Paulo Borges, Even Bergseng, Tron Eid, Terje Gobakken. (2015). Impact of maximum opening area constraints on profitability and biomass availability in forestry – a large, real world case. Silva Fennica vol. 49 no. 5 article id 1347. https://doi.org/10.14214/sf.1347

Keywords: bioenergy; forest management planning; mixed integer programming; area restriction model; green-up

Highlights: We solved a large and real world near city forestry problem; The inclusion of maximum open area constraints caused 7.0% loss in NPV; Solution value at maximum deviated 0.01% from the true optimum value; The annual energy supply of 20–30 GWh estimated from harvest residues could provide a small, but stable supply of energy to the municipality.

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The nature areas surrounding the capital of Norway (Oslomarka), comprising 1 700 km² of forest land, are the recreational home turf for a population of 1.2 mill. people. These areas are highly valuable, not only for recreational purposes and biodiversity, but also for commercial activities. To assess the impacts of the challenges that Oslo municipality forest face in their management, we developed four optimization problems with different levels of management constraints. The constraints consider control of harvest level, guarantee of minimum old-growth forest area and maximum open area after final harvest. For the latter, to date, no appropriate analyses quantifying the impact of such a constraint on economy and biomass production have been carried out in Norway. The problem solved is large due to both the number of stands and number of treatment schedules. However, the model applied demonstrated its relevance for solving large problems involving maximum opening areas. The inclusion of maximum open area constraints caused 7.0% loss in NPV compared to the business as usual case with controlled harvest volume and minimum old-growth area. The estimated supply of 20-30 GWh annual energy from harvest residues could provide a small, but stable supply of energy to the municipality.

Borges, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway E-mail: paulo.borges@nmbu.no
Bergseng, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway E-mail: even.bergseng@nmbu.no
Eid, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway E-mail: tron.eid@nmbu.no
Gobakken, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway E-mail: terje.gobakken@nmbu.no

article id 141, category Research article

Per Kristian Rørstad, Erik Trømborg, Even Bergseng, Birger Solberg. (2010). Combining GIS and forest modelling in estimating regional supply of harvest residues in Norway. Silva Fennica vol. 44 no. 3 article id 141. https://doi.org/10.14214/sf.141

Keywords: bioenergy; forestry; SGIS; supply functions

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New and ambitious targets for renewable energy production put attention to increased supply of biomass. Harvest residues are only to a limited extent demanded by the traditional forest industries and represent an unutilized resource for increased production of renewable energy in Norway. The overall objective of this paper is to study how GIS and forest modelling can be combined to improve estimates of the supply of harvest residues, taking different environmental and economic constraints into consideration. The analyses are based on a case study of a forest area of more than 40 000 ha in Southern Norway divided into about 500 private forest properties. The study was carried out by computations of timber harvest using the forestry scenario model SGIS based on extensive forest inventory data at stand level. In the studied area energy utilization of harvest residues is not profitable below an energy price of about EUR 3.2/GJ (NOK 0.10 /kWh) when the distance from roadside to industry is 20 km. Above this level supply increases rapidly over a rather narrow price range and is nearly inelastic above EUR 4.1/GJ (NOK 0.12/kWh). We did not find significant negative shifts in the residues supply caused by changes in location of roundwood harvest over time. Exclusion of collection from stands with a site index (H₄₀) below 14 reduced the potential supply of residues by 16–27%. The optimisation method combined selection of exogenous variables in order to map observed harvesting level and is probably the best approach to map future harvest.

Rørstad, Norwegian University of Life Sciences, Dept of Ecology and Natural Resource Management, Ås, Norway E-mail: per.kristian.rorstad@umb.no
Trømborg, Norwegian University of Life Sciences, Dept of Ecology and Natural Resource Management, Ås, Norway E-mail: et@nn.no
Bergseng, Norwegian University of Life Sciences, Dept of Ecology and Natural Resource Management, Ås, Norway E-mail: eb@nn.no
Solberg, Norwegian University of Life Sciences, Dept of Ecology and Natural Resource Management, Ås, Norway E-mail: bs@nn.no

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