scholarly journals The use of hyperspectral remote sensing for mapping the age composition of forest stands

2012 ◽  
Vol 58 (No. 6) ◽  
pp. 287-297 ◽  
Author(s):  
O. Skoupý ◽  
L. Zejdová ◽  
J. Hanuš

The paper deals with the issue of mapping the age composition of stand groups using hyperspectral imagery acquired by the AISA Eagle VNIR sensor in the B&iacute;l&yacute; Kř&iacute;ž locality in the Moravian-Silesian Beskids Mts. An object-oriented approach was employed through segmentation and subsequent classification by means of Nearest Neighbour (NN) algorithm in the environment of eCognition Developer 8 and artificial neural network (ANN) classification provided by ENVI 4.7 software. Because of the dominant occurrence of Norway spruce (Picea abies [L.] Karst.) monocultures in the studied locality the work focuses primarily on the distinguishability of two selected age classes of Norway spruce (10&ndash;20 years and 70&ndash;80 years). It studies possibilities of a more detailed age estimation of stand groups aged from 10 to 80 years based on the classification into the boundary classes, which shows similarity to dithering based on random algorithm. Comparison with the outline map of the Forest Management Plan shows a correlation (r<sup>2&nbsp;</sup>=&nbsp;0.83) between the spectral characteristics of Norway spruce stands and their age composition. &nbsp;

2012 ◽  
Vol 50 (No. 6) ◽  
pp. 256-262 ◽  
Author(s):  
P. Čermák ◽  
L. Jankovský ◽  
P. Cudlín

The paper proposes a method of assessing the potential risks of the future development of stands in relation to a climatic change. To assess risks of the future development of a stand simple point scales have been worked up based on primary properties of a site and a stand according to data of the forest management plan (FMP). In assessing the health condition, the risk of damage to stands by Armillaria sp. in the felling age was evaluated on the basis of a present attack by Armillaria sp. and also defoliation of the crown primary structure assessed during a simple field examination. The evaluation was carried out in the region of the Křtiny Training Forest Enterprise (TFE) Masarykův les, ranger district Proklest, in 2002. The study was conducted in <br />118 Norway spruce stands aged more than 20 years. The majority of evaluated stands ranked among the category of high and medium risk from the viewpoint of site and stand risks and among the category of high Armillaria sp. attack. &nbsp; &nbsp;


Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 841
Author(s):  
Iveta Desaine ◽  
Annija Kārkliņa ◽  
Roberts Matisons ◽  
Anna Pastare ◽  
Andis Adamovičs ◽  
...  

The increased removal of forest-derived biomass with whole-tree harvesting (WTH) has raised concerns about the long-term productivity and sustainability of forest ecosystems. If true, this effect needs to be factored in the assessment of long-term feasibility to implement such a drastic forest management measure. Therefore, the economic performance of five experimental plantations in three different forest types, where in 1971 simulated WTH event occurred, was compared with pure, planted and conventionally managed (CH) Norway spruce stands of similar age and growing conditions. Potential incomes of CH and WTH stands were based on timber prices for period 2014–2020. However, regarding the economics of root and stump biomass utilization, they were not included in the estimates. In any given price level, the difference of internal rate of return between the forest types and selected managements were from 2.5% to 6.2%. Therefore, Norway spruce stands demonstrate good potential of independence regardless of stump removal at the previous rotation.


Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 163
Author(s):  
Jan Světlík ◽  
Jan Krejza ◽  
Pavel Bednář

Tree growth depends on many factors such as microsite conditions, vitality, and variations in climate and genetics. It is generally accepted that higher growth indicates both an economic benefit and better vitality of any tree. Here we use a modified approach of evaluating tree social area to study mutual tree competition based on the orientation and shape of trees social area. The investigation was performed in nine Norway spruce stands in the Czech Republic. The objective of this study performed from 2008 to 2012 was to quantify relative tree radial increments with respect to the lowest and highest competition found in specific sectors of tree social area (AS). Specific groups of trees (tree classes) were evaluated according to their classes (dominant, co-dominant and sub-dominant) and their composition status in ninety-degree sectors of AS using established classifying rules. The results showed that a spatially-available area (AA) is an inappropriate parameter for predicting tree growth, whereas AS provided robust explanatory power to predict relative radial growth. Tree size was observed as an important indicator of relative radial increments. A significantly positive correlation was found for a radial increment of sub-dominant trees with the lowest competition from western directions; whereas a negative correlation was observed when the lowest competition was observed from eastern directions. For dominant trees, there was an evident growth reaction only when more than 50% of the AS was oriented towards one of the cardinal points. Individual differences in the orientation of tree AS may be important parameters with regard to competition and its spatial variability within an area surrounding a particular tree and deserve more detailed attention in tree growth models and practice.


2006 ◽  
Vol 77 (1) ◽  
pp. 1-23 ◽  
Author(s):  
Mats Fröberg ◽  
Dan Berggren ◽  
Bo Bergkvist ◽  
Charlotte Bryant ◽  
Jan Mulder

Silva Fennica ◽  
2008 ◽  
Vol 42 (5) ◽  
Author(s):  
Johan Bergh ◽  
Urban Nilsson ◽  
Harald Grip ◽  
Per-Ola Hedwall ◽  
Tomas Lundmark

Ecohydrology ◽  
2014 ◽  
Vol 8 (6) ◽  
pp. 1048-1064 ◽  
Author(s):  
Lars Köhler ◽  
Christoph Leuschner ◽  
Markus Hauck ◽  
Dietrich Hertel

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