云南哀牢山原生林及次生林群落附生地衣物种多样性与分布

附生地衣是森林附生植物的重要类群之一, 在维护森林生态系统的物种多样性以及水分和养分循环等方面发挥着重要作用。作者于2005年12月至2006年5月利用树干取样法调查了云南哀牢山徐家坝地区原生山地常绿阔叶林及其次生群落栎类萌生林、滇山杨(Populus bonatii)林和花椒(Zanthoxylum bungeanum)人工林中525株不同种类和径级树木距地面 0–2.0 m处附生地衣的组成和分布, 并收集了各个群落地面上凋落的地衣, 分析了林冠层附生地衣的物种组成。研究结果表明, 该区森林中附生地衣物种比较丰富。共收集到附生地衣61种, 分属17科29属, 其中原生林、栎类萌生林、滇山杨林和花椒人工林分别有51、53、46和23种。在树干距地面 0–2.0 m位置, 各群落中的附生地衣组成明显不同;但在林冠层中, 各群落内的附生地衣基本相似。原生林中附生地衣种类较多, 但分布不均匀。树干附生地衣的Shannon-Wiener和Simpson多样性指数以栎类萌生林最高, 分别为2.71和0.89;花椒林和滇山杨林次之, 分别为2.43–2.45和0.88–0.89;原生林最低, 为1.25和0.67。树干方位、宿主种类和宿主径级等都对附生地衣的物种组成和多样性有着重要影响, 附生地衣更多地出现于树干南向方位, 云南越桔(Vaccinium duclouxii)的附生地衣最为丰富, 胸径5.0–25.0 cm的树木上附生地衣较多。哀牢山山地森林群落中丰富的附生地衣种类及物种多样性在维系本区山地森林生态系统生物多样性格局方面具有重要的作用。     

A survey method for assessing the richness of epiphytic lichens using growth forms

The species richness of epiphytic lichens is continuously decreasing by degradation and loss of habitat. Considering that taxonomic identification of all species is time and resource consuming, rapid assessment methods to extrapolate the total number of species are needed for practical conservation. This paper describes an alternative method using the correlation between lichens growth forms and species richness. The study was conducted in 406 forest stands located in Central Spain, covering a wide range of mediterranean-climate ecosystem regions, management intensity levels, canopy cover conditions, and tree sizes. The presence/absence of epiphytic lichens was determined in 6090 trees, which were dominated by oak species (Quercus ilex, Q. faginea, and Q. pyrenaica). In all type of forests, the diversity of growth forms was positively correlated with the total epiphytic lichen richness. In all cases, species richness increased in non-managed forest stands with dense canopies. Thus, we propose the use of lichen growth forms as a helpful surrogate of species richness to detect potentially conservation priority areas in the Mediterranean region.     

Responses of the distribution of four epiphytic cyanolichens to habitat changes in subtropical forests

 蓝藻地衣是附生植物类群的重要组成部分, 在森林生态系统的环境监测和养分循环中发挥着重要作用。该研究在云南哀牢山亚热带森林系统的2种原生和6种次生森林群落中, 以粉缘绵毛衣(Leioderma sorediatum)、天蓝猫耳衣(Leptogium azureum)、网肺衣(Lobaria retigera)和双缘牛皮叶(Sticta duplolimbata) 4种常见蓝藻地衣为对象, 共设立120个样地, 调查了它们在3 600株树木0–2 m树干上的分布, 探讨其分布特征及与森林类群、宿主种类以及林龄等生境因子的关系。研究发现4种蓝藻地衣在森林群落间的分布模式明显不同。除双缘牛皮叶的盖度和频度在原生苔藓矮林中最高外, 其他3种蓝藻地衣的最高值均出现于次生林如厚皮香(Ternstroemia gymnanthera)林和滇山杨(Populus bonatii)林中; 而哀牢山地区广布的原生木果柯(Lithocarpus xylocarpus)林中, 4种蓝藻地衣极为少见。4种地衣都能生长于10多个树种上, 但明显表现出对厚皮香、滇山杨和硬壳柯(Lithocarpus hancei)等树种的偏好性, 以及对小花山茶(Camellia forrestii)等的排斥性。森林群落的林龄、胸径、最大胸径、林冠开阔度、基面积、树木密度和树种多样性等因子的变化均对4种附生蓝藻地衣的分布产生重要影响, 但在景观尺度上影响程度相对较小, 在不同森林群落内部却有各自的重要作用。其中, 林龄、林冠开阔度和宿主胸径是影响蓝藻地衣分布的最重要的生境因子。     

Bole epiphytic lichens as potential indicators of environmental change in subtropical forest ecosystems in southwest China

Lichen epiphytes are applied as excellent environmental indicators worldwide. However, very little is known about epiphytic lichen communities and their response to forest dynamics in subtropical China. This paper proposes the applications of the cover, diversity, and functional traits of epiphytic lichens to assess environmental changes associated with succession in subtropical forests of southwest China. Bole lichens were sampled from 120 plots of eight representative forest types in the Ailao Mountains. Total cover, species richness, diversity and community structure of bole lichens differed significantly among forest types, and the highest cover and diversity occurred in the Populus bonatii secondary forest (PBSF). Sixty-one indicator species were associated with particular forest types and more than 50% occurred in the PBSF. Both cover and diversity of most lichen functional groups varied regularly during forest succession. Lichen pioneer species were not displaced by competitively superior species as succession proceeds and cyanolichens were more prevalent in secondary forests. The results also highlight the importance of habitat variables such as canopy openness, host diversity, forest age, tree size, the size of the largest tree, tree density, and basal area on the lichen community. Consequently, our findings support the notion that epiphytic lichens, in terms of cover, diversity, species composition and functional traits can be used as effective indicators for large-scale and long-term forest monitoring. More importantly, the narrowly lobed foliose group was the best candidate indicator of environmental conditions in this region. The combined application of lichen indicator species and functional groups seemed to be a more reliable and more powerful method for monitoring forest dynamics in subtropical montane ecosystems.     

Influence of tree age, tree size and crown structure on lichen communities in mature Alpine spruce forests

Testing the relations between tree parameters and the richness and composition of lichen communities in near-natural stands could be a first step to gather information for forest managers interested in conservation and in biodiversity assessment and monitoring. This work aims at evaluating the influence of tree age and age-related parameters on tree-level richness and community composition of lichens on spruce in an Alpine forest. The lichen survey was carried out in four sites used for long-term monitoring. In each site, tree age, diameter at breast height, tree height, the first branch height, and crown projection area were measured for each tree. Trees were stratified into three age classes: (1) <100 years old, immature trees usually not suitable for felling, (2) 100–200 years old, mature trees suitable for felling, and (3) >200 years old, over-mature trees normally rare or absent in managed stands. In each site, seven trees in each age class were selected randomly. Tree age and related parameters proved to influence both tree-level species richness and composition of lichen communities. Species richness increased with tree age and related parameters indicative of tree size. This relation could be interpreted as the result of different joint effects of age per se and tree size with its area-effect. Species turnover is also suspected to improve species richness on over-mature trees. Similarly to species richness, tree-level species composition can be partially explained by tree-related parameters. Species composition changed from young to old trees, several lichens being associated with over-mature trees. This pool of species, including nationally rare lichens, represents a community which is probably poorly developed in managed forests. In accordance to the general aims of near-to-nature forestry, the presence of over-mature trees should be enhanced in the future forest landscape of the Alps especially in protected areas and Natura 2,000 sites, where conservation purposes are explicitly included in the management guidelines.     

The importance of host tree age, size and growth rate as determinants of epiphytic lichen diversity in boreal spruce forests

The amount of large and old trees has decreased in the boreal forests during the last centuries of forestry. Such trees are important habitats for epiphytic lichens and there is a growing concern for lichen species that are associated with large and old trees. However, only little is known about the relative importance of tree size versus age as determinants of lichen diversity. Here we have determined the size, age and growth rate of 157 Norway spruce trees and recorded the occurrence of epiphytic lichen species on their branches and lower stems. The study includes crustose lichens and was done in two old-growth forests in SE Norway. Tree age and tree size were the parameters that explained the largest part of epiphytic lichen diversity. Only the growth rate of the most recent time period, i.e. 1984–2004, showed a statistically significant relationship to diversity. There was no indication of a stabilising species number with increasing tree age. Slow-growing and old trees were, however, mainly of importance to the lichen species growing on stems, and this set of species were in general adversely affected by a large amount of branches. The opposite was the case for the species that were confined to branches as their diversity increased when the amount of branches increased. Our study adds empirical data to support the importance of large and old trees as bearers of biodiversity in boreal forests. Site preservation and patch retention of groups of old and large trees is recommended as measures to maintain epiphytic lichen diversity.     

Tree and stand level variables influencing diversity of lichens on temperate broad-leaved trees in boreo-nemoral floodplain forests

Tree and stand level variables affecting the species richness, cover and composition of epiphytic lichens on temperate broad-leaved trees (Fraxinus excelsior, Quercus robur, Tilia cordata, Ulmus glabra, and U. laevis) were analysed in floodplain forest stands in Estonia. The effect of tree species, substrate characteristics, and stand and regional variables were tested by partial canonical correspondence analysis (pCCA) and by general linear mixed models (GLMM). The most pronounced factors affecting the species richness, cover and composition of epiphytic lichens are acidity of tree bark, bryophyte cover and circumference of tree stems. Stand level characteristics have less effects on the species richness of epiphytic lichens, however, lichen cover and composition was influenced by stand age and light availability. The boreo-nemoral floodplain forests represent valuable habitats for epiphytic lichens. As substrate-related factors influence the species diversity of lichens on temperate broad-leaved trees differently, it is important to consider the effect of each tree species in biodiversity and conservation studies of lichens. Nomenclature Randlane et al. (2007) for lichens; Leht (2007) for vascular plants.     

Species richness and vertical stratification of epiphytic lichens in subtropical primary and secondary forests in southwest China

An entire-tree investigation was conducted in two primary and three secondary forest types in the subtropical Ailao Mountains of southwest China to determine whether species richness and vertical stratification of epiphytic lichens responded to forest type and host attributes. Lichen species number, composition and cover differed significantly among forest types and tree species, while tree diameter and tree height had a modest influence. Epiphytic lichen species and functional groups showed clear vertical stratification. Epiphytic lichens were richer in canopies than on trunks and exhibited a great preference for the intermediate zones of trees, while five lichen groups showed distinct vertical diversification. The stratification patterns are clearly related to forest type and may reflect the microclimatic requirements of individual species, e.g. light availability and humidity.     

Forest edge-interior differentiation in the epiphytic lichen diversity of the forest steppe in the Khangai Mountains,Mongolia

Aims The effects of traditional land use by mobile livestock keepers on biodiversity in forest steppe ecotones are insufficiently studied. Epiphytes are an important part of forest plant diversity. Here we analyze differences in the diversity and composition of the epiphytic lichen vegetation between the edge and the interior of Siberian larch forests in the Khangai Mountains, western Mongolia, which are highly subdivided into patches. We asked whether the epiphytic lichen vegetation at the forest edge differs significantly from that in the interior, whether the edge is inhabited by more nitrophilous species than the interior and whether the density of nomad camps around the forest affects epiphytic lichen diversity.Methods Cover percentages of epiphytic lichen species were recorded from 20 trees per plot on 6 plots in the interior and 6 plots at the edge of Larix sibirica forests. The position of nomad summer camps was surveyed using Global Positioning System. Data were analyzed with pairwise significance tests, analysis of similarities, nonmetric multidimensional scaling and canonical correspondence analysis.Important findings The composition of the epiphytic lichen vegetation clearly differed between the two habitats, with more species being more frequent at the edge than in the interior. However, there was no difference in species richness (α-diversity). The epiphyte vegetation at the edge was more uniform and characterized by lower variation of tree-level α-diversity and lower β-diversity than in the interior. At the edge, only nitrophytic lichens were dominant, whereas in the interior, nitrophytes and acidophytes were among the dominant species. This pattern is probably attributable to the spatial heterogeneity of the intensity of forest grazing and was shown to be influenced by the density of nomad summer camps in the vicinity of the forests. Tree-level α-diversity increased with stem diameter, but high-diameter trees were rare. The results suggest that the present level of forest patchiness and the effect of forest grazing increases the diversity of epiphytic lichens on the landscape level, while logging of high-diameter trees reduces lichen diversity.     

Epiphytic lichen synusiae and functional trait groups in boreo‐nemoral deciduous forests are influenced by host tree and environmental factors

Deciduous forests with temperate broad‐leaved tree species are particularily important in terms of biodiversity and its protection, but are threatened habitats in northern Europe. Using multivariate analyses we studied the effect of forest site type, environmental variables and host tree properties on epiphytic lichen synusiae as well as on the composition of species‐specific functional traits. Epiphytic lichens were examined on Acer platanoides, Fraxinus excelsior, Quercus robur, Tilia cordata, Ulmus glabra and U. laevis in two types of forests: Humulus‐type floodplain forests and Lunaria‐type boreo‐nemoral forests on the talus slopes of limestone escarpment (klint forests). Klint forests located near the seashore were under greater maritime influence compared to floodplain forests located in inland Estonia which experience stronger air temperature contrasts. In addition to stand level and climatic variables, tree level factors (bark pH, trunk circumference and cover of bryophytes) considerably affected the species composition of the lichen synusiae. Overall, 137 lichen species were recorded, including 14 red‐listed species characteristic of deciduous trees. We defined 13 lichen societies and showed their preference to forests of a specific site type and/or host tree properties. In forests of both types, most of the epiphytic lichens were crustose, and had apothecia as the fruit bodies and chlorococcoid algae as the photobiont. However, the proportion of lichens with a foliose or fruticose growth form, as well as the proportion of lichens with vegatative diaspores, were higher in floodplain forests. In klint forests with a stronger influence from the wind, crustose species completely dominated, while species with vegetative diaspores were rare and most species dispersed sexually. Lichens with Trentepohlia as the photobiont were characteristic of these forests, and lichens with lirellate ascomata were prevailing, indicating the great uniqueness of the kint forests for epiphytic lichens in the boreo‐nemoral region.     

The ecology and distribution of lichens in tropical deciduous and evergreen forests of northern Thailand

During three years of research on epiphytic lichen communities as indicators of environmental change in northern Thailand plots were set up in a range of forest types between 400 and 1600 m in 1991/2 and revisited in 1993. Other areas were visited in 1993 and collections made in a wider range of geographical, altitudinal and vegetation conditions in Thailand. From this data factors influencing the distribution of lichens in a monsoon climate are outlined and characteristic components of the lichen flora given at family, generic and where possible specific level. Dominant taxa of the montane forests include hygrophilous macrolichens of the 'Lobarion' that are also a characteristic component of old growth fagaceous forests in Europe, whereas the evergreen forests are dominated by moisture-dependent crustose taxa with a trentepohlioid photobiont, and the deciduous dipterocarp forests by often brightly coloured xerophytic lichens with a trebouxioid photobiont. Taxa are proposed as indicators of forest type including those that are indicators of old-growth forests and of disturbance. Quantitative recording of selected taxa at genus and species level is suggested to estimate rates of change in monsoon forests in southeast Asia.     

Fire in tropical dry forests: corticolous lichens as indicators of recent ecological changes in Thailand

The distribution of lichens in lowland deciduous and evergreen forests in Thailand is used to interpret recent changes in the distribution of these forests. The role of fire in changing the forest structure, microclimate and species content is discussed. Characteristic corticolous lichen communities of dry deciduous and moist evergreen forests are described, as well as changes in the composition of the flora following fire events. Where frequent fires have altered the forest rates of change in forest type are suggested using lichen data from randomly selected trees in forest plots, and growth rates of sampled species in quadrats. The disjunct nature of the lichen floras in lowland deciduous and evergreen forests is discussed, their origin and use in interpreting changes in forest types in monsoon climates over long periods of time.     

Tree and stand-scale factors affecting richness and composition of epiphytic bryophytes and lichens in deciduous woodland key habitats

Conservation and sustainable forestry are essential in a multi-functional landscape. In this respect, ecological studies on epiphytes are needed to determine abiotic and biotic factors associated with high diversity. The aim of the present study was to evaluate relative sensitivity of conservation targets (epiphytic bryophytes and lichens) in relation to contrasting environmental variables (tree species, tree diameter at breast height, bark crevice depth, pH, tree inclination, pH, forest stand age, area and type) in boreo-nemoral forests. The study was conducted in Latvian 34 woodland key habitat (WKH) boreo-nemoral forest stands. Generalized linear mixed models and canonical correspondence analysis showed that tree species and tree bark pH were the most important variables explaining epiphytic bryophyte and lichen composition and richness (total, Red-listed, WKH indicator species). Forest stand level factors, such as stand size and habitat type, had only minor influence on epiphytic species composition and richness. The results of the present study indicate a need to maintain the diversity of tree species and large trees, particularly Acer platanoides, Carpinus betulus, Fraxinus excelsior, Populus tremula, Tilia cordata, Ulmus glabra and Ulmus laevis in conservation of epiphytic bryophyte and lichen communities in the future.     

Assessing the effects of forest management on epiphytic lichens in coppiced forests using different indicators

Abstract

Epiphytic lichens are one of the taxonomic groups most sensitive to forest management. Nevertheless, they have not yet been exhaustively included in the assessment of Sustainable Forest Management. This work aimed at evaluating the effects of forest management on epiphytic lichens in coppiced forests, exploring the spatial patterns of diversity and the composition of communities. Moreover, the goal was to compare the performance of four potential indicators for monitoring the effects of forest management on epiphytic lichens: total lichen diversity, species associated with intensive management, species associated with aged coppiced woodlands and Indicator Species Ratio (ISR). In humid Mediterranean Liguria, 50 sampling units were chosen in Castanea sativa and deciduous Quercus spp. forests subjected to different forest management practices: intensively managed coppice and aged coppice/high forest. The effect of forest management was evident in terms of species composition, since it was possible to find significantly associated species for each of the two management types. At each sampling site, the four indicators were calculated using Indicator Value Analysis and compared through correspondence analysis. The ISR was shown to be a more effective indicator, being independent of floristic composition and the occurrence of rare species.     

Epiphytic lichen diversity in old-growth and managed Picea abies stands in southern Finland

Abstract. Epiphytic and epixylic lichens were surveyed on 15 1-ha plots in mature Picea abies-dominated boreal forests in southern Finland. The sample plots were classified into three groups according to the age of the dominant tree stand and recent signs of cutting: (1) early mature managed, ‘EM’ (95 -109 yr), (2) late mature managed, ‘LM’ (126 - 145 yr) and (3) old-growth, ‘OG’ (129 - 198 yr). Two data sets on epiphytic and epixylic lichens were recorded from each plot: (1) species on basal trunks and branches of Picea abies and (2) species on all available woody substrates, including basal parts of all tree species, saplings, snags, logs and stumps. 142 epiphytic and epixylic lichen species were found, of which 83 (58%) occurred on P. abies. Mean total numbers of species per sample plot were 69 in EM, 78 in LM and 88 in OG plots, species number on P. abies were 47, 56, and 54 respectively. The LM plots had lower species numbers than OG plots, mainly due to the lack of old Populus tremula trees, but they had higher species number than the EM plots mainly due to the higher age of Picea abies. Differences in species composition, both within and between the three groups, were small. The results suggest that the epiphytic and epixylic lichen diversity in a managed stand can be increased by prolonging the rotation of the stand to >120 yr and by increasing the diversity of habitats in the stand.     

The weight of the crust: Biomass of crustose lichens in tropical dry forest represents more than half of foliar biomass

In recent years, our ecological knowledge of tropical dry forests has increased dramatically. However, the functional contributions of whole ecosystem components, such as lichens, remain mostly unknown. In these forests, the abundance of epiphyte crustose lichens is responsible for the characteristic white bark on most woody plants, conspicuous during the dry season, but the amount of resources that the lichen component represents remains unexplored. We estimated lichen biomass in a Mexican tropical dry forest using the bark area of trees, the dry mass of lichens per unit area and the percentage of bark covered by lichens, together with previously known tree densities. The lowest 2.5 m of the forests main trunks contained 188 kg/ha of lichen biomass, with lichens covering 85% of the available bark for trees <12 cm DBH and 38% for trees >12 cm. Total epiphytic lichen biomass was 1.34–1.99 Mg/ha. Lichen biomass represented 61% of the foliar biomass in the forest. To our knowledge, this is the first time that a lichen biomass estimate is provided for an ecosystem in which crustose lichens are the dominant lichen growth form. Crustose lichens are typically considered to contribute little to the total lichen biomass and to be difficult to include in ecological analyses. The high lichen biomass in this ecosystem implies a significant ecological role which so far is unexplored. We suggest the crustose lichen component should not be underestimated a priori in ecological studies, especially in ecosystems with abundant lichen cover.     

Up in the Tree – The Overlooked Richness of Bryophytes and Lichens in Tree Crowns

Assessing diversity is among the major tasks in ecology and conservation science. In ecological and conservation studies, epiphytic cryptogams are usually sampled up to accessible heights in forests. Thus, their diversity, especially of canopy specialists, likely is underestimated. If the proportion of those species differs among forest types, plot-based diversity assessments are biased and may result in misleading conservation recommendations. We sampled bryophytes and lichens in 30 forest plots of 20 m × 20 m in three German regions, considering all substrates, and including epiphytic litter fall. First, the sampling of epiphytic species was restricted to the lower 2 m of trees and shrubs. Then, on one representative tree per plot, we additionally recorded epiphytic species in the crown, using tree climbing techniques. Per tree, on average 54% of lichen and 20% of bryophyte species were overlooked if the crown was not been included. After sampling all substrates per plot, including the bark of all shrubs and trees, still 38% of the lichen and 4% of the bryophyte species were overlooked if the tree crown of the sampled tree was not included. The number of overlooked lichen species varied strongly among regions. Furthermore, the number of overlooked bryophyte and lichen species per plot was higher in European beech than in coniferous stands and increased with increasing diameter at breast height of the sampled tree. Thus, our results indicate a bias of comparative studies which might have led to misleading conservation recommendations of plot-based diversity assessments.     

Lichens and bryophytes as indicators of old‐growth features in Mediterranean forests

Abstract

This study is focused on the selection of variables affecting lichen and bryophyte diversity in Mediterranean deciduous forests. Plots representing two forest types (Fagus sylvatica and Quercus cerris forests) and two forest continuity categories (old‐growth (OG) and non‐OG forests) were selected in the Cilento and Vallo di Diano National Park (Italy). The presence and the abundance of bryophytes and epiphytic lichens were recorded. Structural variables of the forests and vascular plant species richness have been used as predictors. A strong positive correspondence between the two groups of organisms was found. Higher species richness and the distribution of rare species are related to OG stands, while a qualitative (species composition) rather than a quantitative (species richness) difference between the two forest types was observed. Some species elsewhere considered as indicators of forest continuity, such as Lobaria pulmonaria, Antitrichia curtipendula, and Homalothecium sericeum, are associated with OG forests, independently from forest type, suggesting that they can be regarded as suitable indicators also in Mediterranean forests. Finally, our results suggest that old trees, high levels of basal area, a broad range of diameter classes, and high understory diversity are the main structural features affecting cryptogamic communities, while no correlation was found with the occurrence of deadwood.     

Lichen diversity and red-listed lichen species relationships with tree species and diameter in wooded meadows

This study provides a unique large dataset of total epiphytic lichen diversity (fruticose, foliose and crustose species) and composition on 1,294 trees of 17 tree species in wooded meadows in Sweden and Estonia, the Baltic region. The inventory (25,380 observations and 246 lichen taxa) clearly illustrated that Ulmus minor, Quercus robur and Fraxinus excelsior contributed most significantly to epiphytic lichen richness and number of red-listed species. In Sweden, average single tree α richness was 22.2 on Ulmus (only in Sweden), 21.6 on Quercus (25.0 in Estonia) and 19.8 on Fraxinus (16.7 in Estonia), respectively. Ulmus hosted on average one red-listed species per tree, compared with 0.7 on Fraxinus (0.6 in Estonia), 0.4 on Quercus (0.7 in Estonia) and only 0.05 on Betula (same in Estonia). Lichen species composition and the average number of red-listed lichens were influenced by tree diameter on Fraxinus and Quercus, whilst no such pattern was evident on Ulmus. Randomized species accumulation curves of the dominating tree species illustrated that Fraxinus, Quercus and Ulmus supported α dominated lichen communities where individual trees hosted a substantial part of the total richness. Betula, on the other hand, supported β dominated communities where individual trees tended to be dissimilar and, therefore, more of the total richness existed as species turnover among host trees. Lichen species composition was influenced by tree species, and most notably, lichen species on Ulmus had a strong consistent clumping in ordination graphs, with many rare and red-listed lichens. The broadleaved deciduous trees within the wooded meadows clearly contribute greatly to the biodiversity of the Baltic region.     

Epiphytic and epixylic lichen species diversity in Estonian natural forests

The epiphytic and epixylic lichen flora of natural forests was recorded in different parts of Estonia. Altogether 232 taxa of lichens, lichenicolous fungi, or non-lichenized fungi were recorded, 10 of them listed in the Estonian Red Data Book. We found regional differences in lichen species composition and diversity caused by differences in the forest types. The tree-species-rich boreo-nemoral forests had the most diverse lichen flora, while the boreal forest dominated by coniferous trees or birch had the lowest diversity. The stand age proved to be significant in regard to the number of lichen species in a forest. The most remarkable effect on the diversity of forest lichen species was caused by the presence of Populus tremula. Aspen had the highest number of lichen species on the basal trunk and twigs, and also the highest number of host-specific lichen species.