CONTRIBUTION TO KNOWLEDGE ON THE VARIABILITY OF AROLLA PINE WOODLANDS OF THE NORTH-EASTERN TATRA MOUNTAINS

Knowledge of the overall syntaxonomic and habitat variability of forest communities with Arolla pine (Pinus cembra) within the Tatra Mountains (Western Carpathians) is still insufficient as field research was hindered by their hardly accessible localities and deforestation for high mountain grazing. Arolla pine woodlands were traditionally classified within the association Pino cembrae-Piceetum Myczkowski et Lesinski 1974, but recent surveys recognize more numerous units. Hitherto unpublished releves from the north-eastern part of the Tatra Mountains document the occurrence of several floristically and ecologically distinct Arolla pine communities: (1) acid woodland of Homogyno alpinae-Pinetum cembrae on nutrient-poor habitats over quartzitic bedrock, and (2) calcareous woodlands of species-poor Pyrolo rotundifoliae-Pinetum cembrae of sites with a well-developed, tangled humus soil horizon, Cystopterido montanae-Pinetum cembrae on habitats influenced by both limestones and quartzites, Primulo elatioris-Pinetum cembrae bound to sites with the most favourable humidity, and Seslerio tatrae-Pinetum cembrae with the most pronounced calcareous character.

Specification of Modified Jarvis Model Parameterization for Pinus cembra

The high ambient ozone concentrations cause impairing effects on vegetation leading to plant injuries. The potential ozone uptake to vegetation through open stomata can be quantified using stomatal conductance measurements under the local environmental conditions. This study compares the ozone stomatal conductance to vegetation obtained with a modified Jarvis formula adopted from the Vegetation Manual of United Nations Economic Commission for Europe, and experimental field measurements’ data. The stomatal conductance was measured by a portable photosynthesis and gas exchange analyzer system LiCOR6400. The measurements were performed in the submontane environment of the High Tatra Mountains in Slovakia on Swiss pine (Pinus cembra), as a native species of the local flora. According to previous studies, Swiss pine is considered as an ozone-sensitive species. The modified Jarvis model for the ozone stomatal conductance is compared with the field measurements. The suitable parameterization of the modified Jarvis model for Swiss pine is obtained. The parameterization of stomatal conductance for Swiss pine in the local environment would help understand its specificity and similarity to other conifer species. In the case of using parameterization for a boreal coniferous from the Vegetation Manual of the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops, validation of the model with the measurements without temperature adjustment of the conifer chamber achieved a coefficient of determination of R2=0.75. This result is not in contradiction with the previous researches. With the optimal set of parameters, obtained in this paper, the Jarvis model reaches R2=0.85. The data suggest that Jarvis-type models with appropriate parameterization are applicable for stomatal conductance estimation for Pinus cembra when the measurements do not modify the temperature regime.

Study of the stem growth of heteroplastic grafts of stone pines in the Krasnoyarsk forest-steppe

Changes in the radial growth Pinus sibirica Du Tour and Pinus cembra L. grafts and Scots pine (Pinus sylvestris L.) rootstocks were observed in comparison with control (non-grafted) trees of the corresponding species, whichindicated the mutual influence of the grafting components on each other. The smaller width of the annual rings in Pinuscembra grafts compared to Siberian cedar grafts is due to their species features. In general, the phloem was more conservative in structure than the xylem and in the grafts union zone retained the species characteristics, sometimes manifestedin the form of jagged junction of two types of bark, while in the xylem in the union zone were cells with an intermediatestructure. The study of seasonal dynamics showed that, in comparison with the rootstocks of Scots pine (Pinus sylvestrisL.), the scions of Stone pine quickly passed to the process of maturation of tracheids, especially the scions of Pinus sibirica Du Tour, which also completed the development of xylem annual ring faster. The similarity of some parameters of theanatomical structure, reactions to climatic conditions, synchronization of the development of the annual ring in the scion of the P. cembra with the stock of the Scots pine explain the higher safety of grafts of the P. cembra in comparison withthe P. sibirica.

Cardiorespiratory Interaction and Autonomic Sleep Quality Improve during Sleep in Beds Made from Pinus cembra (Stone Pine) Solid Wood

Cardiorespiratory interactions (CRIs) reflect the mutual tuning of two important organismic oscillators—the heartbeat and respiration. These interactions can be used as a powerful tool to characterize the self-organizational and recreational quality of sleep. In this randomized, blinded and cross-over design study, we investigated CRIs in 15 subjects over a total of 253 nights who slept in beds made from different materials. One type of bed, used as control, was made of melamine faced chipboard with a wood-like appearance, while the other type was made of solid wood from stone pine (Pinus cembra). We observed a significant increase of vagal activity (measured by respiratory sinus arrhythmia), a decrease in the heart rate (as an indicator of energy consumption during sleep) and an improvement in CRIs, especially during the first hours of sleep in the stone pine beds as compared to the chipboard beds. Subjective assessments of study participants’ well-being in the morning and sub-scalar assessments of their intrapsychic stability were significantly better after they slept in the stone pine bed than after they slept in the chipboard bed. Our observations suggest that CRIs are sensitive to detectable differences in indoor settings that are relevant to human health. Our results are in agreement with those of other studies that have reported that exposure to volatile phytochemical ingredients of stone pine (α-pinene, limonene, bornyl acetate) lead to an improvement in vagal activity and studies that show a reduction in stress parameters upon contact with solid wood surfaces.

Comparative anatomy of the conductive tissues of the scions of Pinus sibirica Du Tour, P. cembra L. and their rootstocks P. sylvest

To study the appearance of incompatibility in adult graft trees, we studied the anatomical characteristics ofconducting phloem and sapwood in 55-year-old scions of Pinus sibirica Du Tour and Pinus cembra L. and their rootstocks –Scots pine (Pinus sylvestris L.). It was found that in all variants the width of the sapwood in the rootstock is significantlyhigher than in the scion; however, when only the early tracheids are taken into account, the differences between the scionand the rootstock are not significant, and the total width of the early tracheids from the sapwood is some higher in theP. cembra trees. In the place of rootstock and scion union, the width of the rootstock sapwood decreases due to a decreasein the proportion of late tracheids, while the sapwood of the scion remains almost unchanged. The variability of the sapwood width in scions and rootstocks of the P. cembra is lower and it is less sensitive to the reduction of increments thanin the P. sibirica, it indicates interspecific differences. The average width of the conducting phloem for the growing seasonalso varies less in the P. cembra, and in individuals of the P. sibirica with small xylem increments it approaches the widthof the current xylem increment. The relationship between the width of the conducting phloem and the width of the sapwood is weak; the width of the phloem depends more on the current growth of the xylem. The quantitative differencesin the width of the sapwood and the conducting phloem make it possible to judge the preservation of their species-specificity during long-term coexistence of the scion and the rootstock, as well as the effect of the scion on to the rootstock.

Large-scale historical afforestation failure with Pinus cembra in the Swiss Prealps

Between the nineteenth and early twentieth centuries, large-scale afforestation projects were undertaken in the Swiss Prealps. The Swiss stone pine (Pinus cembra L.), an emblematic alpine tree with important economic potential, conservation value and ecological relevance, was one of the species used in these afforestation efforts. We investigated the distribution and site characteristics of all known natural populations and planted stands in the canton of Fribourg (Switzerland). Between 1885 and 1952, artificial afforestation was carried out in the mountainous regions of the canton of Fribourg. Nearly 450,000 seedlings of P. cembra were planted. One century later, only approximately 650 trees survived (0.15% of all planted trees). Moreover, no natural regeneration can be observed in the afforested stands. Since no known harvest activities were undertaken in these planted stands, the whole afforestation campaign of P. cembra in the canton of Fribourg can be described as a failure. Possible causes are investigated and discussed. In this region, P. cembra occurs naturally only in particular microrefugia with markedly rough topography. We argue that the lack of knowledge or consideration of the ecology of the species at a local scale can be an important factor leading to this failure. In the actual context of large-scale afforestation projects anticipating and mitigating the negative effects of global warming, our study highlights the importance of a precise understanding of species ecology and regional conditions.

Diversity of Essential Oils and the Respective Hydrolates Obtained from Three Pinus cembra Populations in the Austrian Alps

Pinus cembra, stone pine, is an Alpine coniferous tree rich in aromatic compounds. Twigs with needles are used commonly to produce essential oils for various purposes in pharmacy, food industry, and cosmetics. Hydrolates as byproducts of hydrodistillation encounter increasing interest owing to their aromatic properties. The variabilities in the compositions of essential oil and the related hydrolates are studied in samples from individual trees growing on three sites in the Austrian high mountain range. The essential oils have been obtained by steam distillation. All essential oils contained monoterpene hydrocarbons as main compounds, especially α-pinene (36–37%), β-phellandrene (27–30%), and β-pinene (7–9%). In contrast, the volatiles in the corresponding hydrolates were dominated by oxidized compounds as α-terpineol (28–34%), terpinen-4-ol (6–8%), and verbenone (6–7%). The pinene rich essential oils might be used in pharmacy as pinene containing oils from other Pinus species, while the hydrolates are of interest for cosmetics and other well-being promoting products.

Cavitation fatigue in conifers: a study on eight European species

After drought-induced embolism and repair, tree xylem may be weakened against future drought events (cavitation fatigue). Since there are few data on cavitation fatigue in conifers available, we quantified vulnerability curves (VCs) after embolism/repair cycles on eight European conifer species. We induced 50 and 100% loss of conductivity (LC) with a cavitron, and analysed VCs. Embolism repair was obtained by vacuum infiltration. All species demonstrated complete embolism repair and a lack of any cavitation fatigue after 50% LC. After 100% LC, European larch (Larix decidua), stone pine (Pinus cembra), Norway spruce (Picea abies) and silver fir (Abies alba) remained unaffected, while mountain pine (Pinus mugo), yew (Taxus baccata) and common juniper (Juniperus communis) exhibited 0.4 to 0.9 MPa higher vulnerability to embolism. A small cavitation fatigue observed in Scots pine (Pinus sylvestris) was probably biased by incomplete embolism repair, as indicated by a correlation of vulnerability shifts and conductivity restoration. Our data demonstrate that cavitation fatigue in conifers is species-specific and depends on the intensity of preceding LC. The lack of fatigue effects after moderate LC, and relevant effects in only three species after high LC, indicate that conifers are relatively resistant against cavitation fatigue. This is remarkable considering the complex and delicate conifer pit architecture and may be important considering climate change projections.

Larch Cellulose Shows Significantly Depleted Hydrogen Isotope Values With Respect to Evergreen Conifers in Contrast to Oxygen and Carbon Isotopes

The analysis of the stable isotope of the tree-ring cellulose is an important tool for paleo climatic investigations. Long tree-ring chronologies consist predominantly of oaks and conifers in Europe, including larch trees (Larix decidua) and cembran pines (Pinus cembra) that form very long tree ring chronologies in the Alps and grow at the treeline, where tree growth is mainly determined by temperature variations. We analyzed δ13C, δ18O and δ2H isotopes in the cellulose extracted from tree-rings of wood samples collected at high altitude in the Swiss and Tyrol Alps, covering the whole Holocene period. We found that larch cellulose was remarkably more depleted in deuterium than that of cembran pine, with mean δ2H values of −113.4 ± 9.7‰ for larch and of −65.4 ± 11.3‰ for cembran pine. To verify if these depleted values were specific to larch or a property of the deciduous conifers, we extended the analysis to samples from various living conifer species collected at the Bern Botanical Garden. The results showed that not only the larch, but also all the samples of the deciduous larch family had a cellulose composition that was highly depleted in δ2H with regard to the other evergreen conifers including cembran pine, a difference that we attribute to a faster metabolism of the deciduous conifers. The δ18O values were not statistically different among the species, in agreement with the hypothesis that they are primary signals of the source water. While the δ13C values were slightly more depleted for larch than for cembran pine, likely due to metabolic differences of the two species. We conclude that the deciduous larch conifers have specific metabolic hydrogen fractionations and that the larch unique signature of δ2H is useful to recognize it from other conifers in subfossil wood samples collected for paleoclimatic studies. For climate information the absolute δ2H values of larch should be considered carefully and separate from other species.