|IZVORNI ZNANSTVENI ČLANCI
|Idžojtić, M., M. Glavaš, M. Zebec, R. Pernar, Ž. Kušan, Đ. List, M. Grahovac-Tremski
|UDK 630* 442 (001)
|Intensity of Infection with Yellow Mistletoe and White-berried Mistletoe on the Area of the Forest Administrations Zagreb and Koprivnica
|Summary: The intensity of infection of different hosts with yellow mistletoe (Loranthus europaeus Jacq.) and white-berried mistletoe (Viscum album L. ssp. album) was carried out in the area administered by Hrvatske šume d.o.o. (Croatian Forests Co.Ltd.), in the area of 10 forest offices of the Forest Administration Zagreb and 5 forest offices of the Forest Administration Koprivnica. The investigated hosts were: sessile oak (Quercus petraea /Matt./ Liebl.), pedunculate oak (Q. robur L.), narrow-leaved ash (Fraxinus angustifolia Vahl), common locust (Robinia pseudoacacia L.), sycamore (Acer pseudoplatanus L.) and black alder (Alnus glutinosa /L./ Gaertn.). In the selected subcompartments older than 30 years, through a diagonal survey the number of infected and non-infected trees, as well as the number of mistletoe plants on infected trees was registered. The intensity of infection was very different in the individual compartments, management units and forest offices. The spatial distribution of the intensity of infection of the sessile and pedunculate oaks with yellow mistletoe in three management units was shown.
In the area of the Forest Administration Zagreb from the total number of examined sessile oak trees 14.2 % were infected with yellow mistletoe. On the average on each of the infected trees there were 2 mistletoe plants, and the largest number on one tree was 18. The largest infection was noted in the Management Unit Zlatarske prigorske šume, of the Forest Office Zlatar (23.9 %). In the area of the Forest Administration Koprivnica 7.8 % of the examined sessile oak trees were infected with yellow mistletoe. On the infected trees there were 3 mistletoe plants on the average, and the largest number of plants on one tree was 11. In the Management Unit Kalnik-Kolačka, of the Forest Office Križevci, there was the largest infestation (9.7 %).
In the area of the Forest Administration Zagreb, yellow mistletoe was observed on 9.2 % of the examined pedunculate oak trees. On the infected trees there were 2 mistletoe plants on the average, and the highest number of plants on one tree was 12. The largest infestation was found in the Management Unit Obreški lug, of the Forest Office Remetinec, where 16.8 % of the examined trees were infected. Yellow mistletoe was present on 11.9 % of the examined pedunculate oak trees in the area of the Forest Administration Koprivnica. On the average 4 mistletoe plants were growing on the infected trees, and the maximum number of plants counted on one tree was 20. The most infected management unit was Križevačke prigorske šume, of the Forest office Križevci, 22.3 %.
For the sessile oak a data base of stand and habitat parameters was made out of the management facts (elevation, site quality, exposure, age and crown closure). The data were analyzed in order to establish whether there is a correlation between the mentioned parameters and the intensity of yellow mistletoe infestation.
Out of the total number of examined narrow-leaved ash trees in the area of Forest Administration Zagreb (Forest Offices Lipovljani and Kutina), 3.5 %, were infected with white-berried mistletoe, with an average of 3 mistletoe plants per infected tree; the largest number of plants per tree was 47.
Key words: Croatian Forests Co.Ltd.; intensity of infection; narrow-leaved ash; pedunculate oak; sessile oak; white-berried mistletoe; yellow mistletoe
IDŽOJTIĆ, Marilena ŠL
GLAVAŠ, Milan ŠL
ZEBEC, Marko ŠL
PERNAR, FINTIĆ, Renata ŠL
LIST, Đurđica ŠL
GRAHOVAC - TREMSKI, Mirjana ŠL
|Goglia, V., J. Žgela, I. Đukić
|UDK 630* 304 + 964 (001)
|The Effectiveness of Anti-Vibration Gloves: Part I
|Summary: Exposure to vibration of higher intensity over a longer period of time often causes permanent health damages. Occupational deseases play an important role in many activities in forestry, too. Among many protective measures taken against excessive exposure to hand-transmitted vibration is the use of anti-vibration gloves. The assessment of their efectiveness is a complex procedure which doesn´t always yeald expected results.
There is a number of anti-vibration gloves available nowdays and it is a very responsible taks to make the right choice. The vibration transmissibility of the anti-vibration gloves can be assessed by using measurement and evaluation procedures prescribed by ISO 10819-1996 and EN ISO 10819-1996 as well as the National Standard HRN ISO 10819-2000, or by field-testing. The paper deals with advantages and disadvantages of these two assessment methods.
Key words: anti-vibration gloves; ergonomics; testing; vibration
GOGLIA, Vlado ŠL
|Matić, S., D. Delač
|UDK 630* 923 + 231 + 242 + 245
|Silvicultural Treatments as a Method of Increasing the Value of Private Forests in Gorski Kotar
|ge of the young growth and saplings, and tending with thinning.
Tending of the young growth after the final cut is usually done once only, while cleaning or negative selection is done once or twice until the moment the stand reaches its maximal height increment. At this stage future trees are identified, which in beech and spruce forests takes place around the age of 30. At this age stands may be tended with thinning.
Coppices of beech, pubescent oak and other hard broadleaves are regenerated with shelterwood cuts. The goal is to convert a coppice into the forest of high silvicultural form or seed forest.
Regenerating a coppice with clearcutting and planting conifer species is a serious mistake. Conifers may be planted in degraded forest soils which have lost the properties that provide the parent climatogenic stand with optimal conditions for growth and development.
Coppices should be tended throughout the rotation period.
The tending stages in a coppice include reducing the number of poor quality and superfluous shoots on the stump, tending coppices with cleaning or negative selection, and tending coppices with thinning or positive selection.
In the current economic and social conditions in Croatia arable areas are systematically being reduced and the size of abandoned agricultural land is increasing. These areas are subjected to the spontaneous expansion of less valuable tree species and shrubs, classified as pioneer species. Being the first to occur, they are spontaneously followed by transitional species. The 100-year-long process ends with the occurrence of principal or climatogenic species (fir, beech, oaks).
Pioneer and transitional tree species gradually convert degraded forest soil into forest soil suitable for climatogenic or principal species. The basic tree species that bear the characteristics of pioneer species are those from the genera of alders, willows, poplars, birches and others. Domestic, autochthonous tree species from other genera, with the exception of the genera of oaks, beech and fir, belong to transitional tree species. Together with pioneer species, they gradually colonize abandoned agricultural and other lands.
Forest cultures should be established on abandoned agricultural areas in order to increase their market and non-market values. These cultures are established by planting broadleaved species from the genera of wild cherry, pear, apple, as well as maple, ash, lime, whitebeam, rowan, service tree, wild service tree, bird cherry, walnut, and others. Coniferous species to be planted include species from the genera of spruces, larches and pines.
The choice of the tree species depends on the site conditions that prevail in the treated area, where the soil and the climate have a decisive role.
The pioneer, transitional or secondary tree species have an important role in the structure of all Croatian natural forests. They are particularly suitable for the establishment of cultures which supply good quality and valuable timber. Timber of all these species is applied in mechanical and chemical processing industries, and in energy production. The establishment of energy forests with short rotations and small planting distances will gain increasing importance in Croatian forestry.
Due to the present energy crisis, the share of timber in the energy balance of the most developed European countries is constantly growing. Timber from forests has been accepted everywhere in Europe as an important and renewable source of bioenergy.
Although the Croatian forestry is making initial, modest steps in this field, there is no reason that forest owners in Gorski Kotar should not be included in this European trend. They have at their disposal about 3,000,000 m3 of growing stock, the annual increment of 80,000 m3, and the prescribed annual yield of about 40,000 m3, of which 40 % or 16,000 m3 is wood of thinner dimensions suitable for energy. At present, the major portion of this wood remains in the forest and perishes. This alone provides sufficient motive for the owners to pool forces, fight for their place on the market and join the chain of bioenergy producers for both the domestic and foreign markets.Summary: Privately owned forests in Croatia cover an area of 581,770 ha, which is 22 % of the total area of forests and forestland in the Republic of Croatia. The total growing stock in private forests in Croatia amounts to 78 301 000 m3, or 20 % of the overall growing stock of the entire forest management area. The average growing stock is 163 m3/ha and the increment is 4.4 m3/ha or 2.7 %.
Privately owned forests in the area managed by Delnice Forest Administration extend over 22,380 ha. These forests are presently classified into uneven-aged forests, which is not conducive to their future management. Bearing in mind their condition regarding the silvicultural form, biological properties and ecological requirements of the tree species participating in their formation, the management of these forests should follow the methods applied to forests of high silvicultural form or seed forests, which are regular and selection forests, and to coppices. Forests of high silvicultural form are regular or even-aged seed forests covering an area of 13,264 ha, while selection seed forests cover an area of 6,085 ha. Regular coppice forests are found over an area of 3,031 ha.
Placing these different forest forms into a uniform uneven-aged class prevents, among other things, the application of those necessary silvicultural operations which are aimed at attaining better stability, productivity and sustainability, or sustainable development.
Based on the above structural indicators, especially the growing stock and increment of these forests, we may conclude that the current condition of private forests in this area is equally bad and worrying as that of other private forests in Croatia.
Such a situation may be attributed to a number of factors, such as, for example, the inexpert application of silvicultural treatments, the disintegration of rural environments, property fragmentation, the owners’ social status, the insecurity of private ownership, the length of the production cycle, insufficient control and sanctioning, and finally, the disobeyance of legal regulations.
Some objective reasons for which these forests are difficult to manage are:
– Fragmentation of property (the average size of a plot is preceded by two zeros). Unsolved ownership-legal relationships, as well as an unstimulating, slow and expensive system of solving ownership problems,
– Disproportion between the cadastre of cultures and the real condition in the field, and the disproportion between the cadastre and the land registry,
– Management at the level of cadastre units prevents the application of more complex management with forest resources,
– Prejudices of forest owners towards pooling resources (Cooperatives) due to negative experiences from the recent past,
– Movement of the younger, more vital part of the population from rural into urban areas.
Forest owners and forest owners’ associations should direct their activities concerned with increasing forest quality toward the following fields, treatments and activities:
– Tending and regeneration treatments in selection forests with selection cuts.
– Tending and regeneration treatments in regular high forests and coppices.
– Tending and restocking those areas subject to natural succession of pioneer species with valuable broadleaved and coniferous species.
– Establishing cultures of valuable, fast-growing and marketable broadleaved and coniferous species over abandoned grasslands and other areas.
– Organizing timber harvesting and marketing, as well as utilization of timber for bioenergy after the forests have been tended, established and regenerated.
Selection management is the most suitable method for fir forests or for those forests in which the fir is the dominant species, such as, for example, mixed forests of fir and beech, fir, beech and spruce, and fir and spruce.
The management goals in a selection forest are accomplished by selecting and marking the trees to be cut. These management goals are: raise mixed selection stands which will ensure good quality increment, stand stability and plentiful natural new growth; use the productive site capacity to the maximum; and achieve the highest production values.
Felling operations in a selection forest achieve multiple goals of tending and regeneration, forming the selection structure, utilizing forests and maintaining their hygiene. There are two groups of silvicultural procedures; tending of the young generation – young growth and young forest, and selection, which includes thinning and harvesting mature trees. All the procedures in a selection forest are temporally and spatially concentrated, thus creating an indelible whole. If any of the above activities is omitted, the structure of the selection forest will be disrupted and its increment, regeneration and stability will be affected.
Tree marking in a selection forest should always take account of the goals for which this activity is undertaken. These goals are permanent regeneration, stand tending, continuous maintenance of the selection structure, stand utilization and maintenance of the sanitary-hygienic function.
In a normal selection forest with normal growing stock, a 10-year annual increment is cut. Under normal circumstances, this is 25 % of the total growing stock in the stand. If the growing stock is higher than normal, cutting intensity should not exceed 30 %. If it is lower, cutting intensity may be reduced to 15 %. This is borderline intensity which should not be exceeded. This means that cutting should be postponed until another cutting cycle is over, in this case another 10 years. Higher or lower intensities could endanger the selection structure, i.e. the increment, regeneration and stability of the selection stand. Inappropriately applied intensities cannot maintain a selection stand in the optimal structural conditions which will ensure maximal production and optimal regeneration. Regrettably, this is one of the most serious current problems in selection management and selection forests.
Beech and spruce stands which have officially been classified as uneven-aged stands and which have not been managed selectively but with selection cuts show a negative developmental trend. This kind of management results in decreased growing stock, absence of natural regeneration, reduced tree quality and lower increment.
In such stands management based on regular principles should be organized over small areas (each structural unit – special silvicultural treatment). Silvicultural treatments are spatially divided over small areas. In other words, each structural unit represents a special part of the stand which requires a special silvicultural treatment. They are spatially separated but temporally concentrated.
Management with shelterwood cuts in small areas with a longer regeneration period achieves biological diversity of beech and spruce forests. This type of regeneration enables, over a longer time period, a good yield of seeds of the principal and other tree species and the survival of their young generation.
Regeneration in regular forests is generally done in 3 cuts (preparatory, seed and final) and less frequently in 4 or 5 cuts, where subsequent cuts are introduced. The preparatory cut is undertaken with 20 % intensity and the seed cut with 50 % intensity in a good seed year. The remaining wood volume is cut as needed, either with one or two subsequent cuts or, more frequently, with one final cut.
Regular forests are tended throughout the life cycle of the stand, that is, until the shelterwood cuts are applied. Tending consists of the following stages: tending of the young growth after the final cut, cleaning in the developmental sta
Key words: bioenergy; forest cultures; pioneer species; regeneration; regular forests; selection forests; tending; uneven-aged forests
MATIĆ, Slavko ŠL
DELAČ, Damir ŠL
|UDK 630* 272
|Summary: Marko Marulić, a great Renaissance poet and "the father of Croatian literature", a title well deserved, wrote a famous poem "Suzana", in which he described, for the first time in Croatian literature, a park or a garden (vartal, jardin), together with a variety of plants growing in the park.
With this poem, Croatia joined a small group of European nations in which a park was described as early as the Renaissance period.
Where did Marulić find inspiration for the garden? At that time, there was no such vartan (garden) in his town of Split or its surroundings threatened by the Turks.
He may have been influenced by contacts with Renaissance writers from Dubrovnik and by his knowledge of Dubrovnik parks and of Trsteno in particular. However, there is no testimony of this, except for some indirect encounters with Petar Hektorović, who was friendly with and kept correspondence with writers from Dubrovnik.
Petar Hektorović, a writer from Hvar and a contemporary of Marulić, described his park of Tvrdalj, which is very similar to Suzana´s Garden.
It is also possible that Marko Marulić saw a Renaissance park in the course of his travels to Italy and brought back relevant literature. According to some data, his rich library contained, among other valuable works, Crescenzi´s Ruralium Commodorum. Since he learnt Greek in his youth, he was probably also familiar with Alcinous´s garden from Oddyssey.
The influence of Boccaccio´s Decameron could also have played a role, since a park is described in the introduction to the third day.
Marulić´s park, or Suzana´s park,poses a number of open questions related to the profession, but also to the great poet himself.
|Krpan, A. P. B.
|UDK 630* 972
|University of Zagreb – Faculty of Forestry and Department of Forest Engineering in the Bologna Process
|Summary: The paper presents the past course and achievements of the reform of the higher educational system at the Faculty of Forestry of the University of Zagreb. The reform is part of the effort undertaken in order to include the Faculty in the European Area of Higher Education (EHEA) and the European Research Area (ERA). A three-cycle educational system has been adopted and the curricula for undergraduate, graduate and postgraduate studies have been devised on a 3 + 2 + 3 (2) or 180 + 120 + 180 (120) ECTS points basis. Three undergraduate studies have been established: Forestry, Urban Forestry and Wood Technology, whose programmes are already followed by two generations of students. The following graduate study programmes have been developed: Forestry and Urban Forestry, Nature and Environment Protection and Wood Technology Processes and Design of Wood Products. Graduate studies in the Forestry department contain two programmes: Silviculture and Forest Management with Wildlife Management and Techniques, Technologies and Management in Forestry.
An improved proposal for doctoral study has been developed in the Forestry Department consisting of three programmes (Silviculture and Wildlife Management, Techniques, Technologies and Management in Forestry, and Urban Forestry, Nature Protection, Forest Management and Protection), as well as a doctoral study programme Wood Technology. Specialist postgraduate studies have been devised in ten programmes.
Key words: Faculty of Forestry Zagreb; reform of higher educational system
KRPAN, Ante P. B. ŠL
|Konjević, D., U. Kierdorf, Z. Janicki, A. Slavica, K. Severin
|UDK 630* 156 + 132
|Red Deer Hummel – a Unique Feature in a Red Deer Stag
|Summary: Occasionally, antlerless red deer stags, showing complete absence of antlers or possessing only antler knobs, can be observed. In the English literature, antlerless red deer stags are referred to as hummels. In this paper we present the case of a red deer hummel shot during the ruting season of 1981, in the area of Sokolovac, Croatia. The stag was aged at 5 years and weighed approximately 200 kg (undressed). The stag possessed only small pedicles and almost completely lacked antlers. Only small knobs of antler bone were present bilaterally. Furthermore, a discrepancy in height between left (length 17 mm) and right (length 35 mm) cranial outgrowth was observed. In the literature, the occurrence of antlerless red deer stags is mainly attributed to under- or malnutrition during the first year of life when pedicle development takes place, and a resulting underdevelopment of the pedicles. Because growth of antlers (at a normal rate) only starts after the pedicles have reached a critical size, insufficient growth of pedicles will result in a completely antlerless condition or, as in the present case, in the formation of only a very small amount of antler bone. However, also other factors could result in insufficient pedicle growth. As pedicle growth depends on androgenic stimulation, low levels of circulating androgens or a low density of androgen receptors in the antlerogenic periosteum could lead to poor pedicle growth and in consequence to a complete or almost complete lack of antler growth.
Key words: antler; incomplete development; pedicle; red deer hummel