Structure evolution of primary mixed temperate forests depending on disturbance regime

Our thesis reconstructs disturbation history of primary forest remnant in Kornietová reservation in Slovakia. We extracted dendrochronological samples and collected data about the structure of a stand on sampling plots. 6 of total 14 plots were affected by an extreme disturbance around the year 1830. It removed almost complete upper canopy layer. This event was followed by a long period of minimal disturbance activity. The rest of plots was characterized by a regime of weak disturbances returning every 30 or 40 years. Between these two groups of plots, the shape of DBH distibution and the amount of large trees were significantly different. The plots which were affected by the extreme disturbance had distinctly more trees over 600 mm of DBH, because total extend of disturbances was markedly lower after 1830. The other parameters like amount of dead wood, species composition and quantity of saplings were not significantly different. The other studies suppose, that weak disturbances promote regeneration of beech, while large disturbances allow conifers to regenerate. The results of you study do not support such a relation. During data processing and evaluation, we discovered a high error rate the data suffered. It is more difficult to crossdate correctly a beech, then previously thought, but finally..

Effects of forest management on forest biodiversity

Forests host approximately 80 % of species of all terrestrial organisms. Human pressure on forest ecosystems drastically increased during 20th century and poses a constant threat to global biodiversity. The aim of this thesis is to summarize current knowledge of the effects of forest management on organisms and to identify underlying mechanisms. The oldest forms of forest management techniques were coppicing and coppicing with standards which enable relatively high biodiversity of species of early successional stages. Transition to classical intensive forestry caused shielding vegetation from the sun and decrease of heterogeneity. In recent decades some further intensification of management is practiced by using fast growing trees, but awareness of the need to establish sustainable forestry conditions strenghtens. Managed forest contrary to natural one has substantially lower average age of trees, it shows spatial homogeneity and old and dead trees, elements that are tied to high diversity of organisms, do not occur. Species composition of woods changes often. Anthropogenic management also disrupts and weakens the natural disturbation regimes. In many economically developed countries forests have been fragmented for a long time and in vastly forested areas that have persisted to the 20th century massive..

Spolupráce s vojenskou zeměpisnou službou při budování gravimetrických základů České republiky

243

History and Dynamics of old-growth forests In the Maramureș

The Maramureș mountains, located in the Eastern Romanian Carpathians, are of growing interest to researchers because of the great patrimonial forest that the region hosts (Fărcaş, Tanţău, Mîndrescu, & Hurdu, 2013). As a result, some of these forests, considered Old Growth Forests (OGFs) or even primeval forest, have been classified as World Heritage Sites by UNESCO, placed under strict protection, and/or included in the Natura 2000 site list (OMMP 2387, 2011). However, the reasons for characterizing a forest as OGFs remain obscure, relying primarily on the absence of recent human activity, on structural and compositional characteristics, and on abstract human perceptions. Moreover, it seems strange that this region, which has had a long history of intensive mining activity, can host primeval forests.To test the robustness of the OGF and primeval identification criteria, we decided to compare two OGFs (one of which is classified as primeval) to two managed forests (MFs) through an interdisciplinary study combining historical, ecological and social approaches (Py-Saragaglia et al., 2020).In this presentation, I will present some initial results relying on the long-term history of these forests and on their sub-recent dynamics. These preliminary results reveal that MFs and OGFs are very similar and therefore raise several questions such as: were these forests judiciously chosen or is their classification only due to political aspects? On the other hand, might not the Strâmbu-Băiuț forest as a whole be considered an OGFs, due to the very low human impact?It is important to answer these questions in order (1) to assist in the future identification of OGFs and (2) if the entire Strâmbu-Băiuț Forest meets the criteria of an OGF, to propose the establishment of a specific management policy to promote its preservation

History and Dynamics of old-growth forests In the Maramureș

The Maramureș mountains, located in the Eastern Romanian Carpathians, are of growing interest to researchers because of the great patrimonial forest that the region hosts (Fărcaş, Tanţău, Mîndrescu, & Hurdu, 2013). As a result, some of these forests, considered Old Growth Forests (OGFs) or even primeval forest, have been classified as World Heritage Sites by UNESCO, placed under strict protection, and/or included in the Natura 2000 site list (OMMP 2387, 2011). However, the reasons for characterizing a forest as OGFs remain obscure, relying primarily on the absence of recent human activity, on structural and compositional characteristics, and on abstract human perceptions. Moreover, it seems strange that this region, which has had a long history of intensive mining activity, can host primeval forests.To test the robustness of the OGF and primeval identification criteria, we decided to compare two OGFs (one of which is classified as primeval) to two managed forests (MFs) through an interdisciplinary study combining historical, ecological and social approaches (Py-Saragaglia et al., 2020).In this presentation, I will present some initial results relying on the long-term history of these forests and on their sub-recent dynamics. These preliminary results reveal that MFs and OGFs are very similar and therefore raise several questions such as: were these forests judiciously chosen or is their classification only due to political aspects? On the other hand, might not the Strâmbu-Băiuț forest as a whole be considered an OGFs, due to the very low human impact?It is important to answer these questions in order (1) to assist in the future identification of OGFs and (2) if the entire Strâmbu-Băiuț Forest meets the criteria of an OGF, to propose the establishment of a specific management policy to promote its preservation

Drivers of basal area variation across primary late-successional Picea abies forests of the Carpathian Mountains

Disentangling the importance of developmental vs. environmental drivers of variation in forest biomass is key to predicting the future of forest carbon sequestration. At coarse scales, forest biomass is likely to vary along major climatic and physiographic gradients. Natural disturbance occurs along these broad biophysical gradients, and depending on their extent, severity and frequency, could either amplify or dampen spatial heterogeneity in forest biomass. Here we evaluate spatial variation in the basal area of late-successional Picea abies (L./Karst.) forests across the Carpathian Mountain Range of central Europe and compare the roles of coarse-scale biophysical gradients and natural disturbances in driving that variation across a hierarchy of scales (landscapes, stands, and plots). We inventoried forest composition and structure, and reconstructed disturbance histories using tree cores collected from 472 plots nested within 30 late-successional stands, spanning the Carpathian Mountains (approximately 4.5 degrees of latitude). We used linear mixed-effects models to compare the effect of disturbance regimes and site conditions on stand basal area at three hierarchical scales. We found that the basal area of late-successional Picea abies forests varied across a range of spatial scales, with climatic drivers being most important at coarse scales and natural disturbances acting as the primary driver of forest heterogeneity at fine scales. For instance, the stand-level basal area varied among landscapes, with the highest values (48-68 m2 ha-1) in the warmer southern Carpathian Mountains, and lower values (37-52 m2 ha-1 on average) in cooler areas of the eastern and western Carpathians. Finer-scale variation was driven by local disturbances (mainly bark beetle and windstorms) and the legacies of disturbances that occurred more than a century ago. Our findings suggest that warming could increase the basal area of northern sites, but potential increasing disturbances could disrupt these environmental responses

Importance of conserving large and old trees to continuity of tree‐related microhabitats

International audienceProtecting structural features, such as tree-related microhabitats (TreMs), is a cost-effective tool crucial for biodiversity conservation applicable to large forested landscapes. Although the development of TreMs is influenced by tree diameter, species, and vitality, the relationships between tree age and TreM profile remain poorly understood. Using a tree-ring-based approach and a large data set of 8038 trees, we modeled the effects of tree age, diameter, and site characteristics on TreM richness and occurrence across some of the most intact primary temperate forests in Europe, including mixed beech and spruce forests. We observed an overall increase in TreM richness on old and large trees in both forest types. The occurrence of specific TreM groups was variably related to tree age and diameter, but some TreM groups (e.g., epiphytes) had a stronger positive relationship with tree species and elevation. Although many TreM groups were positively associated with tree age and diameter, only two TreM groups in spruce stands reacted exclusively to tree age (insect galleries and exposed sapwood) without responding to diameter. Thus, the retention of trees for conservation purposes based on tree diameter appears to be a generally feasible approach with a rather low risk of underrepresentation of TreMs. Because greater tree age and diameter positively affected TreM development, placing a greater emphasis on conserving large trees and allowing them to reach older ages, for example, through the establishment of conservation reserves, would better maintain the continuity of TreM resource and associated biodiversity. However, this approach may be difficult due to the widespread intensification of forest management and global climate change

Disturbance history is a key driver of tree life span in temperate primary forests

Aims We examined differences in life span among the dominant tree species (spruce, Picea abies; fir, Abies alba; beech, Fagus sylvatica; and maple, Acer pseudoplatanus) across primary mountain forests of Europe. We asked how disturbance history, lifetime growth patterns, and environmental factors influence life span. Locations Balkan Mountains, Carpathian Mountains, Dinaric Mountains. Methods Annual ring widths from 20,600 cores from primary forests were used to estimate tree life spans, growth trends, and disturbance history metrics. Mixed models were used to examine species-specific differences in life span (i.e., defined as species-specific 90th percentiles of age distributions), and how metrics of radial growth, disturbance parameters, and selected environmental factors influence life span. Results While only a few beech trees surpassed 500 years, individuals of all four species were older than 400 years. There were significant differences in life span among the four species (beech > fir > spruce > maple), indicating life history differentiation in life span. Trees were less likely to reach old age in areas affected by more severe disturbance events, whereas individuals that experienced periods of slow growth and multiple episodes of suppression and release were more likely to reach old age. Aside from a weak but significant negative effect of vegetation season temperature on fir and maple life span, no other environmental factors included in the analysis influenced life span. Conclusions Our results indicate species-specific biological differences in life span, which may play a role in facilitating tree species coexistence in mixed temperate forests. Finally, natural disturbance regimes were a key driver of life span, which could have implications for forest dynamics if regimes shift under global change.ISSN:1100-9233ISSN:1654-110