| 1. |
- Svensson, Carl, 1974-, et al.
(författare)
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Norway spruce productivity in southern Sweden is equally limited by nitrogen and phosphorous
- 2024
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Ingår i: Forest Ecology and Management. - : Elsevier. - 0378-1127 .- 1872-7042. ; 572
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Tidskriftsartikel (refereegranskat)abstract
- Nutrient limitation of forest growth, especially nitrogen (N) deficiency, is widespread in the boreal region. N fertilisation has thus become a common silvicultural practice in Fennoscandian Norway spruce stands, but to what extent phosphorus (P) is co-limiting productivity and how initial basal area affects the growth response to N addition remains unresolved. To address these questions, two experiments were established in mid-rotation Norway spruce stands in southern Sweden where decades of high atmospheric N deposition have reduced the severity of N-limitation. In a P experiment initiated in 2011, we tested P addition alone (two applications of 200 kg P ha−1) and in a second study also starting in 2011 (NP experiment), a single dose of N was administered alone (200 kg ha−1 in thinned and unthinned stands, hereafter called N and N-unthinned treatments) and in combination with P (N+P = one-time 200 kg N ha−1, two applications of 200 kg P ha−1 in thinned stands). P addition alone increased PAI (periodic annual increment) significantly by 21 % during the first, moister assessment period up to 2014 and by 18 % in the drier 2015–2019 period, resulting in a 10 % increase in final stem volume yield. In the NP experiment, significant PAI increases under favourable meteorological conditions up to 2014 occurred in all fertilisation treatments. The strongest effects were seen in the N-unthinned treatment while no significant additive effect resulted from the joint addition of N and P (N: +20 %, N-unthinned: +38 %, N+P: +23 %). In the drier 2015–2019 period, only the N+P treatment caused significantly greater PAI (+29 %). Final stem volume yield in the NP experiment significantly increased by 10 %, 39 % and 16 % in the N, N-unthinned and N+P plots, respectively. In both experiments, foliar P and thus P/N rose drastically in response to P addition alone or in combination with N. Minor increases in leaf area index (LAI) only occurred in P-containing treatments. Our findings indicate that Norway spruce productivity in southern Sweden is constrained to a similar extent by both N and P. Sustainable nutrient management in Norway spruce growing regions with high N loading (like southern Sweden) should prioritise P over N supply.
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| 2. |
- Bellner, Anna-Lena, et al.
(författare)
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Virtual Reality in cognitive rehabilitation and understanding of stroke disease
- 2008
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Ingår i: Medical Informatics Europe 2008 - eHealth beyond the horizon – get IT there.
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Konferensbidrag (refereegranskat)abstract
- Physical and cognitive deficits are consequences of traumatic brain injuries (TBI). Without rehabilitation activity problems persist, i.e. limitations to handle personal care, the work situation, and recreational activities. A new approach in the rehabilitation area is the use of Virtual Reality (VR) technology and haptic devices. The aim of this study is to test an application of VR technology with 3D computer games as an occupational assessment/treatment method in rehabilitation. The training activities were virtual games that are used for training purposes. Every time an activity is run, data about the 3D hand movements of the patient is collected and analyzed, i.e. time and tremor in movements. The subject was a 48 years male patient, who in 2002 had a cranio-encephalitic trauma (CET), caused by an accident. Since 4 years he is working par time (50%). In the autumn 2007 he attended the rehabilitation program. Since then he has received two weekly sessions of 60 minutes by a special trained occupational therapist. The first weeks he was extremely tiered, tensed and unmotivated after 5-10 minutes. Cognitive deficits, motor and personality disorders were observed and assessed by using published and commonly used instruments within this knowledge field. The results revealed great problems in most observed and tested areas. After this initial period the patient accepted to take place in front of the VR-station. He was instructed to pick up the haptic stylus and start the tests. The whole procedure took 5 minutes and then he needed to relax the rest of the session. However, forthcoming sessions were breaking points, with an unexpected outcome. The patient increased his exercise potential from 5 to 40 minutes. Quantitative data revealed that the VR tasks gave a possibility to record time and to exact record the movement of the hand during the training. Qualitative data revealed that the patient’s increased motivation supported him to be active in everyday life. One outcome was an invitation from his employer to extend his working time within a computer department.After 6 months of VR-technological treatment sessions the patient improved significantly concerning cognitive and sensory-motor deficits. Thus, he is more competent to do what he wishes to do.
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| 3. |
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| 4. |
- Broeren, Jurgen, et al.
(författare)
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Exploration of computer games in rehabilitation for brain damage
- 2008
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Ingår i: Proceedings of the 7th International Conference on Disability, Virtual Reality and Associated Technologies. ; , s. 75-80
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Konferensbidrag (refereegranskat)abstract
- Cognitive and physical deficits are consequences of stroke/traumatic brain injuries (TBI). Without rehabilitation activity problems persist i.e. limitations to handle personal care, the work situation, and recreational activities. The aim of this study is to test an application of Virtual Reality (VR) technology with 3D computer games as an occupational therapy assessment/treatment method in rehabilitation for patients with cognitive and physical deficits. We also wanted to investigate if playing computer games resulted in improved cognitive function. An easy-to-use semi-immersive workbench with haptic game selection menu was located at an activity centre. The training activities were 3D computer games. Every time an activity was run, data about the hand movements were collected and analyzed. Quantitative variables were time (s) to perform the test, average velocity (m/s) and, tremor or uncertainty in movements HPR). Executive functioning was examined by utilizing Trial Making Test. The intervention involved five patients. Results provide evidence to support the use of 3D computer games in cognitive rehabilitation. As an implementation tool within the occupational therapy area, this technology seems to be well adapted to the technological and economical development of society in Sweden.
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| 5. |
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| 6. |
- Broeren, Jurgen, et al.
(författare)
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Virtual rehabilitation after stroke.
- 2008
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Ingår i: Studies in health technology and informatics. - 0926-9630 .- 1879-8365. ; 136, s. 77-82
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this project was to investigate the effects of Virtual Reality technology and haptics for stroke rehabilitation. Twenty-nine stroke subjects, 17 women, and 12 men aged 44-85 years, participated in three different studies. All participants responded favorable to the use of the VR activity station. A change of attitude took place after the subjects were exposed to playing computer games. The general experience with the VR application approach suggests that this treatment concept is promising in stroke rehabilitation, with a wide range of applicability.
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| 7. |
- Broeren, Jurgen, et al.
(författare)
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Virtual rehabilitation in an activity centre for community-dwelling persons with stroke. The possibilities of 3-dimensional computer games.
- 2008
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Ingår i: Cerebrovascular diseases (Basel, Switzerland). - : S. Karger AG. - 1421-9786 .- 1015-9770. ; 26:3, s. 289-96
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The main purpose of this study was to place a virtual reality (VR) system, designed to assess and to promote motor performance in the affected upper extremity in subjects after stroke, in a nonhospital environment. We also wanted to investigate if playing computer games resulted in improved motor function in persons with prior stroke. METHODS: The intervention involved 11 patients after stroke who received extra rehabilitation by training on a computer 3 times a week during a 4-week period. The control group involved 11 patients after stroke who continued their previous rehabilitation (no extra computer training) during this period. The mean age of all was 68 years (range = 47-85) and the average time after stroke 66 months (range = 15-140). The VR training consisted of challenging games, which provided a range of difficulty levels that allow practice to be fun and motivating. An additional group of 11 right-handed aged matched individuals without history of neurological or psychiatric illnesses served as reference subjects. RESULTS: All the participants reported that they were novel computer game players. After an initial introduction they learned to use the VR system quickly. The treatment group demonstrated improvements in motor outcome for the trained upper extremity, but this was not detected in real-life activities. CONCLUSIONS: The results of this research suggest the usefulness of computer games in training motor performance. VR can be used beneficially not only by younger participants but also by older persons to enhance their motor performance after stroke.
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| 8. |
- Goude, Martin, et al.
(författare)
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Comparing basal area growth models for Norway spruce and Scots pine dominated stands
- 2022
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Ingår i: Silva Fennica. - : Finnish Society of Forest Science. - 0037-5330 .- 2242-4075. ; 56
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Tidskriftsartikel (refereegranskat)abstract
- Models that predict forest development are essential for sustainable forest management. Constructing growth models via regression analysis or fitting a family of sigmoid equations to construct compatible growth and yield models are two ways these models can be developed. In this study, four species-specific models were developed and compared. A compatible growth and yield stand basal area model and a five-year stand basal area growth model were developed for Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.). The models were developed using data from permanent inventory plots from the Swedish national forest inventory and long-term experiments. The species-specific models were compared, using independent data from long-term experiments, with a stand basal area growth model currently used in the Swedish forest planning system Heureka (Elfving model). All new models had a good, relatively unbiased fit. There were no apparent differences between the models in their ability to predict basal area development, except for the slightly worse predictions for the Norway spruce growth model. The lack of difference in the model comparison showed that despite the simplicity of the compatible growth and yield models, these models could be recommended, especially when data availability is limited. Also, despite using more and newer data for model development in this study, the currently used Elfving model was equally good at predicting basal area. The lack of model difference indicate that future studies should instead focus on model development for heterogeneous forests which are common but lack in growth and yield modelling research.
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| 9. |
- Goude, Martin
(författare)
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Hybrid growth models for Norway spruce and Scots pine: Using leaf area and light use efficiency for predicting stemwood production
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- With a changing climate, it has become more challenging to make long-term sustainable forest management decisions because many models and planning systems have difficulties accounting for the effects of climate change. One way to improve these tools is to include ecophysiological variables that respond to changes in weather and climate. The aim of this thesis was to investigate the use and implementation of ecophysiological concepts around light interception and light use in models for Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) forests in Sweden. Different methods for estimating leaf area were compared in eight established forest experiments and showed that tree- and stand-level leaf area could be estimated using stand and tree variables together with indirect optical canopy measurements (Paper I). The higher leaf area for Norway spruce showed the importance of species-specific models. When using leaf area models in practice, measures of stand heterogeneity improve accuracy (Paper II). New species-specific mensurational basal area models were developed using permanent sample plot data (Paper III). There were minor differences in precision between these new models and an existing stand basal area growth model. Climate-sensitive hybrid models were developed from the mensurational models by replacing time with potentially usable light sums modified by climate factors (Paper IV). The hybrid models did not improve prediction precision compared to the mensurational models. However, tests with different climate scenarios demonstrated the ability of the hybrid models to capture both positive and negative effect from changes in temperature and precipitation, with a sizeable local variation in growth response. This thesis shows that it is possible to include climate sensitivity in forest models through light interception and light use. These models allow for better predictions of forest development and better-informed decision making for sustainable forest management.
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| 10. |
- Goude, Martin, et al.
(författare)
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Hyggesfria skogliga fältförsök i Sverige : en sammanställning av tillgängliga långtidsförsök
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I takt med det ökade intresset för ett mer variationsrikt skogsbruk har hyggesfritt skogsbruk, där marken alltid är trädbevuxen utan större kalhuggna ytor, lyfts fram som ett komplement till det traditionella trakthyggesbruket. Det ökade intresset för hyggesfritt skogsbruk beror bland annat på att skogsägare numera ofta vill kunna nyttja olika ekosystemtjänster såsom virkesproduktion, rekreation och biodiversitet i samma skog. Detta ställer krav på ny kunskap om hur de alternativa skötselmetoderna bör bedrivas och vad de har för effekter på ekonomiska, ekologiska och sociala värden. En viktig del i att ta fram ny kunskap är långsiktiga fältförsök, där olika aspekter kring skogsskötsel kan studeras under lång tid. I Sverige finns totalt sett omkring 4 000 långtidsförsök över hela landet. En del av dessa behandlar hyggesfri skogsskötsel, men det har inte funnits en bra sammanställning över vilka de är, vad som gjorts i försöken eller vilka slutsatser som dragits från dem. Syftet med denna rapport är därför att sammanställa information och resultat från de långsiktiga försök som brukats med hyggesfria metoder med fokus på produktion, föryngring och skador. Även kunskapsluckor och behovet av nya försök beskrivs.Vi fann 140 långtidsförsök spridda över landet som uppfyllde våra urvalskriterier. Några av försöken är anlagda redan på 1920-talet, men majoriteten aktiva fältförsök är anlagda från 1980- talet och framåt. De behandlingar som förekommer är olika former av selektiv avverkning där enskilda träd avverkas, såsom blädning och måldiameterhuggning, eller gruppvis avverkning där träd avverkas på grund av sin rumsliga position, såsom luckhuggning och skärmställning. Från drygt hälften av försöken kunde tillväxt, avgångar och utveckling av små träd studeras.Det var stor variation i den löpande tillväxten, som i genomsnitt var 6,2 m3sk/ha, år. Tillväxten började kulminera vid ett virkesförråd runt 200–300 m3sk/ha, ungefär samtidigt som avgångarna ökade kraftigt, vilket tydde på att det i skiktade skogar riskeras höga avgångar vid dessa virkesförråd samtidigt som tillväxten kulminerar. Sju försök som behandlar måldiameterhuggning i blandskog, omföring av enskiktad granskog till flerskiktad, blädning i fullskiktad granskog, luckhuggning i schackrutemönster samt skärmställning av tall respektive gran presenteras mer ingående tillsammans med nya data från återinventeringar som utfördes under 2021 och 2022. Dessa försök visade på bredden i skötselmetoder som behandlas i de långsiktiga försöken samt tillgänglig kunskap om enskilda skötselmetoder.För att få veta mer om de långsiktiga effekterna av hyggesfri skötsel behövs längre mätserier än vad de flesta försök hade i denna sammanställning. Det behövs också fler försök, framför allt kring metoder såsom luckhuggning, måldiameterhuggning och omförandet från enskiktade bestånd till flerskiktade. I väntan på nya försök och längre tidsserier kommer resultat från de försök som finns behöva användas, tillsammans med praktiska erfarenheter, kunskap från andra länder med liknande förutsättningar, samt den kunskap vi har om trakthyggesbrukad skog.
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