Search

Knowledge about the stand structure and dynamics of subalpine forests is crucial to preserve their multifunctionality. In the present study, we reconstructed the spatiotemporal dynamics of a subalpine Pinus cembra forest in the eastern Italian Alps in response to natural disturbances and forest management. We adopted a concurrent point pattern, dendroecological and growth dominance (GD) analysis. We mapped and measured all trees of Pinus cembra and Larix decidua in a 1 ha plot. We analyzed intra- and interspecific spatial patterns and spatial autocorrelation of tree size and age. We explored establishment dynamics and shifts in competition by analyzing growth suppression/release patterns and GD trends. Results showed a clumped, uneven-aged, multilayered structure where pine was dominant. The synergic action of ecological and human-induced factors is discussed to explain the prevalence of pine over time. Spatial pattern and autocorrelation analyses suggest a different colonization strategy of the t...

The Swiss pine (Pinus cembra) is a montane tree in Central Europe and, therefore, known for its hardiness against severe winter colds. The seeds are harvested and eaten as pine nuts. We assembled and characterized the complete chloroplast genome of P. cembra to serve as a valuable resource in future genetic studies. The complete plastome sequence is 116,609 bp in length and contains 113 genes including 79 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. A phylogenetic analysis of 34 Pinus plastome sequences shows that Pinus sibirica is the nearest relative to P. cembra and that there is a distinct clustering together with the other members of the section Quinquefoliae.

Cronartium ribicola causes white-pine blister rust and its main hosts are species of Ribes (telial host) and Pinus (aecial host). Between 2007 and 2010, the distribution and abundance of C. ribicola was surveyed in: (1) Ribes spp. in botanical gardens of southern and northern Finland, and (2) Pinus spp. in five-needle pine plantations and Ribes spp. of northern Finland. The fruit-bearing species Ribes nigrum, Ribes rubrum and Ribes uva-crispa have long been cultivated throughout Finland and Ribes alpinum is a common ornamental. C. ribicola occurred on the leaves of 26 of 36 Ribes species/cultivars. The rust produced spores on all domesticated cultivars of R. nigrum in all botanical gardens each year of the study, whereas some Ribes appeared to be resistant in all locations. Rust infections of Ribes became less common further north and the northernmost infection was found in western Lapland. The rust was not detected on Pinus cembra and Pinus peuce in plantations of northern Finland, although indiv...

Identifying the factors controlling tree mortality is key to understanding the effects of ongoing global change on treeline movement and species composition. One potentially significant but little studied factor that impacts the formation of treelines is mortality caused by snow fungi. We studied the mortality patterns of Pinus cembra, a typical treeline species of the Central Alps of Switzerland, in two plantations located on opposite slopes of the Dischma valley (Northeast [NE] and Southwest [SW]) above the current treeline. In 1975, 33,000 P. cembra trees were planted at the NE site and 550 trees at the smaller SW site. All trees have been periodically monitored for survival since then. After 30 years, only ca. 5% of all P. cembra trees survived in both plantations. Two species of pathogenic snow fungus, Gremmeniella abietina and Phacidium infestans, were major mortality agents for saplings. High rates of infection by Gremmeniella corresponded to late snowmelt and high ratios of rainfall to temperature. High rates of infection by Phacidium corresponded to earlier snowmelt and were spatially associated with P. cembra mature trees that had been present in the area before the time of planting. We provide experimental evidence that snow fungi are a primary cause of sapling tree mortality at treeline. Although additional evidence from different geographic regions and more natural treeline distributions is needed, our results suggest that the prevalence of snow fungi may prevent establishment of trees above the current treeline at present, and under future climate scenarios.

Background and Aims: In contrast to the wealth of information on sap flow characteristics of forest trees at low-elevation sites, knowledge is scarce for trees within the treeline ecotone. Thus, our aim was to identify environmental controls on water loss in P. cembra trees at the treeline. Methods: Three isolated individuals were equipped with thermal dissipation probes for monitoring sap flow density (QS ). A Jarvis-type model and multiple linear regression, with irradiance and vapour pressure deficit as explanatory variables, were applied to compare predicted and measured sap flow density. Results: Both models successfully predicted measured QS . The Jarvis model tended to underestimate QS values by 25% on average, as compared with an underestimate of 8% by multiple linear regression analysis. The multiple linear regression analysis also allowed discrimination between effects of irradiance (RS ) and vapour pressure deficit (D) on QS , indicating that RS (s-coefficient = 0.70) had a greater effect on QS...

Tree-ring width and glacier mass balance are two highly sensitive climatic proxies which are often used as indicators of biological and geophysical changes in high-altitude ecosystems. Tree-ring data have been widely used to reconstruct past temperatures and also to reconstruct past glacier mass balance. Here we show that tree-ring chronologies from a high-altitude Pinus cembra L. dendroclimatic network and glaciers from the same region in the European Alps have non-stationary responses to air temperature, and have also been responding non-proportionally to temperature extremes in recent decades. Both ring-width chronologies and the mass-balance series of some glaciers from the same region have shown an increasing sensitivity to summer (JJA) temperatures. Our results demonstrate that the sensitivity to climate of tree-ring chronologies and glacier mass balance may change over time and has been increasing in recent decades, posing some limitations to tree-ring-based glacier mass-balance reconstruc...

Background and Aims: High elevation treelines occur worldwide at similar mean growing season temperatures. Does this result from direct impact of low temperature on growth or carbon metabolism, or does nutrient limitation, induced by low soil temperature, play a role? Similar treeline elevations at contrasting soil fertility argue against the latter, but the actual nutritional status of treeline trees (here addressed as foliage nitrogen concentration) has never been assessed systematically. Although needle nitrogen (N) concentration does not necessarily indicate growth limitation by N, the relative abundance of N would indicate obvious depletions at the treeline. Methods: A central problem with any foliage nutrient assay is that the units for describing the element concentration are dependent on elevation themselves. Here we separate changes in N per unit tissue from changes in reference units. Results: Needles of Pinus cembra and Picea abies in the Alps do not show elevational differences in N concentrat...

This paper reports the results of research carried out in the Roseg Valley (Lower Engadine, Switzerland) that examines debris-flow fan typology, debris-flow activity, and the impact of debris flows on forest vegetation. Depositional landforms from debris flows were subdivided according to their degree of geomorphological hazard. An inventory of debris-flow fans and a detailed geomorphological, vegetational, and dendrochronological study of two of them was undertaken. The dendrochronological analysis allowed dating of historical events and reconstruction of their recent evolution. By dating scars and growth anomalies on Larix decidua Mill. and Pinus cembra L., 24 debris-flow events were identified on the Misaun fan and 16 on the Tschierva fan, and differences in their distribution due to drainage basin characteristics identified. Fans chosen for this investigation are crossed by a hiking trail that is frequently used by tourists during the summer season. A qualitative hazard and risk evaluation were undert...

Due to stresses resulting from their high altitudes, subalpine forests are sensitive to disturbances, including fire. This study analyzes the long-term relationships between fire and subalpine vegetation in the western Alps. High-resolution analyses of charcoal, pollen, macroremains, and other palynomorphs were performed on sedimentary cores from 2 small peaty ponds located above 2000 m asl. in the Maurienne valley, France. Results reveal similar long-term vegetation dynamics, with differences concerning the structure and composition of local and surrounding plant communities. The vegetation pattern appears partially related to local fire occurrence, which was most frequent between 8900 and 6500 cal. BP at one lake and between 4100 and 1800 cal. BP at the second. Fires notably triggered the development and occurrence of populations of Acer and Alnus incana-type during a 2000-y period and the asynchronous alteration of Pinus cembra forests at both sites. Results show that the low-competitive species, i.e., Larix decidua or Pinus uncinata, were never stimulated by increasing fire frequency. This highlights the past importance of local-scale processes such as fire, which favoured pioneer broad-leaved species but did not threaten the resilience of the subalpine forests dominated by the cembra pine.

In the Aigue Agnelle Valley (Queyras, southern French Alps), between 2200 and 2300 m a.s.l., several travertine deposits are present. Some, containing leaf imprints and pine cones, have been dated back to the early Holocene. Others containing charcoal fragments and dating back to the middle Holocene have also been found. The study of the plant imprints and charcoal within these travertines allowed us to reconstruct the vegetation dynamics of this valley. During the early Holocene (9800 B.P.), Pinus uncinata (mountain pine) was the most common tree. It was gradually replaced by Pinus cembra (arrola pine) in association with Betula (birch) and Vaccinium sp. (berry), probably as a result of climatic warming (ca. 7600 B.P.). Since ca. 5600 B.P., Pinus cembra seems to have regressed in correlation with the development of Larix decidua/Picea abies (larch/spruce) as a consequence of fire events related to climatic and/or anthropogenic factors.

US-Central and Eastern European (CEE) collaborative studies on the distribution and effects of air pollution on CEE forests have been conducted since 1992. Based on 1997-1999 ambient ozone (O 3 ) monitoring, maps of O 3 distribution in the Carpathian Mountains of central Europe were developed. These maps helped to understand air pollution risks in the Carpathian forests and to develop national regulations for the protected areas and for forest vegetation monitoring. The Carpathian study led to the establishment of two international long-term ecological research (ILTER) sites in the Retezat (Romania) and Tatra Mountains (Poland and Slovakia). During 2000-2002, differences in responses of natural versus managed forest to air pollution, including biodiversity changes, were investigated. During 2003-2005, research in these two ILTER sites focuses on the evaluation of resources and responses of Swiss stone pine (Pinus cembra L.) to the increasing O 3 concentrations. The US-CEE collaboration helps in establishing a strong partnership between scientists and managers, and comparing the status and effects of air pollution in mountain forests of North America and Europe.

The enantiomeric contents of monoterpenes have been determined in essential oils from the following species: Pinus cembra, Pinus nigra, Pinus pinaster, Pinus montana, Pinus sylvestris, Abies alba and Abies sibirica. A gas chromatographic method with a formamide solution of a-cyclodextrin as a stationary phase was applied for the separation and determination of enantiomers.

The biomass of Pinus sylvestris, Pinus contorta and Pinus cembra seedlings that were raised in three different growing media, as well as of naturally regenerated P. sylvestris saplings, was estimated using functions based on variables measured non‐destructively. These included stem diameter, seedling height, number of needles and branches, length of the longest needle, and projected seedling or sapling crown area. Projected area of a two‐dimensional video image of the seedling or sapling was measured using computer‐based image analysis. The variables were tested in all possible combinations to achieve the best biomass estimate. Projected area alone explained more than 97% of the variation in seedling or sapling mass. Addition of stem diameter increased the degree of explanation to more than 98%, whereas the other variables did not contribute further. Separate functions for species and growing media resulted in more precise estimates than if general functions were used.