Metla Project 3383

Fluxes of elements in boreal forest ecosystem after forest managements

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Duration: 2004-2007   Keywords: carbon, catchment, cations, clear-cutting, decomposition, deposition, drainage, groundwater, nitrogen, nutrient, nutrient leaching, phosphory, simulation models, soil organisms, soil scarification, stream discharge, sulphur
Research project group: Distinct projects 1 - Structure and function of forest ecosystems

Objectives

The aim of the study is to provide information and to develop tools for evaluating the impacts of forest management operations, primarily harvesting and stand regeneration, on the fluxes and stocks of carbon and nutrients associated with the stand biomass and soil in small catchments. The influence of the size and location of clear-cutting area on carbon and nutrient leaching loads to streams draining the catchments and the width of riparian buffer strips to minimize such loadings will be evaluated. It is intended to synthesize the results in the form of a book to be written towards the end of the project.

The specific objectives of the study are to

  1. determine the amounts of nutrient released from logging residues, retained by vegetation, and leaching with soil water to groundwater and streamwater over the first 10 years following clear-cutting in a catchment located in eastern Finland (sub-project 1)
  2. assess the influence of clear-cutting and site preparation on ground water quality and flow in groundwater area (sub-project 2)
  3. determine the stocks and fluxes of carbon and nutrients in wood ant nests and changes after timber harvesting. The role of ant-aphid symbiosis on tree growth will also be studied (sub-project 3)
  4. develop a general modelling tool that will simulate the influence of forest management operations on streamwater quality and on the long-term nutrient status of forest ecosystems (FEMMA-model, sub-project 4)
  5. model the influence of ditching, ditch maintenance and peatland restoration on water course quality (KUNTO-model; sub-project 5)




Sub-projects:




Results

Subproject 1: Ground vegetation biomass and associated nutrient pools decreased by half or more after clear-cutting. Dwarf shrubs (Vaccinium myrtillus L., Vaccinium vitis-idaea L.) and feather mosses (Pleurozium schreberi Brid. and Hylocomium splendens (Hedw.) B. S. & G.), in particular, suffered from clear-cutting.

The ground vegetation was thus capable of taking up only a small fraction of the nutrients released from logging residues, organic layer and upper mineral soil during the first two years after clear-cutting but, with the exception of K, nutrients were being efficiently retained through microbial immobilization and adsorption deeper in the soil (B-horizon).

The retention of P by the soil was particularly efficient. After 4-5 years the biomass and nutrient pools of ground vegetation had returned to pre-cutting levels, with the pools of P and K becoming even larger. Colonization by pioneer species such as Epilobium angustifolium L. and Deschampsia flexuosa L. particularly increased after clear-cutting, and markedly contributed to the retention of nutrients after 3 years.

Project leader: Piirainen, Sirpa
The Finnish Forest Research Institute, Joensuu Office, PL 68, FI-80101 JOENSUU, FINLAND
Phone: +358 29 532 3188
E-mail: sirpa.piirainen@metla.fi

Other researchers: Ahti, Erkki, VA (2007), Domisch, Timo (2004-05), Finér, Leena, JO (2005-07), Juntunen, Marja-Liisa, SU (2007), Koivusalo, Harri, JO (2006-07), Lauren, Ari, JO (2004-07), Palviainen, Marjo (2006), Ruokolainen, Maija, ME (2004-07), Starr, Michael, VA (2004)


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Updated 12.06.2012
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