Establishment and height development of harvested and naturally regenerated Scots pine near the timberline in North-East Finnish Lapland

Abstract

Researchers and professionals in practical forestry have faced problems concerning the regeneration success of Scots pine in natural regeneration near the timberline in North-East Lapland. The aim of the study was to analyze the seedling establishment and seedling height development of Scots pine in seed-tree stands in the area. The average number of living pine seedlings in the study stands was about 1000 ha -1 , but there was considerable variation between the stands. The seedling density was modelled using a multinomial logistic regression with a random factor. Forest site type and the time since seed-tree cutting were the most significant explanatory variables in the model. The probability of reaching the acceptable seedling density was higher on dry site types than on the more fertile ones. The probability increased with the time elapsed since the regeneration activities. Effective temperature sum and the number of intermediate pines also positively affected the probability, but the presence of residual trees negatively. On northern and eastern slopes the probability was lower than on southern and western ones. Seedling height was modelled using a linear mixed model. The age of a dominant seedling was the most positively effective explanatory variable in the height development model. Other positively affecting significant predictors were time since seed-tree cutting, number of intermediate birches, and distance between a seedling and the nearest seed tree. Degree of paludification had a negative effect. The study suggests that the regeneration of Scots pine in North-East Lapland is a relatively slow process.

The contradictory role of understory vegetation on the success of Scots pine regeneration

“…Poor natural regeneration of Scots pine in harsh climate conditions is known to be associated with northern latitude, high elevation, and low temperature sum causing small seed crops, a low seedling establishment rate, slow height growth and high seedling mortality (Varmola et al 2004;Hyppönen et al 2005;Juntunen and Neuvonen 2006). In North-East Finland, the regeneration of Scots pine has been even more difficult than elsewhere in the timberline regions (Niemelä 2002;Hallikainen et al 2007). One reason has been assumed to be ground vegetation (Hallikainen et al 2007).…”

“…In a recent study by Hallikainen et al (2007) Scots pine regeneration on these kinds of sites was generally slow and poor in spite of site preparation, but there was quite a variation in the results. Results of that study suggest that soil properties, field and ground layer vegetation, fungal infections, and reindeer grazing may be associated with slow and poor regeneration, but closer inspection is needed to reveal the ultimate causes.…”

“…The study area is located in a part of Finland that is characterized by the highest abundance of heather in Finland (Salemaa 2001). Based on earlier findings (Hallikainen et al 2007), we hypothesized that in addition to the harsh climatic conditions, the ground-and field-layer vegetation, especially heather, crowberry, mosses, and lichens, would inhibit the establishment and growth of pine seedlings and contribute to seedling mortality.…”

“…In this study, we aimed to find out the relationships between understory vegetation and the regeneration of Scots pine in an area in North-East Finland where especially heather has been implicated as a contributor to the considerable problems of pine regeneration (Hallikainen et al 2007). The study area is located in a part of Finland that is characterized by the highest abundance of heather in Finland (Salemaa 2001).…”

Effect of soil scarification on natural regeneration of mature scots pine (Pinus sylvestris) stands in Greece

“…Many previous studies have shown significant relationships between the succession of natural regeneration and site factors as well as the mother stand (Tegelmark, 1998;Hille and Ouden, 2004;Hallikainen et al, 2007). More specifically, soil scarification has proved to be particularly favourable for other species of the boreal coniferous zone, such as spruce, beech and birch (Huss and Burshcel, 1972;Dohrenbusch, 1997).…”