A picture of growth rings of a tree can be obtained on paper by placing it over a disc of a trunk or stump and rubbing it with a pencil. The ‘shadows’, while not yielding the complex data obtainable from the actual wood, do show the proportion of the growth rings composed of spring wood and the denser summer wood. It is possible to collect large amount of data by using an unexperienced staff cheaply and quickly, and the samples may be mailed at little expense. The method may be used to study the previous cuttings of a stand from stumps. The shadowing of tree rings is possible to do even from rather decayed stumps.

The article includes a Finnish abstract.

Rogers, E-mail: mr@mm.unknown

Category : Article

article id 7610, category Article

Matti Leikola. (1969). The influence of environmental factors on the diameter growth of forest trees : Auxanometric study. Acta Forestalia Fennica no. 92 article id 7610. https://doi.org/10.14214/aff.7610

Keywords: Pinus sylvestris; Norway spruce; birch; Picea abies; Scots pine; temperature sum; environmental factors; temperature; diameter increment; Betula sp.; xylem; daily increment

Abstract | View details | Full text in PDF | Author Info

The influence of various environmental factors on the diameter growth of trees has been studied based on data collected by following daily increment of trees and various environmental factors during the growing season in 1964–1967. The field work was carried out in two experimental stands, a Scots pine (Pinus sylvestris L.) stand and a mixed stands growing birch (Betula sp.), Norway spruce (Picea abies (L.) H. Karst.) and Scots pine, in Southern Finland.

The results show that the temperature sums preceding the beginning of diameter growth were of the same magnitude in the years studied, which indicates dependence in the relationship. Formation of new xylem cells took place in the pine stem ca. every third day when the diameter growth was most active. No summer growth inhibition was detected in diameter growth.

None of the cumulative temperature sums tried determined the time of cessation of diameter growth. In several cases, positive correlation was found between the length of the growing season and the width of the annual ring formed. When studying the relationships between the diameter increment and the environmental factors, it was found that diameter increment was totally masked in the records by the hydrostatic changes in the stem. Relationships between the diameter increment and the environmental factors of the second day preceding growth were found to be poor. In studying the deviations of the recorded daily increments from the regression surface, no clear general trend was seen for pine and spruce, but clear diminishing trend toward the end og the growing season could be seen for birch in 1967.

Leikola, E-mail: ml@mm.unknown

Category : Research article

article id 394, category Research article

Rafael Calama, Gregorio Montero. (2005). Multilevel linear mixed model for tree diameter increment in stone pine (Pinus pinea): a calibrating approach. Silva Fennica vol. 39 no. 1 article id 394. https://doi.org/10.14214/sf.394

Keywords: mixed model; diameter increment; calibration; stone pine

Abstract | View details | Full text in PDF | Author Info

Diameter increment for stone pine (Pinus pinea L.) is described using a multilevel linear mixed model, where stochastic variability is broken down among period, plot, tree and within-tree components. Covariates acting at tree and stand level, as breast height diameter, density, dominant height or site index are included in the model as fixed effects in order to explain residual random variability. The effect of competition on diameter increment is expressed by including distance independent competition indices. The entrance of regional effects within the model is tested to determine whether a single model is sufficient to explain stone pine diameter increment in Spain, or if, on the contrary, regional models are needed. Diameter increment model can be calibrated by predicting random components using data from past growth measurements taken in a complementary sample of trees. Calibration is carried out by using the best linear unbiased predictor (BLUP) theory. Both the fixed effects model and the calibrated model mean a substantial improvement when compared with the classical approach, widely used in forest management, of assuming constancy in diameter increment for a short projection period.

Calama, CIFOR-INIA, Grupo Selvicultura Mediterranea, Apdo. 8111, 28080 Madrid, Spain E-mail: rcalama@inia.es
Montero, CIFOR-INIA, Grupo Selvicultura Mediterranea, Apdo. 8111, 28080 Madrid, Spain E-mail: gm@nn.es

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