Most parks that owe their origin to forest fires have charcoal beneath the surface. A little digging commonly reveals charred logs or roots. Occasionally, too, a blackened tree-snag stands suggestively in these treeless gardens. In the competition for this territory, in which grass, spruces, aspens, and kinnikinick compete, grass was successful. Just what conditions may have been favorable to grass cannot be told, though probably one point was the abundance of moisture. Possibly the fire destroyed all near-by seed trees, or trees not destroyed may not have borne seed until the year following the fire. Anyway, grass often seizes and covers fire-cleared areas so thickly and so continuously with sod that tree seeds find no opening, and grass thus holds possession for decades, and, in favorable places, possibly for a century. Trees grow up around these areas and in due time the grassy park is surrounded by a forest. The trees along the edge of this park extend long limbs out into it. These limbs shade and kill the grass beneath. Tree seeds sprout where the grass is killed, and these seedlings in turn produce trees with long limbs reaching into the park. These shade and smother more grass and thus advance the forest another limb's length. Slowly but surely the park is diminished. Struggling trees may sometimes obtain a place in advance of the others or a start in the centre of the park, and thus hasten the death of the park and speed the triumph of the trees. A mere incident may shorten the life of a park. A grizzly bear that I followed one day, paused on a dry point in a park to dig out some mice. In reaching these he discovered a chipmunk burrow. By the time he had secured all these he had torn up several square yards of sod. In this fresh earth the surrounding trees sowed triumphant seeds, from which a cluster of spruces expanded and went out to meet the surrounding advancing forest. Fighting deer sometimes cut the sod and thus allow a few tree seeds to assert themselves. Wind may blow down a tall tree which lands in the edge of the park. Along its full length grows a line of invading forest. Occasionally the earth piled out by a gopher, or by a coyote in digging out a gopher, offers an opportunity that is seized by a tree seed. An ant-hill in a meadow may afford a footing for invading tree seeds. On one occasion a cliff tumbled and a huge rock-fragment bounded far into the sloping meadow. Trees sprang up in each place where the rock tore the sod and also around where it came to rest in the grass. These breaks in the sod made by animals or other agencies do not always give triumph to the trees. Seedlings may eagerly start in these openings, but, being isolated, they are in greater danger, perhaps, than seedlings in the forest. Rabbits may nibble them, woodchucks devour, or insects overrun them. The surrounding grass may smother them and reclaim the temporarily lost opening.