Effect of Site Preparation and Reforestation Method on Survival and Height Growth of Scots Pine

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Moose (Alces alces) damage in forest plantations have been at a high level in Finland in recent decades. Nowadays, moose is the most severe pest in Scots pine plantations also in Finnish Lapland. So far, despite the high level of damage and different bio-geographical conditions in Northern Finland, most of the moose-damage research has been carried out in Southern Finland. A number of research have also been performed to analyse factors affecting browsing but predictive models are rare. Data from 123 randomly selected and artificially regenerated pine plantations in Northern Finland were used in modelling the risk of moose browsing. The stands had been regenerated during 1984-1995. A total of 508 sample plots (range 2-8 plots per stand) were measured. Hierarchical logistic regression models with a random factor were constructed to predict the probability of leader-shoot browsing of pine on a plot. The number of planted pines and deciduous trees overtopping the pines were the most important predictors increasing the browsing probability. The results support earlier findings that deciduous trees overtopping or reaching the height of the pines should be cleaned from the immediate vicinity of the pines. Seedlings with a height ranging from 75 to 299 centimetres were more susceptible to browsing. Heavy soil scarification, such as ploughing or mounding, increased the browsing probability compared with lighter scarification methods. Soil type did not affect the browsing probability, but paludification decreased it. The within-stand variation in deciduous trees density and height should be taken into account in future moose browsing risk assessments. In Lapland, high moose damage risk areas are characterized by a low elevation and higher temperature sum.

Section: Discussionmentioning

confidence: 94%

Modelling the factors predisposing Scots pine to moose damage in artificially regenerated sapling stands in Finnish Lapland

Nikula¹,

Hallikainen²,

Jalkanen³

et al. 2008

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“…In Nordic growing conditions, effects of soil preparation on success of spruce seedlings are rather well known (Örlander et al 1990, 1998, 2002, Hansson and Karlman 1997, Mäkitalo 1999, Nordborg 2001, Hallsby and Örlander 2004, Saksa et al 2005. Survival of spruce is better and growth faster after an intensive soil preparation, such as spot mounding, compared with the lighter methods, such as disc trenching (Nordborg 2001, Örlander et al 2002, Saksa et al 2005, Nordborg et al 2006.…”

Section: Introductionmentioning

confidence: 99%

Effect of soil preparation method on economic result of Norway spruce regeneration chain

Uotila

Rantala

Saksa³

et al. 2010

Economic result of forest regeneration chains, based either on spot mounding or on disc trenching and planting of Norway spruce (Picea abies [L.] Karst.) seedlings, were clarified and compared to each other. First, effects of soil preparation method on early development of Norway spruce stands were measured from field experiments. Second, the effects of soil preparation method on stand level management programs were modelled. The modelling was based on growth simulation and investment calculations. The soil preparation methods substantially affected early development of a stand. The density of the removed trees in early cleaning was 56% higher on the disc-trenched area compared to the spot-mounded area. The difference was especially high (120%), close by (<25 cm) the remained spruce seedlings. There was also a difference between the methods in the growth of crop spruces; at biological age of 8 years, the mean height of spruce was 110 cm on the spot-mounded area and 68 cm on the disc-trenched area. The differences led to divergent management programs between the areas. The disc-trenched area needed three young stand management operations whereas two was enough at the spot-mounded area. Although disc trenching is a less expensive method than spot mounding, the total management costs were higher in disc trenching than in spot mounding. Furthermore, incomes from the first commercial thinning were higher when regeneration based on spot mounding. At the interest rate of 3%, the investment in spot mounding had 329 € ha -1 higher net present value than the investment in disc trenching.

“…Örlander et al 1990, 1998, Hansson and Karlman 1997, Mäkitalo 1999. However, research on spruce has largely been based on three-to four-year-old bare-root transplants, which have now been phased out.…”

Section: Introductionmentioning

confidence: 99%

Multilevel modelling of height growth in young Norway spruce plantations in southern Finland

Saksa¹,

Heiskanen²,

Miina³

et al. 2005

Height development of Norway spruce (Picea abies (L.) Karst.) transplants was studied on 22 sites prepared by disc trenching or mounding. At the age of 4-9 years the plantations were surveyed using a multistage sampling design. For every planted spruce on a plot, the past annual height increments were measured as far into the past as possible. Multilevel mixed linear modelling was used to analyse the variation in growth at different levels (year, stand, cluster, plot, tree) and the effects of climatic and site characteristics on height growth. The within-plantation variation in height growth was higher on mounded sites than on disc-trenched sites. The mean temperature and the precipitation sum of the summer months affected height growth positively. Soil characteristics measured from undisturbed soil did not explain the height growth of seedlings on mounded sites, whereas on disc-trenched sites, the depth of the organic layer and the soil temperature had a positive effect and the depth of the eluvial horizon a negative effect. The modelling approach used proved to be a useful method for examining the sources of variation in development of young plantations.