Pamphlets on Forestry in Minnesota, Volume 11898 |
Common terms and phrases
alba autumn bark Basswood Birch Black Walnut Box Elder Branch bearing buds catkins climate close grained Cottonwood covered cubic foot cultivation deciduous Distribution.-From durable in contact enlarged evaporation evergreens feet high fire Flowering branch foliage forest Fruiting branch fuel genus Green Ash ground growing growth hardy inches long injury kinds leaf leaves liable light brown Longitudinal section Minnesota moist soil monoecious Mountain Ash northern Norway Pine Norway Spruce occasionally one-half natural one-half natural size ornamental planting ornamental tree ovary Pinus pistillate flower Plate Poplar Populus Populus balsamifera pounds Propagation Propagation.-By seeds Properties of wood.-Light protection pruning ripen roots Salix sapwood Scale of pistillate season seedlings seldom shade shrubs snow Soft Maple sown species Specific gravity spring Spruce staminate Staminate flower surface thick thin transplanted trunk twigs Uses.-The varieties weight White Elm White Pine White Spruce White Willow wind windbreaks winter wood young
Popular passages
Page 75 - The calory is the amount of heat required to raise one kilogram of water one degree Centigrade. The gram-calory is the amount of heat required to raise one gram of water one degree Centigrade.
Page 14 - ... where they are used (as perhaps also on their passage through the tree) with a part of the water, in food preparation. The main part of the mineral substances taken up remains, however, as the water transpires, in the leaves and young twigs, and is returned to the soil when the leaves are shed or when the tree is cut and the brush left to decompose and make humus. Hence the improvement of the fertility of the soil by wood crops is explained, the minerals being returned in more soluble form to...
Page 32 - ... evergreen trees. In this case the deciduous trees transpired about eleven times as much as the evergreens. "The variability of transpiration from day to day is of wide range; a birch standing in the open and found to have 200,000 leaves was calculated to have transpired on hot summer days. 700 to 900 pounds, while on other days its exhalations were probably not more than 18 to 20 pounds. But while trees transpire large amounts of water, our agricultural crops and other low vegetation transpire...
Page 13 - This process of food preparation, called "assimilation," can be carried on only in the green parts, and in these only when exposed to light and air; hence foliage, air, and light at the top are essential prerequisites for tree growth, and hence, other conditions being favorable, the more foliage and the better developed it is, and the more light this foliage has at its disposal for its work, the more vigorously will the tree grow. In general, therefore, pruning, since it reduces the amount of foliage...
Page 22 - This protection when present serves to lessen the fuel necessary to warm dwelling houses and also lessens the food eaten by animals. It also keeps the surface soil in fields from being blown away. In these five principal ways a single tree affects the conditions of climate and soil in its immediate vicinity. To be sure some of them are not so very evident where a single tree grows in an open field, but where trees are growing in groups or on large tracts of land all of these factors are important...
Page 32 - In discussing the elements of dissipation as to the degree of their effect under forest-cover, compared with the same elements at work in the open field, we have seen that the shade, the low temperature, the relative humidity, the absence of violent air-currents, the water capacity of the forest floor, are all acting as factors of conservation. We have seen that the quantity of water lost by evaporation — the...
Page 30 - Fahr. in twenty-four hours (of which 36 degrees in five minutes), while the relative humidity sank from 100 to 21 per cent. The degree of forest influence upon rate of evaporation by breaking the force of winds is dependent upon the extent and density of the forest, and especially on the height of the trees; for according to an elementary law of mechanics the influence which breaks the force of the wind is felt at a considerable elevation above the trees. This can be practically demonstrated by passing...
Page 34 - Floods and drouth alternating clearly indicate that the natural physical conditions of the region have been unduly disturbed. In winter and early spring, when heavy masses of snow have been accumulated on treeless precipitous slopes, snow and landslides frequently occur with disastrous result to life and property. Even thus early in the present season a considerable number of valuable lives have been sacrificed in this manner." THE DISTRIBUTION OF WATER. The distribution or "run-off" of the water...
Page 72 - ... (two or three weeks) before cutting to size. With conifers this is a good practice at any season, and while not practical, yet theoretically all winter-cut trees should be left to leaf out in the spring before being worked. In this way most of the sap is evaporated, but in the care of timber that is to go at once into the water these precautions are not so important. Heat (60 Degrees to 100 Degrees Fahr.), Moisture and Air in moderate quantities produce conditions under which wood quickly decays.
Page 23 - ... which, after the rest had fallen to the cooled earth, remained suspended and is never precipitated. The circulating water capital is that part which is evaporated from water surfaces, from the soil, from vegetation, and which, after having temporarily been held by the atmosphere in quantities locally varying according to the variations in temperature, is returned again to the earth by precipitation in rain, snow, and dew. There it is evaporated again, either immediately or after having percolated...