Subject considering fundamentals of the heat and mass transfer in the environment.

The last ice age ended in Scandinavia about 15 000 years ago. The land was gradually occupied by present tree species. Human settlement followed the vegetation. The first forest uses were hunting and gathering. Animal husbandry and forest grazing came later. Shifting cultivation was a wide spread form of agriculture, especially in Sweden and Finland. Wood was first used for domestic purposes and for construction, In the 18th century, wood became a commercial product. Overcutting, grazing and agricultural cultivation caused deforestation and degradation of forests. These problems accelerated the creation of forest policy.

The principles of sustained yield wood production were first applied in Scandinavia in the 18th century. In the 19th century, forests became a source of raw material for the forest industry. Recently, increasing urbanization has created the need for renewed contact with nature and led to the development of modern multiple-use forestry management. A general trend in the definitions has been a move away from the listing of products and functions to defining problems and setting goals. Also the components of multiple use have changed. The new objectives of forest management include carbon sequestration and preservation of biological diversity.

Nowadays, multiple use is regularly mentioned in policy programs and action plans. Recently, international agreements on sustainable forestry have given a new demanding context to the expertise obtained in the field of multiple use. Realization of the ideals of ecologically, economically and socially sustainable multiple-use forestry requires adjustments in practical forestry as well as development of new forest policy practices.

Sustainability has been the leading principle in forestry for centuries. The goal of forest management has  been  to  organise  timber  harvesting  schedule  according  to  the  forest  growth  potential  in  order  to  maintain  a  continuous  flow  of  timber  production. Consequently,   multi-dimensional    aspects    of    sustainability    were    included    in    forest    management.  At  the  global  level,  the  Brundtland  report  (1987)  brought  forward  the  concept  of  sustainable  development  which  means  a  development  meeting  the  needs  of  the  present  without  jeopardising  the  ability  of  future  generations  to  meet  their  own  needs.  Since  the  Earth  Summit  in  Rio  de  Janeiro  in  1992  (UNCED),  both  forests  and  forestry  have  been  added  to  the  international  agenda  because  of  concerns  about  the  sustainability  of  forests  regarding  biodiversity  and  its  economic  and  social  contribution to the development of the local communities.

Not  only  the  forest  production  but  also  the  whole  set  of  production  chains  using  forest  resources  should  be  evaluated  in  sustainability  impact  assessments  of  Forest-Wood  Chains.  FWCs  consist  of  sets  of  processes  by  which  forestry  resources are converted into services and products.