Modelling individual tree height–diameter relationships for multi-layered and multi-species forests in central Europe

Sharma, Ram P.; Vacek, Zdeněk; Vacek, Stanislav; Kučera, Miloš

doi:10.1007/s00468-018-1762-4

Cited by 48 publications

(54 citation statements)

References 71 publications

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“…Contrasting mixing effects on two or more species in mixed forest stands are common among a range of forest types [9,10,13,50,51]. Our results similarly showed that species-mixing had contrasting effects between species in both the generalized h-d and basal area growth models.…”

Section: Discussionsupporting

confidence: 75%

“…All else being equal, dq measured the degree of inter-tree competition, and secondarily the stage of stand development [41,53,54]. Although the same variables have already been used in several h-d functions for multi-species forest [39,40,50,54], in those studies, the effects of species interactions on h-d relationships were not quantified. Here, we show that for mixed stands, the explicit evaluation of mixing proportion based on species-specific growing space requirements could be advantageous for modeling the more complex effects of the vertical structure of mixed species stands compared to pure stands.…”

Section: Influence On Species-mixing In Tree Allometrymentioning

confidence: 99%

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Species Mixing Effects on Height–Diameter and Basal Area Increment Models for Scots Pine and Maritime Pine

Riofrío

Rı́o

Maguire

et al. 2019

Forests

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Models that incorporate known species-mixing effects on tree growth are essential tools to properly design silvicultural guidelines for mixed-species stands. Here, we developed generalized height–diameter (h-d) and basal area growth models for mixed stands of two main forest species in Spain: Scots pine (Pinus sylvestris L.) and Maritime pine (Pinus pinaster Ait.). Mixed-effects models were fitted from plot measurement and tree rings data from 726 Scots pine and 693 Maritime pine trees from mixed and pure stands in the Northern Iberian Range in Spain, with the primary objective of representing interactions between the species where they are interspersed in mixtures of varying proportions. An independent dataset was used to test the performance of the h-d models against models previously fitted for monospecific stands of both species. Basal area increment models were evaluated using a 10-fold block cross-validation procedure. We found that species mixing had contrasting effects on the species in both models. In h-d models, the species-mixing proportion determined the effect of species interactions. Basal area growth models showed that interspecific competition was influential only for Maritime pine; however, these effects differed depending on the mode of competition. For Scots pine, tree growth was not restricted by interspecies competition. The combination of mixed-effect models and the inclusion of parameters expressing species-mixing enhanced estimates of tree height and basal area growth compared with the available models previously developed for pure stands. Although the species-mixing effects were successfully represented in the fitted models, additional model components for accurately simulating the stand dynamics of mixtures with Scots pine and Maritime pine and other species mixtures require similar model refinements. Upon the completion of analyses required for these model refinements, the degree of improvement in simulating growth in species mixtures, including the effects of different management options, can be evaluated.

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Section: Discussionsupporting

confidence: 75%

Section: Influence On Species-mixing In Tree Allometrymentioning

confidence: 99%

Species Mixing Effects on Height–Diameter and Basal Area Increment Models for Scots Pine and Maritime Pine

Riofrío

Rı́o

Maguire

et al. 2019

Forests

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“…Based on the evaluation of the eight versatile growth functions (Table 3), which we considered as base functions based on the principles of their logical behavior and suitability in the practical application. The Chapman-Richards function, which shows the best fitting performance to our data (Table 4), has enough flexibility for modelling different tree attributes, such as growth of diameter and height [68][69][70][71] and height-diameter relationship [67,72,73].…”

Section: Discussionmentioning

confidence: 99%

“…where b is a vector of the fixed parameters of equations (Equations (6) and 7), u j is a vector of the random effects (u i1 , u i2 ), and x i is a vector of the predictors for i th sample plot. The elements (z ij ) of this matrix for sample trees were determined from the partial derivatives of the nonlinear models (Equations (6) and 7) with respect to the fixed parameters associated with the random effects [16,[65][66][67]. Following equations were obtained from the partial derivative solution.…”

Section: Calibrated Response or Localized Diameter Increment Predictionmentioning

confidence: 99%

Generalized Nonlinear Mixed-Effects Individual Tree Diameter Increment Models for Beech Forests in Slovakia

Sharma

Štefančík

Vacek

et al. 2019

Forests

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Individual tree growth and yield models precisely describe tree growth irrespective of stand complexity and are capable of simulating various silvicultural alternatives in the stands with diverse structure, species composition, and management history. We developed both age dependent and age independent diameter increment models using long-term research sample plot data collected from both monospecific and mixed stands of European beech (Fagus sylvatica L.) in the Slovak Republic. We used diameter at breast height (DBH) as a main predictor and other characteristics describing site quality (site index), stand development stage (dominant height and stand age), stand density or competition (ratio of individual tree DBH to quadratic mean diameter), species mixture (basal area proportion of a species of interest), and dummy variable describing stand management regimes as covariate predictors to develop the models. We evaluated eight versatile growth functions in the first stage using DBH as a single predictor and selected the most suitable one, i.e., Chapman-Richards function for further analysis through the inclusion of covariate predictors. We introduced the random components describing sample plot-level random effects and stochastic variations on the diameter increment, into the models through the mixed-effects modelling. The autocorrelation caused by hierarchical data-structure, which is assumed to be partially reduced by mixed-effects modelling, was removed through the inclusion of the parameter accounting for the autoregressive error-structures. The models described about two-third parts of a total variation in the diameter increment without significant trends in the residuals. Compared to the age independent mixed-effects model (conditional coefficient of determination, R c 2 = 0.6566; root mean square error, RMSE = 0.1196), the age dependent model described a significantly larger proportion of the variations in diameter increment ( R c 2 = 0.6796, RMSE = 0.1141). Diameter increment was significantly influenced differently by covariate predictors included into the models. Diameter increment decreased with the advancement of stand development stage (increased dominant height and stand age), increasing intraspecific competition (increased basal area proportion of European beech per sample plot), and diameter increment increased with increasing site quality (increased site index) and decreased competition (increased ratio of DBH to quadratic mean diameter). Our mixed-effects models, which can be easily localized with the random effects estimated from prior measurement of diameter increments of four randomly selected trees per sample plot, will provide high prediction accuracies. Our models may be used for simulating growth of European beech irrespective of its stand structural complexity, as these models have included various covariate variables describing both tree-and stand-level characteristics, thinning regimes, except the climate characteristics. Together with other forest models, our models will be used as inputs to the growth simulator to be developed in the future, which is important for decision-making in forestry.

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“…However, we did not consider this because of computational complexity, but species-specific effects on the height-diameter relationships were included using the dummy variable modelling approach. This approach is considered suitable for modelling height-diameter relationships using the data originated from multi-layered and multi-species stands [57,71,72]. We chose the best functional form (Näslund function) to adequately describe the variations in the height-diameter relationship of individual trees for each vegetation type (Figure 3).…”

Section: Tree Height-diameter Model and Description Of The Managementmentioning

confidence: 99%

Defining Deforestation Patterns Using Satellite Images from 2000 and 2017: Assessment of Forest Management in Miombo Forests—A Case Study of Huambo Province in Angola

et al. 2018

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A few studies have recently been published on changes in land use/land cover (LU/LC) of Angolan Miombo forests, however, none have attempted to offer forest management solutions for degraded Miombo forests. Landscapes are witness to past and present natural and social processes influencing the environment, where each period in the past leaves footprints on the landscape's development, which can be described by a continual decrease in forest area over time. The expansion of degraded areas from 2000 to 20017 began near urban areas where many Miombo forests have been eliminated or highly degraded, particularly in the southwest and northeast of the Huambo province. Large areas of degraded forests were observed along the Benguela railway (Caminho de ferro de Benguela). Our detailed analysis of the landcover map suggests that the impact has been devastating and there is no form of forest protection, which leads to unregulated exploitation. Descriptions of the Miombo forest dynamics are explained using height-diameter curves developed for different vegetation types that provide important insights about forest structures in the management zones. The height-diameter models differed for all vegetation types, and four management zones (MZ) were created based on a set of particular attributes. The vegetation types differed in each management zone, which included agricultural land and bare soil (MZ-E), grassland or savanna (MZ-C), open Miombo forests (MZ-B), and closed Miombo forests (Miombo forests). The four management zones were easily identified on the available maps and the height-diameter models developed represent a fundamental tool for future studies on forest planning.Sustainability 2019, 11, 98 2 of 20 agreed definition of forest degradation which makes the discussion more complex [3]. Deforestation is considered the result of the clearing of land for agriculture [4], both for the large-scale production of global commodities [5,6] and, in Africa, for small-scale production of food and cash crops [7]. Deforestation is among the most commonly studied phenomena in the frontier literature, as it is often associated with negative impacts on the global climate and biodiversity [6,8]. The scale of the environmental legacy of deforestation is dependent on both the magnitude and timing of historic land cover changes, not merely the snapshot of forest cover that is directly observable today [9][10][11][12][13][14]. The most important anthropogenic alterations of natural environments have always been the clearing of forests to establish cropland and pasture, and the exploitation of forests for fuelwood and construction materials. Analysing landscape changes due to past and present natural and social processes at different scales over time constitutes the departure point for landscape management because of close links between forests and physical attributes of the landscape. The mix of LC and LU (landscape composition) usually includes agricultural lands and native vegetation, and human dwellings in villages and urban areas. Th...

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Modelling individual tree height–diameter relationships for multi-layered and multi-species forests in central Europe

Cited by 48 publications

References 71 publications

Species Mixing Effects on Height–Diameter and Basal Area Increment Models for Scots Pine and Maritime Pine

Species Mixing Effects on Height–Diameter and Basal Area Increment Models for Scots Pine and Maritime Pine

Generalized Nonlinear Mixed-Effects Individual Tree Diameter Increment Models for Beech Forests in Slovakia

Defining Deforestation Patterns Using Satellite Images from 2000 and 2017: Assessment of Forest Management in Miombo Forests—A Case Study of Huambo Province in Angola

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