Competition indices and the prediction of radial growth in Scots pine.

Pukkala, Timo; Kolström, Taneli

doi:10.14214/sf.a15463

Cited by 79 publications

(50 citation statements)

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“…6). Reference trees' competitors were identified by a virtual reverse cone approach (Pukkala and Kolström 1987;Biging and Dobbertin 1992;Pretzsch 1995): the axis of the reverse cone and tree axis were overlaid, and the cone's axis was placed in the tree crown. We used a 60°-vertex angle and defined 60% of tree height as basis height.…”

Section: Discussionmentioning

confidence: 99%

Climate change impacts on stand structure and competitive interactions in a southern Swedish spruce–beech forest

et al. 2009

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It is believed that European beech (Fagus sylvatica L.) will increase its competitive ability at its northern range margin in Scandinavia due to climate change. In mixed old-growth forests of beech and Norway spruce (Picea abies (L.) Karst.) at Siggaboda nature reserve (southern Sweden), stand structure characteristics were sequentially recorded in the years 2004, 2005 and 2007 as well as growth in stem diameter using tree-coring analyses. Using these measurements, we studied the effects on stand dynamics of an extreme storm event (2005 ''Gudrun'' hurricane), drought and heat (mid-summer 2006, spring 2007) and subsequent bark beetle attacks on spruce (growing season 2007), overlaid with warming tendencies. The storm, which caused disastrous damage in many stands nearby, had comparatively little impact on the structure of the spruce-beech stand. All together, only 32 trees (19 spruces, 10 beeches, 3 other species) per hectare were thrown or broken mainly in the leeward direction (NE) or impacted by secondary damage by uprooted neighbour trees; this represents 7% of the total tree number and 11% of the growing stock. Diameter and height structure did not change significantly. However, the 2006 drought and the 2007 attack of biotic agents changed the stand structure and composition strongly due to the death of about 19% of the dominating older spruce trees that accounted for 35% of total stand volume. This resulted in a considerable increase in beech's contribution to stem number (4% increase) and wood volume of the living stand (7% increase). A comparison of diameter growth of beech and spruce during the periods 1894-1949 and 1950-2005 showed a distinct decrease in growth superiority of spruce during the last 50 years. These results support the idea of a northward migration of European beech as a nemoral tree species in Sweden, due to a higher tolerance to the abiotic and biotic threats accompanying climate change and an increased competitive ability compared to boreal tree species Norway spruce.

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Section: Discussionmentioning

confidence: 99%

Climate change impacts on stand structure and competitive interactions in a southern Swedish spruce–beech forest

et al. 2009

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“…Basal area of larger trees (BAL) Wykoff et al (1982) BAL relative Hegyi (1974) Martin and Ek (1984) Daniels et al (1986) Pukkala andKolström (1987) Crown cross-sectional area (CCS)…”

Section: Competition Index Equationmentioning

confidence: 99%

Modelling modulus of elasticity of Pinus pinaster Ait. in northwestern Spain with standing tree acoustic measurements, tree, stand and site variables

et al. 2014

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IntroductionPinus pinaster Ait. is one of the most important coniferous species used in the timber industry in Spain, especially in Galicia (NW Spain) where it covers around 587,000 ha of land and is the main forest industry resource. More than 2.8 million cubic meters of Pinus pinaster round wood are produced annually in Galicia, representing 72% of the total production of the species in Spain. Recent studies have demonstrated the good mechanical properties of Galician P. pinaster timber, which make it suitable for structural use (Riesco and Díaz González, 2007;Carballo et al., 2009).Forest management and climatic and soil factors have important effects on softwood properties (e.g. Lasserre et al., 2004;Moore et al., 2009;Roth et al., 2007;Watt et al., 2006;. Studies carried out in different regions have assessed the influence of these factors on the variation in wood properties in coniferous species (e.g. Lei et al., 2005;Liu et al., 2007, or Ikonen et al., 2008. The use of portable acoustic devices that estimate timber stiffness from measurements made on standing trees (e.g. Wang et al., 2001b;Merlo et al., 2008Merlo et al., , 2009Santaclara et al., 2011) is a key element of these studies. Stiffness (quantified by the modulus of elasticity, MOE) is an important mechanical property of timber and it is commonly measured in machine grading of timber strength. It is also the index parameter considered by Abstract Aim of study:Modelling the structural quality of Pinus pinaster Ait. wood on the basis of measurements made on standing trees is essential because of the importance of the species in the Galician forestry and timber industries and the good mechanical properties of its wood. In this study, we investigated how timber stiffness is affected by tree and stand properties, climatic and edaphic characteristics and competition.Area of study: The study was performed in Galicia, north-western Spain. Material and methods:Ten pure and even-aged P. pinaster stands were selected and tree and stand variables and the stress wave velocity of 410 standing trees were measured. A sub-sample of 73 trees, representing the variability in acoustic velocity, were felled and sawed into structural timber pieces (224) which were subjected to a bending test to determine the modulus of elasticity (MOE).Main results: Linear models including wood properties explained more than 97%, 73% and 60% of the observed MOE variability at site, tree and board level, respectively, with acoustic velocity and wood density as the main regressors. Other linear models, which did not include wood density, explained more than 88%, 69% and 55% of the observed MOE variability at site, tree and board level, respectively, with acoustic velocity as the main regressor. Moreover, a classification tree for estimating the visual grade according to standard UNE 56544:2011 was developed.Research highlights: The results have demonstrated the usefulness of acoustic velocity for predicting MOE in standing trees. The use of the fitted equations together with existing d...

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“…The angle which defines the width of the cone was 60°. The index itself is calculated by the sum of the diameters in breast height (dbh) of all selected overstorey trees divided by their distance to the subject seedling i. CI 2 represents the competition index of Pukkala and Kolström (1987) …”

Section: Assessment Of Below Ground Resources and Indices Indicating mentioning

confidence: 99%

Evaluation of different approaches for modelling individual tree seedling height growth

Wagner¹,

Madsen

Ammer

2009

Trees

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We compared different approaches for modelling height growth of individual beech seedlings in a controlled factorial experiment as well as in field data from naturally regenerated beech seedlings under the canopy of overstorey mature beech trees. Several competition indices, a model of overstorey fine root density, relative photosynthetically active radiation (PAR) values, and soil water values were used in these approaches. In the factorial experiment relative PAR and soil water content were measured and used for the prediction of seedlings height growth. In the field experiment this was done by using relative PAR and estimated fine root biomass as a surrogate for below ground resource availability. The latter approach was compared with a model where we used various competition indices representing the impact of overstorey trees on beech seedlings. Our results suggested that (1) models which combine resource based growth functions are suitable for the prediction of individual height growth of beech seedlings. Resource based models offer the opportunity to investigate on the independent multiplicative effect of irradiance and water supply and their interactions on tree seedlings. It was (2) shown that a combined model could be used not only to predict individual height growth of beech seedlings in a controlled experiment but also in the field. The model parameters of a pure light response function for the controlled factorial experiment are comparable to those obtained in the field study. The results showed (3) that the precision of predicting beech seedlings height growth is comparable between the model types tested within this study. Approximately half of the observed variation in seedlings relative height growth rate could be explained. However, the simple competition index approach provides no information on the environmental factors constraining tree seedlings growth; whereas the multiplicative combined models can be used to get a better understanding of growth dynamics in the field.

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Competition indices and the prediction of radial growth in Scots pine.

Cited by 79 publications

References 0 publications

Climate change impacts on stand structure and competitive interactions in a southern Swedish spruce–beech forest

Climate change impacts on stand structure and competitive interactions in a southern Swedish spruce–beech forest

Modelling modulus of elasticity of Pinus pinaster Ait. in northwestern Spain with standing tree acoustic measurements, tree, stand and site variables

Evaluation of different approaches for modelling individual tree seedling height growth

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