Forests Sourcebook - HCV Resource Network

selecting the technology. Technology selection should
ensure that a balanced approach is taken with regard to use
of remote sensing. The extent to which remote sensing is
used should be based on a clear understanding of what it is
good for, what its strengths are, and the overall efficiency
of the inventory. For example, remote sensing may be
effective in identifying change, but not in classifying it.
Remote sensing may also assist with stratification to
improve precision.
Data interpretation. Data interpretation is a critical part
of inventories. If spatial data are being used, interpretation
is often preceded by field reconnaissance to develop an
interpretation key. Interpretation of data can require the use
of available historical air photographs; available thematic
maps; photos taken during the field trips; and descriptions of
the vegetation in selected representative sites and forest and
land use classes in selected, geo-referenced sites. Image interpretation
can be carried out digitally. Photo-interpretation
and classification must be followed by validation by air, following
selected transects all over the country.
Capacity to conduct inventory. Capacity for executing
an inventory is often lacking and can require additional support
(see box 7.7). In cases where capacity needs to be
strengthened, a field manual and training program can
assist in implementing the inventory.
Linking Inventory to decision-making. Considerations
regarding integrating the inventory data into decision-making
processes should shape the inventory process from the
beginning. Often inventories feed into larger forest management
information systems (see note 7.2, Establishing Forest
Information Management Systems).
LESSONS LEARNED AND RECOMMENDATIONS
FOR PRACTITIONERS
Phased approach. Designing, coordinating, and conducting
national forest inventories can pose numerous challenges.
A phased approach, starting with inventories at a
subnational scale, can help identify the most cost-effective
and timely way of conducting a national-scale inventory.
Draw on good practice. Drawing from good practice in
countries where inventories are well-developed offers significant
assistance. For countries in the Europe and Central
Asia region, lessons from the United States, Canada, Sweden,
and Finland could be used. The national inventories in
the latter countries and other countries in the region provide
a good foundation. However, inventories from other
countries will not provide “off-the-shelf” approaches
because of the details of the methods used. For example,
plot densities may differ, and what can realistically be
afforded may be different.
Use current and well-tested technology. It is important
to draw on current and well-tested technologies, to the
extent possible. These technologies and the latest science in
inventories can assist in designing a cost-effective system
Box 7.11
Estimating Costs
Project cost estimations often require numerous
assumptions. In Tanzania, the following assumptions
were made for estimating the costs associated with
mapping:
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The country is covered by 50 Landsat scenes.
Procurement of the satellite images, training, and
preparatory work for the mapping (equipment,
manuals, interpretation key, preprocessing, and the
like) require four months.
One month of field reconnaissance is required at
the onset of the project by three people—thus, three
person-months of work.
Source: FAO 2007.
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One person interprets one scene in three weeks, on
average. This gives a total of 35 working months or
up to 12 months work for 4 people.
Field and air checking require two months of three
people, or a total of six person-months.
Revision and finalization of the map requires about
three months of three people or nine personmonths.
Storage of the map in the database and reproduction
of the map in hard copies will take two months
for three people—or six person-months.
The total person-months for mapping by technicians
is 24 months 3 people = 72 person-months.
260 CHAPTER 7: MONITORING AND INFORMATION SYSTEMS FOR FOREST MANAGEMENT