%0 Research article
%T A comparison of one- and two-compartment neighbourhoods in heuristic search with spatial forest management goals
%A Heinonen, Tero
%A Pukkala, Timo
%D 2004
%J Silva Fennica
%V 38
%N 3
%R doi:10.14214/sf.419
%U https://silvafennica.fi/article/419
%X This study presents a comparison of the performance of four heuristic  techniques with one- and two-compartment neighbourhoods in harvest  scheduling problems including a spatial objective variable. The tested  heuristics were random ascent, Hero, simulated annealing and tabu  search. All methods seek better solutions by inspecting the  neighbourhood solutions, which are combinations that can be obtained by  changing the treatment schedule in one (one-compartment neighbourhood)  or two (two-compartment neighbourhood) compartments. The methods and  neighbourhoods were examined in one artificial and four real landscapes  ranging from 700 to 981 ha in size. The landscapes had 608 to 900 stand  compartments, and the examined planning problems had 2986 to 4773 binary  decision variables. The objective function was a multi-objective  utility function. The spatial objective variable was the percentage of  compartment boundary that joins two compartments, both of which are to  be cut during the same 20-year period. The non-spatial objectives were  net incomes of three consecutive 20-year management periods and the  remaining growing stock volume at the end of the third 20-year period.  In another problem formulation, the total harvest of the first 20-year  period was used as an objective variable together with the spatial  objective. The results showed that a two-compartment neighbourhood was  systematically and often clearly better than a one-compartment  neighbourhood. The improvements were greatest with the simplest  heuristics, random ascent and Hero. Of the four heuristics, tabu search  and simulated annealing proved to be the best methods, but with a  two-compartment neighbourhood the differences between methods were  negligible.