Establishment and•Tending of Subalpine Forest: Research and Management.
H. Turner and W. Tranquillini, eds.
Proc. 3rd IUFR0 Workshop P 1.07-00, 1984. Eidg. Anst. forstl. Versuchswes., Ber. 270 (1985): 221-223.
FUNGAL DISEASES IN AFFORESTATIONS OF HIGH ALTITUDE: EXPERIENCES WITH SCLERODERRIS AND LARCH CANCER EPIDEMICS
Ch. Tomiczek
Institute of Forest Protection, Forest Research Station Vienna, Austria
ABSTRACT:
Scleroderris lagerbergii Gr. and Encoeliopsis laricina (Ettl.) Groves are recorded to cause servere fungal diseases in afforestations of high altitude in Austria. Epidemics built up slowly first but have accelerated during the last years. The various symptoms of the diseases are decribed. Remarks on .Morphology and Epidemiology of Scleroderris cancer and Larch cancer are given. Some methods for control and prevention are discussed.
INTRODUCTION:
Centuries ago the central Alps in Austria were covered by forests up to an altitude of about 2.200 - 2.300 meters.
During the last two to three centuries the upper tree-line has moved down because of extensive clear-cuts in the course of mining activities and to obtain grazing grounds for sheep and cattle. (Fromme, 1957)
During the period of 1971 - 1980 forest inventory mea- sured ea. 500.000 hectars forest area of high altitude for Austria. This is equivalent to 13 percent of the Austrian forest area.
The main part of these forests of high altitude has been afforested during the last 30 years as part of an avalanche control project of the Austrian Government (pilot studies showed, that two/thirds of all avalanches originate from former forested areas).
Pinus cembra and Larix europaea are beside Picea abies the mainly used species for afforestations of high altitudes in Austria.
About 15 years ago first epidemics were noticed and in the meantime hundreds of hectars of these afforestation areas have been killed by fungal diseases.
In order to minimize further losses a long term project has been started in the year 1967. The following abstract shall give an overview what is already know about this problem - and what has still to be investigated more intensively.
METHODS:
First attention was directed at morphological studies on the various fungal diseases on P. cembra and Larix europaea.
Further investigations were layed on epidemiological and physiological questions and on provenance trials. Therefore observation plots were established in several existing planta- tions and afforestations. A great number of plants from defined seed sources (mother trees) were marked and severity
of attack by Scleroderris lagerbergii and Encoeliopsis cancer has been checked annually since 1975. Besides that a trial for chemical control of fungal diseases was carried out in a young plantation at an altitude of 2.000 meters.
RESULTS:
Scleroderris lagerbergii Gr. causing dieback on Pin us cembra and Encoeliopsis laricina (Ettl.) Groves causing dieback on Larix europaea have been recognized as most important diseases in afforestations of high altitude in the Austrian mountains.
Remarks on Morphology and Epidemiology of the Sclero- derris cancer:
As reported earlier by Donaubauer (1974) Pinus cembra is infected by the long-spore form of the Fungus (pycnidia spores with greater numbers of septa). These long spores are seldom seen on P. nigra and Pinus sylvestris in lower altitudes and were never detected on Picea abies in Austria.
The annually control of observation plots in various afforestations with P. cembra in high altitudes has shown, that the development of the Scleroderris cancer disease has accelerated and initial epidemics in most cases appear in between 4 - 5 years after afforestation. In some cases, espe- cially when inadequate provenances of Pinus cembra were used (long term provenance trial Zirbitskogel, Styria) first infections by the Scleroderris cancer occured inbetween two years after establishment.
Till today it is unknown if this acceleration of the infec- tion rate was caused by the increasing amount of inoculum or is due to a change of virulence of the fungus.
Early symptoms of infection by Scleroderris cancer are in most cases very similar:
The first symptoms occur in early summer showing disco- loration of needles starting near the needle basis. This stage of infection can easely be mixed up with the symptoms of frost-damage.
The die-back of one-year old shoots occurs on trees of all ages. In young plants the leader seems to be infected more frequently, but there is no proven explantation known for this phenomena.
First fructifications may be found in autumn on the basal part of the needles. The perenial cancers develop slowly at first. They are confined to small areas, sometimes for more than a year, and are surrounded by wound periderm.
Cancer enlargement obviously takes place during autumn and/or early spring. The older shoots are able to restrict the fungus during the growing season. Girdling takes place sometimes 3 -4 years after infection. (Donaubauer, 1983)
Sometimes infection symptomes are different and the Scleroderris fungus seems to attack the buds first. No discoloration of needles can be seen. In these cases there seems to be a certain relation between frost damage of the buds and Scleroderris attack, although we believe, that in most other cases Scleroderris cancer is not directly core·
lated to frost damage.
In some cases the fungus penetrates into the shoots through wounds, which are often induced by snow-pressure, or by frost. (Yokota, 1983)
Very often Scleroderris occurs in association with the snow mold-fungus (Phacidium infestans Karst) on Pinus cembra.
After several years of investigations we may state a strong correlation between plantation altitude, provenance used and mortality of the plants after Scleroderris attack, as the following tables 1 and 2 indicate.
Table 1: percentage of non affected, affected, and dead Pinus cembra plants of a small scale trial with progenies of 33 mother trees from various locations, 4 years after afforestations.
Provenance Altitude A B C
No Locality ma.s.l.
599 Pall 1740 0 14 86
625 Stumm, Hochburg 1680 0 21 79 Zi 11 erta l
557 Zirbitzkogel 1750 4 32 64
585 Gurk, Flattnitz 1600-1700 6 14 80 590 Kaunerta 1 1800-1900 6 26 68 581 Gurk, Flattnitz 1600-1700 6 38 56
608 Starns 1760-1780 8 25 67
622 Stumm, Hochburg 1680 8 25 67 Zi llerta l
570 Gurk, Flattnitz 1600-1700 9 30 61
591 Kaunertal 1800-1900 9 30 61
612 Turrach 1750-1800 10 39 51
575 Gurk, Flattnitz 1600-1700 11 25 64
607 Starns 1760-1780 15 25 60
614 Turrach 1750-1800 15 57 28
589 Kaunertal 1800-1900 16 10 74
611 Turrach 1750-1800 17 30 53
615 Turrach 1750-1800 17 45 38
602 Paal 1740 18 28 54
587 Gurk, Flattnitz 1600-1700 19 24 57 628 Stumm, Durach 1680-1820 19 29 52 627 Stumm, Durach 1680-1820 19 38 43 631 Stumm, Durach 1680-1820 21 13 66 576 Gurk, Flattnitz 1600-1700 21 34 45 574 Gurk, Flattnitz 1600-1700 21 35 44 573 Gurk, Flattnitz 1600-1700 24 11 65
613 Turrach 1750-1800 24 40 36
619 Stumm, Hochburg 7680 24 40 36 Zi 11 erta 1
582 Gurk, Flattnitz 1600-1700 26 9 65 632 Stumm, Durach 1680-1820 27 30 43 569 Gurk, Flattnitz 1600-1700 29 32 39
606 Starns 1760-1780 31 42 27
512 Dachstein 1600 36 36 28
571 Gurk, Flattnitz 1600-1700 41 25 34 A=Percentage of dead trees 4 years after afforest.
B=Percentage of affected trees 4 y.
C=Percentage of non affect.tr. 4 y.
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Table 2: Scleroderris cancer mortality on planting sites of different altitudes in subalpine afforestations (exam·
pies). (Donaubauer, 1983)
Plot A1t1tude
no. m rgs2 1gsr I97S BJ'7
2000-2300 97 83 0 0
2000-2200 92 60 0 0
1900-2100 73 60 0 0
1750-1850 22 ll 0 0
This provenance trial on the Zirbirskogel indicates a wide variability in mortality. Within the 4-year period of obser·
vation all 3 3 progenies have been infected. In two progenies (599,625) no mortality occured, whereas others had morta·
lity rates up to 41 % (percentage of infected plants up to 57
%). These preliminary results suggest further investigations in selections and breeding for resistance.
Remarks on Morphology and Epidemiology of Larch cancer:
First reports on Larch Cancer Epidemics in afforestations of high altitude were made by Ettlinger (1945) for Switzer·
land. Funk (1969) and Groves (1969) reported about the occurrence of Encoeliopsis laricina in Northern America and Canada, and Schlapfer·Bernhard (1969) for France.
The first occurrance of the Larch cancer disease in Austria was reported by Donaubauer (1971).
Similar to the Scleroderris Cancer Disease, Larch Cancer Epidemics obviously appeared only after the increase of Larch-afforestations in subalpine stands.
The early symptoms of infection are similar to those of the Scleroderris cancer· showing discoloration of needles starting near the needle basis. This stage can easely be mixed up with the symptoms of frost damage.
Donaubauer (1971) stated, that in most cases· in differen- ce to the Scleroderris Cancer · Larch bark necroses first occur on two-years old shoots, whereas the cambium of the youn·
ger shoots is still green and alife. Usually the cancer develop very slowly and are surrounded by wound periderm. Girdling takes place sometimes 5 · 6 years after infection. Sometimes the plants are able to restrict the fungus by building callus formations · so that no girdling occurs. In some cases the de- velopment of the epidemics has accelerated seriously between a few years and the majority of plants was killed by the fungus. In other cases the development of the disease has built up vety slowly and last controls have indicated a certain 'standstill' of the epidemics.
But for all Larch afforestations in subalpine zones may be stated a strong correlation between severity of attack by the fungus,altitude of plantation site and provenance.
Till today it is not quite clear how exposure, climatic stress and snow cover ( depth and duration) influence severity of attack of Encoeliopsis laricina.
Air Pollution as a Stress Factor.
Since 1982 acidity in snow and rain and the SO2, NOx and Ozone concentrations of air were studied at different elevations between the bottom of the valleys and about 2000 m altitude. All results obtained up to the present time, show no correlations berween severity of fungal disease and air pollution as a stress factor (Donaubauer, 1983 ).
Control and Prevention:
In 1978 500 hectars of a Pinus cembra plantation at Hippach, Tirol (2000 m altitude) was treated with aerial low volume application of a fungicide (5 kg Maneb per 20 liters of water/hectar). In spite of the very high concentration used, the large area sprayed showd no difference in mortality to unsprayed surrounding plantations.
Mechanical control trials by cutting, removal and burning of infected plant material of Pinus cembra and Larix euro- paea in order to reduce the inocculum density and infection rate showed in all cases no positive results.
It may be stated that till today no acceptable mechanical and chemical methods for prevention of dieback diseases in afforestations of high altitude are known in Austria.
We expect to receive better prevention results by selecting proper provenances.
Until we don't have enough plants from more resistant provenances, we do not plan to establish further plantations in altitudes above 2000 meters anymore.
LITERATURE CITED:
Donaubauer E., 1971: Ober ein Larchen-Triebsterben in Hochlagenaufforstungen. Cbl. f. d. ges. Forstw., 88:
65 - 72.
223
Donaubauer E., 1974: Ober das Kieferntriebsterben in Oster- reich (Scleroderris lagerbergii Gremmen und Cenan- gium ferruginosum Fr.). In: 100 Jahre Forstliche Bundesversuchsanstalt, Mitt. Versuchsanstalt Wien:
67-98.
Donaubauer E., 1983: Experiences with Scleroderris Canker on Pinus cembra L. in Afforestations of High Alti- tude. Symposium uber das Kiefernsterben, Sclero- derris lagerbergii Gr., Syracuse, N.Y., 17. - 24. 6.
1983.
Ettlinger L., 1945: Ober die Gattung Crumenula sensu Rahm mit besonderer Berucksichtigung des Crumenula- Trieb-Sterbens der Pinus-Arten. Dissertation Eidgen.
Techn. Hochsch. Zurich, Bern, 73 pp.
Fromme G., 1957: Der Waldriickgang im Oberinntal (Tirol) Mitt. Versuchsanst. F orstl. Bundesversuchsanst.
Mariabrunn, H. 54, 3 - 221.
Funk A., 1969: A shoot-blight disease of western larch in British Columbia. Can. J. Bot. 47, 1509-1511.
Groves J.W., 1969: Notes on the genus Encoeliopsis. Can. J.
Bot. 47, 1319-1331.
Schlapfer-Bernhard E., 1969: Beitrag zur Kennmis der Dis- comycetengattungen Godronia, Ascocalyx, Neogro- dronia und Encoeliopsis. Sydowle (Ann. Mycol.) 22, 26 - 39.
Yokota S., 1983: Etiological and Pathological Studies on Scleroderris Canker in Hokkaido, Japan. Bulletin of the Forestty and Forest Products Research Inst.
No. 321, Japan.
