Private forest owner characteristics affect European spruce bark beetle management under an extreme weather event and host tree densityMaarten De Groot
, Jurij Diaci
, Kaja Kandare
, Nike Krajnc
, Rok Pisek
, Špela Ščap
, Darja Stare
, Nikica Ogris
Povzetek: In the last few decades, an increasing number and intensity of bark beetle outbreaks have plagued the forests of Europe and North America. Bark beetle management is directly related to forest owner characteristics, although this relationship is not well understood. The purpose of the study was to investigate the influence of forest owner characteristics on the amount and timing of sanitary felling under different disturbance regimes and quantities of Norway spruce. We combined different databases on sanitary felling, the timing of sanitary felling, and forest owner characteristics for Slovenia from 2014 to 2018 and analyzed the amount and timing of sanitary felling in relation to forest owner characteristics. We found that the timing in winter and the amount of sanitary felling were positively associated with the distance of the owner%s residence to the forest parcel. Larger parcels were more affected by bark beetles but did not have later timing of cutting in the summer period as was hypothesized. The timing of sanitary felling decreased with property size, while with the probability of sanitary felling, the effect of property depended on the ice storm and the amount of spruce. The size of the settlement, the permanent address of the private owner, and timing of sanitary felling were positively associated but also depended on the amount of spruce. Gender and age did not have an important influence on the amount and timing of sanitary felling. Forest owners are an important factor in effective bark beetle management. This study highlights the private forest ownership characteristics that should be emphasized in order to fight bark beetle outbreaks in the event of large-scale disturbances. Governments should support forest owners who are at greater risk of bark beetle outbreaks and less efficient in managing outbreaks. Furthermore, landowner characteristics should be included when forecasting bark beetle outbreaks.
Ključne besede: close-to-nature management, sanitary felling, Ips typographus, forest pest management, forest owner characteristics
DiRROS - Objavljeno: 22.03.2021; Ogledov: 685; Prenosov: 434
Celotno besedilo (444,49 KB)
Combining an occurrence model and a quantitative model for the prediction of the sanitary felling of Norway spruce because of bark beetlesMaarten De Groot
, Nikica Ogris
Povzetek: The European spruce bark beetle (Ips typographus L.) is an eruptive forest pest that has caused a great deal of damage in the last decades because of increasing climatic extremes. In order to effectively manage outbreaks of this pest, it is important to predict where they will occur in the future. In this study we developed a predictive model of the sanitary felling of Norway spruce (Picea abies (L.) H. Karst.) because of bark beetles. We used a time series of sanitary felling because of bark beetles from 1996 to 2020 in Slovenia. For the explanatory variables, we used soil, site, climate, geographic, and tree damage data from the previous year. The model showed that sanitary felling is negatively correlated with slope, soil depth, soil cation exchange capacity, and Standard Precipitation Index (less sanitary felling in wet years). On the other hand, soil base saturation percentage, temperature, sanitary felling because of bark beetles from the previous year, sanitary felling because of other abiotic factors from the previous year, and the amount of spruce were positively correlated with the sanitary felling of Norway spruce due to bark beetles. The model had an R2 of 0.38. A prediction was performed for 2021 combining an occurrence model and a quantitative model. The model can be used to predict the amount of sanitary felling of Norway spruce due to bark beetles and to refine the risk map for the next year, which can be used for forest management planning and economic loss predictions.
Ključne besede: sanitary felling, prediction, Ips typographus, Picea abies, Slovenia, forecasting, insect outbreak forest pest
DiRROS - Objavljeno: 21.02.2022; Ogledov: 169; Prenosov: 151
Celotno besedilo (1,24 MB)
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Effects of boom-corridor thinning on harvester productivity and residual stand structureDan Bergström
, Raul Fernandez-Lacruz
, Teresa de la Fuente
, Christian Höök
, Nike Krajnc
, Jukka Malinen
, Yrjö Nuutinen
, Matevž Triplat
, Tomas Nordfjell
Povzetek: Biomass derived from small-diameter, dense, thinning stands is largely underutilized within the European Union, mainly because of in-effective harvesting methods and cutting technology, leading to high supply costs. Therefore, the efficacy of boom-corridor thinning (BCT) and selective thinning (ST) on harvester felling and bunching productivity was compared for the first thinning of whole tree biomass in small-diameter, dense stands. BCT working method is when trees are cut with linear movements of the harvester’s boom reach, along narrow corridors, instead of cutting each tree selectively (ST). Trials were performed in six forest stands, one in Sweden, two in Finland, and three in Slovenia, using the same harvester and operator. A time-and-motion study was carried out in 64 pre-marked study units (32 replications per method), across a variety of stand conditions. The biomass removal for both treatments averaged 40.2 dry t ha -1 and BCT productivity averaged 5.4 dry t PMh -1. For BCT, harvester work time consumption (sec tree -1) and productivity (dry t PMh -1) were on average 27% lower and 16% higher, respectively, compared with ST. The effectiveness of the accumulating felling head technology used could potentially be increased by implementing a feed-roller system when handling excessive tree lengths. Developing dedicated harvesting technology for BCT could further boost productivity, facilitating cost-effective and sustainable utilization of low-value small-diameter tree biomass and replacing fossil resources.
Ključne besede: bioenergy, accumulating felling head, multi-tree handling, silviculture, bioeconomy, forestry
DiRROS - Objavljeno: 20.04.2022; Ogledov: 166; Prenosov: 122
Celotno besedilo (8,29 MB)