scholarly journals Regional Variability of the Romanian Main Tree Species Growth Using National Forest Inventory Increment Cores

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 409
Author(s):  
Gheorghe Marin ◽  
Vlad C. Strimbu ◽  
Ioan V. Abrudan ◽  
Bogdan M. Strimbu
Keyword(s):  
Mixed Models ◽  
Forest Inventory ◽  
Basal Area ◽  
National Forest Inventory ◽  
Forest Growth ◽  
National Forest ◽  
Sessile Oak ◽  
Basal Area Growth ◽  
Temporal Grouping ◽  
Area Growth

In many countries, National Forest Inventory (NFI) data is used to assess the variability of forest growth across the country. The identification of areas with similar growths provides the foundation for development of regional models. The objective of the present study is to identify areas with similar diameter and basal area growth using increment cores acquired by the NFI for the three main Romanian species: Norway spruce (Picea abies L. Karst), European beech (Fagus sylvatica L.), and Sessile oak (Quercus petraea (Matt.) Liebl.). We used 6536 increment cores with ages less than 100 years, a total of 427,635 rings. The country was divided in 21 non-overlapping ecoregions based on geomorphology, soil, geology and spatial contiguousness. Mixed models and multivariate analyses were used to assess the differences in annual dimeter at breast height and basal area growth among ecoregions. Irrespective of the species, the mixed models analysis revealed significant differences in growth between the ecoregions. However, some ecoregions were similar in terms of growth and could be aggregated. Multivariate analysis reinforced the difference between ecoregions and showed no temporal grouping for spruce and beech. Sessile oak growth was separated not only by ecoregions, but also by time, with some ecoregions being more prone to draught. Our study showed that countries of median size, such as Romania, could exhibit significant spatial differences in forest growth. Therefore, countrywide growth models incorporate too much variability to be considered operationally feasible. Furthermore, it is difficult to justify the current growth and yield models as a legal binding planning tool.

scholarly journals Zur Auswirkung der Hangneigungskorrektur auf Schätzwerte im Schweizerischen Landesforstinventar (LFI) | Investigation of the effect of the slope correction method as applied in the Swiss National Forest Inventory of estimates

2001 ◽  
Vol 152 (6) ◽  
pp. 215-225 ◽  
Author(s):  
Michael Köhl ◽  
Peter Brassel
Keyword(s):  
Forest Inventory ◽  
Basal Area ◽  
Correction Method ◽  
National Forest Inventory ◽  
National Forest ◽  
Average Deviation ◽  
Forest Inventories ◽  
Slope Correction ◽  
Number Of Stems ◽  
Elliptical Area

For forest inventories on slopes, it is necessary to correct the test areas, because the circular areas, when projected, become elliptical. Based on 93 samples from the Swiss National Forest Inventory (FNI), it was determined whether the simplified method, which increases the radius to match that of the elliptical area, leads to a distortion of the results. An average deviation of 2% was found between the FNI estimated values and the actual values for the basal area and the number of stems. For estimations of smaller units, greater distortions of the results are expected.

Variation in forest inventory field measurements

1994 ◽  
Vol 24 (9) ◽  
pp. 1766-1770 ◽  
Author(s):  
Ronald E. McRoberts ◽  
Jerold T. Hahn ◽  
Glenda J. Hefty ◽  
Jerry R. Van Cleve
Keyword(s):  
Forest Inventory ◽  
Basal Area ◽  
Field Measurements ◽  
Site Index ◽  
Upper Peninsula ◽  
The North ◽  
Basal Area Growth ◽  
Coefficients Of Variation ◽  
Area Growth ◽  
Forest Experiment Station

Field crews from the North Central Forest Experiment Station independently measured two forest inventory plots in Michigan's Upper Peninsula; one plot was measured by eight crews and the other was measured by nine different crews. For 61 trees, the variation in measurements of diameter at breast height (DBH), crown ratio, and site index is described. For DBH, the distribution of field crew mistakes and the distribution of measurements without mistakes are described separately. For crown ratio, the distribution of differences between individual estimates and the most frequently occurring estimate for corresponding trees is described. For site index, the distribution of differences between individual estimates and the mean of plot estimates is described. Coefficients of variation were less than 5% for DBH, approximately 73% for crown ratio, and 13% and 16% for site index for the two plots. The effects of variation in measurements on 20-year predictions of basal area and cumulative basal area growth were estimated for the two plots using STEMS, TWIGS, and Monte Carlo simulations. Coefficients of variation were 2% and 3% for basal area and 7% and 9% for cumulative basal area growth for the two plots. Variation in site index estimates had the greatest effect on variation in the output variables.

scholarly journals Fluctuations in gross volume increment estimated by the Lithuanian National Forest Inventory compared with annual variations in single tree increment

2019 ◽  
Vol 25 (2) ◽  
pp. 273-280
Author(s):  
Gintaras Kulbokas ◽  
Vaiva Jurevičienė ◽  
Andrius Kuliešis ◽  
Algirdas Augustaitis ◽  
Edmundas Petrauskas ◽  
...  
Keyword(s):  
Land Use ◽  
Volume Change ◽  
Forest Inventory ◽  
Basal Area ◽  
National Forest Inventory ◽  
Reference Level ◽  
National Forest ◽  
Growing Stock ◽  
Volume Increment ◽  
Stock Volume

There are significant inter-annual fluctuations of growing stock volume changes of living trees estimated by the Lithuanian National Forest Inventory (NFI). In the current study, we compared two sources of information on forest productivity: conventional NFI data and dendrochronological data based on tree cores collected in parallel with the measurements of the fourth Lithuanian NFI cycle during 2013–2017 on the same permanent plots (total number of cores was 4967). The main finding is that the dendrochronological basal area increment data confirmed the depression of gross stand volume increment around 2006–2007 (based on Lithuanian NFI measurements in 2008–2009), followed by a steep increase during 2008–2011 (NFI from 2010–2013). The findings explain the differences between projected growing stock volume change, which have been used for forest reference level estimation according to land use, land-use change and forestry sector regulation, and the one recently provided in National Greenhouse Gas Inventory Reports. Key words: Growing stock volume change, basal area increment, forest reference level, greenhouse gas reporting

Basal Area Growth Estimators for Survivor Component: A Quality Control Application

1990 ◽  
Vol 14 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Charles E. Thomas ◽  
Francis A. Roesch
Keyword(s):  
Quality Control ◽  
Quality Assurance ◽  
Forest Inventory ◽  
Data Use ◽  
Basal Area ◽  
Forest Inventory And Analysis ◽  
Basal Area Growth ◽  
Area Growth ◽  
Forest Experiment Station ◽  
Control Application

Abstract Several possible estimators are available for basal area growth of survivor trees, when horizontal prism (or point plots (HPP) are remeasured. This study's comparison of three estimators not only provides a check for the estimate of basal area growth but suggests that they can provide a quality control indicator for yield procedures. An example is derived from remeasurements in Alabama for the Southern Forest Experiment Station by Forest Inventory and Analysis. Remeasurements are for 1962-72 and 1972-82. It is suggested that computation of two or perhaps all three of the estimators be routinely incorporated in analysis of remeasured HPP data. Use of the two elemental estimators can provide a quality assurance check on field procedures. South. J. Appl. For. 14(1):12-18.

scholarly journals Evaluation of the basal area growth models in the Finnish stand simulator MOTTI with data from the Estonian network of permanent forest growth plots / Soome puistukasvusimulaatori MOTTI rinnaspindala juurdekasvumudelite prognoositäpsuse hindamine Eesti metsa kasvukäigu püsiproovitükkide võrgustiku mõõtmisandmete põhjal

2011 ◽  
Vol 55 (1) ◽  
pp. 80-97
Author(s):  
Ando Lilleleht ◽  
Allan Sims ◽  
Andres Kiviste ◽  
Jari Hynynen ◽  
Mika Lehtonen
Keyword(s):  
Decision Support ◽  
Decision Support Systems ◽  
Support Systems ◽  
Growth Models ◽  
Model Performance ◽  
Basal Area ◽  
Forest Growth ◽  
Tree Level ◽  
Basal Area Growth ◽  
Area Growth

Abstract Forest management has become a more complex issue than it has ever been before. Foresters need to fulfill the demands of several interest groups, often which are conflicting. Finding the balance between different management objectives can be facilitated with the use of decision support systems. Since no decision support systems have been developed in Estonia, the aim of this study is to assess the applicability of the Finnish stand growth simulator MOTTI in Estonia. The evaluation focuses on the basal area growth models; the data used originates from the Estonian network of permanent forest growth plots. Tree-level bias models were constructed for all major tree species in order to assess model performance. Also, bias was examined visually with the use of residual plots. Results show that bias levels and variables which contribute to bias differ by species. Based on the fit statistics of the bias models, Common aspen shows the highest bias level whereas the growth of Gray alder seems to be predicted most accurately. Although model performance is decent for a model that is used outside of its application limits, calibration should still be considered as a prerequisite to implement the MOTTI system in Estonian forestry practice.

scholarly journals Comparison of height-diameter models based on geographically weighted regressions and linear mixed modelling applied to large scale forest inventory data

2016 ◽  
Vol 25 (3) ◽  
pp. e076
Author(s):  
María Quirós Segovia ◽  
Sonia Condés Ruiz ◽  
Karel Drápela
Keyword(s):  
Spatial Analysis ◽  
Geographically Weighted Regression ◽  
Mixed Models ◽  
Forest Inventory ◽  
Large Scale ◽  
Pinus Halepensis ◽  
Linear Mixed Models ◽  
National Forest Inventory ◽  
Weighted Regression ◽  
National Forest

Aim of the study: The main objective of this study was to test Geographically Weighted Regression (GWR) for developing height-diameter curves for forests on a large scale and to compare it with Linear Mixed Models (LMM).Area of study: Monospecific stands of Pinus halepensis Mill. located in the region of Murcia (Southeast Spain).Materials and Methods: The dataset consisted of 230 sample plots (2582 trees) from the Third Spanish National Forest Inventory (SNFI) randomly split into training data (152 plots) and validation data (78 plots). Two different methodologies were used for modelling local (Petterson) and generalized height-diameter relationships (Cañadas I): GWR, with different bandwidths, and linear mixed models. Finally, the quality of the estimated models was compared throughout statistical analysis. Main results: In general, both LMM and GWR provide better prediction capability when applied to a generalized height-diameter function than when applied to a local one, with R2 values increasing from around 0.6 to 0.7 in the model validation. Bias and RMSE were also lower for the generalized function. However, error analysis showed that there were no large differences between these two methodologies, evidencing that GWR provides results which are as good as the more frequently used LMM methodology, at least when no additional measurements are available for calibrating.Research highlights: GWR is a type of spatial analysis for exploring spatially heterogeneous processes. GWR can model spatial variation in tree height-diameter relationship and its regression quality is comparable to LMM. The advantage of GWR over LMM is the possibility to determine the spatial location of every parameter without additional measurements. Keywords: Spatial analysis; Pinus halepensis Mill; forest modelling.Abbreviations: GWR (Geographically Weighted Regression); LMM (Linear Mixed Model); SNFI (Spanish National Forest Inventory).

Steigende Bestandszahlen bei Spechten und anderen Vogelarten dank Zunahme von Totholz? | An increase in the population of woodpeckers and other bird species thanks to an increase in the quantities of deadwood?

2009 ◽  
Vol 160 (11) ◽  
pp. 334-340 ◽  
Author(s):  
Pierre Mollet ◽  
Niklaus Zbinden ◽  
Hans Schmid
Keyword(s):  
Forest Inventory ◽  
Bird Species ◽  
National Forest Inventory ◽  
Population Increase ◽  
National Forest ◽  
Forest Species ◽  
Breeding Populations ◽  
Willow Tit ◽  
Middle Spotted Woodpecker ◽  
Important Habitat

Results from the monitoring programs of the Swiss Ornithological Institute show that the breeding populations of several forest species for which deadwood is an important habitat element (black woodpecker, great spotted woodpecker, middle spotted woodpecker, lesser spotted woodpecker, green woodpecker, three-toed woodpecker as well as crested tit, willow tit and Eurasian tree creeper) have increased in the period 1990 to 2008, although not to the same extent in all species. At the same time the white-backed woodpecker extended its range in eastern Switzerland. The Swiss National Forest Inventory shows an increase in the amount of deadwood in forests for the same period. For all the mentioned species, with the exception of green and middle spotted woodpecker, the growing availability of deadwood is likely to be the most important factor explaining this population increase.

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