The big translocation experiment – a unique research project begins

Last changed: 25 October 2021
A person marks a tree trunk with warning tape. Photo.

In this unique project researchers at SLU will investigate if insects, wood fungi, bryophytes and lichens that live in or on dead wood can be moved to a new stand and survive in the new environment. This project will generate new important knowledge that can be used to develop strategies for compensation of biodiversity loss at different types of land exploitation.

When the Aitik copper mine south of Gällivare in northern Sweden planned an expansion this would involve destroying 380ha of forest of which 170ha were old growth forest with very high natural values. The forest area contained a large number of threatened red-listed species associated with old-growth forest and dead wood. The mining company Boliden set-aside two compensation areas covering a total area of approximately 800ha to fulfill the legal requirement on ecological compensation.

Dead trees were relocated

The two compensation areas, Sarkanenä and Sjnjirrá, situated 15km from the mining area in the county Norrbotten are production forest without very high environmental values. Sarkanenä was used for the experiment and 640 dead wood object together with the insects, wood fungi, bryophytes and lichens living in and on the dead trees were translocated to this area.

Before clear-felling of the old growth forest with very high natural values in the impact area were dead and some living trees suitable for translocation carefully selected by nature consultant with expert knowledge and personnel from the forest company Sveaskog, that together with SLU owns the forest in the compensation area. Selected trees should preferably be pine or spruce of considerable age and diameter and of different decomposition stages (making up for 8 classes in total) to ensure that as many organisms as possible were moved together with the dead trees.

The trees were individually marked, branches removed and they were divided into 5m log pieces to make them possible to transport. The 640 were transported to the compensation area where they were distributed in different densities (0, 16 or 48 logs) in 30 experimental plots. Two live trees were cut down on site to provide substrate for translocated organism colonize.

 Forest machine lifting tree trunks. Photo.
Photo: Malin Söderlind
Stacked tree trunks. Photo.
Photo: Maria Nordlund
Two people work by a lying tree. Photo.
Photo: Maria Nordlund
 A person notices a tree trunk with warning tape. Photo.
Photo: Jean-Michel Roberge
 Tree trunks are scattered in the forest. Photo.
Photo: Olov Tranberg
 People with backpacks walk in the woods. Photo.
Photo: Olov Tranberg
 Tree trunk with a plastic container attached. Photo.
Photo: Olov Tranberg

Research will begin

Researchers from SLU designed an experimental set-up with 30 experimental plots were translocated logs were placed in different densities (0, 16 or 48 logs per plot). All plots the received translocated logs had equal amounts of logs from each of the 8 dead wood classes (two tree species, standing or downed logs and two decomposition classes). One year prior to translocation baseline data was collected both from the impact area and compensation area as well as from a reference area (10 plots) situated 20km from the impact area. The baseline data on biodiversity, dead wood density and diversity as well as forest structure provide the baseline to which future measures of response variables can be compared. Which allow us to assess the effect of translocation on biodiversity and substrate availability.

The aim with the project is to assess if it is possible to compensate for biodiversity loss in one area by translocation dead wood and associated organism from that area to a compensation area.  

The evaluation will be step-wise

  • The first step will be to assess if the translocation of dead wood will improve habitat quality and diversity in the compensation area. The density and diversity of dead wood in the compensation area after translocation will be compared to baseline data from the compensation and impact area.
  • The second step, that is more difficult, is to assess if the translocation will fully compensate for the biodiversity loss in the impact area (if no-net-loss of biodiversity is achieved). To test this, species richness and assemblage composition in the compensation area will be compared with that found in the impact area prior to exploitation.
  • In addition to this, cost and cost-efficience will be assesed by comp+aring the cost and biodiversity benefits with translocating different types of substrates. 

Facts:

Project title: Translocation of dead wood and associated species: a cost-efficient method to modernize ecological compensation and restoration?

Collaboration: The project is a collaboration between researchers at SLU, Lathrobe University, Australia, UQAM, Canada, Boliden (mining company) and Sveaskog (forest company). 

Project duration: The project is a long-term field experiment initiated in 2017.

Funding: Formas, Göran Gustafssons Stiftelse, Boliden and SLU

Project group: Joakim Hjältén1, Olov Tranberg1, Jörgen Sjögren1, Marie Jönsson2, Therese Löfroth1, Anne-Maarit Hekkala1, Ola Lindroos3, Heloise Gibb4 och Timothy Work5.

1Dept of wildlife, fish, and environmental studies, SLU, Umeå. 2 Artdatabanken, SLU, Uppsala, 3 Forest Economy, SLU, Umeå, LaTrobe University, Australien, 5 UQAM, Canada.