Epsilon Archive for Student Projects

Abstract

Gallring och gödsling är i Sverige två vanliga och viktiga skogskötselåtgärder. Gallring är den arealsmässig vanligaste skogsbruksåtgärden. Skogsgödsling däremot har varierat i omfattning de senaste årtiondena och är idag inte särskilt omfattande. Gallring görs främst för att främja beståndsegenskaper medans gödsling görs för att öka tillväxten inför kommande slutavverkning. Vid gallring minskar den totala tillväxten i beståndet men tillväxten ökar för de enskilda träd som står kvar. Gödsling ökar tillväxten genom att de näringsämnen som begränsar tillväxten tillförs. Ett vanligt intervall för denna typen av studier är 5 - 10 år, i det här försöket analyserade vi tillväxteffekter 33 år efter gallring och gödsling, ett förhållandevis mycket långt tidsperspektiv. Försöket var beläget på Svartbergets försökspark utanför Vindeln i Västerbotten. Försöket var utlagt med en split-plot design och innefattade fyra behandlingar och tolv upprepningar. Behandlingarna var 1) kontroll, 2) gödsling, 3) gallring, 4) gallring och gödsling. Gallring minskade den totala och den löpande tillväxten i beståndet 33 år efter behandling. Gallring ökade grönkronans storlek och diametertillväxten för de enskilda träden. Gödsling gav inga tillväxteffekter för de 33 år som försöket varit utlagt. Sammanfattningsvis visar den här studien att tillväxten för tall i norra Sverige kan långsiktigt förändras med skogsskötselåtgärder. Gallring förändrade egenskaper både på enskilt träd och på beståndsnivå, gödsling däremot gav inga så långvariga effekter.

Abstract

Thinning and fertilization are two common and important forest management measures in Sweden. Thinning is the areal-vice most common forestry measure. Forest fertilization on the other hand, has varied widely in recent decades and is currently not very extensive. Thinning is done primarily to promote stock properties while fertilization is done to increase growth for future final harvesting. In the case of thinning, overall growth in the stock decreases, but growth increases for the individual trees remaining. A common interval for this type of study is 5 to 10 years. In this experiment, we analyzed growth effects 33 years after thinning and fertilization, a relatively long time perspective. The experiment was located at Svartberg's experimental park outside Vindeln in Västerbotten. The trial was done with a split-plot design and included four treatments and twelve repetitions. The treatments were 1) control, 2) fertilization, 3) thinning, 4) thinning and fertilization. Thinning decreased the overall and the current growth in the stock 33 years after treatment. Thinning increased the size of the green crown and the diameter growth for the individual trees. Fertilization did not give rise to any growth effects after 33 years of the trial. In summary, this study shows that the growth of a pine stand in northern Sweden can be changed in the long term by using forest management measures. Thinning changed the properties of both individual trees and tree stands, however, fertilization did not produce such long-term effects

Thinning and fertilization are two common and important forest management measures in Sweden. Thinning is the areal-vice most common forestry measure. Forest fertilization on the other hand, has varied widely in recent decades and is currently not very extensive. Thinning is done primarily to promote stock properties while fertilization is done to increase growth for future final harvesting. In the case of thinning, overall growth in the stock decreases, but growth increases for the individual trees remaining. A common interval for this type of study is 5 to 10 years. In this experiment, we analyzed growth effects 33 years after thinning and fertilization, a relatively long time perspective. The experiment was located at Svartberg's experimental park outside Vindeln in Västerbotten. The trial was done with a split-plot design and included four treatments and twelve repetitions. The treatments were 1) control, 2) fertilization, 3) thinning, 4) thinning and fertilization. Thinning decreased the overall and the current growth in the stock 33 years after treatment. Thinning increased the size of the green crown and the diameter growth for the individual trees. Fertilization did not give rise to any growth effects after 33 years of the trial. In summary, this study shows that the growth of a pine stand in northern Sweden can be changed in the long term by using forest management measures. Thinning changed the properties of both individual trees and tree stands, however, fertilization did not produce such long-term effects