The degree of decomposition (humification) of l0 peats, ranging from undecomposed to completely decomposed, was determined by the following methods: (l) von Post's method using 10 classes of humification, (2) pyrophosphate-soluble organic matter determination using an index derived from Munsell color charts, (3) unrubbed fiber content in percent of total, (4) rubbed fiber content in percent of total. All four methods provided reliable and useful information. The von Post

In northern Ontario, layering of black spruce occurs within the range of the species. It is a characteristic feature of black spruce and takes place whenever parent trees are present with green branches sustained at their bases, provided there is a moist rooting medium capable of imbedding them. Because of specific requirements, layering is more abundant on wet sites than on well drained ones.All trees identified as layerings originated from branch layering. The transverse sections of all layering connections examined showed the anatomy typical of a branch. No trees originating from root suckers or by rooting were found.It is reasonable to assume that once layerings have become established and are physiologically independent, their further development will be similar to that of seedlings. Both are subjected to the prevailing growing conditions, can participate in stand establishment, and may develop into merchantable trees.

No abstract

Peatland types were compared to reveal differences in growth of dominant and codominant trees from undrained and artificially drained sites. The comparisons, based on tree height attained at the age of 100 years, indicate that growth improves by about 6 m in bog types and by about 4 m in fen–marsh types. To allow identification of similar sites in different localities and prediction of growth potential of sites not directly under study, 15 peatland types were assigned to five trophic groups on the basis of macronutrient content of the peat, using an automatic clustering method. The nutrient elements considered are known to influence growth on peatlands. The paper gives an account of site conditions. sampling technique, methods of comparison, and clustering. Detailed results are presented and explained.

Blaclc sp)>uces of layer o r seed o?.igin develop i n t o me?*chantable t?*ees w i t h similar g?'ozuth in height, diantete?. and volume. Layerings tend t o h a v e a poorer s t e m f o r m t h a n seedlings