High-elevation Spruce Research Articles

Influences of Succession and Biogeoclimate on Forage Resources for Elk in Northern Idaho

Natural disturbance shaped forest communities for millennia, but fire suppression and timber harvest declines have altered forest structure across the western United States, reducing the abundance of forage for ungulates. We evaluated quality and quantity of forage resources for lactating elk (Cervus canadensis) and their calves in relation to season, succession, and biogeoclimate, the latter indexed by potential vegetation (PV) zones, across 36,500 km2 in Idaho's Clearwater and St. Joe River basins. In 0.2-ha macroplots (n = 359), we measured characteristics of forest overstory, biomass of current annual growth of undergrowth vegetation (kg ha-1), and nutritional content of these plants. Using biomass, digestible energy (kJ g-1), digestible protein (DP, g per100 g forage), and prior knowledge of elk diet selection and nutritional constraints, we developed 8 forage resource metrics. The greatest abundance of undergrowth vegetation (500 to 1,000 kg ha-1) occurred during the first 20 years after stand-replacing disturbance and declined as the overstory closed in wetter PV zones. Digestible energy decreased, whereas DP increased as stands aged. Evidence of nutritional limitations for lactating elk increased markedly after mid-summer; early-seral, high-elevation spruce–fir forests on productive soils provided the best opportunity for lactating elk to satisfy their requirements in late summer. Our findings demonstrate the importance of disturbance regimes that maintain early-seral communities in mosaics with mid- and late-seral stages, and suggest that implementing stand-replacing disturbance in relatively moist forest zones at mid and high elevations provides the greatest improvement in forage resources for lactating elk and their calves in summer.

Using image analysis for quantitative assessment of needle bladder rust disease of Norway spruce.

High elevation spruce forests of the European Alps are frequently infected by the needle rust Chrysomyxa rhododendri, a pathogen causing remarkable defoliation, reduced tree growth and limited rejuvenation. Exact quantification of the disease severity on different spatial scales is crucial for monitoring, management and resistance breeding activities. Based on the distinct yellow discolouration of attacked needles, it was investigated whether image analysis of digital photographs can be used to quantify disease severity and to improve phenotyping compared to conventional assessment in terms of time, effort and application range. The developed protocol for preprocessing and analysis of digital RGB images enabled identification of disease symptoms and healthy needle areas on images obtained in ground surveys (total number of analysed images n = 62) and by the use of a semiprofessional quadcopter (n = 13). Obtained disease severities correlated linearly with results obtained by manual counting of healthy and diseased needles for all approaches, including images of individual branches with natural background (R 2 = 0.87) and with black background (R 2 = 0.95), juvenile plants (R 2 = 0.94), and top views and side views of entire tree crowns of adult trees (R 2 = 0.98 and 0.88, respectively). Results underline that a well‐defined signal related to needle bladder rust symptoms of Norway spruce can be extracted from images recorded by standard digital cameras and using drones. The presented protocol enables precise and time‐efficient quantification of disease symptoms caused by C. rhododendri and provides several advantages compared to conventional assessment by manual counting or visual estimations.

Effects of opening size and microsite on performance of planted tree seedlings in high-elevation Engelmann spruce–subalpine fir forests managed as mountain caribou habitat in British Columbia

Old-growth, high-elevation spruce–fir forests of the Quesnel Highland in south-central British Columbia provide winter habitat for threatened mountain caribou (Rangifer tarandus caribou (Gmelin)) and contain valuable wood resources. A group selection silvicultural system may protect caribou habitat and allow some timber extraction, if combined with timely regeneration and an extended rotation length. Sporadic seed production can limit natural regeneration and planting may be required to ensure successful regeneration after harvest. However, the opening sizes and planting microsites required for adequate tree growth and survival in these high-elevation sites are unknown. We examined, for 15years following planting, how growth and survival of planted subalpine fir (Abies lasiocarpa (Hook.) Nutt.), Engelmann spruce (Picea engelmannii Parry ex. Engelm.), and lodgepole pine (Pinus contorta Dougl. Ex Loud.) varied with harvest opening size (0.03, 0.13, 1.0ha), planting microsite (raised, protected, rotten wood, scarified, and a control) and elevation.Survival and growth was less in the higher elevation sites and generally increased with opening size, with the increase greater in the lower elevation sites. Survival varied from 12% for lodgepole pine in small openings at higher elevation to 82% for fir in large openings at lower elevation. Overall, fir had the greatest survival. Fir growth increased the most with opening size at higher elevation; pine growth increased the most with opening size at lower elevation. Survival was generally greater on raised, protected, or rotten wood microsites. Growth varied less across microsites than did survival and also varied less across microsites than across opening sizes or elevations. Increased seedling growth and survival for all species was associated with treatments that had earlier snowmelt and higher soil temperatures. Two cycle budworm (Chroistoneura biennis Freeman) decreased seedling growth in years of heavy infestation. In higher elevation sites, pine had the greatest average height, but relatively low survival and vigor. The poor survival of pine, its lower long-term projected growth rates, and a crown structure which does not facilitate lichen accumulation and its accessibility to caribou, make pine unsuitable for regenerating these forests managed for mountain caribou. Using the group selection silvicultural system on appropriate sites with openings greater than 0.13ha and with optimal planting microsites should allow for some extraction of timber while maintaining the old-growth attributes needed for caribou habitat in these subalpine forests.

Abiotic Microhabitat Parameters of the Spruce—Fir Moss Spider,Microhexura montivagaCrosby and Bishop (Araneae: Dipluridae)

Abstract The Spruce—fir Moss Spider (Microhexura montivaga) is a federally endangered species found only in the high-elevation southern Appalachian spruce—fir forests. Little is known about the basic ecology of the spider. The goal of this project was to determine the temperature and humidity parameters of the microhabitat around known spider locations. iButton temperature and humidity data loggers were placed at sites on Mt. Lyn-Lowry, Browning Knob, Whitetop Mountain, and Mt. Rogers (a range that encompasses all metapopulations). No statistically significant (P > 0.05) differences in humidity between positive and negative presence sites, among metapopulations, or individual sites were found. Temperature data showed varied results. This research provides a number of applications for the conservation and management of the Spruce—fir Moss Spider, such as understanding metapopulation variation, better husbandry techniques, and using collected data to determine conversion factors/models for temperature data ...

Recent reduction in the frequency of frost accounts for most of the increased growth of a high elevation spruce forest in northwestern China

Key message Using process-based models in combination with dendrochronological measurements provides a way to explain recent increased tree growth in northwestern China.

Interspecific aggression by the Swainson's Thrush (Catharus ustulatus) may limit the distribution of the threatened Bicknell's Thrush (Catharus bicknelli) in the Adirondack Mountains

ABSTRACT Bicknell's Thrush (Catharus bicknelli) is a threatened species that inhabits high-elevation spruce–fir forests in the northeastern United States. Bicknell's Thrush populations are predicted to shift upslope in response to global warming, leading to local extinctions on mountains that lack the elevational extent to accommodate such shifts. However, biotic interactions may influence how montane species respond to changing abiotic conditions. In territorial songbirds, for example, aggression from dominant low-elevation species has been hypothesized to combine with warming temperatures to “push” populations of subordinate montane species upslope at a faster rate than in the absence of interspecific aggression. This “push” hypothesis could apply to Bicknell's Thrushes: the related Swainson's Thrush (Catharus ustulatus) inhabits lower elevations, Bicknell's Thrushes are largely confined to mountaintops, and interspecific aggression by Swainson's Thrushes toward Bicknell's Thrushes has been anecdotally ...

Effects of calcium treatment on forest floor organic matter composition along an elevation gradient

Calcium amendment is a restorative option for nutrient-depleted, acidic soils in the forests of the northeastern United States. We studied the effects of watershed-scale wollastonite (CaSiO3) application on the structural composition of soil organic matter (SOM) and hot-water-extractable organic matter (HWEOM) at the Hubbard Brook Experiment Forest in New Hampshire 7–9 years after treatment, along an elevation gradient. Soils in the high-elevation spruce–fir–birch (SFB) zone contained significantly greater amounts of HWEOM compared with lower elevation hardwood soils, likely due to differences in litter quality and slower decomposition rates in colder soils at higher elevation. The only significant difference in hot-water-extractable organic carbon concentration between reference and calcium-treated watersheds was in Oie horizons of the SFB zone, which also exhibited the greatest degree of soil chemical change after treatment. The 13C nuclear magnetic resonance (NMR) spectra showed no significant patterns in O-alkyl C abundance for either soil or HWEOM along the elevation gradient, suggesting that there were no elevation-related patterns in carbohydrate concentration. The general absence of long-term effects in this study suggests that effects of Ca amendment at this dosage on the composition of SOM were small or short-lived.

Epiphytic lichen conservation in the Italian Alps: the role of forest type

Epiphytic lichens are a functionally important and species-rich component of Alpine forests, including several species of conservation concern. Their dependence on specific host trees predicts that forests with different tree species composition host different lichen communities, enhancing lichen diversity in forest landscapes. In this study, we tested for the first time the effect of forest type on patterns of epiphytic lichen diversity, in the Italian Alps. We sampled the main forest types of the South Tyrol, a typical Alpine region of Italy. We also assessed the influence of factors related to forest structure and climatic conditions. Our results demonstrate that different forest types host statistically different lichen communities, suggesting that the conservation of lichen diversity is entrusted to the maintenance of forest landscape heterogeneity, including forest types of minor economic value and rural habitats. The highest number of species was found in grazed larch forests and in high-elevation spruce forests, while the poorest pool was found in low-elevation spruce forests, beech forests and Scots pine ( Pinus sylvestris ) forests. High-elevation spruce forests also had the highest number of red-listed lichens, as the non-intensive management of these forest type allows the establishment of a rich lichen biota. Our results also emphasize the role for lichen conservation of some forest types that are of minor economic importance, such as oak ( Quercus pubescens ), riparian, and silver-fir ( Abies alba ) forests. This can also apply to grazed larch ( Larix decidua ) forests that are maintained by traditional farming, which shape one of the most pleasing aspects of the Italian Alpine landscapes. • Does forest type predict epiphytic lichen diversity in the Italian Alps? • We studied epiphytic lichen communities in the main forest types of the Italian Alps. • Significant differences in species composition and richness were found among forest types. • Conservation of lichen diversity is linked to the maintenance of forest landscape heterogeneity. • Forest with low-economic value highlighted also a key role on lichen conservation.

Ecosystem Succession and Nutrient Retention: Vitousek and Reiners' Hypothesis

What mechanisms mediate the flow of energy and cycling of nutrients during ecological succession? Are they linked in time and across space? In 1969, Eugene P. Odum proposed a series of hypotheses that caused the ecological community to think critically about patterns and processes (sensu Watt 1947) during ecological succession and how they might be linked in a causal manner. Odum’s perspective on the process of succession, or “the strategy of ecosystem development” as he termed it, was undoubtedly shaped by the intellectual influence of his mentor, Victor Shelford, as well as Shelford’s contemporaries such as Fredrick Clements. They shared the idea that ecological communities possessed emergent properties, wherein the whole is greater than the sum of its parts (sensu Phillips 1934). Inasmuch, the 24 hypotheses Odum (1969) articulated were an amalgam of holism and reductionism that created his rationale for the way energy flows and nutrients cycle within ecosystems. It is within this context that Peter Vitousek and Bill Reiners derived ideas that are fundamental to our understanding of energy flow and nutrient cycling in terrestrial ecosystems, ideas that have profoundly shaped my thinking as an ecologist.

Separating forest continuity from tree age effects on plant diversity in the ground and epiphyte vegetation of a Central European mountain spruce forest

Forest continuity has been identified as an important factor influencing the structure and diversity of forest vegetation. Primary forests with centuries of continuity are usually more diverse than young secondary forests as forest are colonized only slowly and because the former are richer in old tree individuals. In the present study, performed in unmanaged high-elevation spruce forests of the Harz Mountains, Germany, we had the unique opportunity to separate the effects of forest continuity and tree age on plant diversity. We compared an old-growth spruce forest with century-long habitat continuity with an adjacent secondary spruce forest, which had naturally established on a former bog after 1796 when peat exploitation halted. Comparative analysis of the ground and epiphyte vegetation showed that the plant diversity of the old-growth forest was not higher than that of the secondary forest with a similar tree age of >200 years. Our results suggest that a period of >200 years was sufficient for the secondary forest to be colonized by the whole regional species pool of herbaceous and cryptogam forest plants and epiphytes. Therefore, it is likely that habitat structure, including the presence of old and decaying trees, was more important for determining plant diversity than the independent effect of forest continuity. Our results are probably not transferrable to spruce forests younger than 200 years and highly fragmented woodlands with long distances between new stands and old-growth forests that serve as diaspore sources. In addition, our results might be not transferable to remote areas without notable air pollution, as the epiphyte vegetation of the study area was influenced by SO2 pollution in the second half of the 20th century.

Sustainable forest management of Natura 2000 sites: a case study from a private forest in the Romanian Southern Carpathians

Biodiversity and forest management are analyzed for a 500 ha privately owned forest within the Natura 2000 area “ROSCI0122 Muntii Fagaras”. Habitat types and indicator species are identified to measure environmental quality. Working towards an integrated approach to conservation, a range of options that will result in sustainable forest management are then considered. For beech forests light heterogeneity emerges as a crucial management target to ensure tree species richness and structural diversity as a basis for saving indicator species such as Morimus funereus, Cucujus cinnaberinus, Bolitophagus reticulatus and Xestobium austriacum . For spruce forests thinning over a broad range of diameters and maintenance of veteran trees would provide habitats for indicator species such as Olisthaerus substriatus . The populations of a number of bird species would be increased by strip-harvesting slopes: species such as Tetrao urogallus, Bonasia bonasia and Ficedula parva prefer forest margins. Steep slopes, and the areas around springs and watercourses, as well as rock faces, should remain unmanaged. Future management should start with a grid-based inventory to create an objective database of forest structure and life. An example is presented for high-elevation spruce forest. The inventory should quantify the variations in diameter, height and volume of trees per unit area. Such data would allow the advanced planning of forest operations. We discuss a wide range of administrative and organizational changes; changes that are needed for the sustainable forest management of the vast close-to-natural forests of the Muntii Fagaras, the maintenance of the Nardus grasslands and the protection of wetland vegetation around springs and streams in this Natura 2000-area.

Microbial community diversity and composition across a gradient of soil acidity in spruce–fir forests of the southern Appalachian Mountains

Anthropogenic deposition of sulfur (S) and nitrogen (N) contributes substantially to soil acidity in some forest regions and hence studies have focused on modeling and quantifying depositions in landscapes. The resulting acidity can change the soil chemical balance, nutrient availability, microbial communities, and at a broader scale, ecosystem functioning. In this study, a 16S PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) approach was used to measure the bacterial diversity and identify the dominant bacterial species along a soil acidity gradient in high elevation spruce–fir forests of Great Smoky Mountains National Park (GSMNP). Sample sites were selected based upon modeled S deposition class (6–14, 15–23, 23–32, and 33–41kgha−1). Collected soils were analyzed for pH, C, N, Ca, Al, S, CEC, and base saturation. Average soil pH in the O, A, and B horizons were 3.6, 3.6 and 3.9, respectively. Modeled S deposition was found to be an unreliable predictor of soil S content as well as most other soil chemical properties. DGGE profiles of bacterial partial 16S rRNA genes revealed minor differences in bacterial diversity while communities were similar, dominated by members of phylum Actinobacteria, Acidobacteria, Planctomycetes, Proteobacteria, and Chloroflexi. Dominance of acidophilic bacterial species, often found in highly acidic environment such as acid-mine drainage and sphagnum bogs, suggests that the poorly buffered soils that are endemic to southern Appalachian spruce–fir forests are saturated with acidity. Our results suggest that stricter air quality standards have not resulted in shift to less acid-tolerant bacteria.

Coarse woody debris retention in subalpine clearcuts affects ectomycorrhizal root tip community structure within fifteen years of harvest

Shifts in ectomycorrhizal (ECM) fungal community composition occur after clearcut logging, resulting in the loss of some dominant forest fungi. Because decaying wood is a remnant of the original forest and an important habitat for ECM fungal species, we examined ECM spruce roots and hyphae in 1-ha coarse woody debris (CWD) retention and removal plots (N=3) at a high elevation spruce forest 12 and 13 years after clearcut harvesting to test for a medium-term effect of CWD retention. Root tips from ten Picea engelmannii (Parry ex. Engelm.) saplings per plot were grouped morphologically, and the ECM fungal symbiont identified by Sanger sequencing. Sand-filled hyphae-trapping mesh bags were buried amongst the roots of saplings for one year. PCR product from all bags per plot was pooled and submitted for GS-FLX Titanium sequencing. Forty-six of 89 operational taxonomic units (OTUs) from root tips and 50 OTUs from hyphae were identified as ECM taxa. The most abundant taxa amongst root tip OTUs were Thelephora terrestris, Alloclavaria purpurea, Amphinema byssoides, and Tylospora asterophora. The most abundant OTUs from mesh bags were ectomycorrhizal taxa, and the most abundant of these were A. byssoides, T. terrestris, Wilcoxina mikolae, and T. asterophora. The retention of CWD had no detectable effect on taxon richness, evenness or diversity of ECM fungi on root tips or in mesh bags; however, there was a detectable shift in species composition. The relative abundance of A. byssoides root tips was significantly higher at removal plots while A. purpurea was a significant indicator species for CWD removal. Our results suggest that the retention of CWD at the time of harvest has affected ECM habitat at this site, and has resulted in altered ECM species composition, even though the logs are still hard and intact.

Rapid recovery of stem increment in Norway spruce at reduced SO2 levels in the Harz Mountains, Germany

Tree-ring width of Picea abies was studied along an altitudinal gradient in the Harz Mountains, Germany, in an area heavily affected by SO2-related forest decline in the second half of the 20th century. Spruce trees of exposed high-elevation forests had earlier been shown to have reduced radial growth at high atmospheric SO2 levels. After the recent reduction of the SO2 load due to clean air acts, we tested the hypothesis that stem growth recovered rapidly from the SO2 impact. Our results from two formerly damaged high-elevation spruce stands support this hypothesis suggesting that the former SO2-related spruce decline was primarily due to foliar damage and not to soil acidification, as the deacidification of the (still acidic) soil would cause a slow growth response. Increasing temperatures and deposited N accumulated in the topsoil are likely additional growth-promoting factors of spruce at high elevations after the shortfall of SO2 pollution.

Elevational gradients of bryophyte diversity, life forms, and community assemblage in the southern Appalachian Mountains

We investigated the influence of fine-scale elevational gradients and overstory disturbance on bryophyte distribution, diversity, and community composition. Bryophyte species cover and richness were sampled across 60 randomly selected plots within high-elevation spruce–fir ( Picea – Abies ) forests of Great Smoky Mountains National Park. Ordination and regression analyses revealed a fine-scale elevation gradient (700 m) in bryophyte community composition. Observed changes in bryophyte diversity and community composition were also associated with variation in deciduous basal area and thus litter composition, the prevalence of herbaceous plants, and the degree of canopy openness resulting from balsam woolly adelgid ( Adelges piceae Ratz.) infestation. Although overstory disturbances, such as those caused by the adelgid, create suitable substrate for bryophyte colonization, the corresponding increase in light availability and deciduous basal area may alter bryophyte diversity and community assemblages.

A New Vole (Cricetidae: Arvicolinae: Proedromys) from the Liangshan Mountains of Sichuan Province, China

Abstract In 2000, 2002, and 2006 we captured small mammals in the Liangshan Mountains, Mabian Dafengding National Nature Reserve and Meigu Dafengding National Nature Reserve, Sichuan Province, China. Among the collected specimens we identified a new species of the genus Proedromys. Its identifying characteristics are its relatively long tail, broad upper incisors without grooves, comparatively short lower incisors, and features of the molar teeth. The glans penis of the new species also is distinctive, the proximal and distal bacula are bony, whereas the lateral bacula are only slightly ossified. The proximal baculum is flask-shaped, the distal baculum is cap-shaped, and the lateral bacula are stick-shaped. This species is associated with high-elevation spruce–fir forest habitat, an unusual setting for Proedromys across its geographic range.

Soil organic carbon dynamics along a climatic gradient in a southern Appalachian spruce–fir forest

A field study was conducted in a high-elevation spruce–fir ( Picea rubens Sarg. – Abies fraseri (Pursh.) Poir) forest in the Great Smoky Mountains National Park to assess the effect of temperature on soil C storage and dynamics. In eight plots along an elevation gradient (1500–1900 m), we measured soil temperature, forest floor and mineral soil C, litter decomposition, soil respiration, and forest floor mean residence time. Mean annual soil temperature and annual degree-days above 5 °C were inversely correlated with elevation. Total soil C (166–241 Mg·ha–1) showed no trend with elevation, while forest floor C accumulation (16.3–35.9 Mg·ha–1) decreased significantly with elevation. Carbon dynamics did not follow a consistent elevation pattern; however, the cooler upper elevations showed the lowest C turnover as indicated by the lowest needle decomposition rate (k = 0.0231·year–1) and the longest mean residence time of forest floor C (22 years). Mean annual CO2efflux from the soil (1020–1830 kg C·ha–1·year–1) was negatively correlated with mean annual soil temperatures and annual degree-days above 5 °C. This gradient study offers useful insights into C release patterns under future warming scenarios, and suggests that the highest elevation may be most susceptible to global warming.

Carbon sources and sinks in high-elevation spruce–fir forests of the Southeastern US

Abstract This paper examines carbon (C) pools, fluxes, and net ecosystem balance for a high-elevation red spruce–Fraser fir forest [Picea rubens Sarg./Abies fraseri (Pursh.) Poir.] in the Great Smoky Mountains National Park (GSMNP), based on measurements in fifty-four 20 m × 20 m permanent plots located between 1525 and 1970 m elevation. Forest floor and mineral soil C was determined from destructive sampling of the O horizon and incremental soil cores (to a depth of 50 cm) in each plot. Overstory C pools and net C sequestration in live trees was estimated from periodic inventories between 1993 and 2003. The CO2 release from standing and downed wood was based on biomass and C concentration estimates and published decomposition constants by decay class and species. Soil respiration was measured in situ between 2002 and 2004 in a subset of eight plots along an elevation gradient. Litterfall was collected from a total of 16 plots over a 2–5-year period. The forest contained on average 403 Mg C ha−1, almost half of which stored belowground. Live trees, predominantly spruce, represented a large but highly variable C pool (mean: 126 Mg C ha−1, CV = 39%); while dead wood (61 Mg C ha−1), mostly fir, accounted for as much as 15% of total ecosystem C. The 10-year mean C sequestration in living trees was 2700 kg C ha−1 year−1, but increased from 2180 kg C ha−1 year−1 in 1993–1998 to 3110 kg C ha−1 year−1 in 1998–2003, especially at higher elevations. Dead wood also increased during that period, releasing on average 1600 kg C ha−1 year−1. Estimated net soil C efflux ranged between 1000 and 1450 kg C ha−1 year−1, depending on the calculation of total belowground C allocation. Based on current flux estimates, this old-growth system was close to C neutral.

Performance of planted Engelmann spruce and subalpine fir seedlings in British Columbia's southern mountains

We compared survival and growth of planted seedlings of Engelmann spruce and subalpine fir across a range of harvest opening sizes (> 10 ha, 1 ha, 0.2 ha, 0.1 ha, 0.03 ha and individual tree selection) from three silvicultural systems trials in high-elevation spruce – subalpine fir forests in south-central British Columbia. Climatic patterns and growing season air and soil temperatures were similar across sites. Seedling survival decreased with opening size. Local site climates, influenced by aspect and moisture and air drainage, were more influential than elevation. Seedling growth was best in large openings and similar in opening sizes from 1 ha to 0.1 ha. Smaller openings created by group selection and individual tree selection methods were not favourable for successful planting at elevations close to timberline. The two species had similar absolute and relative growth rates but spruce responded more strongly to better growing environments. Key words: planted seedlings, Engelmann spruce, Picea engelmannii Parry ex Engelm., subalpine fir, Abies lasiocarpa (Hook.) Nutt., opening size, elevation effects, silvicultural systems, British Columbia, mountain forests

Spatial reconstruction of summer temperatures in Central Europe for the last 500 years using annually resolved proxy records: problems and opportunities

Most palaeoclimate studies in Central Europe, utilizing annually resolved proxies such as tree-ring and documentary sources to reconstruct past temperatures, have focused mainly upon single sites or regional studies. The combined information of published summer temperature reconstructions from the Alpine region show a generally coherent picture of cool conditions for the periods c. 1450–1475, 1575–1610, 1660–1710, 1800–1850 and 1875–1925. These reconstructed cool periods can be partly explained by external forcing (e.g. low solar activity and volcanic events). However, these reconstructions, in their present form, cannot be used to comparatively assess spatial summer temperature variability through the region due to methodological differences in their development and the fact that many of them were not originally developed to emphasize spatial patterns. We propose that a network of tree-ring chronologies which have been processed in a consistent way would allow the robust reconstruction of spatial summer temperature variability for high elevations in Central Europe. Unfortunately, most living tree-ring chronologies only go back into the 18th century — so restricting the length of reconstruction. As a possible solution, we introduce a historical database of ring-width series, measured from string instruments, that could be used to extend high elevation spruce chronologies in Central Europe back for at least 500 years.