Individual tree diameter increment model for managed even-aged stands of ponderosa pine throughout the western United States using a multilevel linear mixed effects model

Based on a data set from 164 permanent sample plots, an age-independent individual tree diameter increment model is presented for white spruce (Piceaglauca (Moench) Voss) grown in the boreal mixed-species stands in Alberta. The model is age independent in that it does not explicitly require tree or stand age as input variables. Periodic diameter increment is modelled as a function of tree diameter at breast height, total tree height, relative competitiveness of the tree in the stand, species composition, stand density, and site productivity. Because data from permanent sample plots are considered time series and cross sectional, diagnostic techniques were applied to identify the model's error structure. Appropriate fit based on the identified error structure was accomplished using weighted nonlinear least squares with a first-order autoregressive process. Results show that (1) all model parameters are significant at α = 0.05 level, and (2) the plot of studentized residuals against predicted diameter increment shows no consistent underestimate or overestimate for diameter increment. The model was also tested on an independent data set representing the population on which it is to be used. Results show that the average prediction biases are not significant at α = 0.05 level, indicating that the model appropriately describes the data and performs well when predictions are made.

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Distance-independent individual tree diameter-increment model for Thuya [Tetraclinis articulata (VAHL.) MAST.] stands in Tunisia

Forest Systems ◽

10.5424/fs/2013223-03511 ◽

2013 ◽

Vol 22 (3) ◽

pp. 433 ◽

Cited By ~ 2

Author(s):

T. Sghaier ◽

M. Tome ◽

J. Tome ◽

M. Sanchez-Gonzalez ◽

I. Cañellas ◽

...

Keyword(s):

Individual Tree ◽

Tree Diameter ◽

Diameter Increment ◽

Tetraclinis Articulata ◽

Diameter Increment Model ◽

Independent Individual

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Tree- and stand-scale factors shape the probability of wind damage to birch in hemiboreal forests

Silva Fennica ◽

10.14214/sf.10483 ◽

2021 ◽

Vol 55 (2) ◽

Author(s):

Māra Kitenberga ◽

Guntars Šņepsts ◽

Jānis Vuguls ◽

Didzis Elferts ◽

Ieva Jaunslaviete ◽

...

Keyword(s):

Slenderness Ratio ◽

Mixed Effects ◽

Mixed Effects Model ◽

Wind Damage ◽

Deciduous Tree ◽

Stand Age ◽

Strong Wind ◽

Individual Tree ◽

Linear Mixed Effects Model ◽

Linear Mixed Effects

Strong wind is the major natural disturbance in European forests, that periodically causes tremendous damages to forestry. Yet, factors that affect the probability of wind damage for birch ( Roth and Ehrh.), the most common deciduous tree species in hemiboreal forests, are studied scarcely. This study aimed to assess the effects of several tree- and stand-scale variables on the probability of wind damage to birch using data from the Latvian National Forest Inventory (2004â2018), and determine individual tree characteristics that affect the height of the stem breakage. The data analysis was done using the Bayesian binary logistic generalized linear mixed-effects model and a linear mixed-effects model. The probability of wind damage significantly increased by stand age, basal area, and slenderness ratio. Trees with prior damage had a significantly higher probability (odds ratio 4.32) for wind damage. For wind-damaged trees, the snapping height was significantly decreased by an increase in the slenderness ratio (â=â0.03) and prior damage (â=â0.003). Previously damaged trees were more frequently (73%) snapped in the lowest 40% of tree height than trees without prior damage (54%). The probability of wind damage is largely set by factors related to the selection of site, species composition, and rotation. The damage probability could be decreased by management measures that lower competition within the stand with particular regard to preserving intact remaining trees during these manipulations. Factors that reduce the probability of the damage simultaneously increase the snapping height, emphasizing their relevance for mitigation of the wind damages.Betula pendulaB. pubescenspp

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Growth of tree diameter and stem taper as affected by reduced leaf area on selected branch whorls

Canadian Journal of Forest Research ◽

10.1139/cjfr-2017-0279 ◽

2018 ◽

Vol 48 (4) ◽

pp. 317-323 ◽

Cited By ~ 8

Author(s):

Shannon D. Kidombo ◽

Thomas J. Dean

Keyword(s):

Leaf Area ◽

Mixed Effects ◽

Stem Growth ◽

Relative Height ◽

Growth Responses ◽

Linear Mixed Effects Model ◽

Linear Mixed Effects ◽

Tree Diameter ◽

Stem Taper ◽

Individual Branch

Leaf area on branches is linked to the stem through hydraulic and physiological functions. We investigated whether this relationship extends to growth responses by examining coordinated growth between leaf area on selected branches in the crown and growth in form and taper of the main stem. The growth impact of leaf area carried on individual branch whorls on the stem profile and internodes was tested using a series of defoliation and shade treatments. The data were analyzed using a linear mixed-effects model relating relative diameter to the relative height of the measured internodes. Defoliation and shade treatments on selected branches significantly affected the stem profile compared with untreated trees. The effect of reduced leaf area due to defoliation and shading of branch whorls was localized to internodes immediately below or above treated whorls. The stem profile showed curvature in the regions affected by reduced leaf area. These findings demonstrate that branch and stem growth is sensitive to minor changes in leaf area. The results emphasize the localized contribution of branches to stem growth.

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