during the period of Byzantine economic growth (ca. 1000 AD) is evidenced by forest clearance through fire, affecting mainly the Abies populations. The Livaditis record bears evidence about both, arboriculture and cereal cultivation as well as animal husbandry during the first period of human activities in the uplands, while a shift towards pastoralism is most likely associated with the establishment of the Vlach population in the region (ca. 1200 AD). Subsequently, a short-lived expansion of the Pinus percentages could be attributed to the afforestation of abandoned pasture land during the Little Ice Age. Finally, a further intensification of pastoralism is most likely concurrent with the population expansion documented during the Ottoman period (after 1500 AD). The Livaditis pollen record shows significant vegetation shifts in the upland area of southern Rhodope Mountains that could be associated with changes in climate, population mobility and density, as well as evolving land-use practices.

The Role of Environmental Factors in the Formation of the Genetic Structure of the P. abies Populations

For the determination of the impact of environmental factors on the differentiation of Picea abies populations, 20 cenopopulations from four geographical points are investigated. The study shows that environmental conditions affect the genotypic composition of populations more than geographical distance. The structure of the intrapopulational genetic variability of Picea abies is determined to a higher extent by the effect of ecological isolation than by the effect of isolation-by-distance (IBD).

A multiproxy record of the Younger Holsteinian Oscillation (YHO) in the Ossówka profile, eastern Poland

The laminated lacustrine succession at Ossówka in eastern Poland, which is largely the equivalent of MIS 11c, is amongst the best‐developed sites in Europe that cover this time period. Close inspection of the depth interval between 35.0 and 42.5 m in a 55‐m‐long core shows an environmental crisis at a depth of 40.95 m that lasted approximately 800 years and resulted in almost complete extinction of fir (Abies) from the communities existing at that time. Geochemical analyses reveal a simultaneous increase in sulphur in the deposits and a change in stable carbon and oxygen isotope ratios towards higher values, as well as a significant increase in the thickness of the laminae (up to 5 mm). Diatom studies show a clear increase in benthic diatoms in this interval, implying a decrease in water level. However, the predominance of such forms was probably caused by the elimination of planktonic diatoms by invasive blooms of Tetraedron, rather than lower lake levels, evidence of which was not noted in the pollen spectra. Hence, all these changes in the lake may have been triggered by the destruction of fir trees, the gradual decomposition of dead trunks and some inconspicuous geomorphological disturbances caused by wind throw. They resulted in a supply of micronutrients to the basin, an increase in varve thickness and rapid oscillations in the abundance and composition of algae and changes in the geochemical status of the lake. Rapid and significant drops in winter temperatures appear to be responsible for the extinction of fir. Alternatively, late frost in spring or hot and dry summers may have affected microsporophyll growth and the fir physiology as known from extant Abies populations. This environmental crisis, which is termed the Younger Holsteinian Oscillation (YHO), is noted at only a few sites. At Dethlingen (Germany), where hornbeam communities disappear at that time, a drop in summer temperatures is suggested to have been the driving force. We suggest that, at Ossówka, a drop in winter temperatures, late frost, or summer drought at the very start of the YHO are possible causes of the near‐extinction of fir.

Use of Nuclear Microsatellite Loci for Evaluating Genetic Diversity of Selected Populations of Picea abies (L.) Karsten in the Czech Republic

DNA polymorphism at nine nuclear microsatellites of nine selected naturally-regenerated Norway spruce populations growing mainly within gene conservation units in different parts of the Czech Republic was studied. To verify the genetic quality of the selected gene conservation unit, we analyzed nine Norway spruce subpopulations from gene conservation unit GZ 102–Orlické hory. Genetic parameters can be used in state administrative decision making on including stands into gene conservation units. The level of genetic diversity within 17 investigated Czech Norway spruce units was relatively high. Mean values for the number of different alleles ranged from 12.2 (population SM 08) to 16.2 (subpopulation SM T4). The values of observed heterozygosity (Ho) ranged from 0.65 to 0.80 and expected heterozygosity (He) from 0.74 to 0.81. Pairwise population FST values ranging from 0.006 to 0.027 indicated low genetic differentiation between units, and values of Nei’s genetic distance among Norway spruce units ranged from 0.046 to 0.168, thus structuring of the investigated Norway spruce units was confirmed. Closer genetic similarity was seen in subpopulations from the gene conservation unit in Orlické hory than in the studied populations from other genetic conservation units. Additionally, the populations SM 01 and SM 05, both of Hurst ecotypes, were the closest to one another and the populations of mountain and alpine ecotypes were assembled into another group.

The role of environmental factors in the formation of the genetic structure of P. аbies populations

Summary: Background. Norway spruce (Picea abies (L.) Karst.) is one of the main forest forming spruce species in Europe. Their populations are characterized by the genetic heterogeneity between individuals in population. The genetic structure of P. abies populations studied supported a hypothesis of an environment impact on the degree of genetic differentiation among populations.
 Materials and methods. Analysis of genetic diversity of natural populations in distinct geographical regions from North-West Russia, South-West Russia, South Norway were done using nuclear microsatellites. The needles were collected from the 20-30 adult trees in each geographical spot taking into account the local environment. The statistical calculations were performed with GenAlEx 6.5.03 and Structure 2.3.4.
 Results. The analysis highlighted the environmental impact on the genetic diversity. The genetic structure of spruce cenopopulations from poor conditions are extremely different from those of cenopopulations growing under rich environmental conditions in one geographic region. The genetic differences between them are comparable with the genetic differences between spatially remote populations.
 Conclusion. The role of the isolation by environment as a pattern in which genetic differentiation increases with environmental differences independent of the geographic distance is essential for genetic structure of spruce populations.

Spring water deficit and soil conditions matter more than seed origin and summer drought for the establishment of temperate conifers.

In anticipation of more severe summer droughts, forestry in temperate Europe is searching for drought-resistant ecotypes of native tree species that might maintain ecosystem services in the future. We investigated how spring precipitation and soil conditions interact with summer drought and affect the establishment of conifer seedlings from different climatic origin. Emergence, establishment and subsequent performance of seedlings originating from autochthonous, Central Alpine, continental Eastern European, and Mediterranean Pinus sylvestris and Picea abies populations were studied in the dry Alpine Rhine valley, Switzerland, at three sites with differing soil water holding capacities and in 3years with contrasting weather conditions. In addition to this natural inter-annual variation, precipitation was manipulated within sites with throughfall reduction roofs. Seedling establishment and growth were principally affected by the spring weather in the year of emergence. In years with average to positive spring water balance, seedlings grown at the site with the highest water holding capacity had 2-5 times more aboveground biomass than seedlings grown at sites with less favourable soils. Effects of seed origin were marginal and only detectable at the drier sites: contrary to our expectations, seedlings from the Central Alpine Rhone valley, where the climatic spring water deficit is large, outperformed those from the Mediterranean. Consequently, plantation of non-native populations from dryer origin will mitigate the effects of increased summer drought at driest sites only, while the inter-annual variability of spring precipitation will continue to enable temperate conifers to regenerate on a wide range of forest soils independent of seed origin.

Different Alleles of a Gene Encoding Leucoanthocyanidin Reductase (PaLAR3) Influence Resistance against the Fungus Heterobasidion parviporum in Picea abies.

Despite the fact that fungal diseases are a growing menace for conifers in modern silviculture, only a very limited number of molecular markers for pathogen resistance have been validated in conifer species. A previous genetic study indicated that the resistance of Norway spruce (Picea abies) to Heterobasidion annosum s.l., a pathogenic basidiomycete species complex, is linked to a quantitative trait loci that associates with differences in fungal growth in sapwood (FGS) that includes a gene, PaLAR3, which encodes a leucoanthocyanidin reductase. In this study, gene sequences showed the presence of two PaLAR3 allelic lineages in P. abies. Higher resistance was associated with the novel allele, which was found in low frequency in the four P. abies populations that we studied. Norway spruce plants carrying at least one copy of the novel allele showed a significant reduction in FGS after inoculation with Heterobasidion parviporum compared to their half-siblings carrying no copies, indicating dominance of this allele. The amount of (+) catechin, the enzymatic product of PaLAR3, was significantly higher in bark of trees homozygous for the novel allele. Although we observed that the in vitro activities of the enzymes encoded by the two alleles were similar, we could show that allele-specific transcript levels were significantly higher for the novel allele, indicating that regulation of gene expression is responsible for the observed effects in resistance, possibly caused by differences in cis-acting elements that we observe in the promoter region of the two alleles.

Identification of Salt Stress Biomarkers in Romanian Carpathian Populations of Picea abies (L.) Karst.

The Norway spruce (Picea abies), the most important tree species in European forests, is relatively sensitive to salt and does not grow in natural saline environments. Yet many trees are actually exposed to salt stress due to the common practice of de-icing of mountain roads in winter, using large amounts of NaCl. To help develop strategies for an appropriate use of reproductive seed material on reforestation sites, ensuring better chances of seedling survival in salt-affected areas, we have studied the responses of young spruce seedlings to salt treatments. The specific aim of the work was to identify the optimal salt stress biomarkers in Picea abies, using as experimental material seedlings obtained by germination of seeds with origin in seven populations from the Romanian Carpathian Mountains. These responses included general, conserved reactions such as the accumulation of ions and different osmolytes in the seedlings needles, reduction in photosynthetic pigments levels, or activation of antioxidant systems. Although changes in the contents of different compounds involved in these reactions can be associated to the degree of stress affecting the plants, we propose that the (decreasing) levels of total phenolics or total carotenoids and the (increasing) levels of Na+ or K+ ions in Picea abies needles, should be considered as the most reliable and useful biomarkers for salt stress in this species. They all show very high correlation with the intensity of salt stress, independently of the genetic background of the seeds parental population, and relatively easy, quantitative assays are available to determine their concentrations, requiring simple equipment and little amount of plant material.

The Lateglacial and Holocene in Central Europe: a multi‐proxy environmental record from the Bohemian Forest, Czech Republic

The Hercynian mountain ranges were islands of mountain glaciation and alpine tundra in a Central European ice‐free corridor during the Late Pleistocene. Today they are notable areas of glacial landforms, alpine‐forest free areas, peatlands and woodlands. However, our knowledge of the Lateglacial and early Holocene environmental changes in this region is limited. We present a new multi‐proxy reconstruction of a mid‐altitude environment in the Bohemian Forest spanning this period. A core (5.2 m length) in the Černé Lake cirque (1028 m a.s.l.) was subjected to lithological, geochemical, pollen and macrofossil analysis supplemented by two optically stimulated luminescence (OSL) and 10AMSradiocarbon dates. We determined the impact of regional and supraregional climate changes on the environment. The two most significant changes in sedimentation during the Lateglacial (17.6 and 15.8–15.5 cal. kaBP) were synchronous with regional glacial chronostratigraphy. Unlike Central European mountain ranges, in the Bohemian Forest the Younger Dryas was not coincident with glacier re‐advance, but was a dry, cold episode with low lake levels, which prevailed until the early Preboreal. Plant macrofossils indicate local establishment ofBetula nanaandBetula pendula/pubescensat 15.4–13.4 cal. kaBP. Comparison with Holocene records from Central Europe shows a similar immigration history of vegetation at mid and higher altitudes. The tree line exceeded an altitude of ~1000 m a.s.l. around 10.5 cal. kaBPand coincided with rapid geochemical changes in the sediment. The 8.2 kaBPevent did not have any response in the sedimentary record, but corresponded to stabilization of thePicea abiespopulation and expansion ofFagus.Faguscolonized the Bohemian Forest earlier than other Hercynian mid‐mountains, but never predominated in the composition of the forest at higher elevations.Abies albawas the last tree species that immigrated to the study area.

Physiological Changes and Osmoregulation in Several Romanian Spruce Populations Exposed to Salt and Drought Stress

Due to global warming and anthropogenic activities, drought and salinity are becoming two of the major abiotic stresses affecting coniferous forests in Romania. Seedlings from several Romanian populations of Picea abies were subjected to drought and salt stress treatments and the responses of each of them were analysed in terms of changes in dry mass percentages and proline levels. The highest fluctuations were recorded in the population from Valea Mare and the lowest in those from Sudrigiu and GioriE™tea-CAƒlimAƒnuE›.

Genetic heterogeneity in age classes of naturally regenerated old growth forest of Picea abies (L.) Karst

AbstractThe Białowiez·a Primeval Forest is located northeastern Poland. It is one of Europe’s most precious old growth forests in terms of abundance and richness of vegetation, retaining features of a primeval lowland forest which cannot be found anywhere else on the European continent. The aim of the study was to assess the genetic heterogeneity of the naturally regenerated Picea abies population using five chloroplast microsatellite markers. In total, 290 trees representing five age classes were studied. Clear patterns of genetic differentiation in relation to demographic substructuring were found within the population. The class of embryos exhibited the greatest genetic richness as evident from the highest number of alleles and haplotypes, the highest mean number of private alleles and haplotypes and the highest haplotype diversity. In the subsequent age classes, a significant decrease in the level of genetic variation was observed. Our data demonstrate that long-lived, highly outcrossing tree species growing in continuous stands can be genetically heterogeneous on a small geographic scale. The heterogeneity is related to age structure and it is likely due to the underlying mating system and selection processes.

Differences in wood properties of Picea abies L. Karst. in relation to site of provenance and population genetics

Abstract Chemical and physical characteristics of wood from six European populations of Picea abies were investigated taking into consideration their genetic differentiation determined by four microsatellites markers. The growth conditions of investigated spruce trees differed significantly. As a consequence, several adaptations were observed in samples from varying environments. The adaptation mechanisms include a variation to the annual rings morphology as well as the physical properties of the wood. It was proved that some properties, such as wood density or latewood ratio, are strictly correlated to the environmental variables. Results show that trees from geographically distinct populations present some diversity in the genotypes. It was also noticed that some trees did not share their genetic profile with other plants from the same location due to high intrapopulation variability. Samples from Finland possessed the lowest level of internal differentiation, while samples from northern Poland presented the lowest allele richness and were most divergent from the others. It was not possible to correlate any wood properties (chemical or physical) to genetic features of the population due to high intrapopulation diversity.

Phenotype features in juvenile populations of Picea abies and their growth

The young populations of Norway spruce (Picea abies) can be evaluated in terms of both variability in the quantitative characteristics and share of different phenotypes according to the needle types. A set of two-years-old seedlings produced in the nursery and several populations of natural regeneration in the Krkonoše Mts. and the Krušné hory Mts. were evaluated using the needle anatomy, size and colour. The tree height growth was measured simultaneously. The growth was related to some needle features. Four basic anatomical types of needles were distinguished in the mountain Norway spruce seedlings: flat needles, intermediate needles, inversion type and sclerotized needles. The growth of natural regeneration populations is mainly correlated with the needle width and the <br /> length/width ratio. The population variability according to growth can be related to the variability of some phenotype characteristics. This relationship differs in natural regeneration and planting.  

Technology for Restoring and Maintaining Sustainability of Populations: Practical and Theoretical Results of Genourbanology

Genourbanology (the synthesis of system ecology and population genetics) is a new scientific and practical school of thought, founded and developed by the authors. The task of genourbanology consists in studying the genetic parameters and laws of stability conservation of ecosystems and ecosystem restoration in anthropogenic and, in particular, urbanized landscapes. An ecological genetic technology for restoring and maintaining sustainability of populations viability, including the method for assessing the state and duration of existence of populations as well as the enrichment and control of the population gene pool in urban ecosystems was developed in the framework of genourbanology. The results of quantitative assessment of the state of the gene pool of 40 populations are described and the recommendations for restoring its viability are given using the following model species of animals and plants inhabiting the fragmented landscape of Moscow and Moscow region: 20 populations of the terrestrial bush snail (Bradybaena fruticum (Mull.), 16 populations of brown frogs Rana temporaria L. and Rana arvalis Nills., and 4 populations of Norway spruce Picea abies (L.) Karst.). A sharp decline in the genetic diversity (up to 70%) in the urban isolated compared to the natural populations was found. Comparative analysis of the gene pool of natural populations and planted spruce stands revealed a correlation between the state of the gene pool of spruce populations and the degree of their lesion with the bark beetle (Ips typographus (L.).

Holocene fire frequency variability in Vesijako, Strict Nature Reserve, Finland, and its application to conservation and management

Fire disturbance is considered paramount for regeneration and biodiversity in the boreal forest with prescribed burning widely advocated in present day forest management. Palaeoecological knowledge is beneficial in understanding the role of fire as a driver of past vegetation dynamics. We use a sedimentary pollen and charcoal record to reconstruct 5000years of fire and vegetation history from a small forest hollow (approximate area 12m2) in the Vesijako Strict Nature Reserve, currently one of the few remaining old-growth forest stands in southern Finland. Results indicate three distinct periods in the environmental history (1) 5000–2000cal. yrs. BP; semi-natural low frequency (430year return period), low intensity fires in a diverse mixed stand with little evidence of anthropogenic disturbance and an expanding Picea abies (Norway spruce) population (2) 2000–750cal. yrs. BP; anthropogenic-driven high frequency (180year return period), high intensity stand-replacing fires in a low diversity stand with evidence of slash and burn cultivation and a decline of Picea population, (3) 750cal. yrs. BP to present day; fire absence through a reduction in human-induced fire or active fire suppression and the expansion of the currently dominant Picea forest. The changing fire frequency has had a major influence on the forest composition during the last 5000years. The loss of floristic diversity is associated with an increase in the human use of fire and without this human interference the previously high biodiversity in the stand may have remained up until the present day. If fire remains absent in Vesijako then it is likely that the Picea population will continue to dominate in the stand supporting a negative feedback mechanism that will result in lower frequency, higher intensity fires in the future.