engleski

Forestry and Life Cycle Assessment

Life cycle assessment is an approach in assessing how technologies and industrial systems used in forestry affect the environment. It is a so called “cradle-to-grave” approach because it begins from the use of raw materials and ends with recycling of the materials so that all environmental effects of a product through its entire life cycle: production, use, recycling, and final disposal are gathered. ISO/EN 14040 standard defines LCA as a tool for assessing the potential impacts of a product through: 1) goal and scope definition ; 2) inventory compilation of system’s relevant inputs and outputs ; 3) evaluation of environmental impacts of system’s inputs and outputs ; 4) result interpretation. LCA can be used for comparing environmental aspects of specific products because it enables ecological comparison of products made of different raw materials, but used for the same purpose and accordingly, ecological comparison of products made of same raw materials but used for different purpose is also possible. Goal of LCA, according to ISO standards, is to improve product manufacturing (or service guarantees), product development, strategic planning, decision-making support and marketing in environmental aspects of a product through its life cycle. It is recommended that processing machines, manpower, buildings and land-use are not included in gathering inventory data for LCA because analyses can become very complex. Major reasons for introducing LCA in forestry is to obtain sound information on environmental impact of products, to improve system production and recycling, enable comparison between products and to determine which information in product’s life cycle are missing. COST action E9 defined certain problems for the use of LCA in forestry: 1) forestry uses considerable areas of land ; 2) forest products have relatively long production period and use chains which start with wood production in the forest and end with disposal or burning for energy. The steps in between can be processing, trading, secondary processing, usage (including maintenance) and recycling ; 2) life cycle of forest product can range from relatively short (e.g. paper) to very long (e.g. structural timber) and 4) relations between products, by-products and waste in forestry in not always clearly defined. Classical LCA corresponds to a static approach where temporal and spatial dimensions are not being considered. On the other hand forestry is a dynamic model where temporal dimension is fundamental because predictions are based on time dimension of growing stock (rotation period) and spatial component is crucial, as forests, according to FAO, cover 4 billion hectares or 31 % of the total land area and therefore have a huge effect on the environment. LCA is considered especially challenging for forestry because: 1) forests are a part of the environment and therefore should be considered as an impact category of their own ; 2) because forests are a substantial part of the global ecosystem they are negatively influenced not only by forestry itself (wrong decision-making in management, technology use etc.), but also by an overall man influence on the planet Earth (manifestation of air pollution, acid rain etc.). Another challenge for LCA in forestry is a “thin line” between definitions of waste and products in forestry industry. Even though general definitions of waste and products are provided within ISO 14000 family of standards, because of that general meaning they do not apply well into forestry sector and wood industry. For example sawdust is generally a waste in sawmills, but can be used as a product (for energy purpose or in construction) and then it should be reclassified as a by-product or a co-product. Data bases availability are also crucial in performing LCA and while data on operations such as “transport” (for example statistical data of transported tones or cubic meters of timber per kilometer) and “harvesting” (statistical data of cut timber in m3/ha etc.) can be found, other such as “use of pesticides”, “stand establishment”, “forest road design, construction and maintenance” (environmental loadings caused by road construction and maintenance) etc. are difficult to find. Different ways of data collection can provide considerable differences in results. Basically there are two ways of gathering data in forestry: 1) statistical data of actual cut or transported wood and 2) work studies of productivity and production efficiency. Latter can be collected according to origin: 1) measurements, 2) measurements and constants, 3) local averages and 4) general averages. Because of daily increasing ecological awareness it is also possible to acquire manufacturer’s data on different machines used in forestry. For example environmental impact throughout different life cycle phases of harvester and forwarder can be found in so called environmental declarations. These declarations provide production rate, maintenance and repair rate, rate of machine manufacturing, use and post-use phase and their share in the total environmental impact along with recyclability rate of the machine and its parts. Even though timber is a primal forest product, there are many secondary forest products such as: resin, mushrooms, berries, cork and even game animals etc. which should also be included in LCA because forests also supply these (and many other) products. LCA is a useful tool in determining an environmental impact of each product (and production processes in which product is produced), especially today when environmentally friendly technologies and renewable energy sources are globally recognized. Maybe the greatest use of LCA in forestry is in comparing different logging systems for selecting environmentally friendly versions and machines. Due to the lack of quality data sources, and conversion of a static character of life cycle assessment into a dynamic, further research of this very complex tool should be done.

life cycle assessment study, environmental acceptability

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