Effects of field plot configurations on the uncertainties of ALS-assisted forest resource estimates

The effects of field plot configurations on the uncertainties of plot-level forest resource estimates were analyzed using airborne laser scanner data, aerial photographs and field measurements. The aim was to select a field sample plot configuration that can be used for both large area and management inventories. Error estimates were evaluated at the plot level using six different training plot configurations. Additionally, separate plots with two different sizes were used for evaluation. Stem volume and five other forest resource characteristics were considered. The field measurement costs of the different plot configurations were also studied. RMSEs and mean deviations for airborne laser scanning ALS-assisted estimates were practically the same for the fixed radius plot, the two concentric plots and the angle count plot with a basal area factor of q = 1 for all three evaluation plot sizes. Angle count plots with basal area factors of q = 1.5 and 2 increased the RMSEs. For the former plot configurations, the RMSEs for the ALS-assisted estimates could be attributed to inaccuracy in the predicted relationships between the field data and ALS data, not to the training plot configuration. Tree measurements and costs can, therefore, be reduced from those of the Finnish management inventories without increasing RMSEs.     

Glycosylated Hemoglobin Concentration for Assessment of Glycemic Control in Diabetic Cats

Blood glycosylated hemoglobin (GHb) concentration was quantified in 84 healthy cats, 9 cats with stress-induced hyperglycemia, 37 cats with newly diagnosed diabetes mellitus, and 122 diabetic cats treated with insulin or glipizide. Diabetic control was classified as good or poor in insulin-treated or glipizide-treated cats based on review of history, physical examination findings, changes in body weight, and measurement of blood glucose concentrations. Blood GHb concentration was determined using an affinity chromatography assay. Mean blood GHb concentration was similar for healthy normoglycemic cats and cats with transient, stress-induced hyperglycemia, but was significantly (P < .001) higher in untreated diabetic cats when compared with healthy normoglycemic cats. Mean blood GHb concentration was significantly (P < .001) higher in 84 cats with poorly controlled diabetes mellitus when compared with 38 cats in which the disease was well controlled. Mean blood GHb concentration decreased significantly (P < .01) in 6 cats with untreated diabetes mellitus after insulin and dietary treatment. A similar significant (P < .01) decrease in mean blood GHb concentration occurred in 7 cats with poorly controlled diabetes mellitus after diabetic control was improved by an increase in insulin dosage from 1.1 ± 0.9 to 1.4 ± 0.6 U/kg/ 24 h and by feeding a diet containing increased fiber content and in 6 cats with transient diabetes mellitus 8.2 ± 0.6 weeks after discontinuing insulin treatment. There was a significant (P< .01) stress-induced increase in mean fasting blood glucose concentration and mean blood glucose concentration for 12 hours after administration of insulin or glipizide but no change in mean blood GHb concentration in 5 docile diabetic cats 12.2 ± 0.4 weeks after the cats became fractious as a result of frequent hospitalizations and blood samplings. Results of this study suggest that evaluation of blood GHb concentration may be a clinically useful tool for monitoring glycemic control of diabetes in cats.     

Epiphytic lichen diversity in late-successional Pinus sylvestris forests along local and regional forest utilization gradients in eastern boreal Fennoscandia

Pinus sylvestris-dominated forests have been heavily utilized across all of boreal Fennoscandia and the remaining natural forests are generally highly fragmented. However, there are considerable local and regional differences in the intensity and duration of past forest utilization. We studied the impact of human forest use on the diversity of epiphytic and epixylic lichens in late-successional Pinus sylvestris-dominated forests by assessing species richness and composition along both local and regional gradients in forest utilization. The effects of local logging intensity were analysed by comparing three types of stands: (i) near-natural, (ii) selectively logged (in the early 20th century) and (iii) managed stands. The effects of regional differences in duration and intensity of past forest use were analysed by comparing stands in two contrasting regions (Häme and Kuhmo–Viena). The species richness of selectively logged stands was as high as that of near-natural stands and significantly higher in these two stand categories than in managed stands. Species richness increased with the density of small understorey Picea, which correlated strongly with decreasing intensity of local forest use and increasing structural complexity of selectively logged and near-natural stands. Stands in the Häme region hosted a lower number of species, and were less likely to host many old-growth indicator species than the Kuhmo–Viena region, suggesting that species have been lost from stands in the Häme region due to a longer history of intensive forest use. We conclude that selectively logged stands, along with near-natural stands, are valuable lichen habitats particularly for species confined to old-growth structures such as coarse trees and deadwood. In landscapes where natural forests have become fragmented, the management or restoration of the remaining late-successional Pinus-dominated forests, e.g. through the use of fire, should be carefully planned to avoid adverse effects on lichen species richness.     

Seedling emergence in uneven-aged Norway spruce stands in Finland

The emergence of Norway spruce seedlings on different types of germination sites in uneven-aged Norway spruce dominated stands four years after selection harvesting was studied. The data were collected from 20 stands in southern Finland. In each stand, ground cover was measured from a set of 64 one square metre subplots on a permanent experimental plot of 1600?m². Correlation analysis, direct comparison of subplots with and without seedlings and mixed-effects models were used to estimate the influence of ground and tree cover on seedling occurrence. Grass cover, dwarf shrub cover, cover of certain moss species and close vicinity of trees decreased the occurrence probability and number of seedlings, while greater stand and local basal area around the subplots increased the seedling number. The cover of vegetation free surfaces, usually considered as good germination sites, was rather low. Variation in seedling emergence between plots was high. We concluded that spruce regeneration was slightly more abundant in stands with greater overall stand density and local density within a stand in postharvest conditions.