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root system makes the tree less dependent on the few roots growing down 

 deep into the soil. 



It may be obser\'ed, especially in the province of Brandenburg, that the 

 healthy condition of pines ceases if the sand flats most suitable for this 

 growth have depressions in the ground where the accumulated water forms 

 marshy pools. Up to the edge of these marshy places the trees stand erect 

 and are comparatively long needled. At the point where the black moor 

 begins, the growth becomes weakened, the needles shorter and the tree 

 shows very small annual rings which not infrequently cease entirely. 



In the increased planting of the very profitable pine trees, carrying 

 them even on to damp soils, it is not surprising that root decay is found 

 there to a very marked extent. It is advisable to limit the culture of pines 

 to sandy, open positions and to choose for heavy, wet soils, such species of 

 trees as are found by experience to best endure moisture. In places where 

 no definite agricultural system regulates the tracts, the suitable kinds of 

 trees make a natural appearance in the course of years, because of their 

 greater power of resistance in the struggle for existence. It is approximately 

 the same as the gradual control of the position in frost holes by the kinds of 

 trees which resist frost (hornbean, birch, aspen). The red alder can best 

 endure the strain of stagnant water. Besides this, black and silver poplars, 

 as well as most willows and the sweet birch, thrive on moist soils. The ash 

 is often found also, but under these conditions the trunks are entirely 

 covered with moss and canker-like swollen spots. 



In order to overcome the injury due to turning land into swamps, its 

 cause must be determined exactly. At times the condition is due only to a 

 lack of air circulation, and here the partial clearing of the land of its tree 

 vegetation by the removal of the undergrowth and the lower branches of the 

 trees, together with proper thinning, would be beneficial. Even when the 

 land only becomes shghtly swampy, especially in mountains, it may be re- 

 stored by planting with conifers (Spruces). This holds good for the cases 

 when increased evaporation of the upper surface is sufficient to overcome the 

 accumulations of water in the soil. As the trees grow, and because of their 

 close proximity, their evaporating surface not only increases but also less 

 and less water can fall to the soil, because of the thick shelter of leaves. 



The very radical means of removing the water by drainage or ditches 

 should be used in forest tracts only after careful consideration of all local 

 conditions since this method is often attended by greater disadvantages than 

 advantages. This is especially true in mountain forests where the lowering 

 of the water level of one district may easily have wide spread effects on the 

 surrounding region. In some cases, areas, especially slopes, with a strong 

 tree grow^th, where there is no excess of water, become drier. Trees accus- 

 tomed to the former amount of moisture deteriorate and may partially die. 

 On plains such sharp changes due to drainage are less to be feared. 



It would not be necessary to further discuss the formation of marshes 

 if, aside from the exhalation of gases, injuries to cultivated land did not 



