17. REMOTE SENSING REQUIREMENTS TO SUPPORT FOREST
INVENTORIES
155
forest damage characteristics, as well as damages caused by processes other
than air pollution.
3.5
Consequences
To satisfy the increasingly specific and diverse requests for scientifically
substantiated information, efficient methods are needed to measure forest
resources, their status, and the components of the whole forest ecosystem.
This includes forest area, volumes, annual growth and their annual changes.
It is not enough to know the volume of growing stock, although that single
variable is already difficult to estimate for the whole Earth. The areal extent
of forests is immense and the natural questions are: ‘How can one measure
forests in a cost-effective way?’ and ‘How can that be repeated with
sufficient frequency?’ The requirements can be summarized as follows:
new methods are needed in national and global level forest inventories to
answer to increasingly urgent demands
in some areas or cases, the cost-efficiency of inventories should be
improved
the potential of satellite remote sensing must be further demonstrated
and exploited.
4.
REQUIREMENTS OF FOREST INVENTORIES
FOR REMOTE SENSING
The utilization of airborne remote sensing has a long tradition in forest
inventories. A common methodological approach has been the visual
interpretation of images. The EFICS study, concerning forest inventories of
15 EU countries, Norway and Switzerland and some countries in Eastern
Europe showed that space-borne remote sensing is used operationally only in
Finland. Few other countries used satellite images for supporting forest
inventories, e.g., for stratification the area for different sampling units. One
reason for the minor utilization may the requirements of inventories. Usually
estimates for about 100–400 different parameters are needed. There are also
some other requirements which cannot easily be fulfilled with space-borne
remote sensing data. On the other hand, investigators in forestry and remote
sensing (especially those dealing with space technology) do not often meet.
Examples of forest inventory issues are:
time frequency
INVENTORIES
155
forest damage characteristics, as well as damages caused by processes other
than air pollution.
3.5
Consequences
To satisfy the increasingly specific and diverse requests for scientifically
substantiated information, efficient methods are needed to measure forest
resources, their status, and the components of the whole forest ecosystem.
This includes forest area, volumes, annual growth and their annual changes.
It is not enough to know the volume of growing stock, although that single
variable is already difficult to estimate for the whole Earth. The areal extent
of forests is immense and the natural questions are: ‘How can one measure
forests in a cost-effective way?’ and ‘How can that be repeated with
sufficient frequency?’ The requirements can be summarized as follows:
new methods are needed in national and global level forest inventories to
answer to increasingly urgent demands
in some areas or cases, the cost-efficiency of inventories should be
improved
the potential of satellite remote sensing must be further demonstrated
and exploited.
4.
REQUIREMENTS OF FOREST INVENTORIES
FOR REMOTE SENSING
The utilization of airborne remote sensing has a long tradition in forest
inventories. A common methodological approach has been the visual
interpretation of images. The EFICS study, concerning forest inventories of
15 EU countries, Norway and Switzerland and some countries in Eastern
Europe showed that space-borne remote sensing is used operationally only in
Finland. Few other countries used satellite images for supporting forest
inventories, e.g., for stratification the area for different sampling units. One
reason for the minor utilization may the requirements of inventories. Usually
estimates for about 100–400 different parameters are needed. There are also
some other requirements which cannot easily be fulfilled with space-borne
remote sensing data. On the other hand, investigators in forestry and remote
sensing (especially those dealing with space technology) do not often meet.
Examples of forest inventory issues are:
time frequency