bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the photoreactivity of some hardwood species studied by their leaf characteristics
Authors: Van Miegroet M. 
Published: July 2016

A certain number of measurable characteristics of tree leaves (morphological characteristics, absorption of light radiation, intensity of respiration and photosynthesis) are clearly linked with the presence of physiologically active pigments in the leaves. Leaf characteristics are highly and inequally influenced by changing conditions of light environment, especially those related to light intensity, light quality and duration of the daily illumination period. These modifications do not only apply to light radiation as created under laboratory conditions, but also to light conditions ensuing from the place in the crown of a single tree, the social position of the tree in a forest stand and the site factors in general. There are also changes taking place due to the progression of the vegetation period, at the end of which all species are less tolerant or more light demanding. The reaction of the leaves towards light radiation out of different regions of the spectrum is also different. The so-called blue light radiation (λmax = 440 nm) seems to be of the greatest importance in this relation, as species react quite different to its action. The biggest variation in leaf characteristics due to changing light environment was measured for oak and beech, which both react quickly and are qualified as 'photolabile species'. No important variations occur in leaves of ash and maple, which therefore are qualified as 'photostable species'. As a consequence of variable reactions to changing light conditions, the relationships between the species are continually modified, even in such a way that their potential for dominance is not constant. The classical division into tolerant and intolerant species or classification of the species based upon the degree of light demand, is highly inaccurate and it seems preferable to speak of relative light demands and relative tolerance. All these observations and conclusions bring about a clear confirmation of the necessity to recognize the individuality of the single tree, the special character of each growth condition, the own structure of each forest stand, the specific reaction to one sided modifications of environmental factors. This is especially important for an intensive sylvicultural practice. They also prove the necessity for more physiological and biochemical research to arrive at a better understanding of growth and its mechanism. Sylviculture in fact must try to regulate, on an expanded scale, the phenomens of growth, which is the exchange, absorption and transformation of energy. A practical interpretation and regulation of fundamental laws of physiology and growth will be possible as soon as a clinical form of sylviculture is created and the adequate instrumentarium developed.
L'état d'équilibre des futaies jardinées sur le territoire de l'Ancienne Republique de Venise
Authors: Lust N. 
Published: July 2016

The equilibrium of some selection forests of the Ancient Republic of Venetia - The actual selection forests of the Ancient Republic of Venetia distinguish very clearly from those of central Europe: 1. The maximal diamter (DE) is very low (50-55 cm). 2. The number of stems in the last size-class (O) is very high. 3. The felling: the greatest part of the trees is cut in the last size-class. In the lower classes only few trees are felled. ln order to calculate the equilibrium, we have finally admitted the formula: q = (log O -log V - 4,68713 log DE + 8,30490)/(11,58048 - 7,17988 log DE) The most important characteristics of a forest of first or second quality-class are as follows : a q DE O N V Ba Vol.M. % large timber 1. cl 120,1 1,36 75 3 325,3 347,1 31,0 1,07 34,1 2. cl 150,0 1,54 65 2 274,1 207,6 19,7 0,76 16,2
Berücksichtigung neuer parameter in der strukturanalyse von tropischen urwäldern
Authors: Finol H. 
Published: July 2016

Consideration of new parameters in the analysis of the structure of tropical virgin forests - Till now in the analysis of the structure of tropical forests only parameters of the horizontal structure have been taken in consideration, when calculating the importance value index on base of relative frequency, abundancy and dominance. However in many cases the importance value index did not result to be a correct ecological value for the species componing the forests. In the present article it is proposed to take into account the vertical structure also, based on the new parameters "sociological position", and "natural regeneration". As the mentioned example shows (table 3), the ecological value of each species seems more correctly represented in the investigated forest type in this case as by the importance value index only.
Le forestier et les problèmes de l'environnement
Authors: Van Miegroet M. 
Published: July 2016

Forestry and the Ecological Crisis - The principal aim of forestry is to obtain an optimal, continuous and multiple use of the forest. Actually forest use is characterized by qualitative and quantitative variations in time and space. In the industrialized countries a continuous deplacement of the centres of gravity is taking place and forestry is confronted with an alternative choice between economic and social objectives. As far as environmental problems are concerned the essential functions of the forest are: the physical presence, the protection of agricultural land and living space, the recreative function and the building of a soil reserve. The forester can give considerable help in matters concerning protection of nature, landscaping and soil conservation. The actual and multiple function of forestry requires a sound social motivation and a modification of the profile or the profession. These changes must be taken into consideration in planning and organizing forestry education.
La respiration et la photosynthèse de frênes qui poussent dans des conditions différentes
Authors: Lust N. 
Published: July 2016

Respiration and photosynthesis of ashes, grown up under different circumstances - Some physiological characteristics have been researched on ashes of different ages and height and grown up under different Iight circumstances : - the respiration pro unit of leaf surface and pro unit of weight. - the photosynthesis pro unit of leaf surface and pro unit of weight. - the apparent photosynthesis - the relation photosynthesis-respiration - the relation photosynthesis-chlorophyll content. Besides the influence of the light characteristics of the leaves, the research proves also the influence of age, height and provenance on the amount of photosynthesis and respiration. The respiration and photosynthesis pro unit of leaf surface is higher with sun leaves as with shade leaves. With ashes, grown up at the same level of light intensity, not only the relation photosynthesis-respiration, but also the apparent photosynthesis is higher with shade leaves as with sun leaves.
Recherches sur la structure des peuplements vierges de hêtre oriental (Fagus orientalis Lipsky), dans les futaies du Nord de l'Iran
Authors: Asli A. , Nedialkov S. T. 
Published: July 2016

Research in stand of virgin community of beech 'Fagus orientalis Lipsky in the Caspian forests of the northern Iran - The forest communities of Fagetum ilexesumof the northern slopes of the Elborz Mountains are studied and analysed. Density, basal area, height and stem volume are studied as ecological characteristics. Data are presented by curves, tables and figures. Comparisons are made between present stand characteristics and those of optimum conditions for growth of an uneven-aged forest. Data presented provide the basic information necessary to optimize sustained yield management of the Caspian forests.
Fundamental options in silvicultural management
Authors: Van Miegroet M. 
Published: July 2016

Fundamentele opties van de bosbedrijfsvoering - De bosbedrijfsvoering wordt bestendig geconfronteerd met alternatieve keuzemogelijkheden, die betrekking hebben op de hiernavolgende aspecten Het bos De bostypes Het bosgebruik De waardevoortbrengst De bosbouwpraktijk a. De boomsoortenkeuze b. De keuze van de behandeling c. De keuze van de verjongingswijze In de hoogst mogelijke mate moet een veelzijdige waardevoortbrengst in polyvalente bossen worden beoogd. Een pluralistische conceptie van de bosbouw houdt rekening met drie fundamentele opdrachten of partiele doelstellingen: Het behoud van het bos. De organisatie van het sociaal bosgebruik. De vrijwaring van de materiële productie op het hoogst mogelijke niveau van bestendiging.
A classification-ordination analysis of a Belgian mixed forest in the transition zone of two phytogeographical districts. I. Summer data
Authors: Van Hecke P. , Impens I. , Van Tilborgh T. , Veroustraete V. 
Published: July 2016

In een gemengd bos van ongeveer 19 ha in het grensgebied van het Vlaams en het Brabants District (België) werden 115 opnamen verricht in evenzovele systematisch uitgelegde proefvlakken. Drie cluster- en één ordinatietechniek werden toegepast. Normale Associatieanalyse (NAA) en Principale Componenten Analyse (PCA) gaven betere resultaten wanneer beide boomlagen, struik- en kruidlaag als één geheel werden beschouwd, de overige twee Clusteranalysen (HG en UPGC) echter wanneer de laatste twee apart werden bekeken. In de NAA leverde de haltdrempel van 1 % wat duidelijker groepen dan die van 5 %. Povere resultaten werden verkregen met het klassificeren der taxa (nl. 122) zowel met HG, UPGC als PCA . Met PCA kwamen gradienten duidelijker tot uiting wanneer de variantie-covariantie matrix steunde op taxa en deze van correlatiecoëfficiënten op opnamen. HG en UPGC waren in staat vijf vegetatietypen te onderscheiden. NAA echter enkel drie : in totaal zes goed en één veel minder te omschrijven vegetatietype.In een gemengd bos van ongeveer 19 ha in het grensgebied van het Vlaams en het Brabants District (België) werden 115 opnamen verricht in evenzovele systematisch uitgelegde proefvlakken. Drie cluster- en één ordinatietechniek werden toegepast. Normale Associatieanalyse (NAA) en Principale Componenten Analyse (PCA) gaven betere resultaten wanneer beide boomlagen, struik- en kruidlaag als één geheel werden beschouwd, de overige twee Clusteranalysen (HG en UPGC) echter wanneer de laatste twee apart werden bekeken. In de NAA leverde de haltdrempel van 1 % wat duidelijker groepen dan die van 5 %. Povere resultaten werden verkregen met het klassificeren der taxa (nl. 122) zowel met HG, UPGC als PCA . Met PCA kwamen gradienten duidelijker tot uiting wanneer de variantie-covariantie matrix steunde op taxa en deze van correlatiecoëfficiënten op opnamen. HG en UPGC waren in staat vijf vegetatietypen te onderscheiden. NAA echter enkel drie : in totaal zes goed en één veel minder te omschrijven vegetatietype.
The early stages of spontaneous forest regeneration on poor soils and continental sand dunes in northern Belgium
Authors: Van Miegroet M. 
Published: July 2016

Spontaneous natural regeneration under variable conditions on sandy soils and continental sand dunes were analysed in 5 locations in N.E. Belgium. The number of seedlings varies between 14.000 and 522.000/ha. The most prominent invading species are red oak, pedunculate oak and Scots pine. Two principal types of regeneration are recognized : homogeneous groups of oak or pine and mixtures, predominantly composed by the same species. Pioneers such as birch, willow, white poplar and wild black cherry do not play an important role. Social differentiation sets in quite early and is mainly provoked by age differences. Therefore early silvicultural intervention is advisable. The growth relationships between the species indicate that Scots pine is not in danger of spontaneous elemination by other species. Because of the density and variability of spontaneous forest regeneration, the conversion of pure pine stands into mixed forest, using group regeneration to this end, poses no real technical problems.
Contribution a l'étude de l'éducation des peuplements: Les placettes C.C.T.
Authors: Delvaux J. 
Published: July 2016

On décrit les principes directeurs et l'installation pratique en Ardenne belge moyenne, pour l'épicéa commun (Picea abies Karst.) d'un dispositif de parcelles C.C.T. (Correlated Curve Trend). Il s'agit essentiellement d'une série de placettes, plantées initialement à faible écartement, dont le nombre de tiges est progressivement réduit par prélèvements systématiques avant que se manifestent les effets de la competition inter-individuelle. Ces effets sont détectés par la comparaison des placettes à effectifs récemment réduits avec une placette faisant office de témoin temporaire. Le dispositif établit sans ambiguïté le régime maximum d'intensité de l'éclaircie, au-delà duquel aucun gain d'accroissement individuel moyen ne peut plus être obtenu sans modification du milieu, pour l'essence et la station considéréés. Le dispositif installé en 1975 couvre les écartements de 0,5 x 1, 1 x 1, 1 x 2,2 x 2,2 x 4 et 4 x 4 m, avec trois répétitions, et deux répétitions complémentaires de placettes plantées dès l'origine à 2 x 2, 2 x 4 et 4 x 4 m. Les réductions d'effectifs à concurrence de 1 x 2 et de 2 x 2 m ont eu lieu respectivement en 1978 et en 1982.
Analysis of natural regeneration of Scots pine forest in the high Campine after a fire
Authors: Lust N. 
Published: July 2016

The study deals with the spontaneous resettlement of a fire area, after destruction of 600 ha Scots pine forest. The following items have been examined in particular: the composition of the tree species, the duration of the regeneration period, the influence of the parent stand, the exposition, the slope, the treatment, the fire regime and the social differentiation. The resettlement took place very quickly and over a very short period. Birch and Scots pine take up 95 % of the stem number. The regeneration result is precarious, yet mostly good. The parent stand is favourable both to seed supply and to microclimate, but only over a short distance. The Scots pine prefers more open and dry areas, whereas birch needs more humidity. Practice has shown that natural regeneration of Scots pine stands is possible. The forest treatment, however, is very important. It determines not only the immediate result of the regeneration, but also the composition and the structure of the future stand.
Typology of the natural regeneration in a middle-aged Scots pine forest
Authors: De Schepper C. 
Published: July 2016

The study describes the natural regeneration state of a forest on coarse sandy soils. The natural regeneration was studied in three different ecological conditions: in 30 to 60 year old Scots pine stands, in a 62 year old mixed stand of pedunculate oak and red oak, and on the free field. The analysis of the regeneration groups revealed that the first settler maintained a dominant social position during the following years after the settlement. The structural basis is consequently laid out early. This means that the forest practice has to consider the very first phase of the regeneration as determining for the following evolution of the regeneration groups.
Analysis of natural regeneration in a 200 years old beech stand
Authors: Muys B. , Van Den Berge K. , Roskams P. , Maddelein D. , Meyen S. 
Published: July 2016

A 200 year old beech stand near Brussels (Belgium) has been studied on some regeneration characteristics. As the stand is entering the natural degradation phase, a score of big trees have been uprooted during the past 6 years, creating canopy gaps and causing local soil tillage. The study focuses principally on the possibly beneficial effect of these gaps on natural regeneration. Number, age, height and browsing damage of seedlings are measured. Seedling number is found more influenced by soil tillage than by light input. Finally, some predictions of the future development of the stand are formulated.
Rehabilitation of forest ecosystem on former heathlands by a first generation of Scots pine
Authors: Lust N. , Maddelein D. , Meyen S. 
Published: July 2016

In an attempt to rehabilitate degraded heathland areas, an important reafforestation program, based on the introduction of Scots pine, was executed at the end of the 19th century. Today, after one generation of Scots pine, results can be considered to be very good. On various locations a dense substratum, dominated by red oak and black cherry, has settled spontaneously under the pine canopy. This offers serious opportunities to conduct an indirect conversion towards mixed oak-pine forests or oak-dominated deciduous forests. Massive presence of black cherry in the understory of many pine stands inhibits the settlement of other deciduous tree species or pine regeneration and thereby prevents the stand conversion. The reintroduction of autochtonous tree species by underplanting or sowing under pine canopy deserves recommendation, keeping in mind the lack of seed trees and the high browsing damage on all seedlings present. In absence of an understory a second pine generation can settle under canopy of an older pine stand. Natural regeneration is also dominated by Scots pine on the clearcutted areas and under canopy when the soil vegetation and organic horizons have been removed. Summarising, we can state that one generation of Scots pine has created various possibilities for the development of a complex, diverse and structural forest ecosystem. It is the task of the forest manager to fully turn to account these possibilities.
Growth, structure and shape characteristics of a 12 year old grey alder stand (Alnus incana L. Moench.)
Authors: Lust N. 
Published: July 2016

In the experimental forest Aelmoeseneie at Gontrode (Belgium), a 12 year old artificial plantation of grey alder has been analysed on growth, structure and shape characteristics. In the plot some ten tree cells and tree pairs were examined in particular. The tree cells consisted of one central tree, which was surrounded by six other ones. The tree pairs were the dominant tree and the most dominated tree in these cells. In the first place height, diameter, basal area and leaf mass were determined. Then, the vertical and horizontal structures were analysed, with special attention being paid as well to the social differentiation in the tree cells as to the crown areas. Finally, several tree shape characteristics were determined. The alder grew very well. The internal competition and differentiation had already started. The position of the dominant trees, however, is not stabilised yet. The treatment of the thicket, in continuity with the thinning, will be necessary in the next future.
Thin section preparation of poplar tree-rings for computer-aided image analysis in dendrochronological investigations
Authors: Amparado R. F. , Beeckman H. , Lemeur R. 
Published: July 2016

A methodology is outlined to measure histological poplar treering variables like vessel area, being sensitive ecological indicators. Thin section preparation methods and a staining schedule are suggested to enhance contrast and to obtain best intensity colour for subsequent analyses of poplar treering variables, using a computeraided image analysis technique.
Structure and dynamics of a 215-years old broadleaved forest stand recently installed as a total forest reserve
Authors: Van Den Berge K. , Roskams P. , Verlinden A. , Quataert P. , Muys B. , Maddelein D. , Zwaenepoel J. 
Published: July 2016

Since 1983, a 215-years old broadleaved stand in the state owned Zoniën Forest (Belgium, Flanders) has been withdrawn from all silvicultural treatments. Thanks to the completely reviewed forest law in Flanders of 1990, the stand is now officially installed as a total forest reserve. The present contribution gives an overview of the principal site characteristics, and then focuses on the woody component of the ecosystem. Stand structure analysis starts from the situation of 1986, i.e. dating from before the spring tempests of 1990. Subsequently, the impact of those gale forces is evaluated as a driving factor in forest dynamics. In this particular stand, it was found that an abrupt change-over took place from the regeneration phase to a real decaying phase, resulting in a mosaic pattern with remnants of the old stand, consolidated regeneration, canopy gaps and windfall areas of different size.
The attitude of the Flemish private forest owner towards multiple use forestry and the new forest decree
Authors: Lust N. 
Published: July 2016

The importance of private forest in the multiple use forestry in Flanders should not be underestimated. Generally speaking, the attitude of the private forest owner is far from negative. Practice has shown some positive achievements. The private forest owner is not only interested in wood production and investment, but he also takes a very keen interest in hunting, nature conservation and recreation. Forest legislation is a good means to increase the significance of multiple use forestry in private forests. In this respect, the recent Flemish Forest Decree makes a considerable contribution, on the one hand by imposing some obligations, such as a management plan, and on the other hand by promoting wood production as well as forest conservation, recreation and nature development in the forest.
Le bois comme composant d'écosystème
Authors: Beeckman H. , Vander Mijnsbrugge K. 
Published: July 2016

Wood as an ecosystem component - An ecological study of wood as a material has to define two ecosystems of a different level of integration. The small-scale ecosystems are the dwelling houses, where a considerable amount of wood is used for several purposes. Positive effects of wood on the health of the inhabitants are reported. These effects establish the significance of the typical association wood-mankind. The large-scale ecosystem is the global ecosystem of the earth. Ecological diagnostics on this level have to take into account the Second Law of Thermodynamics. Forestry and intelligent use of wood are able to slow down entropy and heat accumulation in the atmosphere.
Silvicultural characteristics of a Scots pine stand on drift sands
Authors: Maddelein D. , Lust N. 
Published: July 2016

The study of a seventy years old stand of Scots pine on drift sands proves that Scots pine growth on these sites was and is still relatively good: average diameter 27.6 cm, average height 19.4 m, standing volume 213 m3 and an annual increment of 4.9 m3.ha-1.yr-1. All Scots pines belong to the upper storey. Yet considerable differences in crown development and vitality are observed. The current growth rate and the spontaneous settlement of pine seedlings under canopy show the ideal conditions for the creation of a high forest with reserves. Anyway a rotation period of more than 70 years is recommendable. On several places a consolidated regeneration of Scots pine seedlings under canopy occur. Groups with a stem number of 700 to 3,500 seedlings per are, ranging in age from 3 to 11 years and in height from 10 to 170 cm, are present. This Scots pine regeneration has developed in a normal mor humus layer and in a dense Deschampsia mat. Broadleaved regeneration is not so abundant, and consists for 75 % of black cherry. Absence of seed trees, browsing damage and the exclusive character of black cherry are the limiting factors for the installation and survival of valuable indigenous species, such as pedunculate oak. Provided that black cherry is removed and that the regeneration is protected against wild damage, it is possible to create a mixed forest dominated by Scots pine but with a considerable admixture of indigenous broadleaved trees. However, if black cherry will not be sufficiently controlled, it can be expected that in a first phase black cherry will dominate the understorey, that it will prevent the regeneration of all other species and that, very soon, it will form an almost single-species dominated stage in forest succession.