Conclusions
Structural diversity at different scales can be linked to biodiversity
and carbon uptake as well as attractiveness of landscapes and
recreational activities. Possibilities for forest management in
considering these more varied objectives are acknowledged but objective
measures of structural diversity have been lacking as 3D information on
structure of forests and trees has practically been unavailable before
various laser scanning sensors. This study provides an example how
structural complexity of individual trees can be quantitatively assessed
and how it is affected by forest management. We demonstrated the use of
so-called box dimension in characterizing structural complexity of
individual Scots pine trees in managed plots. Thinning intensity
affected structural complexity and intensive thinning resulted in
increased structural complexity. Increasing crown size (i.e. width,
surface area and volume) and tree growth also increased structural
complexity but there was no relationship between structural complexity
and benefit-to-cost ratio (i.e. relationship between crown surface area
and stem volume) or light availability (i.e. competition). More research
is required to better understand the specific drivers behind structural
complexity of different tree species. For example, how regeneration and
growth of other than traditional attributes (e.g. DBH and height) affect
the structural complexity. It can be concluded that thinning had an
effect on structural complexity of individual Scots pine trees and stem,
crown, and growth attributes were identified as drivers for the
structural complexity in managed boreal forests.