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There are many factors that determine what forestry activities forest owners carry out in their forest properties and that influence whether forest owners engage in entrepreneurial activity. This paper explores whether the values and objectives of forest owners influence their forestry behaviour and their engagement in entrepreneurial activity. This is done through a review of the literature on private forest owners' typologies based on owners' objectives. The review reveals that typologies typically divide forest owners into two main groups. The primary objective of the first group of owners is production (of wood and non-wood goods and services) usually, although not exclusively, so as to generate economic activity. The primary objective of the second group is consumption (of wood and non-wood goods and services). There is a tacit assumption in the studies reviewed that goals Á . Ní Dhubháin (and objectives do influence forestry behaviour but few studies have actually assessed whether this is the case. The general finding is that forest owners whose objectives are timber production and who are business-oriented are more likely to manage and harvest their stands. No research focusing on the link between owners' objective and wider entrepreneurial activity in forests was found.

Afforestation has become an important tool for soil protection and land reclamation in Iceland. Nevertheless, the harsh climate and degraded soils are growth-limiting for trees, and little is know about changes in soil nutrients in maturing forests planted on the volcanic soils. In the present chronosequence study, changes in C, N and total P in soil (0-10 and 10-20 cm depth) and C and N in foliar tissue were investigated in stands of native Downy birch (Betula pubescens Enrh.) and the in Iceland introduced Siberian larch (Larix sibirica Ledeb.). The forest stands were between 14 and 97 years old and were established on heath land that had been treeless for centuries. Soils were Andosols derived from basaltic material and rhyolitic volcanic ash. A significant effect of tree species was only found for the N content in foliar tissue. Foliar N concentrations were significantly higher and foliar C/N ratios significantly lower in larch needles than in birch leaves. There was no effect of stand age. Changes in soil C and the soil nutrient status with time after afforestation were little significant. Soil C concentrations in 0-10 cm depth in forest stands older than 30 years were significantly higher than in heath land and forest stands younger than 30 years. This was attributed to a slow accumulation of organic matter. Soil N concentrations and soil P tot were not affected by stand age. Nutrient pools in the two soil layers were calculated for an average weight of soil material (400 Mg soil ha À1 in 0-10 cm depth and 600 Mg soil ha À1 in 10-20 cm depth, respectively). Soil nutrient pools did not change significantly with time. Soil C pools were in average 23.6 Mg ha À1 in the upper soil layer and 16.9 Mg ha À1 in the lower soil layer. The highest annual increase in soil C under forest compared to heath land was 0.23 Mg C ha À1 year À1 in 0-10 cm depth calculated for the 53-year-old larch stand. Soil N pools were in average 1.0 Mg N ha À1 in both soil layers and did not decrease with time despite a low N deposition and the uptake and accumulation of N in biomass of the growing trees. Soil P tot pools were in average 220 and 320 kg P ha À1 in the upper and lower soil layer, respectively. It was assumed that mycorrhizal fungi present in the stands had an influence on the availability of N and P to the trees.

Apart from its function as co-receptor for fibroblast growth factor-23 (FGF23), Klotho is thought to regulate insulin signaling, intracellular oxidative stress, and parathyroid hormone (PTH) secretion in an FGF23 independent fashion. Here, we crossed Klotho deficient (Kl−/−) mice with vitamin D receptor (VDR) mutant mice to examine further vitamin D independent functions of Klotho. All mice were fed a rescue diet enriched with calcium, phosphorus, and lactose to prevent hyperparathyroidism in VDR mutants, and were killed at 4 weeks of age after double fluorochrome labeling. Kl−/− mice displayed hypercalcemia, hyperphosphatemia, dwarfism, organ atrophy, azotemia, pulmonary emphysema, and osteomalacia. In addition, glucose and insulin tolerance tests revealed hypoglycemia and profoundly increased peripheral insulin sensitivity in Kl−/− mice. Compound mutants were normocalcemic and normophosphatemic, did not show premature aging or organ atrophy, and were phenocopies of VDR mutant mice in terms of body weight, bone mineral density, bone metabolism, serum calcium, serum phosphate, serum PTH, gene expression in parathyroid glands, as well as urinary calcium and phosphate excretion. Furthermore, ablation of vitamin D signaling in double mutants completely normalized glucose and insulin tolerance, indicating that Klotho has no vitamin D independent effects on insulin signaling. Histomorphometry of pancreas islets showed similar beta cell volume per body weight in all groups of animals. In conclusion, our findings cast doubt on a physiologically relevant vitamin D and Fgf23 independent function of Klotho in the regulation of glucose metabolism, bone turnover, and steady-state PTH secretion in vivo.