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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2021

Abstract

This study investigated the potential of in-season airborne hyperspectral imaging for the calibration of robust forage yield and quality estimation models. An unmanned aerial vehicle (UAV) and a hyperspectral imager were used to capture canopy reflections of a grass-legume mixture in the range of 450 nm to 800 nm. Measurements were performed over two years at two locations in Southeast and Central Norway. All images were subject to radiometric and geometric corrections before being processed to ortho-images, carrying canopy reflectance information. The data (n = 707) was split in two, using half the data for model calibration and the remaining half for validation. Several powered partial least squares regression (PPLSR) models were fitted to the reflectance data to estimate fresh (FM) and dry matter (DM) yields, as well as crude protein (CP), dry matter digestibility (DMD), neutral detergent fibre (NDF), and indigestible neutral detergent fibre (iNDF) content. Prediction performance of these models was compared with the prediction performance of simple linear regression (SLR) models, which were based on selected vegetation indices and plant height. The highest prediction accuracies for general models, based on the pooled data, were achieved by means of PPLSR, with relative root-mean-square errors of validation of 14.2% (2550 kg FM ha−1), 15.2% (555 kg DM ha−1), 11.7% (1.32 g CP 100 g−1 DM), 2.4% (1.71 g DMD 100 g−1 DM), 4.8% (2.72 g NDF 100 g−1 DM), and 12.8% (1.32 g iNDF 100 g−1 DM) for the prediction of FM, DM, CP, DMD, NDF, and iNDF content, respectively. None of the tested SLR models achieved acceptable prediction accuracies.

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Abstract

Since the beginning of the twentieth century, forest regeneration management and policy in the Nordic–Baltic region (Denmark, Sweden, Norway, Finland, Estonia, Latvia and Lithuania) have gone through significant changes. For decades forest as a key natural resource was managed with main focus on timber production. However, several factors influenced shifting forest management, including forest regeneration to meet a wide range of society needs. This review study aims to reveal the historical development of forest regeneration identifying knowledge gaps and supporting decisions that promote sustainable regeneration of future forests. The development of forest regeneration management and policy in the Nordic–Baltic countries is analyzed through reforestation and afforestation practices as well as legislation aspects using a narrative review approach. Trends in forest regeneration practices within the region are identified and explored over a timeframe spanning from 1900 until today. Despite diverse forestry management structures and differing political, social situations, the study shows that forest regeneration development has followed similar patterns over time in all Nordic–Baltic region countries: extensive forestry, clear-cut forestry, retention forestry and currently evolving climate-adaptive forestry. Nevertheless, regional differences among the Nordic–Baltic countries, especially in forest regeneration-related legislation, were identified due to a mixture of international and local driving forces.