Development of new forest stands after a large scale forest decline in the Krušné hory Mountains

1994 ◽  
Vol 3 (1) ◽  
pp. 57-69 ◽  
Author(s):  
Pavel Moravčík
Author(s):  
Marc Rhainds ◽  
Ian DeMerchant ◽  
Pierre Therrien

Abstract Spruce budworm, Choristoneura fumiferana Clem. (Lepidoptera: Tortricidae), is the most severe defoliator of Pinaceae in Nearctic boreal forests. Three tools widely used to guide large-scale management decisions (year-to-year defoliation maps; density of overwintering second instars [L2]; number of males at pheromone traps) were integrated to derive pheromone-based thresholds corresponding to specific intergenerational transitions in larval densities (L2i → L2i+1), taking into account the novel finding that threshold estimates decline with distance to defoliated forest stands (DIST). Estimates of thresholds were highly variable between years, both numerically and in terms of interactive effects of L2i and DIST, which limit their heuristic value. In the context of early intervention strategy (L2i+1 > 6.5 individuals per branch), however, thresholds fluctuated within relatively narrow intervals across wide ranges of L2i and DIST, and values of 40–200 males per trap may thus be used as general guideline.


2020 ◽  
Author(s):  
Giulia Mazzotti ◽  
Richard Essery ◽  
Johanna Malle ◽  
Clare Webster ◽  
Tobias Jonas

<p>Forest canopies strongly affect snowpack energetics during wintertime. In discontinuous forest stands, spatio-temporal variations in radiative and turbulent fluxes create complex snow distribution and melt patterns, with further impacts on the hydrological regimes and on the land surface properties of seasonally snow-covered forested environments.</p><p>As increasingly detailed canopy structure datasets are becoming available, canopy-induced energy exchange processes can be explicitly represented in high-resolution snow models. We applied the modelling framework FSM2 to obtain spatially distributed simulations of the forest snowpack in subalpine and boreal forest stands at high spatial (2m) and temporal (10min) resolution. Modelled sub-canopy radiative and turbulent fluxes were compared to detailed meteorological data of incoming irradiances, air and snow surface temperatures. These were acquired with novel observational systems, including 1) a motorized cable car setup recording spatially and temporally resolved data along a transect and 2) a handheld setup designed to capture temporal snapshots of 2D spatial distributions across forest discontinuities.</p><p>The combination of high-resolution modelling and multi-dimensional datasets allowed us to assess model performance at the level of individual energy balance components, under various meteorological conditions and across canopy density gradients. We showed which canopy representation strategies within FSM2 best succeeded in reproducing snowpack energy transfer dynamics in discontinuous forests, and derived implications for implementing forest snow processes in coarser-resolution models.</p>


CERNE ◽  
2016 ◽  
Vol 22 (1) ◽  
pp. 111-120 ◽  
Author(s):  
Guilherme de Castro Oliveira ◽  
Elpidio Inacio Fernandes Filho

ABSTRACT Permanent Preservation Areas (PPAs) on hilltops are among the many areas protected by the New Forest Code in Brazil. Mapping of these involves difficult interpretation and application of the Law, as well a complex task of translating it in map algebra. This paper aims to present, in detail, a methodological model for delimitation of PPAs on hilltops, according to the Brazilian new Forest Code (NFC, Law 12,651/2012). The model was developed in Model Builder for ArcGIS 10.2, and is able to map the PPAs in any digital terrain model. However, field validations are required to verify its efficiency. There is need for legal standardization of criteria that may cause subjectivity in delimitation. The organization of these data on a large scale is very important, as example, to the Rural Environmental Registry, which provides georeferencing of all rural properties and its protected areas in Brazil.


2021 ◽  
Vol 13 (13) ◽  
pp. 2476
Author(s):  
Hiroshi Masuda ◽  
Yuichiro Hiraoka ◽  
Kazuto Saito ◽  
Shinsuke Eto ◽  
Michinari Matsushita ◽  
...  

With the use of terrestrial laser scanning (TLS) in forest stands, surveys are now equipped to obtain dense point cloud data. However, the data range, i.e., the number of points, often reaches the billions or even higher, exceeding random access memory (RAM) limits on common computers. Moreover, the processing time often also extends beyond acceptable processing lengths. Thus, in this paper, we present a new method of efficiently extracting stem traits from huge point cloud data obtained by TLS, without subdividing or downsampling the point clouds. In this method, each point cloud is converted into a wireframe model by connecting neighboring points on the same continuous surface, and three-dimensional points on stems are resampled as cross-sectional points of the wireframe model in an out-of-core manner. Since the data size of the section points is much smaller than the original point clouds, stem traits can be calculated from the section points on a common computer. With the study method, 1381 tree stems were calculated from 3.6 billion points in ~20 min on a common computer. To evaluate the accuracy of this method, eight targeted trees were cut down and sliced at 1-m intervals; actual stem traits were then compared to those calculated from point clouds. The experimental results showed that the efficiency and accuracy of the proposed method are sufficient for practical use in various fields, including forest management and forest research.


2019 ◽  
Vol 11 (24) ◽  
pp. 2966
Author(s):  
Stefan Erasmi ◽  
Malte Semmler ◽  
Peter Schall ◽  
Michael Schlund

Synthetic aperture radar (SAR) satellite data provide a valuable means for the large-scale and long-term monitoring of structural components of forest stands. The potential of TanDEM-X interferometric SAR (InSAR) for the assessment of forest structural properties has been widely verified. However, present studies are mostly restricted to homogeneous forests and do not account for stratification in assessing model performance. A systematic sensitivity analysis of the TanDEM-X SAR signal to forest structural parameters was carried out with emphasis on different strata of forest stands (location of the study site, forest type, and development stage). Forest structure was parameterized by forest height metrics and stem volume. Results show that X-band volume coherence is highly sensitive to the forest canopy. Volume scattering within the canopy is dependent on the vertical heterogeneity of the forest stand. In general, TanDEM-X coherence is more sensitive to forest vertical structure compared to backscatter. The relations between TanDEM-X volume coherence and forest structural properties were significant at the level of a single test site as well as across sites in temperate forests in Germany. Forest type does not affect the overall relationship between the SAR signal and the forests’ vertical structure. The prediction of forest structural parameters based on the outcome of the sensitivity analysis yielded model accuracies between 15% (relative root mean square error) for Lorey’s height and 32% for stem volume. The global database of single-polarized bistatic TanDEM-X data provides an important source for mapping structural parameters in temperate forests at large scale, irrespective of forest type.


2014 ◽  
Vol 51 ◽  
pp. 805-827 ◽  
Author(s):  
D. Zilli ◽  
O. Parson ◽  
G. V. Merrett ◽  
A. Rogers

In recent years, the field of computational sustainability has striven to apply artificial intelligence techniques to solve ecological and environmental problems. In ecology, a key issue for the safeguarding of our planet is the monitoring of biodiversity. Automated acoustic recognition of species aims to provide a cost-effective method for biodiversity monitoring. This is particularly appealing for detecting endangered animals with a distinctive call, such as the New Forest cicada. To this end, we pursue a crowdsourcing approach, whereby the millions of visitors to the New Forest, where this insect was historically found, will help to monitor its presence by means of a smartphone app that can detect its mating call. Existing research in the field of acoustic insect detection has typically focused upon the classification of recordings collected from fixed field microphones. Such approaches segment a lengthy audio recording into individual segments of insect activity, which are independently classified using cepstral coefficients extracted from the recording as features. This paper reports on a contrasting approach, whereby we use crowdsourcing to collect recordings via a smartphone app, and present an immediate feedback to the users as to whether an insect has been found. Our classification approach does not remove silent parts of the recording via segmentation, but instead uses the temporal patterns throughout each recording to classify the insects present. We show that our approach can successfully discriminate between the call of the New Forest cicada and similar insects found in the New Forest, and is robust to common types of environment noise. A large scale trial deployment of our smartphone app collected over 6000 reports of insect activity from over 1000 users. Despite the cicada not having been rediscovered in the New Forest, the effectiveness of this approach was confirmed for both the detection algorithm, which successfully identified the same cicada through the app in countries where the same species is still present, and of the crowdsourcing methodology, which collected a vast number of recordings and involved thousands of contributors.


2020 ◽  
pp. 3-23
Author(s):  
Yu. A. Semenishchenkov ◽  
R. S. Korsikov

The results of the comparative analysis of traditional forest typology data and the data of floristic classification by the J. Braun-Blanquet approach for large-scale mapping of forest vegetation from the Southern Nechernozemye of Russia are presented. 3 model forest areas located in the forestries in borders of different botanic-geographical districts with specific climatic and edaphic conditions have been chosen to make the comparative analysis of cartographic materials (Bryansk and Smolensk Regions). A comparison of existing afforestation plans and created geobotanical maps demonstrates the difference in the number of recognized typological units. In all cases, a smaller number of units are noted for the geobotanical maps with a scale 1 : 25 000. A decrease in the number of typological units can be explain by the lack of information on the age of tree stands. Another reason is, probably, the assignment of some forest stands with the predominance of different indigenous species to a single association. However, the same typological units, distinguished by the predominance of tree species, may correspond to different units of floristic classification, which may increase the number of typological units on the geobotanical map. Some features of the Braun-Blanquet approach such as the allocation of units, primarily based on a comparison of the floristic composition of plant communities, allows attributing both natural stands and forest cultures to a single syntaxon. This also reduces the number of typological units on the geobotanical map. The plans of afforestation show the present-day species composition and the age of the studied stands, but the dynamic interrelations of forest communities are not reflected there. Therefore, it is more effective to reflect the dynamics of vegetation of forest communities in accordance with the methodology adopted when creating geobotanical maps. In this case, the succession state of communities and their links to classification units of higher ranks has been taken into account by the allocation of temporary facies with the predominance of small-leaved species at the site of indigenous broad-leaved or coniferous forests. The deductive approach with the identification of non-rank «communities» also makes it possible to separate into separate syntaxa and time-unstable, unformed or poorly floristic communities. Typically, such forests are formed by coniferous cultures in the zone of deciduous forests. The unformed «semi-forest» communities in the lowland swamps are also placed into the same category. They are often formed after felling, initiating or intensifying bogging under conditions of fluctuating moisture. The use of a single colorimetric scheme for forest stands in different climatic and edaphic conditions, reflected in the TLU (forest conditions) system, can be considered not quite correct. Stands with the predominance of the same species can correspond to different zonal-conditioned TLUs. At the same time, communities of some syntaxomomical taxa of floristic classification can be formed in different TLUs and their diversity corresponds to the width of the ecological amplitude of the types of plant communities. The more stenotopic communities, the smaller number of TLUs corresponding to their habitats. The afforestation plans and geobotanical maps can be used by different ways in forestry. The traditional afforestation plans are widely used in forestry planning. However, the geobotanical map supplemented with information on the dynamic relationships of stands allows making more efficient prediction of scenarios of forest stand development under known forest conditions. In addition, cartographic materials on the proposed geobotanical basis reflect the general botanical and geographical trends of vegetation, and the syntaxa of the floristic classification always have a certain chorological content, thus, they can be used as zonal-climatic indicators. This feature is reflected in their compliance with TLU, which are specifically distinguished for different natural zones.


2010 ◽  
Vol 56 (No. 11) ◽  
pp. 531-540 ◽  
Author(s):  
D. Zahradník ◽  
S. Vacek ◽  
L. Bílek ◽  
I. Nosková ◽  
Z. Vacek

Horizontal structure on 38 permanent research plots is described for juvenile growth and developmental phases (natural seeding, advance growth, plantations) and tree layer of a parent stand. Hopkins-Skellam index, Pielou-Mountford index, Clark-Evans index and Ripley's K-function were computed. The results are presented separately for beech stands, mixed stands, spruce stands, stands in the timberline ecotone and relict pinewood. The numbers and distribution of natural and combined regeneration recruits are mostly sufficient from the aspect of ecological, environmental and production functions of forest. The horizontal structure of juvenile growth and developmental phases of natural and combined regeneration shows mostly clustering; it is random or moderately regular at places with a single dominant proportion of artificial regeneration. In the tree layer the horizontal structure of forest stands is mostly random to moderately regular. In the future silvicultural measures should be aimed to support the structure of homogeneous stands of younger growth phases that have originated on a large scale after the air-pollution disaster.


Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 1008
Author(s):  
Anna Napierała-Filipiak ◽  
Maciej Filipiak ◽  
Piotr Łakomy

In nearly 600 randomly selected forest stands including elms (Ulmus spp.), we conducted field research to identify them to species level and to find trees showing symptoms of Dutch elm disease (DED). The presented data show that all the 3 native elms (U. glabra, U. laevis, and U. minor) still exist in the whole ranges of their distribution in Poland reported earlier, but their role as forest-forming species has changed. In comparison to published data, the contribution of U. minor has markedly decreased, while an increased contribution was observed in the case of U. laevis, a species which in the past was predominantly located out of woodland and was rarely cultivated. In mountains, where the most frequent is U. glabra, the contribution of elms to forest stands is currently clearly lower than in the lowlands and uplands of Poland. The observed changes most probably result from Dutch elm disease. It cannot be excluded that the changes are at least partly linked with natural correction of forest stand composition modified earlier by human activity (silviculture). In all parts of Poland, trees with symptoms of Dutch elm disease are found, but large-scale decline (of a majority of elm trees) is observed only in about 1.5% of the directly investigated localities.


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