accordant latitudes in the Southern Hemisphere), the boreal forest has developed
in climates that have short, cool summers and long, cold winters. Growing seasons
average about four months so that accumulated biomass is low. Here, there is a rel-
ative lack of numbers of species and ecological diversification compared to the
tropical forests. Soils tend to be poor and acidic (spodosols). The coniferous trees
are needle-leafed and close enough together to prevent full solar penetration to the
ground and this limits the biomass of understory plants and animals.Friction of Distance
A spatial concept that relates distance tointeraction, and a key concept in the
geography of economic development. Interaction in this case may take many
forms, such as economic exchange or transfer of cultural attributes. Simply put,
the greater the distance involved the greater the resistance to movement across
space, resulting in a lower degree of contact. A closely related geographical notion
isdistance decay. The notion of friction of distance plays a role in a number of
geographical theories, including thevon Thunen model. Friction of distance
affects an array of processes:cultural diffusion, migration,trade,andmany
others show the correlation between increased distance and a diminution of activity.
This typically happens because both actual costs and time invested increase as
the space between two points grows, and thus the incentive to interact is inversely
proportional to increases in distance. The degree of “friction” may be influenced
by several factors, including physical barriers (mountain ranges, deserts, bodies of
water), politicalboundaries, and the sophistication of the communications and
transportation systems involved.
In societies that enjoy highly mechanized transport opportunities, for example,
the friction of distance is generally reduced in comparison to those in which trans-
port is not technologically as advanced, because travel by automobile, train or air-
craft will efficiently cover more distance than travel on foot or on the back of an
animal. Many people inrural settlementsin developingregionsnever travel
more than 50 miles from their place of birth, while it is common for residents of
economically advanced countries to cover this distance on a daily basis as they
commute to and from their place of work. Even in regions with well-developed
transport systems, however, political boundaries can greatly increase the friction
of distance by increasing costs of transport, both in terms of time (time spent for
customs inspections, etc.) and actual costs (tariffs on imported goods).
In practical terms, thetypeof exchange may affect the degree of friction between
twolocations. In an economic exchange, low cost goods will have a high degree of134 Friction of Distance