Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2024
Sammendrag
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Sammendrag
Mapping individual tree quality parameters from high-density LiDAR point clouds is an important step towards improved forest inventories. We present a novel machine learning-based workflow that uses individual tree point clouds from drone laser scanning to predict wood quality indicators in standing trees. Unlike object reconstruction methods, our approach is based on simple metrics computed on vertical slices that summarize information on point distances, angles, and geometric attributes of the space between and around the points. Our models use these slice metrics as predictors and achieve high accuracy for predicting the diameter of the largest branch per log (DLBs) and stem diameter at different heights (DS) from survey-grade drone laser scans. We show that our models are also robust and accurate when tested on suboptimal versions of the data generated by reductions in the number of points or emulations of suboptimal single-tree segmentation scenarios. Our approach provides a simple, clear, and scalable solution that can be adapted to different situations both for research and more operational mapping.
Sammendrag
Uneven-aged forests set certain challenges for cut-to-length harvesting work. It is a challenge to cost-effectively remove larger trees while leaving a healthy understory for regrowth. The study’s aim was to evaluate productivity and costs of harvesting two-storied silver birch (Betula pendula Roth) and Norway spruce (Picea abies (L.) H. Karst.) stands by creating time consumption models for cutting, and using existing models for forwarding. Damage to the remaining understory spruce was also examined. Four different harvesting methods were used: 1) all dominant birches were cut; 2) half of them thinned and understory was preserved; compared to 3) normal thinning of birch stand without understory; and 4) clear cutting of two-storied stand. Results showed the time needed for birch cutting as 26–30% lower when the understory was not preserved. Pulpwood harvesting of small sized spruces that prevent birch cutting was expensive, especially because of forwarding of small amounts with low timber density on the strip roads. Generally, when taking the cutting and forwarding into account, the unit cost at clear cuttings was lowest, due to lesser limitations on work. It was noted that with increasing removal from 100 to 300 m3 ha–1, the relative share of initial undamaged spruces after the harvest decreased from 65 to 50% when the aim was to preserve them. During summertime harvesting, the amount of stem damage was bigger than during winter. In conclusion, two-storied stands are possible to transit to spruce stands by accepting some losses in harvesting productivity and damages on remaining trees.
Sammendrag
Eucalyptus plantations are a notable source of income for smallholders and private landowners in Thailand. The main uses of eucalyptus are for energy purposes and as pulpwood, sawn timber, and veneer. Among private eucalyptus forest owners there is a need for decision support tools that can help in optimizing tree bucking, according to the available properties of the site and bucking patterns. The precise characterization of plantation properties is key to delivering appropriate timber assortment to markets and optimizing timber value. Our study has developed and tested dynamic and linear programming models for optimizing the tree bucking of eucalyptus trees. To achieve this, tree taper curves for use in volumetric models were defined for optimization. Our results indicate that both the tree spacing and the increment of diameter of breast height are significant factors when estimating profitability. The income would be significantly higher if bucking timber in different assortments were used, instead of the current approach of selling as bulk based on mass. For implementation, we created a free mobile application for android phones (EVO—eucalyptus value chain optimization) to utilize the study results at the grass root-level.
Forfattere
Heikki KorpunenSammendrag
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Sammendrag
Background: Small-scale forests (woodlots) increasingly account for a greater proportion of the total annual harvest in New Zealand. There is limited information on the extent of infrastructure required to harvest a woodlot; road density (trafficable with log trucks), landing size, or the average harvest area that each landing typically services. Methods: This study quantified woodlot infrastructure averages and evaluated influencing factors. Using publicly available aerial imagery, roads and landings were mapped for a sample of 96 woodlots distributed across the country. Factors such as total harvest area, average terrain slope, length/width ratio, boundary complexity and extraction method were recorded and investigated for correlations. Results: The average road density was 25 m/ha, landing size was 3000 m2 and each landing was serviced on average 12.8 ha. Notably, 15 of the 96 woodlots had no internal infrastructure, with the harvest completed using roads and landings located outside of the woodlot boundary. Factors influencing road density were woodlot length/width ratio, average terrain slope and boundary complexity. Landing size was influenced by average terrain slope, woodlot length/width ratio, and woodlot area. Conclusion: The results provide a contemporary benchmark of the current infrastructure requirements when harvesting a small-scale forests in New Zealand. These may be used at a high level to infer the total annual infrastructure investment in New Zealand's woodlot estate and also project infrastructure requirements over the foreseeable future. Keywords: forest infrastucture, small-scale forestry
Sammendrag
Large clear-cut areas as a consequence of drought and bark beetle infestations necessitate extensive replanting efforts in German forests, leading to an increased interest in efficient planting systems. In addition to manual planting, mechanized and semi-mechanized systems utilizing surplus forest machine capacities available after completion of salvage logging operations are likely required for timely reforestation of the clear-cut areas. A semi-mechanized system utilizing a standard forwarder with a grapple-actuated soil borer for both, the transport of planting material and the preparation of planting pits, combined with two workers carrying out manual planting, was investigated in a time-and-motion study. The frequency method was used after video recording of a planting operation that covered an area of approximately 1.2 hectares. A total of 815 alder saplings (Alnus glutinosa L.) with heights of 1.2–1.5 m were planted. Observed productivity was 93 saplings per system work hour (SWH). With additional placement of stakes for stabilizing the plants, the productivity decreased to 42 saplings per SWH. While directly comparable results were not found in the literature, available productivity figures of purely manual planting systems do not suggest an increased productivity of this semi-mechanized system. Considering ergonomics, however, forwarder utilization provides reduced workload not only in plant hole preparation but also with material transport and clearing of planting spots. Both the ergonomic aspects of the system and, in particular, the suitability of the soil borer for different soil textures should be further investigated.
Sammendrag
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Sammendrag
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