scholarly journals Models for diameter and height growth of Scots pine, Norway spruce and pubescent birch in drained peatland sites in Finland

Silva Fennica ◽  
2018 ◽  
Vol 52 (5) ◽  
Author(s):  
Jaakko Repola ◽  
Hannu Hökkä ◽  
Hannu Salminen
Keyword(s):  
Norway Spruce ◽  
Scots Pine ◽  
Growth Models ◽  
Mineral Soil ◽  
Height Growth ◽  
Growth Patterns ◽  
Repeated Measurements ◽  
Site Quality ◽  
Individual Tree ◽  
Tree Diameter

The aim of this study was to develop individual-tree diameter and height growth models for Scots pine, Norway spruce, and pubescent birch growing in drained peatlands in Finland. Trees growing in peatland sites have growth patterns that deviate from that of trees growing in mineral soil sites. Five-year growth was explained by tree diameter, different tree and stand level competition measures, management operations and site characteristics. The drainage status of the site was influencing growth directly or in interaction with other variables. Site quality had a direct impact but was also commonly related to current site drainage status (need for ditch maintenance). Recent thinning increased growth of all species and former PK fertilization increased growth of pine and birch. Temperature sum was a significant predictor in all models and altitude for spruce and birch. The data were a subsample of the 7th National Forest Inventory (NFI) sample plots representing northern and southern Finland and followed by repeated measurements for 15–20 yrs. Growth levels predicted by the models were calibrated using NFI11 data to remove bias originating from the sample of the modelling data. The mixed linear models technique was used in model estimation. The models will be incorporated into the MOTTI stand simulator to replace the current peatlands growth models.

Regional Height Growth Models for Scots Pine in Poland

2020 ◽  
Author(s):  
Jarosław Socha ◽  
Luiza Tymińska-Czabańska ◽  
Stanisław Zięba ◽  
Dominika Cywicka ◽  
Paweł Hawryło
Keyword(s):  
Scots Pine ◽  
Growth Models ◽  
Site Index ◽  
Height Growth ◽  
Growth Patterns ◽  
Natural Forest ◽  
Growth Trajectories ◽  
Regional Models ◽  
Site Productivity ◽  
Forest Regions

Abstract Background: Site productivity remains a fundamental concern in forestry as a significant driver of resource availability. The site index (SI) reflects the overall impact of all environmental parameters that determine tree height growth and is the most commonly used indirect proxy for forest site productivity estimated using stand age and height. One of the most critical challenges in the site index (SI) concept are local variations in climate, soil, and genotype-environmental interactions that lead to variable height growth patterns among ecoregions and cause inappropriate estimation of site productivity. Developing regional models can solve this problem and allow us to determine forest growth and SI appropriately.Results: Therefore, the purpose of this study was to develop regional height growth models (RMs) for the Scots pine in Poland. For height growth modelling, we used the growth trajectory data of 855 sample trees, representing the entire range of geographic locations and site conditions of the Scots pine in Poland. Collected growth trajectories were used for the development of the global height growth model (GM) for Poland and RMs for six natural forest regions, which were adopted as the spatial unit for the model regionalisation. Height prediction errors by the global model were found to be significantly larger than those obtained with regional models in all regions. The results showed significant differences between growth trajectories in natural forest regions I, II, and III located in northern Poland compared to stands in natural forest regions IV, V, and VI in southern Poland.Conclusions: The presented study showed differences in height growth patterns of Scots pines in Poland and revealed that the use of local models could improve the growth prediction and quality of the SI estimation. Developed RMs show better fit statistics and predictive validity than the GM developed for the countrywide scale. Differences in climate and soil conditions which distinguish natural forest regions affect height growth patterns of Scots pine. Therefore, extending this research to models which directly describe the interactions of height growth with site variables, such as climate, soil properties, and topography, can provide additional valuable forest management information.

scholarly journals Regional height growth models for Scots pine in Poland

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jarosław Socha ◽  
Luiza Tymińska-Czabańska ◽  
Karol Bronisz ◽  
Stanisław Zięba ◽  
Paweł Hawryło
Keyword(s):  
Scots Pine ◽  
Growth Models ◽  
Height Growth ◽  
Growth Patterns ◽  
Forest Growth ◽  
Natural Forest ◽  
Trajectory Data ◽  
Site Productivity ◽  
Forest Regions ◽  
Modelling Approaches

AbstractSite productivity remains a fundamental concern in forestry as a significant driver of resource availability for tree growth. The site index (SI) reflects the overall impact of all environmental factors that determine tree height growth and is the most commonly used indirect proxy for forest site productivity estimated using stand age and height. The SI concept challenges are local variations in climate, soil, and genotype-environmental interactions that lead to variable height growth patterns among ecoregions and cause inappropriate estimation of site productivity. Developing regional models allow us to determine forest growth and SI more appropriately. This study aimed to develop height growth models for the Scots pine in Poland, considering the natural forest region effect. For height growth modelling, we used the growth trajectory data of 855 sample trees, representing the Scots pine entire range of geographic locations and site conditions in Poland. We compared the development of regional height growth models using nonlinear-fixed-effects (NFE) and nonlinear-mixed-effects (NME) modelling approaches. Our results indicate a slightly better fit to the data of the model built using NFE approach. The results showed significant differences between Scots pine growth in natural forest regions I, II, and III located in northern Poland and natural forest regions IV, V, and VI in southern Poland. We compared the development of regional height growth models using NFE and NME modelling approaches. Our results indicate a slightly better fit to the data of the model built using the NFE approach. The developed models show differences in height growth patterns of Scots pines in Poland and revealed that acknowledgement of region as the independent variable could improve the growth prediction and quality of the SI estimation. Differences in climate and soil conditions that distinguish natural forest regions affect Scots pine height growth patterns. Therefore, extending this research to models that directly describe height growth interactions with site variables, such as climate, soil properties, and topography, can provide valuable forest management information.

scholarly journals Modelling individual tree diameter growth for Norway spruce in the Czech Republic using a generalized algebraic difference approach

2017 ◽  
Vol 63 (No. 5) ◽  
pp. 227-238 ◽  
Author(s):  
Sharma Ram P ◽  
Vacek Zdeněk ◽  
Vacek Stanislav ◽  
Jansa Václav ◽  
Kučera Miloš
Keyword(s):  
Czech Republic ◽  
Growth Models ◽  
Site Quality ◽  
Diameter Growth ◽  
Individual Tree ◽  
The Czech Republic ◽  
Growth Series ◽  
Tree Diameter ◽  
Algebraic Difference ◽  
Generalized Algebraic Difference Approach

Individual tree-based growth models precisely describe the growth of individual trees irrespective of stand complexity. These models are more useful than the stand-based growth models for effective management of forests. We developed an individual tree diameter growth model for Norway spruce (Picea abies /Linnaeus/ H. Karsten) using permanent research plot data collected from Krkonoše National Park in the Czech Republic. The model was tested against a part of the Czech National Forest Inventory (NFI) data that originated from the western region of the country. Among various models derived by a generalized algebraic difference approach (GADA), the GADA model derived from the Chapman-Richards function best suited to our data. Tree-specific parameters unique to each growth series, which describe tree-specific growth conditions, were estimated simultaneously with global parameters common to all growth series using the iterative nested regressions. The model described most of the variations in diameter growth for model calibration data (R<sup>2</sup><sub>adj</sub> = 0.9901, RMSE = 0.5962), leaving no significant trends in the residuals. A test against NFI data also confirms that the model is precise enough for predictions of diameter growth for ranges of site quality, tree size, age, and growth condition. The model also possesses biologically desirable properties because it produces the curves with growth rates and asymptotes that increase with increasing site quality. The GADA model is path-invariant and therefore applicable for both forward and backward predictions, meaning that the model can precisely predict diameter growth at any past ages of the trees.

Comparing individual-tree growth models using principles of stand growth for Norway spruce, Scots pine, and European beech

2015 ◽  
Vol 45 (8) ◽  
pp. 1006-1018 ◽  
Author(s):  
Sonja Vospernik ◽  
Robert A. Monserud ◽  
Hubert Sterba
Keyword(s):  
Norway Spruce ◽  
Scots Pine ◽  
Tree Growth ◽  
Growth Models ◽  
Basal Area ◽  
European Beech ◽  
Growth And Yield ◽  
Individual Tree ◽  
Individual Tree Growth ◽  
Volume Increment

We examined the relationship between thinning intensity and volume increment predicted by four commonly used individual-tree growth models in Central Europe (i.e., BWIN, Moses, Prognaus, and Silva). We replicated conditions of older growth and yield experiments by selecting 34 young, dense plots of Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.), and European beech (Fagus sylvatica L.). At these plots, we simulated growth, with mortality only, to obtain the maximum basal area. Maximum basal area was then decreased by 5% or 10% steps using thinning from below. Maximum density varied considerably between simulators; it was mostly in a reasonable range but partly exceeded the maximum basal area observed by the Austrian National Forest Inventory or the self-thinning line. In almost all cases, simulated volume increment was highest at maximum basal area and then decreased with decreasing basal area. Critical basal area, at which 95% of maximum volume increment can be achieved, ranged from 0.46 to 0.96. For all simulators, critical basal area was lower for the more shade-tolerant species. It increased with age, except for Norway spruce, when simulated with the BWIN model. Age, where mean annual increment culminated, compared well with yield tables.

scholarly journals Comparison of selected Nordic stand growth models for Norway spruce, Scots pine and birch

2011 ◽  
Vol 55 (1) ◽  
pp. 46-59 ◽  
Author(s):  
Kjell Andreassen ◽  
Bernt-Håvard Øyen
Keyword(s):  
Norway Spruce ◽  
Scots Pine ◽  
Test Data ◽  
Growth Models ◽  
Management Practice ◽  
Tree Size ◽  
Site Quality ◽  
Data Set ◽  
Stand Growth ◽  
Stand Characteristics

Abstract Thirteen Nordic stand growth models have been validated by use of a test data set from long-term research plots in Norway. The evaluated data was from time-series of even-aged, pure stands of Norway spruce, Scots pine and birch (silver birch and downy birch). In selected models from Finland, Norway and Sweden measures of site productivity, mean tree size and various stand characteristics are represented. Different models display both strengths and weaknesses in their predicting ability. Several measures of precision and bias have been calculated and the models are ranked due to their performance. We observed site quality, stand density and average tree size as the three main components in the models. Basal area increment model for spruce from Sweden had the lowest standard deviation with 23%. The mean R2 between residuals and stand characteristics from this model was also low (1.3%), which indicates that independent variables are well included. For Scots pine and birch, Finnish volume increment models showed the best fit to the Norwegian test data, with a R2 between residuals and stand characteristics of 2.8 and 6.7%, respectively. Several of the models from Sweden and Finland predicted the growth as well as stand models frequently in use in Norway. The results indicated that similar forest conditions and traditional even-aged forest management practice in the Nordic countries could be seen as a suitable basis for developing a joint family of growth models. By careful recalibration of existing models, a reasonable accuracy could be achieved and the prediction bias could be reduced.

Suitability of two methods of evaluating site quality for sugar maple in central Ontario

2006 ◽  
Vol 82 (5) ◽  
pp. 733-744 ◽  
Author(s):  
Nicholas J Buda ◽  
Jian R Wang
Keyword(s):  
Sugar Maple ◽  
Quality Evaluation ◽  
Growth Models ◽  
Site Index ◽  
Height Growth ◽  
Site Quality ◽  
Dominant Height ◽  
Index Site ◽  
Species Mixture ◽  
Stand Conditions

Stem analyses data collected in central Ontario stands were used to develop site index (height and age) and site form (height and diameter) models and curves for sugar maple. The suitability of both methods for evaluating sugar maple site productivity was examined. Two different equation forms were evaluated for both site index and site form models. A common modification of Richard's (1959) equation was most suitable for predicting dominant height at index age (site index) and reference diameter (site form). Potential effects of species mixture on sugar maple site index were examined. We found no significant effects on sugar maple height growth and site index in mixed stand conditions common in the region when compared to pure stands. The potential of site form as an alternative to site index was investigated through correlation analyses with site index and other site variables known to influence sugar maple height growth. Site form was not related to site index, nor any site variables related to sugar maple height growth. It is therefore inadequate for evaluating sugar maple site quality. We recommend height growth models and site index curves developed in this study be used to replace those from other regions currently used in central Ontario. Key words: site index, site form, sugar maple, site quality evaluation, mixedwood, uneven-aged

Effects of overstory competition on canopy recruitment patterns of naturally regenerated longleaf pine on two site types

2020 ◽  
Vol 50 (7) ◽  
pp. 624-635
Author(s):  
Patrick J. Curtin ◽  
Benjamin O. Knapp ◽  
Steven B. Jack ◽  
Lance A. Vickers ◽  
David R. Larsen ◽  
...  
Keyword(s):  
Longleaf Pine ◽  
Pinus Palustris ◽  
Height Growth ◽  
Growth Patterns ◽  
High Density ◽  
Low Density ◽  
Individual Tree ◽  
Pine Trees ◽  
Overstory Trees

Recent interest in continuous cover forest management of longleaf pine (Pinus palustris Mill.) ecosystems raises questions of long-term sustainability because of uncertainty in rates of canopy recruitment of longleaf pine trees. We destructively sampled 130 naturally regenerated, midstory longleaf pines across an 11 300 ha, second-growth longleaf pine landscape in southwestern Georgia, United States, to reconstruct individual tree height growth patterns. We tested effects of stand density (using a competition index) and site quality (based on two site classifications: mesic and xeric) on height growth and demographics of midstory trees. We also compared height growth of paired midstory and overstory trees to infer stand regeneration and recruitment dynamics. In low-density stands, midstory trees were younger and grew at greater rates than trees within high-density stands. Midstory trees in low-density stands were mostly from a younger regeneration cohort than their paired overstory trees, whereas midstory–overstory pairs in high-density stands were mostly of the same cohort. Our results highlight the importance of releasing midstory longleaf pine trees from local competition for sustained height growth in partial-harvesting management systems. They also demonstrate patterns of long-term persistence in high-density stands, indicating flexibility in the canopy recruitment process of this shade-intolerant tree species.

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