Inter-tree competition analysis in undebarked cork oak plantations as a support tool for management in Portugal

Faias, Sónia Pacheco; Paulo, Joana Amaral; Tomé, Margarida

doi:10.1007/s11056-019-09739-4

Cited by 6 publications

(7 citation statements)

References 21 publications

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“…The CLBD results obtained in this study are lower than those from several other studies (see Table S6; [85][86][87][88][89][90][91][92][93][94]). One reason for that difference could be that the NFI plots include many stands with low tree cover whereas studies planned to obtain CLBD values typically focused on stands with more trees per hectare, larger basal areas (Table S6) and therefore closer canopies.…”

Section: Discussioncontrasting

confidence: 91%

Bulk Density of Shrub Types and Tree Crowns to Use with Forest Inventories in the Iberian Peninsula

Nunes

Pasalodos-Tato

Alberdi

et al. 2022

Forests

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Bulk density for shrubs and tree crowns is an important variable, useful for many purposes, namely estimations for biomass and carbon sequestration and potential fire behavior prediction. In the latter case, bulk density is required to predict the rate of spread and intensity of crown fires. However, bulk density information is scarce. The estimation of bulk density is crucial to help choosing proper pyrosilviculture options to decrease fire susceptibility. Due to the similar environmental conditions and fuel characteristics in Portugal and Spain, we modelled bulk density for the most common woody species in all the Iberian Peninsula. We used 10 different shrub type formations and a set of tree species or groups common to both countries. Equations for bulk density, in both forest canopy and understory layers, were fitted as a function of biometric variables commonly used in forest inventories for the selected species. Standardized estimates of bulk density can be associated with data from the National Forest Inventories from Portugal and Spain, to estimate biomass of the forest ecosystems and to evaluate potential fire behavior involving tree canopies and shrubs.

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Section: Discussioncontrasting

confidence: 91%

Bulk Density of Shrub Types and Tree Crowns to Use with Forest Inventories in the Iberian Peninsula

Nunes

Pasalodos-Tato

Alberdi

et al. 2022

Forests

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“…Stand local density, characterized by distance-dependent competition indices, and the hierarchical position of the tree within the stand, characterized by distance-independent competition indices, performed better than stand density to explain individual tree growth, particularly for diameter growth. The low importance of stand density in the stands is in accordance with the findings in [17].…”

Section: Discussionsupporting

confidence: 90%

“…Climatic information was characterized by minimum (Tmin), mean (Tmean), maximum (Tmax) of monthly temperatures and annual precipitation according to the 1981-2010 climatic normals, provided by the Instituto Português do Mar e da Atmosfera (IPMA), available at http://www.portaldoclima.pt/ (accessed on 30 July 2022). Further site description can be found on previous studies [17,25]. d is the tree diameter at breast height (cm); h is the tree total height (m); t is the age of the cork oak plantation (years); N is the number of trees per ha; dg is the quadratic diameter (cm); hdom is the mean height of the 25 thickest trees per ha (m); S is the site index value (m); estimated with the model developed by [12]; CC is the sum of tree crown area divided by plot area; estimated from the diameter under cork; according to the fixed effects model from [25]; Tmin, Tmean and Tmax are the minimum, mean and maximum monthly temperatures observed in the group of used inventory plots; Precipitation is the annual precipitation observed in the group of used inventory plots.…”

Section: Tree and Stand Measurementsmentioning

confidence: 99%

“…Most of the existing diameter growth models have been developed for cork oak trees that are already under cork production [7,12,[14][15][16], usually designated as adult trees. Additional work was carried out focusing on undebarked trees, usually referred to as juvenile trees [11,17]. The distinction between these two stages is crucial for the cork oak species, especially for diameter growth since it is influenced by cork extraction [18].…”

Section: Introductionmentioning

confidence: 99%

“…The integration of competition indices in growth models has been widely used in forest studies (e.g., [6,[22][23][24]). In the cork oak species case, some research is found on this topic [11,[15][16][17], but modelling with distance-dependent indices has never been applied to juvenile trees growing in high-density plantations.…”

Section: Introductionmentioning

confidence: 99%

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Do Distance-Dependent Competition Indices Contribute to Improve Diameter and Total Height Tree Growth Prediction in Juvenile Cork Oak Plantations?

Firmino

Tomé

Paulo

2023

Forests

Self Cite

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Competition indices may improve tree growth modelling in high-density stands, found often in new cork oak plantations. Distance-dependent competition indices have hardly been considered for juvenile cork oak plantations since existing models were developed for low-density mature stands. This study aims at inspecting the potential of including distance-dependent competition indices into diameter at breast height (d) and total height (h) growth models for Quercus suber L., comparing several distance-dependent and distance-independent competition indices. Annual d and h growth were modelled with linear and non-linear growth functions, formulated as difference equations. Base models were initially fitted considering parameter estimates depending only on site index (S) and/or stand density (N). They were refitted, testing the significance of adding each competition index to the model parameters. Selected models included the best-performing distance-dependent or -independent competition indices as additional predictors. Best base d and h growth models showed a modelling efficiency (ef) of ef = 0.9833 and ef = 0.9900, respectively. Adding a distance-dependent competition index slightly improved growth models, to an ef = 0.9851 for d and ef = 0.9902 for h. Best distance-dependent competition indices slightly overperformed distance-independent ones in diameter growth models. Neither S nor N were included on best fitted models. If inter-tree competition is present in juvenile undebarked cork oak plantations, it does not yet strongly impact individual tree growth, which may diminish the importance of using, at this stage, more complex spatially explicit competition indices on predicting individual tree growth.

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How do soil and topographic drivers determine tree diameter spatial distribution in even aged cork oak stands installed in average to high productivity areas

Firmino,

Paulo,

Lourenço

et al. 2024

New Forests

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Local terrain or microsite conditions influence the development of trees, particularly at early ages. These conditions might be described by edaphic or topographic variables. We mapped soil and topographic variables from four even-aged and even-spaced cork oak plantations located in two climatically distinct Portuguese regions. The major goal of this research was to understand the relation between soil and topographic fine-scale conditions and tree growth expressed by diameter without cork annual growth (idu). The methodology consisted in (1) analysing the spatial variability and autocorrelation of idu; (2) modelling idu with ordinary least squares (OLS) regressions; (3) comparing with spatial modelling of idu, incorporating spatial autocorrelation. The driest stands A and B, exhibited weaker spatial autocorrelation, distributed in smaller clusters (R2 < 0.03, OLS models), while stands C (R2 = 0.18, OLS models) and D (R2 = 0.11, OLS models) showed higher predictive capacity. Spatial models increased R2 scores, keeping most variables from OLS models and accounting for spatial autocorrelation. A + B + C + D OLS model obtained an R2 = 0.34 and respective spatial model R2 = 0.58. Apparent electrical conductivity at 0.5 (ECa0.5) and 1 m of soil depth, slope, elevation and topography position index were included as predictors (OLS), but only ECa0.5, slope and elevation were selected in the spatial model. Models were fitted using average to high productivity stands and should be used cautiously outside this range. Local terrain conditions determine the growth of young cork oak trees. Mapping soil and topographic variables before establishing new plantations may identify limiting microsite conditions where using cork oak species is not suitable due to low growth rates expectations.

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Inter-tree competition analysis in undebarked cork oak plantations as a support tool for management in Portugal

Cited by 6 publications

References 21 publications

Bulk Density of Shrub Types and Tree Crowns to Use with Forest Inventories in the Iberian Peninsula

Bulk Density of Shrub Types and Tree Crowns to Use with Forest Inventories in the Iberian Peninsula

Do Distance-Dependent Competition Indices Contribute to Improve Diameter and Total Height Tree Growth Prediction in Juvenile Cork Oak Plantations?

How do soil and topographic drivers determine tree diameter spatial distribution in even aged cork oak stands installed in average to high productivity areas

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