V Juronis - Pathological condition of introduced conifers - страница 1

Страницы:
1  2  3 

ВІСНИК ЛЬВІВ. УН-ТУ

Серія біологічна. 2009. Вип. 49. С. 43-52

VISNYK OFLVIV UNIV. Biology series. 2009. Is. 49. P. 43-52

Ботаніка

UDK 581

PATHOLOGICAL CONDITION OF INTRODUCED CONIFERS (GENERA ABIES, PICEA, PINUS AND PSEUDOTSUGA) IN FORESTS OF LITHUANIA

V. Juronis*, V. Snieskiene*, A. Ziogas**, R. GabrilaviCius***

*Kaunas Botanical Garden of Vytautas Magnus University Z. E. Zilibero 6, LT-46324 Kaunas, Lithuania е-mail: v.juronis@bs.vdu.lt, v.snieskiene@bs.vdu.lt **Agricultural University of Lithuania Studenty g. 11, Akademija, LT-53361, Kaunas distr., Lithuania е-mail: aa@nora.lzua.lt ***Lithuanian Forest Research Institute Liepi{ g. 1, Girionys, LT-53101, Kaunas distr., Lithuania e-mail: genetsk@mi.lt

Tree condition of Abies, Picea, Pinus and Pseudotsuga genera was stu­died in the forests of six forest enterprises and twelve forest districts in the south -western and western Lithuania in 2003-2007. According to our studies, the most perspective species for growing in these parts of Lithuania could be con­sidered Pinus contorta and Pseudotsuga menziesii. Acclimatization success of other tree species: Abies alba, A. sibirica, A. concolor; Pinus banksiana, P. peuce, P. strobus; Picea glauca, P. pungens; Pseudotsuga caesia - is restricted by biotic (disease pathogens and pests) and abiotic (edaphic and climatic condi­tions) factors.

Key words: introduction, conifers, diseases, pests, condition.

It has been studied about growing introduced trees in forests and other related problems since the 19th century [19, 27, 29]. Earlier (15th century) introduced trees were an important component of estates, but later they were more grown in town parks [33]. They occupied pre­vailing positions in towns and settlements; rather frequently they occurred in the plantations of roadsides, homesteads and even fields. If assortment of tree species is properly chosen the positive features of them such as: exotic and decorative appearance, specific resistance against adverse edaphic and other conditions, reveals in urban territories sufficiently well. The most important aspect of some introduced plants comparing to local species is higher or complete immunity to local plant pests and diseases [30, 31].

However, if landscape design and park specialists are satisfied with the mentioned fea­tures of woody introducents, then foresters, seeking to establish productive, resistant and pro­ducing high-quality timber stands of introduced plants, tend to be more careful. In this case the relation between forests introducents and harmful organisms plays a very important role.

Pathogens can restrict the spreayng of several introduced species producing economi­cally valuable timber very effectively [1].

Introduction of perspective species is determined by species evolution, biological and eco­nomic value of under natural growth conditions, adaptation to new site conditions and climate, amplitude of species adaptability, species genetic diversity which is proportional to the native range and geographical latitude [22]. The evaluation of introduced trees is carried out by the method of experimental plantations which are established in different habitats and natural regions.

Some of the first introducents which were started growing in Lithuanian forests in the 19th century are different Larix species originated from geographically different regions [2]. It

© Juronis V., Snieskiene V., Ziogas A., Gabrilavicius R., 2009

is thought that practically important also can be some Abies, Picea, Pinus, Pseudotsuga spe­cies. In Lithuania about 20 species of Pinus, and - 20 Picea were introduced, however, only some of them in forests [3].

The condition of woody introducents in Lithuanian forests is studied insufficiently. Intro­duced trees which grow in parks and green town areas are described, their condition is assessed [7], while in the forests only trees of local coniferous species have been studied until now [16, 17, 28].

The aim of the work is to assess the sanitary state of introduced trees species in Lithua­nian forests and to ascertain the most important damage sources in stands.

The condition of introduced conifers was assessed in 2003-2005 in stands of twelve forest districts of six forest enterprises in the western and south-western Lithuania.

The trees were described according to G. Krussmann [10] and M. Navasaitis [15], methods the taxonomy of plants compiled by M. Navasaitis [15] was applied.

Describing precise growing places, forest district, area, species composition were recorded.

The pathological condition of trees (not less than 50 trees in the account) was assessed based on methodic by A. Ziogas [24], R. Ozolincius [17], A. Juodvalkis and A. Vasiliauskas [9] as well as methodic used in the Forest Protection Manual [25] and applied in our studies. Tree condition was assessed in 5 grade scale (table 1).

Mean damage grade was calculated for the studied trees of each tree species based on modified and used in agriculture and forestry methodic [9, 23] according to the formulae:

V = I(nb)/N, when

V - mean damage grade,

X(n-b) - number of plants damaged to the same grade as well as product sum of it and the grade,

N - number of checked plants.

Pathogens were identified according to disease symptoms, cultural and morphological traits of distinguished microorganisms, based on the descriptors [1, 5, 14, 18, 32]. Pests were described according to [5, 6, 12, 20, 31].

During the studies, the most attention was paid to the condition of the most widespread in Lithuanian forests plants of four genera of introduced coniferous species: Abies, Pinus, Picea and Pseudotsuga.

Table 1

Tree condition assessment scale

Degree of tree condition

Signs of damage

Grades

Relatively healthy

No signs of damage, crown characteristic of the species, trees have no signs of weakening

1

Weakened

Trees with slight openness of the crown, reduced increment, up to 1/3 of needles are damaged. Individual branches are dry. Small patches of the trunk and branches are dead

2

Weak

Open crown. Strongly reduced or absent increment. Up to 2/3 of needles, branches are damaged or dead. Tree tops are dead. Large damaged areas on the trunk

3

Drying

Strong openness of the crown, light green, yellowing and falling needles. 2/3 of the needles are damaged. Dry tops of trees. There are signs of stem pest attack

4

Freshly dead trees

Trees which died in recent year. Needles are dry and remain on trees or have fallen down. Bark beetles have already left or are staying in the wood

5

Abies Mill.

A. alba Mill., A. concolor Gord. et Glend) Lindl. ex Hildebr. and A. sibirica Ledeb

The data in table 2 show that the condition of Abies concolor (V is from 3,28±0,05 to 3,35±0,05) is worst. The majority of trees are strongly weakened, about 30% - drying out. Bad pathological condition is typical for A. sibirica and A. alba (average grade - 2.88-3.02). An exception is A. alba plantings in Kuro forest district, which, are very young comparing to other plants (15 years).

Abies trees of all species growing in Alytus, Vaisvydava and Kuras forest districts are da­maged by Aphrastasia pectinatae (Cholodkovsky, 1888), (Hemiptera, Adelgidae) the abundance depends on localization and trees age. A. pectinatae cause mass defoliation, heavily worsen the condition of the whole plant, while 30-40-year-old trees are sentenced to death (table 2).

It was recorded in Vaisvydava on Abies concolor and A. sibirica forest district a large out­break of Dreyfusia piceae (Ratzeburg, 1844), (Hemiptera, Adelgidae) which occupied the whole stand. Damaged Abies are characterized by abundant defoliation and branches drying. Larvae fee­ding on the bark of Abies damage the cambium and lead to the formation of large necrotic areas. Splits and cup-shakes appear on the bark. In 6-8 years trees damaged by the pest die [6].

All the data show that because of the damage caused by this pest Abies are non-perspective introducents in our forests. In some places better solution is to try growing a slightly more resistant to Abies nordmanniana (Steven) Spach needle pest (Dreyfusiapiceae) [8].

Picea A. Dietr.

P. pungens Engelm and P. glauca (Moench) Voss ex C. A. Schenck

Both Picea species trees were observed in Alytus and Silenai forest districts where they

Table 2

Condition of Abies in Lithuania in 2003-2007

Forest district (Forest enterprise)

Species

Year

Number of trees by the degree of damage

Average grade of damage

 

 

 

Total

1

2

3

4

5

 

 

 

2003

276

170

76

20

10

0

1,53±0,02

 

Abies alba

2004

 

167

88

10

11

0

1,51±0,02

Kuras (Dubrava)

 

2005

 

171

79

16

10

0

1,51±0,02

 

 

2007

 

171

79

16

10

0

1,51±0,02

 

 

2003

263

0

62

180

20

1

2,85±0,01

Silenai (Dubrava)

Abies alba

2004

262

0

58

180

23

1

2,87±0,01

 

 

2005

261

0

60

168

32

1

2,90±0,01

 

 

2007

260

0

60

166

32

2

2,90±0,01

 

 

2003

261

0

57

169

33

2

2,92±0,01

Vaisvydava

Abies alba

2004

259

0

55

171

32

1

2,92±0,01

(Dubrava)

 

2005

258

0

55

174

29

0

2,90±0,00

 

 

2007

258

0

55

174

28

1

2,90±0,01

 

 

2003

74

0

4

47

20

3

3,30±0,04

 

Abies concolor

2004

71

0

3

47

19

2

3,28±0,05

Alytus (Alytus)

 

2005

69

0

1

45

23

0

3,32±0,05

 

 

2007

69

0

1

44

23

1

3,35±0,05

 

 

2003

213

0

20

172

20

1

3,01±0,01

Vaisvydava

Abies sibirica

2004

212

0

17

175

19

1

3,02±0,01

(Dubrava)

 

2005

211

0

14

169

27

1

3,07±0,02

 

 

2007

210

0

13

168

27

2

3,09±0,02

grow together (80% of the P. pungens). In Silenai forest district the same sites also contain Abies and other local tree species. In Birstonas forest district grow only individual trees of the P. pungens. On all growth sites P. pungens are damaged by Oligonychus unnunguis Jackobi, 1905, (Acari, Tetranychidae) especially heavily in Alytus forest district where young trees grow poorly in an open area. In Silenai forest district Picea trees are older and more damaged by stem pests. In all the places increment is low, while defoliation is high (table 3).

The worst condition of Picea pungens trees is in Alytus and Silenai forest areas (V -3,20 and 3,00). About 30% in Alytus forest district and 15% in Silenai forest district are da­maged by Dendroctonus micans Kug. (Scolytidae (Ipidae) Coleoptera). 60-70% of the trees is strongly damaged or dried out.

Pseudotsuga Carriere

P. caesia (Schwer.) Flous, P. menziesii (Mirb.) Franco and P. menziesii var. glauca (Beissn.) Franco

In all forest districts, where Pseudotsuga are grown, remains only a small portion of healthy trees, while the average damage grade is rather high (from 2,14 to 3,28) (table 4).

Due to inappropriate ecological conditions (too heavy soil, high density) trees are being weakened. The crowns are open also due to damages by Phaeocryptopus gaeumannii (Rohde) Petrak and Rhabdoclinae pseudotsugae Sydow needle casts. Following infection by Phaeoc-ryptopus gaeumannii Pseudotsuga cast their needles in 1-3 years. Manifestation of the disease and its spreading rate depends on the general condition of plants: it may become an epidemic if trees are weak [1]. In all observed places trees of all Pseudotsuga species and varieties were damaged by this pathogen (the damage comprised 3-4 grades in Vaisvydava forest district, while in other forest districts the condition was slightly better).

Rhabdoclinae pseudotsugae of Pseudotsuga doesn't appear every year it spreads in spring when there is more precipitation [21]. It is possible that due to Rhabdoclinae pseu-dotsugae Pseudotsuga in Vaisvydava forest district pertain rather open crowns. Although dur­ing 2003-2007 disease pathogens were detected (up to 2 grades) and the needles during recent years stayed almost undamaged, however, 3-4 years ago defoliation was extremely intensive. Pseudotsuga of different varieties resist to this pathogen differently: less resistant - P. caesia and P. menziesii var. glauca, more resistant - P. menziesii [1, 13].

Table 3

Condition of the Picea pungens in Lithuania in 2003-2007

Forest district

Year

Number of trees by the degree of damage

Average grade

(Forest enterprise)

 

Total

1

2

3

4

5

of damage

 

2003

168

0

20

102

38

8

3,20±0,02

 

2004

160

0

19

96

43

2

3,18±0,02

Alytus (Alytus)

2005

158

0

18

95

42

3

3,19±0,02

 

2007

155

0

18

93

41

3

3,19±0,02

 

2003

74

0

51

20

3

0

2,35±0,05

 

2004

 

0

48

23

3

0

2,39±0,05

Birstonas (Alytus)

2005

 

0

50

22

2

0

2,35±0,05

 

2007

 

0

49

23

2

0

2,36±0,05

 

2003

307

0

15

280

10

2

3,00±0,01

Silenai (Dubrava)

2004

305

0

21

274

7

3

2,97±0,01

 

2005

302

0

25

268

5

4

2,96±0,01

 

2007

298

0

21

268

6

2

2,36±0,01

Table 4

Condition of Pseudotsuga in Lithuania in 2003-2007

Forest district (Forest enterprise)

Year

Number of trees by the degree of damage

Average grade of damage

 

 

Total

1

2

3

4

5

 

 

2003

160

0

10

96

48

6

3,31±0,02

Alytus (Alytus)

2004

154

0

9

100

44

2

3,25±0,02

 

2005

152

0

8

99

44

1

3,25±0,02

 

2007

151

0

8

95

47

1

3,27±0,02

 

2003

87

0

19

Страницы:
1  2  3 


Похожие статьи

V Juronis - Pathological condition of introduced conifers