Analysis of seven spodosols from southeast Alaska formed on contrasting parent materials show that the soils have similar chemical properties in upper horizons in spite of some wide differences in parent materials. With soils formed on basalt and limestone, influences of parent materials on chemical properties are evident only in the lowest horizons. Considerable accumulation of organic matter is found in these soils in surface layers and within the mineral profile. Also, nitrogen and mineral element contents of the surface organic layers are relatively high. Upper layers of the soil remain moist throughout the season and rooting is largely limited to the surface organic layers and the top few inches of mineral soil. The shallow rooting with the high rainfall of the area apparently limits the influence of lower horizons and parent materials on chemical properties of the upper soil.

Concentrations of P, K. Ca. Mg, Mn, and Zn in black spruce foliage were examined in relation to forest succession on north slopes in interior Alaska. decline in levels of P and K in the foliage appear to be deficient on sphagnum soils. Mg levels show a slight decrease, but do not fall below deficiency status even on deeper sphagnum soils. Ca, Mn, and Zn show no relationship to forest succession and are at adequate levels on all stages. Concentrations of available phosphorus and exchangeable cations in the soils show no differences between soils corresponding to those found in nutrient levels in the foliage. However, total quantities of P, K. and Mg in available and exchangeable forms are consistently lower in sphagnum soils. Also, the depth distribution of these nutrients on a volume basis differs among soils: in sphagnums they are located at deeper depths, while on mineral soils they are concentreted in surface layers. this distribution difference and the incrasing coldness of the soil as moss accumulates appear to be sufficient to reduce the availability of these nutrients. Radiocarbon dates showed that 18—28 inches (41—71 cm) of sphagnum peat, weighing 270,000—510,000 kg/ha, had accumulated in less than 185 years. The average annuual increase of 1,500—2,800 kg/ha indicates that, in spite of low growth of trees on sphagnum soils, total productivity in dry weight is appreciable.

Forest succession on north slopes in interior Alaska results in the development of sphagnum bogs on sites formerly occupied by productive forest. This process is one of gradual deterioration of site associated with the accumulation of moss layers on the forest floor. Advancing succession is accompanied by an increasing nitrogen deficiency in black spruce trees. Black spruce growing on the sphagnum bogs are extremely nitrogen deficient. As the moss layers thicken, the soils become increasingly cold with permafrost rising to within as little as 15 inches of the surface of the sphagnum soils. Examination of the depth distribution of nitrogen revealed very small quantities of nitrogen in the upper and warmer portions of these profiles, with the bulk of the nitrogen located in the very cold and latest to thaw, lower layers. In contrast, in the soils under birch of the nitrogen was located in the warmest upper layers. Under these conditions, much higher rates of mineralization of soil nitrogen must be obtained. The results show why burning, although changing many factors including volatilization of an undetermined amount of nitrogen, may lead to a large increase in available nitrogen because of the change in depth distribution of the nitrogen in the soil.

AbstractAnalyses were made of composite samples of needles, live branches, dead branches, bark and wood of 70 Douglas‐fir trees taken from five areas and ranging in age from 30 to 50 years. The fertilized trees were from plots that had been fertilized at rates of 200, 300, 500 and 660 pounds of elemental nitrogen per acre.The data show increased concentration of nitrogen and decreased concentration of phosphorus and potassium in the foliage, as a result of nitrogen fertilization. The nitrogen concentration of other components was also increased, but the concentration of phosphorus and potassium in these tissues did not demonstrate dilution effects that were observed in the needles. The nitrogen:phosphorus ratio in the foliage showed promise for use in diagnosis of nitrogen deficiency of Douglas‐fir by foliar analysis.The data on total weight of nutrients in the trees on an area basis show that almost twice as much nitrogen, greater quantities of potassium and approximately equal amounts of phosphorus were contained in the vegetation on certain fertilized plots as were contained in the unfertilized vegetation. Needles showed the greatest increase in nitrogen, with branches and bark showing lesser increases, and wood no increase.