Locations of the pine sites (N, M, S) superimposed on high-resolution 10 °ø 10 grids (gray lines) showing spatial differences in June–August (a) temperature, (b) precipitation, and (c) drought anomalies (with respect to 1903–2000). Drought (i.e., soil moisture availability) values were calculated using relative ZIND according to Trnka et al. (2009), and negative values refer to comparatively dry regions. (d) Mean monthly air temperature values (lines) and precipitation sums (columns) computed for the three grid boxes corresponding to the three pine sites during the 1903–2000 period. It should be noted that (a–c) were based on combinations of high resolution (10 °ø 10) grid CRU TS 1.2 data points and values derived from a digital terrain model to highlight the main topographic features throughout the study region.
Abstract:
Carpathian pine growth at its natural range limit, where small hydroclimatic fluctuations are indicated by tree-ring width anomalies, may provide insight into past ecological responses to climatic changes. Tree-ring chronologies from extreme cliff sites may also contain annually resolved and accurately dated information to facilitate the development of palaeoclimatic reconstructions. Complex and spatiotemporally inconsistent relationships between biotic and abiotic factors, however, often complicate our understanding of forest growth dynamics. In this study, we utilized a novel ensemble approach of 3240 growth–climate interactions to evaluate the likelihood of temporal fluctuations in the hydroclimatic sensitivity of three newly developed tree-ring width chronologies from 515 Scots pines (Pinus sylvestris).
The data represent undisturbed cliff habitats across the northwestern Carpathian arc between 700 and 1050 m asl. These sites are located in the northern (N) and southern (S) Tatra Mountains and in-between (M). Two sites (N, S) share common interannual to multi-decadal ring width variability (r = 0.73), and they significantly capture variations in 20th-century summer drought conditions (r = 0.52–0.65). Temporal
instability in the growth–climate response, however, occurred in all three tree-ring chronologies, thus challenging any possible palaeoclimatic value. Orographic-induced climatology was found to dominate the observed growth–climate inconsistency, whereas age-related physiological mechanisms and differences in the absolute growth levels of the trees, as well as methodological standardization constraints and seasonal climate differences appeared to be less important. Our results suggest that environmental and ecological site criteria should be routinely supplemented by statistical data assessments prior to employing tree-ring chronologies for climate reconstructions.
In: 160: 100-109