RESUME

Tree etiolation as significant and expected issue of forest protection
Radomír Mrkva (pp. 246-249)

Tree etiolation is sometimes, as impress of introduced diseases, considered an epiphytocis caused by saprophyte pathogens. However it is a more complex phenomenon. With the immission problem and global climate changes having risen this phenomenon has had a more frequent and even a permanent character. It is suggested to understand the phenomenon as a disease and to apply the concept of a disease spiral (Manion 1981) and the stress theory to investigate its development. Also significance of a proportional relationship of roots and the crown is necessary to be accounted for. Namely the good function of roots is a driving force in this system and therefore their damage and revitalisation capacity respective the age and species have to be studied. The lack of precipitation and a complex immission effect on plants or disturbance of their water regime are supposed a primary cause of a large-scale etiolating. The forestry solution cannot consist in a large-scale fungicide treatment but in preventive measures directed to application of site appropriate species and their ecotypes and their natural regeneration.

Phytopathologic aspects of forest tree species root damage
Libor Jankovský (pp. 250-253)

The tree’s root system can be understood a static and nutritive base of these living systems. Any disturbance in the root system functioning affects the functional stability of the whole tree or the whole forest ecosystem. From this view, the health conditions of roots represent an important and prospective issue of phytopathology, which can throw light on the causes of tree etiolation from many aspects. A change of external conditions and consequent changed parameters of internal balance related directly or indirectly to the crown affect the rhisosphere. These changes often are accompanied even by the destruction of symbiotic mycorrhyzae followed by worsened tree nutrition. The wood-damaging fungi react by an increased activity to the damage of roots, in the coniferous namely Armillaria ostoyae, Armillaria gallica a Heterobasidion annosum, and in deciduous primarily Ustulina deusta, Ganodernma sp. div. and others. The root damage manifests visually in various symptoms of non-specific etiolation. The basic assumption of a sound and dynamic development of a tree or the whole tree stand consists in a well-developed root system. From this aspect, the natural regeneration is the very appropriate, when the development of the root system is not affected by any disturbance. Moreover, there are mechanisms of natural selection in action with a great number of genetically differentiated material.

Outbreak of Gonioctena quinquepunctata in rowans
Jaroslav Urban (262-264)

The article deals with a mass outbreak of Gonioctena quinquepunctata F. in rowans Sorbus aucuparia L. which occurred in the forest districts Polnička and Škrdlovice (Dr. R. Kinský’s Forest Property Administration at Žďár nad Sázavou) in 1995 - 1997. In the inspected sites, beetles leave the winter habitats at the turn of April and May. After several days of maturation feeding on freshly flushed leaves and after copulation they lay eggs with developed embryos or egg larvae. Female birth rate is low (about 25 pieces). The larvae develop on the abaxial side of young leaves, through four instars. The larvae mature within 21 days. Feeding usually culminates in the half of June, the larvae pupate in ground and the pupa stage takes about 10 days. Young beetles appear in trees from the middle of June till the end of August, randomly even later. Yesteryear’s beetles damage in average 580 sq. mm of reduced rowan’s foliage area, larvae about 300 sq. mm and this year’s beetles 650 sq. mm. Significant damage to forests the insect may cause namely in mountain immission regions where the rowan is applied as an important substitute species.mentation of ecological and nature close technologies, e.t.c. The total sum the state endowed to the forest management was 1.119 millions of CZK.

At present there culminates a discussion on the amendment to the Forest Act supposed to enter the legislative procedure in the Parliament by the end of the year. The amendment will supposedly regulate not only some professional questions concerning forest management but also the relations among the state, state forest administration, forest owners, and professional forest managers.