Podatność drzewostanów sosnowych na zasiedlanie przez owady kambio- i ksylofagiczne w rejonie Tarnobrzeskiego Zagłębia Siarkowego
AbstractA study concerning the susceptibility of pine stands to infestation by cambioand xylophagous insects was conducted in the Tarnobrzeg Sulphur Basin during 1983-1990. The stands were weakened as a result of forest environment pollution by toxic substances, mainly sulphur oxides (SO O, hydrogen sulphide (H2S) and fluorine (F), which created favourable conditions for the reproduction of cambio- and xylophagous insects causing trees to die, The objectives of this study were: — to determine the level of mortality threat to stands on the basis of health groups (fractions) of trees, distinguished using the indices developed by the author, in given time intervals (4 and 8 years), — to determine the trend and seasonal dynamics of tree mortality in the spring and summer, — to evaluate the dynamics of infestation of weakend trees in the stands damaged and not damaged by individual species of cambia- and xylophagous insects. During 1983-1990, 55 fractions of trees characterized by their health state were distinguished in the investigated pine stands. During the 8-year prognostication period, dead trees were found in 11 fractions, and during the 8-year period — in 15 fractions. Out of these fractions, 6 were strongly threatened with becoming eliminated from the stand. Usually, the dying trees belonged to the same fractions, though they originated from different age classes. This proved that in pine stands it is possible to distinguish tree fractions endangered by mortality to a similar degree. Trees in endangered fractions always had a reduced number of annual needle sets and their vitality was low. In control stands, not damaged by industrial emissions, such trees were present almost exclusively in the lower tree layer, while in damaged stands of the Tarnobrzeg Sulphur Basin the percentage of dead trees was greater in the middle and upper tree layers. All dead trees were infested by cambio- and xylophagous insects. The mortality of trees attacked by bark- and wood-boring insects in the spring was higher than in the summer. In the investigated groups of stands spring mortality varied from 60.2 to 72.7%. In the stands of the Tarnobrzeg Sulphur Basin the number of trees infested by insects during the summer was greater than in the undamaged stands, which may be considered as evidence suggesting that damaged stands create better condition for the reproduction of cambia- and xylophagous insects colonizing trees in the summer. The associations of bark- and wood-boring insects colonizing trees in the spring differed from those colonizing trees in the summer. In the spring, the association of species infesting trees of age class II in the Tarnobrzeg Sulphur Basin included Tomicus piniperda and Pissodes piniphilus as dominant species and Rhagiuin inquisitor, Hylurgops palliates, Pissodes castaneus, Pogonoch.erus lasciculatus, Tomieus minor and Sirex noctilio as auxiliary species. In stands of age class III the group of dominant species mentioned above also included Rhagium inquisitor, while in the group of auxiliary species Pissodes eastaneus was replaced by Archopalus rusticus. In stands of age classes IV and V also Tomieus minor and Acanthocinus aedilis were the dominant species, while Pissodes pini, Pityogenes bidentatus and Ips acuminatus were important species among the auxiliary insects. In the summer, the basic insect association inhabiting trees of age class II in the Tarnobrzeg Sulphur Basin was less abundant than in the spring and included Pissodes piniphilus as a dominant species and Pogonocherux fasciculatus and Archopalus rusticus as auxiliary species. Pissodes piniphilus was the only dominant species in stands of age classes III, IV and V. In stands of age class III also Pissodes pini was among the auxiliary species, while in stands of age classes IV and V — a few other species. Pityogenes bidentatus, Tetropium fuscum, Tetropium castaneum, Monochamus galloprovincialis and Magdalis violet:ea are especially worthy of notice. Based on the results of this study, some recommendations were drawn up concerning preventive measures which would decrease insect threat in the stands damaged by industrial emissions. These measures include sanitary cuttings to be carried out not less frequently than every 4 years with the aim of removing trees of particularly endangered fractions (fractions: 3369, 1369, 2369, 3359, 2359 and 3368) from the stand. Such cuttings are justified because the removal of dead trees reduces the potential reproduction base for harmful insects, decreases the number of trees competing with those of better characteristics, and enables the harvesting of fully valuable timber. Efficient protection of stands against cambio- and xylophagous insects would be ensured by two sets of measures: 1. reduction of the insect feeding base through sanitary cuttings executed according to the proposed method, and 2. regular removal of the trees infested by cambio- and xylophagous insects according to the generally accepted rules of protection of endangered stands.
|Other language title versions||Susceptibility of pine stands to infestation by cambio- and xylophagous insects in the area of the Tarnobrzeg Sulphur Basin|
|Publisher||Uniwersytet Rolniczy im. Hugona Kołłątaja w Krakowie, MNiSW |
|Publishing place (Publisher address)||Kraków|
|Book series /Journal (in case of Journal special issue)||Zeszyty Naukowe Akademii Rolniczej im. H. Kołłątaja w Krakowie. Rozprawy, ISSN 1233-4189, (0 pkt)|
|Publication size in sheets||7.2|
|Citation count*||1 (2015-12-22)|
* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.