Metla Project 3249
The alternatives of the forest regeneration methods and their ecological and social sustainability in Northern Finland
Keywords: biodiversity, landscape, wood production
Research project group: Distinct projects - Forest-based enterprise and business activities
Objectives The goal of the project it to study what are the regeneration results obtained by using different forest regeneration methods including the methods that have been described in the new forest management guidelines in Northern Finland, particularly in Lapland. Furthermore, a goal is to study the effect of various environmental factors on the regeneration results. In addition, a goal of the project is to study the ecological and social effects of the regeneration methods in the forest stand and landscape level.
Results Sub-project 1. Forest regeneration
In Lapland the conditions for natural regeneration of Scots pine are good on dry and dryish site types. This can be discovered so that in Lapland there are abundantly advance growth seedling-stands. Despite the regeneration success has been poor in the 1960s, 1970s and 1980s. The main reason for this was lack of site preparation in connection with natural regeneration. Accordingly, site preparation has a crucial importance in natural regeneration of Scots pine. The research on natural regeneration of Scots pine will be still needed especially concerning the establishment cuttings in the end of the rotation, and the dynamics of emergence and mortality of seedlings. More research data are also needed about the natural regeneration of Norway spruce.
Artificial regeneration has been relatively successful in Lapland during the 1980’s and 90’s. The results are clearly better than those obtained in earlier inventory studies. The site preparation methods used in connection with artificial regeneration during these two decades have guaranteed a good result. Intensive site preparation has been shown to have a long-term effect on the moisture content and aeration status of the soil. This may be of decisive importance for the successful development of seedlings during wet growth periods, especially on spruce-dominated sites where the water-holding capacity of the soil has been shown to be significantly greater than that on pine-dominated sites. Naturally regenerated pine seedlings have played an important role as supplementary seedling material in artificially regenerated stands. The effect of reindeer grazing on the height development and quality of birch (Betula pubescens) seedlings has, however, been significant, especially on sites repeatedly subjected to summer grazing. The project has concentrated on the modelling of regeneration success, and modelling techniques and modelling methods have been developed especially in the field of mixed models.
The long-term effect of site preparation on the soil physical characteristics and the performance of planted pines were studied on the plots of a reforestation experiment in Finnish Lapland. Two decades after site preparation, the heavy site-preparation machines and ploughing showed effect neither on the water-retention characteristics, nor on the soil water content and air-filled porosity of the intact intermediate areas. However, ploughing had a long-term, positive effect on the air-filled porosity in the ploughed ridges, which may crucial for the survival of seedlings during rainy growing seasons. The survival of planted pines, 25 years after planting, was higher on the ploughed plots than on those treated with lighter methods. The average temperature sum and the soil hydraulic properties of the intermediate areas showed a significant effect on the survival. The soil air-filled porosity in intermediate areas influenced significantly on the height growth. However, in another study, site prepartion was unable to contribute to permanent changes in soil water regimes in general, and site-specific soil water regimes appeared to be attributable to spatial variability of soil physical properties rather than mechanical site preparation.
In addition, results suggested that Scots pine was concentrated on tills derived from granitoid rocks. Norway spruce dominated sites on tills particularly derived from the mafic metavolcanic rocks of the Greenstone Belt but was lacking on tills derived from granulite. The edaphic constraint for pine appeared to be θv>0.27 cm3cm-3 (ε>15) and for spruce σ<0.5 mS/m, respectively.
Sub-project 3. The importance of key biotopes, safety zones and retained trees to the biodiversity
In an isolate of western Finland, the genetic diversity of Siberian Jay population was significanlty lower that in Siberian Jay populations living in continuous distribution of the species. However, for the other declining sederary bird species, the Siberian Tit, no such decrease in genetic diversity was observed. Probably occasional invasions by the Siberian Tit from northern Finlnad to southern Finland are maintaining the genetic diversity of the Siberian tits. Small-scale gaps produced by windfalls (0.2-0.5 ha) or forest cuttingss (1,5 ha) seem not be harmful for breeding forest bird species. Species prefereing open habitats might even benefit from those small-scale openings in the cannopy cover.
According the artificial nest predation experiment, nest predation rate of the ground breeding bird species varies greatly between years. The secondary prey hypothesis cannot explain this variation. Nest predation rate was highest during years with great numbers of rodents.
The Finnish Forest Research Institute,
PL 16, FI-96301 ROVANIEMI, FINLAND
Phone: +358 29 532 4469
Alenius, Virpi, RO (2003-06), Derome, John, RO (2003), Heiskanen, Juha, SU (2002-06), Hyppönen, Mikko, RO (2002-06), Jalkanen, Risto, RO (2002-05), Kiviniemi, Sari (2004), Martz, Francoise, RO (2004), Mikkola, Kari, RO (2004), Mäkitalo, Kari, RO (2002-06), Sutinen, Marja-Liisa, RO (2003-06), Timonen, Mauri, RO (2002), Vartiamäki, Henna, VA (2002)
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