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Articles by Tero Heinonen

Category: Research article

article id 474, category Research article
Tero Heinonen, Mikko Kurttila, Timo Pukkala. (2007). Possibilities to aggregate raster cells through spatial optimization in forest planning. Silva Fennica vol. 41 no. 1 article id 474. https://doi.org/10.14214/sf.474
This study divided the forest into raster cells and used these cells as calculation units in optimisation instead of predefined stand compartments. It was hypothesized that raster cells would result in feasible treatment units and more efficient utilization of the production potential of the forest when spatial optimisation is used to compile the plan. The optimization problems of this study included both ecological and economic objectives. The raster cells were hexagons (721 m2) and their data were derived from traditionally defined forest compartments. Three forest plans were developed by using the rasterized forest, and they were compared to the corresponding forest plans developed by using compartments. Cutting areas were aggregated in all plans, by maximizing the proportion of the boundaries between two adjacent calculation units that were both cut during the same management period, and by minimizing the proportion of cut-uncut boundaries. In the first plan, only cutting areas were aggregated. In the second and third plan, also old forests were aggregated by using two different spatial objectives. The first maximized the proportion of the boundary between adjacent calculation units that were both considered as old forest. The second objective maximized the mean of the neighbourhood minima of the calculation units’ old forest indices. The neighbourhood included the calculation unit itself and all the adjacent calculation units. The growing stock volume targets at the end of the 60-year planning period and the cutting volume targets of the three 20-year management periods were set to the same levels in all plans. The results showed that the raster approach was able to aggregate old forest patches and cutting areas similar in shape and size as the conventional approach. When the aggregation of old forest was a management objective, the total old forest area was larger in the raster forest but the mean size of the old forest patches was larger with predefined compartments. The trade-off curve between harvested volume and old forest area was further from the origin for the raster forest.
  • Heinonen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: tero.heinonen@joensuu.fi (email)
  • Kurttila, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Pukkala, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 419, category Research article
Tero Heinonen, Timo Pukkala. (2004). A comparison of one- and two-compartment neighbourhoods in heuristic search with spatial forest management goals. Silva Fennica vol. 38 no. 3 article id 419. https://doi.org/10.14214/sf.419
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.
  • Heinonen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Pukkala, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: timo.pukkala@joensuu.fi (email)

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