Bootstrap confidence intervals for red spruce ring-width chronologies and an assessment of age-related bias in recent growth trends

1990 ◽  
Vol 20 (9) ◽  
pp. 1326-1331 ◽  
Author(s):  
Edward R. Cook
Keyword(s):  
Growth Rate ◽  
Confidence Intervals ◽  
Radial Growth ◽  
Ring Width ◽  
Red Spruce ◽  
Tree Age ◽  
Bootstrap Confidence Intervals ◽  
Age Related ◽  
Growth Increase ◽  
Recent Trends

Bootstrap confidence intervals are developed for mean ring-width chronologies of red spruce (Picearubens Sarg.). These confidence intervals are robust, easy to compute, and useful for determining the "significance of recent trends in radial growth that may be related to forest decline. By comparing the mean chronologies of different age-classes of red spruce trees in two different collections, it is shown that a serious age-related bias may result if the series are blindly averaged without considering the differences in growth rate related to tree age and stand dynamics. However, even when age differences are taken into account, there is evidence for a common increase in radial growth rate of red spruce in the 1950s followed by rapid and sustained decrease after 1960. The cause of this widespread growth increase and decrease has not yet been established, and some current hypotheses are discussed.

scholarly journals Growth and yield estimation of Chamaecyparis spp. through tree ring analysis

2013 ◽  
Vol 22 (2) ◽  
pp. 36-42 ◽  
Author(s):  
D. K. Kharal ◽  
T. Fujiwara
Keyword(s):  
Tree Ring ◽  
Radial Growth ◽  
Ring Width ◽  
Forest Products ◽  
Growth And Yield ◽  
Tree Age ◽  
Biomass Estimation ◽  
Tree Ring Analysis ◽  
Ring Density ◽  
Ring Analysis

Tree ring analysis is one of the most useful methods in volume and biomass estimation especially of the conifer trees. Ring width and ring density are important parameters in dendrochronological research. The present research was carried out with the aim of estimating the radial and volumetric growth of the Japanese Cypress trees (Chamaecyperis obstusa and C. pisifera). Destructive method was used while collecting the wood samples from the selected trees. Ring width and ring density were measured using soft X-ray densitometry method using micro-densitometer. Computer programme, developed by the Forestry and Forest Products Research Institute, Japan was used to analyze the ring with and ring density data. The average ring width of the Chamaecyparis spp. was found to be about 3.4 mm at the age of 30 years. However, two types of growth pattern were observed in the trees. Average radial growth was about 5% every year during the first 20 years of the tree age, whereas, the average radial growth was negative during the age of 20–30 years. Average density of the tree rings were increased by about 11% in each height of the trees starting from the ground. Similarly, the stem density decreased by about 3.4% annually along the radial direction from the pith.DOI: http://dx.doi.org/10.3126/banko.v22i2.9197Banko Janakari: A Journal of Forestry Information for NepalVol. 22, No. 2, 2012 November Page: 36-42 Uploaded date: 12/1/2013 

Forest growth and the effects of energy production: a method for detecting trends in the growth potential of trees

1984 ◽  
Vol 14 (3) ◽  
pp. 437-440 ◽  
Author(s):  
P. Hari ◽  
H. Arovaara ◽  
T. Raunemaa ◽  
A. Hautojärvi
Keyword(s):  
Growth Rate ◽  
Radial Growth ◽  
Energy Production ◽  
Forest Growth ◽  
Growth Potential ◽  
Component Model ◽  
Tree Age ◽  
Long Term Trends ◽  
Tree Growth Rate

An increase in the CO2 content of the atmosphere and in the acidity of rain has been detected in large regions of the northern hemisphere. Both these factors can affect the productivity of trees. A three-component model has been employed for the detection of possible trends in the growth potential of trees. The components are (i) the growth intensity associated with tree age, (ii) the effect of weather, and (iii) the effect of possible long-term trends on the radial growth. The model was tested with a limited set of data from conservation stands in southern and central Finland. Preliminary results indicate that an increase in tree growth rate since the beginning of the 20th century has occurred.

scholarly journals Climate Warming Alters Age-Dependent Growth Sensitivity to Temperature in Eurasian Alpine Treelines

Forests ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 688 ◽  
Author(s):  
Raúl Sanchez-Salguero ◽  
J. Camarero ◽  
Emilia Gutiérrez ◽  
Antonio Gazol ◽  
Gabriel Sangüesa-Barreda ◽  
...  
Keyword(s):  
Climate Warming ◽  
Tree Growth ◽  
Radial Growth ◽  
Terrestrial Ecosystems ◽  
Tree Age ◽  
Growth Responses ◽  
Polar Urals ◽  
Cold Environments ◽  
Age Related ◽  
Old Trees

Treeline ecotones are considered early-warning monitors of the effects of climate warming on terrestrial ecosystems, but it is still unclear how tree growth at treeline will track the forecasted temperature rise in these cold environments. Here, we address this issue by analysing and projecting growth responses to climate on two different cold-limited alpine treelines: Pinus uncinata Ram. in the Spanish Pyrenees and Larix sibirica Ledeb. in the Russian Polar Urals. We assess radial-growth changes as a function of tree age and long-term climate variability using dendrochronology and a process-based model of tree growth. Climate‒growth relationships were compared considering young (age < 50 years) and old trees (age > 75 years) separately. Warm summer conditions enhanced radial growth, particularly after the 1980s, in the Polar Urals sites, whereas growth was positively related to warm spring and winter conditions in the Pyrenees sites. These associations were stronger in young than in old trees for both tree species and regions. Forecasted warm conditions are expected to enhance growth rates in both regions, while the growing season is forecasted to lengthen in the Pyrenees treelines, mostly in young trees. The observed age-related responses to temperature also depend on the forecasted warming rates. Although the temperature sensitivity is overall increasing for young trees, those responses seem more divergent, or even reversed, throughout the contrasting emission scenarios. The RCP 8.5 emission scenario corresponding to the most pronounced warming and drier conditions (+4.8 °C) could also amplify drought stress in young trees from the Pyrenees treelines. Our modelling approach provides accessible tools to evaluate functional thresholds for tree growth in treeline ecotones under warmer conditions.

Sapwood thickness in Pinuscontorta var. latifolia

1992 ◽  
Vol 22 (12) ◽  
pp. 2004-2006 ◽  
Author(s):  
K.C. Yang ◽  
H.G. Murchison
Keyword(s):  
Growth Rate ◽  
Radial Growth ◽  
Growth Ring ◽  
Ground Level ◽  
Tree Age ◽  
Western Slope ◽  
Strongly Correlated ◽  
Radial Growth Rate ◽  
Growth Rings ◽  
Individual Trees

The vertical variation in the number of sapwood growth rings and sapwood thickness in Pinuscontorta Dougl. var. latifolia Engelm. was studied in relation to aspect, tree age, bole diameter, sapwood radial growth rate, and whole-xylem radial growth rate. Samples from 19 trees growing on the western slope of the Rocky Mountains near Kamloops, British Columbia, Canada, formed the data base. Sapwood width for individual trees ranged from 20 to 26 mm for both the east and west aspects, and was constant at various heights of the tree bole. Sapwood width for this species was found to be independent of age, diameter, sapwood radial growth rate, and whole-xylem radial growth rate. Sapwood consisted of 25 to 50 growth rings and decreased from the ground level upward to the tree crown. The number of sapwood growth rings was strongly correlated with age, diameter, and radial growth rates for both sapwood and the whole tree. No significant correlation existed between sapwood width and sapwood growth-ring counts.

Maturation Rate of Tracheid Lengthening in Slow-Grown Young Sugi (Cryptomeria Japonica) Trees

IAWA Journal ◽  
1993 ◽  
Vol 14 (3) ◽  
pp. 267-272 ◽  
Author(s):  
Takafumi Kubo ◽  
Miwako Koyama
Keyword(s):  
Growth Rate ◽  
Cryptomeria Japonica ◽  
Radial Growth ◽  
Juvenile Wood ◽  
Ring Width ◽  
Mature Wood ◽  
Annual Rings ◽  
Tracheid Length ◽  
Rate Of Increase ◽  
Maturation Rate

Maturation rate, the rate of increase in tracheid length in juvenile wood, was examined in sugi (Cryptomeria japonica D. Don) saplings grown for five years under different shading conditions: 10%, 20% 40% and 100 % of relative illumination intensity. The lowest photointensity dramatically suppressed radial growth and slowed tracheid lengthening. Radial variation of tracheid length within the stem was associated with distance from the pith, rather than the number of annual rings from the pith. Furthermore, maturation rate was closely related to the rate of the radial growth, which changed proportionally with growth rate below a 2-3 mm ring width. A lower maturation rate of tracheid length is associated with a delay in the transition from juvenile to mature wood.

Sapwood–heartwood proportion related to tree diameter, age, and growth rate in Piceaabies

1994 ◽  
Vol 24 (5) ◽  
pp. 1022-1028 ◽  
Author(s):  
Arne Sellin
Keyword(s):  
Growth Rate ◽  
Radial Growth ◽  
Age And Growth ◽  
Tree Age ◽  
Radial Growth Rate ◽  
Stem Base ◽  
Tree Diameter ◽  
Competition For Light ◽  
Transverse Area

The relationships of sapwood radial width and transverse area to tree diameter, age, and growth rate were investigated in Piceaabies (L.) Karst. A total of 125 trees growing with (suppressed trees) and without (dominant trees) competition for light were sampled. Both sapwood and heartwood amounts showed an increase with diameter at the stem base, with the heartwood portion increasing more rapidly. In young trees sapwood prevails both in terms of diameter and transverse area. After trees have reached a certain age, the width of the sapwood band remains more or less constant (on average 7.8 cm for dominant and 2.0 cm for suppressed trees), and the heartwood amount exceeds that of sapwood. The percentage of heartwood in suppressed trees is substantially greater than in dominant trees of the same age. Sapwood amount is closely correlated with the tree diameter, but not with age. Tree age controls the number of rings in sapwood, while the sapwood width depends on the tree's radial growth rate as well.

Stand history: an alternative explanation of red spruce radial growth reduction

1990 ◽  
Vol 20 (2) ◽  
pp. 250-253 ◽  
Author(s):  
Gregory A. Reams ◽  
Manuela M.P. Huso
Keyword(s):  
Growth Rates ◽  
Radial Growth ◽  
Alternative Explanation ◽  
Red Spruce ◽  
Radial Increment ◽  
Growth Reduction ◽  
Subsequent Increase ◽  
Growth Release ◽  
Growth Increase ◽  
The 1960S

We classified red spruce (Picearubens Sarg.) sites from northern Maine by radial growth release history. Two major releases were apparent for a majority of the sites. The first was a reduction and subsequent increase in radial increment in 1920. The second was an increase in radial increment from 1935 to 1955. Red spruce radial growth reduction in the 1960s is apparent only for sites released from 1935 to 1955 (approximately 54% of the sites in this study). These sites are now approaching the radial growth rates of the unreleased stands. Birch dieback is suggested as a probable contributor to the 1935–1955 red spruce growth increase and subsequent 1960s growth reduction.

Two-Condition Within-Participant Statistical Mediation Analysis: A Path-Analytic Framework

2019 ◽  
Author(s):  
Amanda Kay Montoya ◽  
Andrew F. Hayes
Keyword(s):  
Confidence Intervals ◽  
Indirect Effect ◽  
Mediation Analysis ◽  
Analytic Approach ◽  
Analytic Framework ◽  
Hypothesis Tests ◽  
Bootstrap Confidence Intervals ◽  
Complex Models ◽  
Path Analytic ◽  
Statistical Mediation Analysis

Researchers interested in testing mediation often use designs where participants are measured on a dependent variable Y and a mediator M in both of two different circumstances. The dominant approach to assessing mediation in such a design, proposed by Judd, Kenny, and McClelland (2001), relies on a series of hypothesis tests about components of the mediation model and is not based on an estimate of or formal inference about the indirect effect. In this paper we recast Judd et al.’s approach in the path-analytic framework that is now commonly used in between-participant mediation analysis. By so doing, it is apparent how to estimate the indirect effect of a within-participant manipulation on some outcome through a mediator as the product of paths of influence. This path analytic approach eliminates the need for discrete hypothesis tests about components of the model to support a claim of mediation, as Judd et al’s method requires, because it relies only on an inference about the product of paths— the indirect effect. We generalize methods of inference for the indirect effect widely used in between-participant designs to this within-participant version of mediation analysis, including bootstrap confidence intervals and Monte Carlo confidence intervals. Using this path analytic approach, we extend the method to models with multiple mediators operating in parallel and serially and discuss the comparison of indirect effects in these more complex models. We offer macros and code for SPSS, SAS, and Mplus that conduct these analyses.

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