The aim of this investigation is to fulfill the needs of
field foresters to assess productivity as a measure of
site potential when suitable site trees are not available,
as it is the case in agricultural land before forest
plantation. This study examined the relationship
between site index and environmental factors in
Douglas-®r (Pseudotsuga menziesii var. menziesii)
plantations in central Italy. This species plays a major
role in Italian plantation forestry because, within its
optimal vegetation zone, no indigenous conifer has
similar characteristics of productivity and timber
quality. Furthermore, after more than 50 years of
planting, no serious diseases have been observed
(Ciancio et al., 1982; Corona et al., 1993).