scholarly journals Climate-sensitive radial increment model of Norway spruce in Tyrol based on a distributed lag model with penalized splines for year-ring time series

2018 ◽  
Vol 48 (8) ◽  
pp. 930-941 ◽  
Author(s):  
Arne Nothdurft ◽  
Sonja Vospernik
Keyword(s):  
Time Series ◽  
Norway Spruce ◽  
High Temperatures ◽  
Time Lag ◽  
Ring Width ◽  
Penalized Regression ◽  
Penalized Splines ◽  
Radial Increment ◽  
Model Framework ◽  
Lag Model

A novel methodological framework is presented for climate-sensitive modeling of annual radial stem increment using year-ring width time series. The approach is based on a generalized additive model with penalized regression splines together with a distributed time lag model taking into account smooth nonlinear effects of a series of monthly temperature and precipitation values, as well as their interactions. Climate effects are also assumed to vary smoothly with time lag. The model framework enables both the detrending of the individual time series and the regression modeling to be performed simultaneously in a single model step. The approach is applied to year-ring width time series of Norway spruce (Picea abies (L.) H. Karst.) trees in Tyrol, Austria. The marginal response curves show that tree growth is mainly promoted by high temperatures in late spring and early summer and by precipitation in fall and winter. Summer drought does not have a negative influence on the current year’s radial increment; however, when it is associated with high temperatures, it lowers the increment in the subsequent growth period. Higher winter precipitation in conjunction with lower temperatures has a positive effect. A significant non-climate related long-term growth trend is demonstrated, probably reflecting NOx and SO2 emission trends in Austria.

Ecological memory effects in Norway spruce ring-width chronologies across managed forests of Central-East Germany: Implications for modelling and planning

2020 ◽  
Author(s):  
Jakob Wernicke ◽  
Christian Torsten Seltmann ◽  
Michael Körner
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Drought Tolerance ◽  
Norway Spruce ◽  
Memory Effect ◽  
East Germany ◽  
Ring Width ◽  
Managed Forests ◽  
Ecological Memory ◽  
Study Results

<p>The combined negative effects of climate change and adverse forest structures currently result in large amounts of random timber use all over Central Europe. Particularly Norway spruce (Picea abies [L.] Karst) is threatened by summer droughts and secondary pests. Hence, achieving insights in the drought tolerance of spruce is highly relevant to reduce the vulnerability of forest systems under climate change. Especially long-living spruce individuals witness several periods of drought in their ring-width variability. A common measure of trees drought tolerance is referred to resistance, resilience and recovery ability. Besides forest management and site characteristic, the ecological memory of trees might distinctly affect spruce drought tolerance.</p><p>Therefore we investigate the spatio-temporal variability of the ecological memory effect from more than 1500 individual ring-width time series of spruce trees collected from the managed forests of Central-East Germany. The memory effect is examined via time series first to third autocorrelation. We are particularly interested in the question: ‘can trees with a ‘good memory’ cope better with climate extremes than trees with a ‘bad memory’? If so, is it possible to influence the memory of trees via specific thinning strategies? Finally, how can autocorrelation improve the assessment of site productivity, taking the climate change induced displacement of growth areas into consideration? The study results reveal crucial insights in the drought vulnerability of spruce dominated forests in relation to forest structure and management strategies.</p>

scholarly journals Oak decline in a southern Finnish forest as affected by a drought sequence

2014 ◽  
Vol 41 (1) ◽  
pp. 92-103 ◽  
Author(s):  
Kristina Sohar ◽  
Samuli Helama ◽  
Alar Läänelaid ◽  
Juha Raisio ◽  
Heikki Tuomenvirta
Keyword(s):  
Tree Ring ◽  
Time Lag ◽  
Ring Width ◽  
Summer Drought ◽  
Radial Increment ◽  
Pedunculate Oak ◽  
Climate Data ◽  
Tree Ring Data ◽  
The Dead ◽  
Old Trees

Abstract We investigated the decline of a pedunculate oak (Quercus robur L.) forest growing on shallow soil at the northern distributional limit of the species in southern Finland, using the dendroclimatic approach. About 200-year-old trees in three vigour classes — healthy, declining and dead — were sampled in 2008. Annual tree-ring, earlywood and latewood widths were measured and chronologies were established. The tree-ring data were correlated with monthly and seasonal climate data. Radial increment of oaks was positively related to the June and July precipitations. This was expressed especially in total ring width and latewood width, whereas the earlywood was more influenced by the warmer winter and spring. Furthermore, the correlation between the current year earlywood width and the preceding year latewood width was higher than between the earlywood and latewood of the same year. The analyses showed that the dead oaks and part of the declining oaks had ceased growing during 2005–2007 after a decadelong summer drought series. This indicates a time lag in the oak dieback. The radial growth of the declining and the dead oaks had dropped already since the 1990s, while the healthy oaks had better longterm growth and higher adaptive capacity to climate variation.

scholarly journals Pruning effect on Norway spruce (Picea abies (L.) Karst.) growth and quality

2017 ◽  
Vol 66 (1) ◽  
pp. 33-48 ◽  
Author(s):  
Endijs Baders ◽  
Janis Donis ◽  
Guntars Snepsts ◽  
Andis Adamovics ◽  
Aris Jansons
Keyword(s):  
Picea Abies ◽  
Norway Spruce ◽  
Ring Width ◽  
Stand Density ◽  
Stand Age ◽  
Radial Increment ◽  
Annual Increment ◽  
Management Activity ◽  
Spruce Stands ◽  
Occlusion Rate

Abstract Pruning requires significant investment, therefore, the aim of the study was to characterize occlusion of branch wounds and changes in radial increment as well as frequency of browsing damages after pruning of Norway spruce (Picea abies (L.) Karst.) in order to provide data for financial calculations and recommendations for practical forestry. Altogether 1,614 pruned and 4,368 unpruned trees from 45 Norway spruce stands were measured and cored. Degree of wound occlusion and browsing damages were assessed, and additional volume increment estimated in each stand. Pruning resulted in significant increase of length of branch-free section: for unpruned trees it was 0.3 ± 0.07 m, but for pruned 3.4 ± 0.10 m. Branch wounds for most of the trees (68%) were filled with resin (occluded), for lower share of trees (31%) – still open, but for some trees (1%) completely occluded. Branch wound occlusion rate was not affected by differences in stand density, but was significantly affected by stand age: proportion of trees with occluded branch scars increased with age. Trees with occluded branch wounds had a significantly higher increase in tree ring width after the pruning in comparison to the period before pruning than trees with open branch wounds, emphasizing the importance of radial increment in development of branch-free layer of wood. Pruning resulted in minor (−7% or −0.28 ± 0.05 m3 ha−1) reduction of annual increment that was statistically significant only up to 3 years after this forest management activity for stands younger than 17 years and with mean height up to 10.5 m. Pruned trees were significantly more browsed than unpruned (6.1% and 2.7%, respectively).

scholarly journals Disturbances in variation of the annual ring width of Norway spruce in the Polish Western Beskids Mountains

2012 ◽  
Vol 51 (No. 12) ◽  
pp. 539-547 ◽  
Author(s):  
S. Wilczyński ◽  
E. Feliksik
Keyword(s):  
Norway Spruce ◽  
Annual Ring ◽  
Ring Width ◽  
Substantial Effect ◽  
Early Spring ◽  
Late Winter ◽  
Radial Increment ◽  
Growth Responses ◽  
Annual Ring Width ◽  
Spruce Stands

Changes in radial increment of Norway spruce in 25 stands more than 100 years old were analysed. Stands were growing on sites of different exposure situated at 450–1,200 m above sea level in the Polish Western Beskids Mountains. In the mid-1990s a considerable increase in annual ring width was observed. The greatest increase occurred in trees growing at the highest altitudes. This phenomenon occurred after a long period of increment decrease at the turn of the 1970s. After 1990 as the annual ring width was increasing, the variation and amplitude of ring width also increased. The cause of a long-term increase in radial increment was the improvement of thermal and pluvial conditions during late winter and early spring having a substantial effect on Norway spruce growth. In the 1990s the period of rapid changes in thermal and pluvial conditions of summer began. After moist and cold summers there were hot and dry summers. This resulted in increased variations and amplitude of the growth responses of Norway spruce and contributed to the weakening of trees above 100 years of age. The increasing break-up of Norway spruce stands growing in the lower mountain zone of the Polish Western Beskids Mountains, observed in recent years, is the final effect of this process.

A distributed vaporization time-lag model for gas turbine combustor dynamics

1992 ◽  
Author(s):  
JAYESH MEHTA ◽  
P. MUNGUR ◽  
W. DODDS ◽  
L. DODGE
Keyword(s):  
Gas Turbine ◽  
Time Lag ◽  
Gas Turbine Combustor ◽  
Lag Model

scholarly journals A Novel Approach to Evaluate the Effect of Neighboring Trees and the Orientation of Tree Social Area on Stem Radial Increment of Norway Spruce Trees

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 163
Author(s):  
Jan Světlík ◽  
Jan Krejza ◽  
Pavel Bednář
Keyword(s):  
Norway Spruce ◽  
Tree Growth ◽  
Growth Models ◽  
Explanatory Power ◽  
Radial Increment ◽  
Important Indicator ◽  
The Czech Republic ◽  
Novel Approach ◽  
Spruce Stands ◽  
Social Area

Tree growth depends on many factors such as microsite conditions, vitality, and variations in climate and genetics. It is generally accepted that higher growth indicates both an economic benefit and better vitality of any tree. Here we use a modified approach of evaluating tree social area to study mutual tree competition based on the orientation and shape of trees social area. The investigation was performed in nine Norway spruce stands in the Czech Republic. The objective of this study performed from 2008 to 2012 was to quantify relative tree radial increments with respect to the lowest and highest competition found in specific sectors of tree social area (AS). Specific groups of trees (tree classes) were evaluated according to their classes (dominant, co-dominant and sub-dominant) and their composition status in ninety-degree sectors of AS using established classifying rules. The results showed that a spatially-available area (AA) is an inappropriate parameter for predicting tree growth, whereas AS provided robust explanatory power to predict relative radial growth. Tree size was observed as an important indicator of relative radial increments. A significantly positive correlation was found for a radial increment of sub-dominant trees with the lowest competition from western directions; whereas a negative correlation was observed when the lowest competition was observed from eastern directions. For dominant trees, there was an evident growth reaction only when more than 50% of the AS was oriented towards one of the cardinal points. Individual differences in the orientation of tree AS may be important parameters with regard to competition and its spatial variability within an area surrounding a particular tree and deserve more detailed attention in tree growth models and practice.

Effects of cambial age, clone and climatic factors on ring width and ring density in Norway spruce (Picea abies) in southeastern Finland

2012 ◽  
Vol 263 ◽  
pp. 9-16 ◽  
Author(s):  
Ane Zubizarreta-Gerendiain ◽  
Jaume Gort-Oromi ◽  
Lauri Mehtätalo ◽  
Heli Peltola ◽  
Ari Venäläinen ◽  
...  
Keyword(s):  
Picea Abies ◽  
Norway Spruce ◽  
Climatic Factors ◽  
Ring Width ◽  
Ring Density ◽  
Cambial Age

scholarly journals Time since death and decay rate constants of Norway spruce and European larch deadwood in subalpine forests determined using dendrochronology and radiocarbon dating

2016 ◽  
Vol 13 (5) ◽  
pp. 1537-1552 ◽  
Author(s):  
Marta Petrillo ◽  
Paolo Cherubini ◽  
Giulia Fravolini ◽  
Marco Marchetti ◽  
Judith Ascher-Jenull ◽  
...  
Keyword(s):  
Picea Abies ◽  
Decay Rate ◽  
Norway Spruce ◽  
Matrix Model ◽  
Rate Constants ◽  
Radiocarbon Dating ◽  
Time Lag ◽  
Larix Decidua ◽  
European Larch ◽  
14C Dating

Abstract. Due to the large size (e.g. sections of tree trunks) and highly heterogeneous spatial distribution of deadwood, the timescales involved in the coarse woody debris (CWD) decay of Picea abies (L.) Karst. and Larix decidua Mill. in Alpine forests are largely unknown. We investigated the CWD decay dynamics in an Alpine valley in Italy using the chronosequence approach and the five-decay class system that is based on a macromorphological assessment. For the decay classes 1–3, most of the dendrochronological samples were cross-dated to assess the time that had elapsed since tree death, but for decay classes 4 and 5 (poorly preserved tree rings) radiocarbon dating was used. In addition, density, cellulose, and lignin data were measured for the dated CWD. The decay rate constants for spruce and larch were estimated on the basis of the density loss using a single negative exponential model, a regression approach, and the stage-based matrix model. In the decay classes 1–3, the ages of the CWD were similar and varied between 1 and 54 years for spruce and 3 and 40 years for larch, with no significant differences between the classes; classes 1–3 are therefore not indicative of deadwood age. This seems to be due to a time lag between the death of a standing tree and its contact with the soil. We found distinct tree-species-specific differences in decay classes 4 and 5, with larch CWD reaching an average age of 210 years in class 5 and spruce only 77 years. The mean CWD rate constants were estimated to be in the range 0.018 to 0.022 y−1 for spruce and to about 0.012 y−1 for larch. Snapshot sampling (chronosequences) may overestimate the age and mean residence time of CWD. No sampling bias was, however, detectable using the stage-based matrix model. Cellulose and lignin time trends could be derived on the basis of the ages of the CWD. The half-lives for cellulose were 21 years for spruce and 50 years for larch. The half-life of lignin is considerably higher and may be more than 100 years in larch CWD. Consequently, the decay of Picea abies and Larix decidua is very low. Several uncertainties, however, remain: 14C dating of CWD from decay classes 4 and 5 and having a pre-bomb age is often difficult (large age range due to methodological constraints) and fall rates of both European larch and Norway spruce are missing.

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