scholarly journals Similar patterns of background mortality across Europe are mostly driven by drought in European beech and a combination of drought and competition in Scots pine

2019 ◽  
Author(s):  
Juliette Archambeau ◽  
Paloma Ruiz Benito ◽  
Sophia Ratcliffe ◽  
Thibaut Fréjaville ◽  
Alexandre Changenet ◽  
...  
Keyword(s):  
Scots Pine ◽  
Tree Mortality ◽  
Latitudinal Gradient ◽  
Basal Area ◽  
European Beech ◽  
Mortality Rates ◽  
Individual Tree ◽  
Southern Limit ◽  
Drought Intensity ◽  
Species Ranges

ABSTRACTAimBackground tree mortality is a complex demographic process that affects forest structure and long-term dynamics. We aimed to test how drought intensity interacts with interspecific and intraspecific competition (or facilitation) in shaping individual mortality patterns across tree species ranges.LocationEuropean latitudinal gradient (Spain to Finland).Time period1985 – 2014.Major taxa studiedScots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.).MethodsWe performed logistic regression models based on individual tree mortality recorded in five European National Forest Inventories. We computed the relative importance of climatic drought intensity, basal area of conspecific and heterospecific trees (proxy of indirect intra- and interspecific competition or facilitation) and the effects of their interactions on mortality along the latitudinal gradient of both species range.ResultsIncrease in drought intensity over the study period was associated with higher mortality rates in both species. Drought was the most important driver of beech mortality at almost all latitudes while Scots pine mortality was mainly driven by basal area. High conspecific basal area was associated with high mortality rates in both species while high heterospecific basal area was correlated with mortality rates that were high in Scots pine but low in beech.Main conclusionsBeech mortality was directly affected by drought while Scots pine mortality was indirectly affected by drought through interactions with basal area. Despite their different sensitivity to drought and basal area, the highest predicted mortality rates for both species were at the ecotone between Mediterranean and cool temperate biomes, which can be explained by the combined effect of drought and competition. In the context of global warming, which is expected to be particularly strong in the Mediterranean biome, our results suggest that populations at the southern limit of species ranges may experience increased mortality rates in the near future.BIOSKETCHThe authors’ research is focused on functional trait ecology and global change, with special attention to mortality and demography processes. The authors use modelling multidisciplinary approaches to understand complex processes in ecology on a large geographical scale.

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 An Individual-Tree Mortality Model for Complex Stands of Southeastern British Columbia

2005 ◽  
Vol 20 (2) ◽  
pp. 101-109 ◽  
Author(s):  
Hailemariam Temesgen ◽  
Stephen J. Mitchell
Keyword(s):  
British Columbia ◽  
Tree Species ◽  
Tree Mortality ◽  
Model Development ◽  
Mortality Rates ◽  
Average Deviation ◽  
Individual Tree ◽  
Permanent Sample Plots ◽  
Diameter Increment ◽  
Mortality Model

Abstract An individual-tree mortality model was developed for major tree species in complex stands (multi-cohort, multiaged, and mixed species) of southeastern British Columbia (BC), Canada. Data for 29,773 trees were obtained from permanent sample plots established in BC. Average annual diameter increment and mortality rates ranged from 0.08 to 0.17 cm/year and from 0.3 to 2.6%, respectively. Approximately 70% of the trees were used for model development and 30% for model evaluation. After evaluating the model, all 29,773 trees were used to fit the final model. A generalized logistic model was used to relate mortality to tree size, competition, and relative position of trees in a stand. The evaluation test demonstrated that the model appears to be well behaved and robust for the tree species considered in this study. For the eight tree species, the average deviation between observed and predicted annual mortality rates varied from −0.5 to 0.7% in the test data. West. J. Appl. For. 20(2):101–109.

Stand, species, and tree dynamics of an uneven-aged, mixed conifer forest type

1995 ◽  
Vol 25 (5) ◽  
pp. 803-812 ◽  
Author(s):  
John P. McTague ◽  
William F. Stansfield
Keyword(s):  
Tree Mortality ◽  
Forest Type ◽  
Species Abundance ◽  
Basal Area ◽  
Logistic Function ◽  
Conifer Forest ◽  
Individual Tree ◽  
Recovery Method ◽  
Parameter Recovery ◽  
Tree Survival

Stand-level equations are presented that project future merchantable tree survival, pole-tree basal area, and sawtimber basal area. Total basal area (excluding ingrowth) is the sum of the pole-tree and sawtimber components. Ratio equations are used for eight species (seven softwoods and one hardwood) to compute the change in species abundance and species basal area over time. Individual-tree mortality is predicted with a logistic function, while individual-tree diameter growth is predicted as a function of stand and individual-tree attributes. The individual-tree and species-level equations are adjusted so that tree frequency and basal area are consistent with the stand-level projection equations. Total ingrowth is computed with a stand-level projection equation and is distributed with a parameter recovery method using the uniform distribution. The presence or absence of ingrowth for a given species is determined with a discriminant function, while the proportion of total ingrowth allocated to a species is predicted with a logistic function.

scholarly journals Resistance of a lowland rain forest to increasing drought intensity in Sabah, Borneo

2004 ◽  
Vol 20 (6) ◽  
pp. 613-624 ◽  
Author(s):  
D. M. Newbery ◽  
M. Lingenfelder
Keyword(s):  
Growth Rates ◽  
Rain Forest ◽  
Tree Mortality ◽  
Mortality Rates ◽  
Stem Growth ◽  
Lowland Rain Forest ◽  
Drought Intensity ◽  
Tree Survival ◽  
Climatic Environment ◽  
Absolute Growth

Occasional strong droughts are an important feature of the climatic environment of tropical rain forest in much of Borneo. This paper compares the response of a lowland dipterocarp forest at Danum, Sabah, in a period of low (LDI) and a period of high (HDI) drought intensity (1986–96, 9.98 y; 1996–99, 2.62 y). Mean annual drought intensity was two-fold higher in the HDI than LDI period (1997 v. 976 mm), and each period had one moderately strong main drought (viz. 1992, 1998). Mortality of ‘all’ trees ≥10 cm gbh (girth at breast height) and stem growth rates of ‘small’ trees 10–<50 cm gbh were measured in sixteen 0.16-ha subplots (half on ridge, half on lower slope sites) within two 4-ha plots. These 10–50-cm trees were composed largely of true understorey species. A new procedure was developed to correct for the effect of differences in length of census interval when comparing tree mortality rates. Mortality rates of small trees declined slightly but not significantly between the LDI and HDI periods (1.53 to 1.48% y−1): mortality of all trees showed a similar pattern. Relative growth rates declined significantly by 23% from LDI to HDI periods (11.1 to 8.6 mm m−1 y−1): for absolute growth rates the decrease was 28% (2.45 to 1.77 mm y−1). Neither mortality nor growth rates were significantly influenced by topography. For small trees, across subplots, absolute growth rate was positively correlated in the LDI period, but negatively correlated in the HDI period, with mortality rate. There was no consistent pattern in the responses among the 19 most abundant species (n≥50 trees) which included a proposed drought-tolerant guild. In terms of tree survival, the forest at Danum was resistant to increasing drought intensity, but showed decreased stem growth attributable to increasing water stress.

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

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 451 ◽  
Author(s):  
Ram P. Sharma ◽  
Igor Štefančík ◽  
Zdeněk Vacek ◽  
Stanislav Vacek
Keyword(s):  
Basal Area ◽  
European Beech ◽  
Site Index ◽  
Development Stage ◽  
Mixed Effects ◽  
Site Quality ◽  
Stand Age ◽  
Sample Plot ◽  
Individual Tree ◽  
Diameter Increment

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.

scholarly journals Precommercial Thinning in a Ponderosa Pine Stand Affected by Armillaria Root Disease in Central Oregon: 30 Years of Growth and Mortality

1999 ◽  
Vol 14 (3) ◽  
pp. 144-148 ◽  
Author(s):  
Gregory M. Filip ◽  
Stephen A. Fitzgerald ◽  
Lisa M. Ganio
Keyword(s):  
Ponderosa Pine ◽  
Tree Mortality ◽  
Basal Area ◽  
Stand Density ◽  
Root Disease ◽  
Diameter Growth ◽  
Individual Tree ◽  
Precommercial Thinning ◽  
Tree Diameter ◽  
Armillaria Root Disease

Abstract A 30-yr-old stand of ponderosa pine was precommercially thinned in 1966 to determine the effects of thinning on tree growth and mortality caused by Armillaria root disease in central Oregon. After 30 yr, crop tree mortality was significantly (P = 0.02) less in thinned plots than in unthinned plots. Tree diameter growth was not significantly (P = 0.17) increased by thinning. Crop-tree basal area/ac growth was significantly (P = 0.03) greater in thinned plots. Apparently, from a root disease perspective, precommercial thinning of pure ponderosa stands significantly decreases the incidence of crop-tree mortality after 30 yr and significantly increases basal area/ac growth but not individual tree diameter growth. Recommendations for thinning based on stand density index (SDI) are given. West. J. Appl. For. 14(3):144-148.

Long-term trends in tree mortality rates in the Alberta foothills are driven by stand development

2012 ◽  
Vol 42 (9) ◽  
pp. 1687-1696 ◽  
Author(s):  
H.C. Thorpe ◽  
L.D. Daniels
Keyword(s):  
Mortality Risk ◽  
Forest Structure ◽  
Tree Mortality ◽  
Mortality Rates ◽  
Tree Level ◽  
Model Parameters ◽  
Stem Density ◽  
Stand Development ◽  
Individual Tree ◽  
Local Competition

Tree mortality is a critical driver of stand dynamics, influencing forest structure, composition, and capacity for ecosystem service provision. In recent years, tree mortality has been gaining attention as dramatic occurrences of forest die-off have been linked to climate change. Using permanent sample plot data, we examined tree mortality rates in mature forests in west-central Alberta from 1956 to 2007. We quantified mortality risk at an individual-tree level as a function of size, local competition, and calendar year, a proxy for increasing temperature, and used maximum likelihood methods to estimate species-specific model parameters. Tree size and local competition were both important predictors of mortality risk. However, once these factors were included in our model, no additional variation could be attributed to calendar year, indicating that the trend of increasing tree mortality over time found in our raw data is primarily a result of stand development processes. This finding is supported by the changes in forest structure and composition that we documented over the study period. Stands generally increased in basal area and stem density, and lodgepole pine ( Pinus contorta var. latifolia Engelm. ex S. Watson) declined in abundance relative to the more shade-tolerant black spruce ( Picea mariana (Mill.) B.S.P.) and white spruce ( Picea glauca (Moench) Voss). Our results indicate that warming-related changes did not affect background tree mortality rates in mature forests in the Alberta foothills over the study period. These results also provide critical information for future studies of forest dynamics in the region.

scholarly journals Generalized Nonlinear Mixed-Effects Individual Tree Crown Ratio Models for Norway Spruce and European Beech

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 555 ◽  
Author(s):  
Ram Sharma ◽  
Zdeněk Vacek ◽  
Stanislav Vacek
Keyword(s):  
Norway Spruce ◽  
Model Fitting ◽  
Basal Area ◽  
European Beech ◽  
Logistic Function ◽  
Mixed Effects ◽  
Mixed Effects Model ◽  
Individual Tree ◽  
Mixed Effects Modeling ◽  
Species Mixture

Tree crowns are commonly measured to understand tree growth and stand dynamics. Crown ratio (CR—crown depth-to-total height ratio) is significantly affected by a number of tree- and stand-level characteristics and other factors as well. Generalized mixed-effects CR models were developed using a large dataset (measurements from 14,669 trees of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica (L.)) acquired from permanent research plots in various parts of the Czech Republic. Among several tree- and stand-level variables evaluated, diameter at breast height, height to crown base, dominant height, basal area of trees larger in diameter than a focal tree, relative spacing index, and variables describing the effects of species mixture and canopy height differentiation significantly contributed to CR variation. We included sample-plot-level variations caused by randomness in the data and other stochastic factors into the CR models using the mixed-effects modeling approach. The logistic function, which predicts the values between 0 and 1, was chosen to develop the generalized CR mixed-effects model. A large proportion of the CR variation (R2adj ≈ 0.63 (Norway spruce); 0.72 (European beech)) was described by generalized mixed-effects model without significant residual trends. Testing the CR model against a part of the model fitting dataset confirmed its high prediction precision. Our CR model can be useful for growth simulation using inventory databases that lack crown measures. Other potential implications of our CR models in forest management are mentioned in the article.

MODELING INDIVIDUAL TREE MORTALITY RATES USING MARGINAL AND RANDOM EFFECTS REGRESSION MODELS

2012 ◽  
Vol 26 (2) ◽  
pp. 131-153 ◽  
Author(s):  
ZHIHAI MA ◽  
CHANGHUI PENG ◽  
WEIZHONG LI ◽  
QIUAN ZHU ◽  
WEIFENG WANG ◽  
...  
Keyword(s):  
Random Effects ◽  
Regression Models ◽  
Tree Mortality ◽  
Mortality Rates ◽  
Individual Tree
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