How environmental friendly is timber production in Germany?

Background and Objective

We analyse environmental impacts caused by forest management activities by assessing relevant material and energy flows of timber production in Germany. Product life cycle assessments are now available for timber products (logs, pulpwood, fuelwood and wood chips) of main tree species (beech, oak, spruce and pine).

Approach

The methodology for life cycle assessments are regulated by the standards 14040 and 14044 of the International Organization for Standardization. We assess the material and energy flows of timber production in Germany. This provides a life-cycle inventory database of forest production. By evaluating the inventory data the environmental impacts of forest production (for example: Global Warming Potential) can be identified. Furthermore, life cycle inventory data sets for goods with wood in their production process is created.

Data and Methods

We use the forest growth simulator SILVA 2.2 to calculate the natural production of forest stands. Technical production in the forest module is based on literature (example: diesel consumption of harvester). We use the life cycle database / software GaBi 4.4 for upstream processes like diesel production and to aggregate data to life cycle inventories and life cycle impact asessments.

Results

The majority of environmental impacts are not caused by preparatory measures (for example planting, pre-commercial thinning, liming or forest road construction) but by logging and skidding activities. Less than 1 % of the carbon dioxide and energy stored in the wood is released or consumed by means of timber production.

The expansion of the product system to the gate of the saw mill, the pulping plant or the panel manufacturer reveals that the environmental impacts of timber production are multiplied by the transportation of logs and pulpwood. Example: Global Warming Potential of logs and pulpwood increases by a factor of 3 to 7. The environmental impacts increase depending on tree species, assortment and impact category. Given the impact of the transportation module, alternative allocation methods or different modelling approaches for the growth simulation in the forest module have a much smaller influence on the results.