SEASONAL CHANGES IN CRUDE PROTEIN AND LIGNIN OF TEN COMMON FORAGE SPECIES OF MOOSE IN NORTH-CENTRAL BRITISH COLUMBIA

Monthly levels of crude protein and lignin were determined for current annual growth of nine woody plants and whole plant samples of one lichen, from May 1972 to April 1973. Crude protein averaged 6.7% for the nine woody species over the year. All these species had a similar annual pattern for protein: levels jumped sharply to peaks of about 14-16% in May and June, declined gradually until October, and remained unchanged at 4-6% until the following spring. Generally, protein levels in leaves were 1.5 to 3 times those in current twigs. Crude protein content in the lichen, Lobaria pulmonaria, remained relatively constant through the year at about 12%. Lignin averaged 9.8% in five of the woody species over the year. Annual means varied between species, with Sorbus spp. having the lowest, and Salix spp. and Betula papyrifera, the highest lignin contents. The annual pattern of lignin showed a decline to a mid-summer minimum and then increase until October, after which levels remained steady