Karaktärisering av Gremmeniella-skadade bestånd inom Holmen Skog AB
Since the end of the eighteenth century forest damage caused by the pathogen Gremmeniella abietina has been observed and documented. During the latest epidemic in Sweden more than 480 000 hectares forest land have been injured and this has lead to considerable economic losses. For the pathogen to su...
| Autor principal: | |
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| Formato: | L3 |
| Lenguaje: | sueco Inglés |
| Publicado: |
SLU/Dept. of Silviculture
2005
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| Materias: |
| _version_ | 1855572124548202496 |
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| author | Frank, Alexandra |
| author_browse | Frank, Alexandra |
| author_facet | Frank, Alexandra |
| author_sort | Frank, Alexandra |
| collection | Epsilon Archive for Student Projects |
| description | Since the end of the eighteenth century forest damage caused by the pathogen Gremmeniella abietina has been observed and documented. During the latest epidemic in Sweden more than 480 000 hectares forest land have been injured and this has lead to considerable economic losses. For the pathogen to succeed with infection, spore dispersal and colonization the right environmental conditions is required. The aim of this paper is to describe the diseased stands using site and stand characteristics and to evaluate the effect of these variables on the disease incidence. Further, the thinning performed during the time for spore dispersal and its relationship to injured stands is examined. The stand data material originates from Holmen Skog AB database for their forest land holdings. This survey was made upon 670 diseased stands and the same number of reference stands. The variable included in the database was used in a logistic regression analyze to detect their effect on the diseased stands. An analysis was also done on whether the diseased stands where over-represented on land that former hold Norway spruce (Picea abies). Two different definitions were used. The analysis revealed that some of the districts in the three analysed regions showed a larger amount of diseased stands than others. These differences may not only depend on variation in stand characteristics but also on differences in recommendations used for the inventory. The logistic regression analyze showed that the variables altitude, latitude, temperature sum, type of vegetation, site index and sites better suitable for spruce were significant. The disease shows a positive correlation with height above sea level because it increased with an increasing altitude. The regression analyze also showed a positive correlation between Gremmeniella abietina and stands on land suited for spruce according to the National Forest Inventory i.e. there is a risk to establish pine on too fertile soil. However, the analysis of the site index variable could not support this. The outcome showed that only 12 percent of the diseased stands were located on former spruce sites. In the comparison between stands thinned in the summer during spore dispersal and later Gremmeniella-injured stands the results showed that there were too few stands diseased to give any significant results. In the future research and evaluation of diseased stands distinguishing features may be used to facilitate the identification of risky objects so that sufficient treatment will be implemented in time. Subjective judgments may be prevented by the use of satellite images when making estimating inventories of Gremmeniella-diseased stands. |
| format | L3 |
| id | RepoSLU12753 |
| institution | Swedish University of Agricultural Sciences |
| language | swe Inglés |
| publishDate | 2005 |
| publishDateSort | 2005 |
| publisher | SLU/Dept. of Silviculture |
| publisherStr | SLU/Dept. of Silviculture |
| record_format | eprints |
| spelling | RepoSLU127532017-10-19T10:27:45Z Karaktärisering av Gremmeniella-skadade bestånd inom Holmen Skog AB Characteristics of Gremmeniella diseased stands within Holmen Skog AB Frank, Alexandra tillämpad skogspatologi skadesvamp Gremmeniella ståndort bestånd gallring skogsskötsel praktiskt skogsbruk monokultur altitud Since the end of the eighteenth century forest damage caused by the pathogen Gremmeniella abietina has been observed and documented. During the latest epidemic in Sweden more than 480 000 hectares forest land have been injured and this has lead to considerable economic losses. For the pathogen to succeed with infection, spore dispersal and colonization the right environmental conditions is required. The aim of this paper is to describe the diseased stands using site and stand characteristics and to evaluate the effect of these variables on the disease incidence. Further, the thinning performed during the time for spore dispersal and its relationship to injured stands is examined. The stand data material originates from Holmen Skog AB database for their forest land holdings. This survey was made upon 670 diseased stands and the same number of reference stands. The variable included in the database was used in a logistic regression analyze to detect their effect on the diseased stands. An analysis was also done on whether the diseased stands where over-represented on land that former hold Norway spruce (Picea abies). Two different definitions were used. The analysis revealed that some of the districts in the three analysed regions showed a larger amount of diseased stands than others. These differences may not only depend on variation in stand characteristics but also on differences in recommendations used for the inventory. The logistic regression analyze showed that the variables altitude, latitude, temperature sum, type of vegetation, site index and sites better suitable for spruce were significant. The disease shows a positive correlation with height above sea level because it increased with an increasing altitude. The regression analyze also showed a positive correlation between Gremmeniella abietina and stands on land suited for spruce according to the National Forest Inventory i.e. there is a risk to establish pine on too fertile soil. However, the analysis of the site index variable could not support this. The outcome showed that only 12 percent of the diseased stands were located on former spruce sites. In the comparison between stands thinned in the summer during spore dispersal and later Gremmeniella-injured stands the results showed that there were too few stands diseased to give any significant results. In the future research and evaluation of diseased stands distinguishing features may be used to facilitate the identification of risky objects so that sufficient treatment will be implemented in time. Subjective judgments may be prevented by the use of satellite images when making estimating inventories of Gremmeniella-diseased stands. Svampen Gremmeniella abietina förekommer över stora delar av Europa och har givit dokumenterade skador i Sverige sedan 1800-talet. Under den senaste epidemin med start 2001 har drygt 480 000 hektar runt om i landet skadats av svampen vilket lett till enorma ekonomiska förluster. Infektion, sporspridning och kolonisation av svampen kräver rätt miljöförhållanden för att lyckas. Syftet med detta examensarbete är att beskriva de angripna bestånden utifrån ståndorts- och beståndsvariabler och att undersöka vilken betydelse dessa variabler har för skadornas uppträdande. Vidare undersöks om sommargallringar under sporspridningsåren är överrepresenterade bland de skadade bestånden. Materialet i undersökningen bygger på data från Holmen Skog AB:s beståndsregister och är uppdelat på alla 670 skadade bestånden och lika många referensbestånd. De variabler som ingick i beståndsregistret analyserades i en logistisk regressionsanalys för att utröna deras inverkan på skadornas omfattning. För att kontrollera om de skadade bestånden var överrepresenterade på så kallade granmarker utfördes en analys av två olika definitioner av begreppet granmark. Den ena enligt Hesselman (1935) och den andra enligt Riksskogstaxeringen. Analysen visade att omfattningen av skadorna hade drabbat distrikten inom de tre analyserade regionerna i olika utsträckning. Skillnader i bestånds- och ståndortsfaktorer eller olikheter i riktlinjer vid inventeringar kan förklara detta. Den logistiska regressionsanalysen resulterade i att variablerna höjd över havet, breddgrad, temperatursumma, vegetationstyp, ståndortsindex och granmark föll ut som signifikanta. En positiv korrelation mellan höjden över havet och skadornas fördelning förekom då skadorna intensifierades med en ökad höjd över havet. Analys utefter riksskogstaxeringens definition av granmark visade på att det fanns en signifikant korrelation mellan dessa typer av marker och förekomst av Gremmeniella abietina, dvs. det finns en risk att anlägga tall på för goda marker där gran skulle vara ett bättre alternativ. Detta kunde dock inte stödjas av resultaten för variabeln ståndortsindex. Analysen av granmarker enligt Hesselman visade att endast 12 procent av de skadade bestånden låg på marker med den högsta trädslagfördelningen av gran. Resultatet av jämförelsen mellan de under sporspridningen gallrade bestånden och de senare skadade bestånden kunde inte påvisa att sommargallringarna ökat risken för skador. I framtiden är det av största vikt att inventeringen av tidigare Gremmeniella-skadade områden sker på ett effektivt sätt. Detta för att i ett tidigt stadium kunna sätta in adekvata åtgärder mot epidemier. Som underlag för inventeringar bör förhållanden på ståndorten för tidigare skadade bestånd utvärderas och användas. För att reducera riskerna för subjektiva bedömningar vid flyginventering kan satellitbilder för kalibrering av skadegrad vara användbara. SLU/Dept. of Silviculture 2005 L3 swe eng https://stud.epsilon.slu.se/12753/ |
| spellingShingle | tillämpad skogspatologi skadesvamp Gremmeniella ståndort bestånd gallring skogsskötsel praktiskt skogsbruk monokultur altitud Frank, Alexandra Karaktärisering av Gremmeniella-skadade bestånd inom Holmen Skog AB |
| title | Karaktärisering av Gremmeniella-skadade bestånd inom Holmen Skog AB |
| title_full | Karaktärisering av Gremmeniella-skadade bestånd inom Holmen Skog AB |
| title_fullStr | Karaktärisering av Gremmeniella-skadade bestånd inom Holmen Skog AB |
| title_full_unstemmed | Karaktärisering av Gremmeniella-skadade bestånd inom Holmen Skog AB |
| title_short | Karaktärisering av Gremmeniella-skadade bestånd inom Holmen Skog AB |
| title_sort | karaktärisering av gremmeniella-skadade bestånd inom holmen skog ab |
| topic | tillämpad skogspatologi skadesvamp Gremmeniella ståndort bestånd gallring skogsskötsel praktiskt skogsbruk monokultur altitud |