Individual tree crown width models for Norway spruce and European beech in Czech Republic

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.

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Transgressive overyielding in mixed compared with pure stands of Norway spruce and European beech in Central Europe: evidence on stand level and explanation on individual tree level

European Journal of Forest Research ◽

10.1007/s10342-008-0215-9 ◽

2008 ◽

Vol 128 (2) ◽

pp. 183-204 ◽

Cited By ~ 177

Author(s):

Hans Pretzsch ◽

Gerhard Schütze

Keyword(s):

Norway Spruce ◽

Central Europe ◽

European Beech ◽

Tree Level ◽

Individual Tree

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Tree biomass allometry during the early growth of Norway spruce (Picea abies) varies between pure stands and mixtures with European beech (Fagus sylvatica)

Canadian Journal of Forest Research ◽

10.1139/cjfr-2017-0177 ◽

2018 ◽

Vol 48 (1) ◽

pp. 77-84 ◽

Cited By ~ 6

Author(s):

Ioan Dutcă ◽

Richard Mather ◽

Florin Ioraş

Keyword(s):

Picea Abies ◽

Norway Spruce ◽

Fagus Sylvatica ◽

Aboveground Biomass ◽

European Beech ◽

Mixed Stand ◽

Pure Stand ◽

Tree Biomass ◽

Mixed Stands ◽

Individual Tree

In this paper, we report an investigation of how forest stand mixture may affect biomass allometric relationships in Norway spruce (Picea abies (L.) Karst.). Analysis of aboveground biomass data was conducted for 50 trees: 25 sample trees from a pure Norway spruce stand and 25 from a mixed stand of Norway spruce with European beech (Fagus sylvatica L.). ANCOVA results demonstrated that individual-tree biomass allometry of the pure stand significantly differed from that of the mixed stand. Allometric characteristics depended on the biomass component recorded and the type of biomass predictor used. When predicted by diameter at breast height and (or) height, the total aboveground biomass of mixed-stand trees was significantly less than that for pure-stand trees. This “apparent” lower aboveground biomass was attributed to the lower branch and needle biomass proportions of trees growing in mixed stand. The findings indicate that caution should be exercised when applying biomass allometric models developed from pure stands to predict tree biomass in mixed stands (and vice versa), as such data treatment may introduce significant bias.

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Modelling tree crown-to-bole diameter ratio for Norway spruce and European beech

Silva Fennica ◽

10.14214/sf.1740 ◽

2017 ◽

Vol 51 (5) ◽

Cited By ~ 9

Author(s):

Ram Sharma ◽

Zdeněk Vacek ◽

Stanislav Vacek

Keyword(s):

Norway Spruce ◽

European Beech ◽

Diameter Ratio ◽

Tree Crown

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Using error-in-variable regression to predict tree diameter and crown width from remotely sensed imagery

Canadian Journal of Forest Research ◽

10.1139/x10-073 ◽

2010 ◽

Vol 40 (6) ◽

pp. 1095-1108 ◽

Cited By ~ 15

Author(s):

Wenhua Zhang ◽

Yinghai Ke ◽

Lindi J. Quackenbush ◽

Lianjun Zhang

Keyword(s):

Measurement Errors ◽

Major Axis ◽

Remotely Sensed ◽

Ordinary Least Squares ◽

Tree Crown ◽

Individual Tree ◽

Tree Diameter ◽

Remotely Sensed Imagery ◽

Crown Width ◽

Response Variables

Automated individual tree detection and delineation from high spatial resolution imagery provides good opportunities for forest inventory at a large scale. However, the accuracy of delineated crown size compared with ground measurements may not be sufficient. Thus, ordinary least squares (OLS) regression is no longer an appropriate approach to estimating and predicting variables from the delineated tree crown because both response variable and regressor are subject to measurement errors. In this study, we describe the functional and structural relationships between field-measured tree variables (i.e., tree diameter and crown width) and delineated tree crown width from remotely sensed imagery. We investigated the performance of OLS and three error-in-variable regression techniques including maximum likelihood estimator (MLE), major axis (MA) regression, and reduced major axis (RMA) regression using field-measured data and simulated data under different conditions. Our results indicated that MLE was desirable for estimating unbiased model coefficients. However, the adjustment assumption of the MLE model should be checked for predicting tree variables from remotely sensed imagery. When the assumption holds, the MLE model performed better for predicting the response variables than did the OLS model. Otherwise, the MLE model produced biased predictions for the response variables.

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

Canadian Journal of Forest Research ◽

10.1139/cjfr-2014-0394 ◽

2015 ◽

Vol 45 (8) ◽

pp. 1006-1018 ◽

Cited By ~ 12

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.

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Tree Recognition on the Plantation Using UAV Images with Ultrahigh Spatial Resolution in a Complex Environment

Remote Sensing ◽

10.3390/rs13204122 ◽

2021 ◽

Vol 13 (20) ◽

pp. 4122

Author(s):

Xuzhan Guo ◽

Qingwang Liu ◽

Ram P. Sharma ◽

Qiao Chen ◽

Qiaolin Ye ◽

...

Keyword(s):

Survival Rate ◽

Complex Terrain ◽

Low Cost ◽

Central China ◽

Ground Vegetation ◽

Tree Crown ◽

Individual Tree ◽

Crown Width ◽

Aerial Vehicle ◽

Uav Images

The survival rate of seedlings is a decisive factor of afforestation assessment. Generally, ground checking is more accurate than any other methods. However, the survival rate of seedlings can be higher in the growing season, and this can be estimated in a larger area at a relatively lower cost by extracting the tree crown from the unmanned aerial vehicle (UAV) images, which provides an opportunity for monitoring afforestation in an extensive area. At present, studies on extracting individual tree crowns under the complex ground vegetation conditions are limited. Based on the afforestation images obtained by airborne consumer-grade cameras in central China, this study proposes a method of extracting and fusing multiple radii morphological features to obtain the potential crown. A random forest (RF) was used to identify the regions extracted from the images, and then the recognized crown regions were fused selectively according to the distance. A low-cost individual crown recognition framework was constructed for rapid checking of planted trees. The method was tested in two afforestation areas of 5950 m2 and 5840 m2, with a population of 2418 trees (Koelreuteria) in total. Due to the complex terrain of the sample plot, high weed coverage, the crown width of trees, and spacing of saplings vary greatly, which increases both the difficulty and complexity of crown extraction. Nevertheless, recall and F-score of the proposed method reached 93.29%, 91.22%, and 92.24% precisions, respectively, and 2212 trees were correctly recognized and located. The results show that the proposed method is robust to the change of brightness and to splitting up of a multi-directional tree crown, and is an automatic solution for afforestation verification.

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Adaption of Norway spruce and European beech forests under climate change: from resistance to close-to-nature silviculture

Central European Forestry Journal ◽

10.2478/forj-2019-0013 ◽

2019 ◽

Vol 65 (2) ◽

pp. 129-144 ◽

Cited By ~ 4

Author(s):

Zdeněk Vacek ◽

Stanislav Vacek ◽

Jiří Slanař ◽

Lukáš Bílek ◽

Daniel Bulušek ◽

...

Keyword(s):

Climate Change ◽

Air Pollution ◽

Norway Spruce ◽

Tree Species ◽

Natural Regeneration ◽

Radial Growth ◽

European Beech ◽

Nature Management ◽

Mixed Stands ◽

Individual Tree

Abstract In time of climate change, close-to-nature silviculture is growing in importance as a tool for future forest management. The paper study the tree layer and natural regeneration of monospecific Norway spruce (Picea abies [L.] Karst.), trough mixed spruce-beech to dominant European beech (Fagus sylvatica L.) forests in Jizerské hory Mts., the Czech Republic. In the locality, shelterwood and selection system have been applied since 2000. The research objectives were to evaluate production parameters, structural diversity, species richness, natural regeneration dynamics and radial growth of individual tree species in relation to climatic factors and air pollution. The stand volume on permanent research plots amounted to 441 – 731 m3 ha−1 in initial stage of transformation. Natural regeneration showed high expansion of beech and decrease of spruce compared to mature tree species composition. Radial growth of spruce was in significant negative correlation with SO2 and NOX concentrations compared to no effect on beech increment. Moreover, spruce was more sensitive to significant years with extreme low radial growth. Beech was more stable in radial growth. Spruce was more resistant to air pollution and climatic stress in mixed stands. Low temperature was limiting factor of radial growth together with climate extremes (such as strong frosts and more frequent droughts) and biotic factors (bark beetle, beech scale). Close-to-nature management supporting admixed tree species should lead in future to diversification of stand structure toward higher species, spatial and age structure to mitigate negative effect of climatic change.

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