| 1. |
- Ara, Mostarin
(författare)
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Establishment and early management of young forest in Sweden : stand structure, spatial design and pre-commercial thinning
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Demands on forests have shifted from one (production) to multiple ecosystem services. New management strategies need to be developed to balance production and other services. In this thesis, I evaluate alternative forest management strategies to balance production, profit, and multiple ecosystem services. I also emphasize describing young Swedish forests. Field experiments and national inventory data from Sweden were analysed in this thesis.No negative effect of rectangular planting design during forest establishment was found on the production of coniferous plantations. This provides an opportunity to select microsites for planting seedlings that can improve regeneration while facilitating existing forest operations or introducing new management practices. Although during establishment, either Norway spruce or Scots pine alone is used as a regeneration tree species, young forests mostly contain a mix of these species together with naturally regenerated broadleaves. Different pre-commercial thinning (PCT) strategies were experimentally applied in young unintended mixed forest (Norway spruce and birch in this case) which showed that some PCT techniques can provide forage for ungulates without losing volume production of Norway spruce. Moreover, such a mixture might also provide a wide range of ecosystem services with no or little economic loss in the long term. In addition, PCT can increase the full rotation profitability of Norway spruce stands compared to no-PCT stands. However, the timing of PCT appears to have little effect on the profitability of Norway spruce.Overall, alternative forest management strategies tested in this thesis show potential to provide multiple ecosystem services and flexible forest management along with profitable production.
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| 2. |
- Ara, Mostarin, et al.
(författare)
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Pre-commercial thinning in Norway spruce-birch mixed stands can provide abundant forage for ungulates without losing volume production
- 2022
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 520
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Tidskriftsartikel (refereegranskat)abstract
- Mixed stands of Norway spruce and birch have the potential to simultaneously produce timber and provide large ungulates with a significant amount of forage during the regeneration phase. While the growth and yield of such mixtures are well studied, little is known about potential trade-offs between timber and forage production and which management techniques are suitable for meeting both goals. In this study, four different pre-commercial thinning (PCT) strategies were used to study the trade-offs between production and available forage for free-ranging ungulates in a Norway spruce-birch mixture. The four PCT strategies were: 1) retaining 2000 birch stems ha(-1) with 2000 Norway spruce ha(-1), 2) removing all birches within a 0.75 m radius around Norway spruce stems, 3) removing all birches and other broadleaves, and 4) no PCT (control). Growth of Norway spruce was higher in the 2000 birch ha(-1) and full removal treatments compared to the untreated control, but these two treatments did not differ from one another in volume production of Norway spruce. We found a negative effect of PCT on forage availability but no effect on ungulate browsing. Therefore, PCT strategies that provide both sufficient birch forage and maximize volume production of Norway spruce can be implemented.
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| 3. |
- Ara, Mostarin, et al.
(författare)
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Pre-Commercial Thinning Increases the Profitability of Norway Spruce Monoculture and Supports Norway Spruce-Birch Mixture over Full Rotations
- 2022
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Ingår i: Forests. - : MDPI AG. - 1999-4907. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Pre-commercial thinning (PCT) is a common measure in Norway spruce (Picea abies L. Karst.) stands but the profitability of doing PCT and timing of PCT has not been fully investigated over a full rotation. Further, limited knowledge is available for mixed forest management compared to monocultures. In this study, different PCT strategies were tested to investigate the effect of PCT and timing of PCT on the production and profitability of Norway spruce monocultures and mixed Norway spruce-birch stands. A forest decision support system was used to simulate stand development during the whole rotation. Our study findings show that there is a positive effect of PCT on Norway spruce plantations' long-term profitability but that the timing of PCT has little effect on profitability. However, site variation might influence the effect of PCT timing on the profitability of Norway spruce stands. Moreover, we also found that retaining 1000 Norway spruce ha(-1) and 1000 birch ha(-1) after PCT supports a mixture of Norway spruce and birch over a full rotation, with little or no economic loss compared to pure Norway spruce stands. Therefore, such a mixture can lead to profitable production while still providing other ecosystem services.
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| 4. |
- Ara, Mostarin, et al.
(författare)
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Regeneration failure of Scots pine changes the species composition of young forests
- 2022
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 37, s. 1445-1457
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Tidskriftsartikel (refereegranskat)abstract
- How seedling mortality and browsing affects species composition of regenerating forests has been mostly studied on a small scale. Yet, large-scale analyses based on extensive data are essential for robust prediction of species composition in young forests. In this study, we used a dataset from a national inventory of young forests (1-4 metres in height) to investigate the species composition of young forests across Sweden. We found that most of the regenerated forest area (almost 90%) was planted with Norway spruce (southern Sweden) and Scots pine (northern Sweden). Regeneration of Norway spruce was generally relatively successful but as a consequence of seedling mortality and browsing, almost 40% of the area regenerated with Scots pine will probably not develop into pine-dominated stands. Thus, low survival of Scots pine seedlings and trees can profoundly change the trajectory of species composition of the young forest from what was originally intended, and a large proportion of the young stands may develop into mixtures of conifers and broadleaves. While such mixtures may benefit certain biodiversity and ecosystem services, a loss of Scots pine dominated stands may also have adverse impacts on the economic returns as well as pine-dependent biodiversity and recreational values.
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| 5. |
- Ara, Mostarin, et al.
(författare)
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Varying rectangular spacing yields no difference in forest growth and external wood quality in coniferous forest plantations
- 2021
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 489
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Tidskriftsartikel (refereegranskat)abstract
- Historically square or almost square spacing design has been used in plantation forest, as it has been claimed to maximize productivity. In this study, based on field experiments established in the mid-1980s, we tested the effect of square or different rectangular planting designs (2 x 2, 1.33 x 3, 1 x 4, 0.8 x 5, 1.46 x 1.46 x 4 m) on productivity, stand heterogeneity, and external wood properties of three coniferous species: Scots pine, Lodgepole pine, and Norway spruce. Stand production (volume, diameter), external wood properties (ovality, branch thickness, living crown height, height-diameter ratio), and stand heterogeneity (Gini coefficient) were not significantly affected by the different rectangular designs. Based on this evidence, we propose that more flexibility is available than previously thought for rectangular spacing layouts and consequently for the choice of planting spots and machinery operations.
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