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

Abstract

The contradictory role of understory vegetation on the success of Scots pine regenerationHyppönen M., Hallikainen V., Niemelä J., Rautio P. (2013). The contradictory role of understory vegetation on the success of Scots pine regeneration. Silva Fennica vol. 47 no. 1 article id 903. 19 p. AbstractIn North-East Finland, severe problems have been encountered in the natural regeneration of Scots pine (Pinus sylvestris L.) on sites where regeneration through site preparation usually is quite successful. We hypothesized that in that area understory vegetation, especially heather (Calluna vulgaris), crowberry (Empetrum hermaphroditum), mosses and lichens, could play a key role in this pattern. We found that in general, ground-and field-layer vegetation tends to be in a negative relationship with the establishment, growth and survival of pine seedlings. Some positive relationships were also observed. Lingonberry (Vaccinium vitis-idea) tended to improve seedling height growth. Heather, instead, seemed to have a contradictory role. It was positively related to seedling establishment but negatively to seedling growth. This dual role raises further questions about the primary reasons for the regeneration problems in North-East Finland. All in all, our results suggest that conventional methods of forest regeneration in these kinds of areas are not always effective enough and additional measures are needed. These might include severe prescribed burning along with site preparation in order to decrease the impact of the dominant ground-and field-layer vegetation on the success of Scots pine regeneration.

Alternative approaches to assessing the natural regeneration of Scots pine in a Mediterranean forest

“…A minimum of 2000 ha −1 (4 seedlings per subplot) denotes a sufficient regeneration density for Scots pine (e.g. Hyppönen et al 2013). In our study, we found that at least 4 seedlings per subplot (2500 seedlings ha −1 ) were present in 99 % of the subplots suggesting regeneration success and good management practices.…”

Impact of postfire management on forest regeneration in a managed hemiboreal forest, Estonia

“…Prescribed burning is often recommended for creating suitable ground for pine (Hyppönen et al 2013), but together with postfire clearing, it may favor ericaceous species that reduce the available nitrogen of the already nutrient-stressed habitat (Mallik 2003), affecting especially pine and other conifers, and may lead to continuous cover of Calluna (Norberg et al 2001). Some studies have shown that pine best regenerates 5 years after fire (Marzano et al 2012), but it may be delayed by competing vegetation, especially the presence of Calluna (Mallik 2003), which may cause conversion of forestland into heathland that may persist for up to 50 years after fire (Norberg et al 2001).…”

The Impact of Moss Species and Biomass on the Growth of Pinus sylvestris Tree Seedlings at Different Precipitation Frequencies

“…A significant proportion of the forest floor in boreal forests is covered by mosses [1,2], and therefore, the rejuvenation of the stand is likely to be influenced by the properties of the moss layer. Rejuvenation of coniferous seedlings appears particularly difficult in forests with an abundant moss presence [3,4], because mosses can outcompete seedlings for resources, such as light, space [5,6] and nutrients [7,8]. Previous work has also shown that these negative effects of mosses on seedlings can vary depending on a variety of external factors, such as the degree of abiotic stress [6,9] and other site characteristics (e.g., the type of growth substrate beneath the mosses) [5,10].…”