Róbert Marušák

Visual complexity and the montado do matter: landscape pattern preferences of user groups in Alentejo, Portugal

Abstract• ContextThe current paradigms for the sustainable development of forests and agriculture involve territorial organization of these activities as well as the multifunctionality of the related landscapes. Accordingly, the new management strategies need to take into account the suitability of the resulting landscapes to produce the goods and services expected by society.• AimsThe aim of the study was to assess the preferred landscape patterns by different groups of users. In focus were the relations between the landscape metrics of preferred patterns and the individual characteristics of respondents.• MethodsA regional quantitative survey of both production and different consumption landscape users was conducted in the Alentejo region, southern Portugal. Respondents composed their preferred patterns on a block diagram representing an area of landscape seen from a single view according to the existing topographic conditions in the study area.• ResultsIn general, the visually complex landscape patterns were preferred more than the homogeneous ones. However, the metrics of preferred patterns varied between the user groups. The montado was the only land cover class that was present in the majority of preferred patterns.• ConclusionFor landscape users in southern Portugal, the visually complex landscapes including the montado are essential to satisfy their expectations. This may be an important fact to be taken into account for policy and landscape management in the future.

ABOVE-GROUND NET PRIMARY PRODUCTIVITY IN YOUNG STANDS OF BEECH AND SPRUCE

Abstract One of the expected consequences of climate change and its inherent phenomena to forest ecosystems is the gradual modification of their tree species composition (i.e. expansion of resistant species instead of less resistant ones). Climate change accompanied with increasing temperatures and a lack of precipitations may present a threat especially to spruce stands in the European part of the temperate zone. European beech is one of the possible forest tree species which might replace the potentially endangered spruce. In this paper, we observed, by using a combination of continual measurements and destructive whole-tree sampling, standing stocks of above-ground biomass (i.e. stem, branches, and foliage) and its annual net primary productivity (NPP) in naturally regenerated young stands of beech and spruce. We intentionally selected a site where the changing climate conditions are better suited to the ecological demands of beech rather than spruce (the species is dominant in the observed area). We recorded only small differences in the standing stock of stems of the beech, if based on tons per ha. However, this is in favor of spruce if based on cubic meters per ha. The largest difference between the species was found for the standing stock of foliage, spruce retained three times the biomass of beech. Also, beech allocated more carbohydrates to stem than spruce. On the other hand, we estimated nearly the same production of foliages and branches in both stands. Resumé V tejto práci sme pomocou kombinácií kontinuálnych meraní a deštruktívnych odberov vzorníkov sledovali a porovnali zásobu nadzemnej biomasy a ročnú primárnu produkciu (NPP) v prirodzene obnovených mladých porastoch buka a smreka. Na vybranej lokalite predpokladáme, že zmenené klimatické podmienky budú lepšie vyhovovať buku pred v súčasnosti prevládajúcim smrekom. Lokalita Vrchslatina sa nachádza v južnej časti Veporských vrchov v nadmorskej výške 977 m nad morom (48° 38΄ 50΄΄ N, 19° 36΄ 07΄΄ E). Priemerné ročné zrážky sa pohybujú okolo 900 mm, priemerná ročná teplota je 5,2 °C. Na sledovanej lokalite sme pozorovali odlišný priebeh rastu buka a smreka. Pri buku bola pozorovaná menšia medziročná mortalita, udržiaval sa až prehustený zápoj, v ktorom sa aj podúrovňové stromy snažili dostať do úrovne. Toto sa prejavilo na tvare kmeňov, ktoré sú tenké a vysoké. Štíhlostný koeficient sa pri stromoch so strednou hrúbkou a strednou výškou postupne zvyšoval od 1,19 do 1,40. Pri smreku dochádza k vyššej mortalite, vrastavé a podúrovňové stromy odumierajú z dôvodu nedostatku svetla. Stromy rastú viac do hrúbky, čo sa odráža aj na štíhlostnom koeficiente, ktorý bol po celé obdobie viac-menej konštantný a pohyboval sa v rozpätí 0,89 až 0,93 (tab. 1). Zásoby kmeňa sú pri smreku v jednotlivých rokoch o 3 - 10 m3.ha-1 väčšie ako pri buku (tab. 3). Po prepočítaní na sušinu je vplyvom rozdielnej objemovej hmotnosti (obr. 5) celková zásoba sušiny drevných častí (kmeň a konáre) väčšia pri buku (tab. 3). Najväčší rozdiel medzi drevinami je v zásobe asimilačných orgánov, ktorá je pri smreku viac než trojnásobná (tab. 3 a 4). Počas rastu dochádza pri obidvoch drevinách k zvyšovaniu podielu kmeňa a znižovaniu podielu asimilačných orgánov (obr. 2). Hlavný medzidruhový rozdiel pri pomerne vyrovnaných hektárových zásobách je v rozdelení nadzemnej biomasy medzi komponenty, kde buk alokuje do kmeňa viac asimilátov ako smrek (obr. 2 - 4). Pri porovnaní ročnej NPP asimilačných orgánov a konárov neboli zistené žiadne signifikantné rozdiely medzi sledovanými drevinami (obr. 6). Ukázali sme, že zásoby nadzemnej biomasy ako aj NPP buka a smreka boli v mladých plnozakmenených porastoch z prirodzeného zmladenia na danom stanovišti podobné (tab. 3 a 4).

Plant Diversity of Forests

Changes in biological diversity of natural ecosystems have in the second half of 20th century become a global problem due to intensive human activities. Therefore, higher attention has been paid to these problems. The year 1992 can be considered as the pivotal year in this field since in this year the Convention on Biological Diversity was approved on the United Nations Conference on Environment and Development in Rio de Janeiro. This document defines biological diversity biodiversity as „the variety and variability among living organisms from all sources including inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part“. This definition covers three fundamental components of diversity: genetic, species, and ecosystem diversity (Duelli, 1997, as cited in Larsson, 2001; Merganic & Smelko, 2004). However, also this widely accepted definition like many others fails to mention ecological processes, such as natural disturbances, and nutrient cycles, etc., that are crucial to maintaining biodiversity (Noss, 1990). The complexity of the understanding of the term biodiversity was well documented by Kaennel (1998). Therefore, Noss (1990) suggested that for the assessment of the overall status of biodiversity more useful than a definition would be its characterisation that identifies its major components at several levels of organisation. Franklin et al. (1981 as cited in Noss, 1990) recognised three primary attributes of ecosystems: composition, structure, and function.

Evaluating similarity of radial increments around tree stem circumference of European beech and Norway spruce from Central Europe

Extracting cores from a tree using an increment borer has been standard practice in dendrochronological studies for a long time. Although empirical rules exist regarding how many samples to take and which methodology to apply, comparatively few studies provide quantification of the similarity of relative tree-ring-widths (TRW) around the stem circumference. The aim of this study was therefore to precisely measure the similarity of standardised TRWs around the stem circumference and to provide objective suggestions for optimal core sampling of Norway spruce (Picea abies Karst. [L.]) and European beech (Fagus sylvatica L.) growing in Central European temperate forests.A large sample of cross-sectional discs was used from Norway spruce and European beech trees growing on various slopes, at different altitudes and biogeographic regions across the Czech Republic and Slovakia. The similarity of TRWs measured in different coring directions was analysed by testing the relativized TRW around the trunk (rTRW). Comparison of rTRWs revealed no significant differences between coring directions, indicating that the relative increment was the same around the radius. The results also showed the high similarity between the rTRWs to be independent of both slope inclination and altitude. Moreover, the reconstruction of proportional tree diameters and basal areas backward in time from one core sample and one measurement of tree diameter (basal area) at the time of sample extraction is possible with reasonable precision.

GIS tool for optimization of forest harvest-scheduling

We created ArcGIS extension for forest harvest scheduling problems.The extension is connected to GUROBI optimization software.The extension facilitates spatial and temporal design of harvest units.The extension provides effective way of creating forest harvest scheduling scenarios. This article describes GIS tool (Optimal) for spatial and temporal optimization of forest harvests. Using Optimal, forest manager can create harvest units by editing polygons of forest stands in digital map. After the harvest units are created manually by the user, the adjacency matrix is automatically produced and passed to a solver module. The solver performs optimization using integer programming and returns spatial distribution of harvest units for each harvest period. User can set number of parameters, such as number and length of harvest periods, acceptable distances and areas of harvest units. The Optimal enables the forest managers to create and explore various scenarios and increase efficiency in forest harvest-scheduling.

Importance of automatic threshold for image segmentation for accurate measurement of fine roots of woody plants / Význam automatického prahovania na obrazovú segmentáciu pre presné merania jemných koreňov drevín

Abstract The fine roots are considered the key organs for plant survival, growth and productivity. Measurement of fine roots variables is easily and conveniently achieved by means of digital image. The descriptive variables like root area, surface, total length and diameter distribution may be obtained from the image. Analysis of digital image consists from several steps, each of them represents potential source of the error. In this article we want to evaluate the automatic thresholding and its impact on principal variables obtainable from digital scans of the fine roots. We compare 16 different thresholding methods and compare them with the human processed binary images of roots of cork oak (Quercus suber L.). We found some of the thresholding methods perform significantly better than others in the estimation of total projected area however the length estimation error points out a little different order of accuracy Abstrakt Jemné korene sú považované za kľúčové orgány zabezpečujúce prežitie rastliny, jej rast a produkciu. Merania jemných koreňov sú ľahko a pohodlne vykonávateľné pomocou digitálneho obrazu. Popisné veličiny ako plocha koreňov, ich povrch, celková dĺžka či hrúbková štruktúra sa dajú získať z digitálneho obrazu. Analýza digitálneho obrazu pozostáva z niekoľkých krokov, z ktorých každý predstavuje potenciálny zdroj chyby merania. V tomto článku sa zameriavame na automatickú segmentáciu prahovaním a jej vplyv na veličiny získavané z digitálnych skenov jemných koreňov korkového duba (Quercus suber L.). Porovnávame 16 rôznych prahovacích metód a ich správnosť v porovnaní s binárnymi obrazmi vytvorenými ľudským hodnotiteľom. Zistili sme, že niektoré prahovacie metódy dávajú lepšie výsledky ako ostatné v odhade plochy koreňov, ale pred odhad dĺžky koreňov je poradie metód podľa ich správnosti len mierne odlišné

Biomass allocation influenced by canopy closure in a young spruce stand.

Growth intensity of particular tree components is controlled by a variety of factors and as a consequence, biomass allocation also changes over time. Since the allocation of biomass controls the carbon regime in a forest stand, tree standing stock and biomass structure, with regard to tree components: fine and coarse roots, stem, branches and needles, were estimated in a young Norway spruce stand based on repeated tree sampling, soil coring and allometric equations (modelled for 2009 and 2013, i.e. for 12- and 16-years-old trees). Large differences were found between the two models in the contribution of the tree components to aboveground biomass. Between the first and fifth year of the experiment, below - ground to aboveground biomass ratio as well as short-lived to long-lived tree part ratio manifested decreasing tendencies. At the same time, the stand possibly reached the maximum standing stock of both needles and fine roots. It is concluded that for biomass allocation estimates in young stands, not only stand-specific but also time-specific allometric relations should be constructed and implemented. Further, there appears to be a canopy closure threshold beyond which biomass allocation is different from the situation in sparse young spruce stands.

Relation between forest stand diversity and anticipated log quality in managed Central European forests

ABSTRACT This study examined the influence of tree species and structural diversity on the production of high-quality logs. The data were from the regional forest inventory of the University Forest Enterprise, Czech Republic, performed from 2009 to 2011 on 1188 sample plots. For every sample plot, we quantified 38 diversity indicators. The plots were divided into four age groups (young, middle-aged, old and uneven-aged stands). The anticipated proportion of high-quality logs was determined using local assortment tables. For each age group, the impact of species and structural diversity indicators on the volumetric proportion of high-quality logs was assessed using backwards multiple regression. The relationship between diversity measures and log quality changed with stand age. In old stands, horizontal structure had a more profound effect on the proportion of high-quality logs. In young stands, species diversity and vertical structure were more influential. In middle-aged stands, the impact of stand diversity on log quality was most complex. In uneven-aged stands, vertical structure was the diversity component most affecting the proportion of high-quality logs. Overall, the proportion of best quality logs increased with the increasing stand diversity in all age classes, suggesting that timber production and stand diversity are not contradictory management goals. EDITED BY Sheila Ward

Alternative Modelling Approach to Spatial Harvest Scheduling with Respect to Fragmentation of Forest Ecosystem.

Fragmentation of the forests affects forest ecosystems by changing the composition, shape, and configuration of the resulting patches. Subsequently, the prevailing conditions vary between patches. The exposure to the sun decreases from the patch boundary to the patch interior and this forms core and edge areas within each patch. Forest harvesting and, in particular, the clear-cut management system which is still preferred in many European countries has a significant impact on forest fragmentation. There are many indices of measuring fragmentation: non-spatial and spatial. The non-spatial indices measure the composition of patches, while the spatial indices measure both the shape and configuration of the resulting patches. The effect of forest harvesting on fragmentation, biodiversity, and the environment is extensively studied; however, the integration of fragmentation indices in the harvest scheduling model is a new, novel approach. This paper presents a multi-objective integer model of harvest scheduling for clear-cut management system and presents a case study demonstrating its use. Harvest balance and sustainability are ensured by the addition of constraints from the basic principle of the regulated forest model. The results indicate that harvest balance and sustainability can be also achieved in minimizing fragmentation of forest ecosystems. From the analyses presented in this study, it can be concluded that integration of fragmentation into harvest scheduling can provide better spatial structure. It depends on the initial spatial and age structure. It was confirmed that it is possible to find compromise solution while minimizing fragmentation and maximizing harvested area.

Spatial and non-spatial harvest scheduling versus conventional timber indicator in over-mature forests

Abstract This paper presents two alternative approaches of final cut scheduling for a fifty year strategic planning horizon. One approach is represented by cutting percentage, which is a classical timber indicator commonly used in the Czech and Slovak Republics. The second approach is represented by two optimisation models of integer programming; the first model without spatial aspect and the second model including adjacency constraints. Both optimisation models are derived for the clear cut management system with the scheduling approaches applied on an example of a forest management area with over-mature stands. The main aim of the paper is to compare two suggested optimisation models with the classical scheduling approach and to demonstrate their positive effect on the age class distribution of forests. The further aim is to include green-up constraints in the scheduling, which respect legislative conditions. The results show that even in the case of a single management system, without considering different ecosystem services, the optimisation model that does not consider the spatial aspect gives comparable results to the approach that r includes the adjacency constraints. The primary hypothesis, that the regular age-class distribution and flow harvesting cannot be achieved when considering green-up constraints, was rejected Abstrakt Práce prezentuje dva alternativní přístupy k plánování mýtních těžeb v rámci 50 letého strategického plánovacího horizontu. Jeden přístup je reprezentován klasickým těžebním ukazatelem, těžební procento, který je běžně používaný v České a Slovenské republice. Druhý přístup je reprezentován dvěma optimalizačními celočíselnými modely; první model je bez prostorového aspektu, druhý pak zahrnuje vztahy omezení sousednosti. Oba dva optimalizační modely jsou odvozeny pro holosečný hospodářský způsob. Alternativní přístupy plánování těžeb jsou aplikovány na příkladu lesního hospodářského celku s převahou přestárlých porostů. Hlavní cíl práce je porovnat navržené optimalizační modely s klasickým postupem plánování mýtní těžeb a demonstrovat pozitivní vliv navržených těžeb těmito modely na věkovou strukturu lesa. Dalším cílem je zahrnout do modelu zákonná omezení vzájemného přiřazování holých sečí. Výsledky ukazují, že i v případě jednoduchého hospodářského způsobu bez zahrnutí různých ekosystémových služeb, poskytuje optimalizační model bez prostorového hlediska srovnatelné výsledky s modelem, který tato hlediska zahrnuje. Primární hypotéza, že nemůže být dosaženo normální věkové struktury a těžební vyrovnanosti i v případě použití omezení týkající se přiřazování sečí, byla zamítnuta