OUR FORESTS 7 



paratively heav} 7 for fliers and consequently do not get very far 

 from the parent tree. Heavier seeds, such as the nuts and acorns, 

 may be carried away from the parent tree by birds and small animals 

 which feed upon them. 



Most trees provide great quantities of seed, but when the seeds 

 have fallen from the tree their fate becomes a matter of chance, and 

 out of thousands perhaps only one will take root where it can grow 

 to be a tree and in its turn bear seed (fig. 3). 



RELATIONSHIP OF TREES 



Forest trees are in many ways dependent upon their neighbors. 

 They increase the fertility of the soil in which they grow ; and their 

 combined shade keeps the soil about their roots cooler in summer 



r 



L 



Figure 4. — Young and Old Members of Tree Families. 



Young trees are growing up under the protection of their parents. 



than it would be if each tree stood alone. Their interlacing crowns 

 form a canopy under which the seedlings of all members of the 

 forest community are sheltered in early youth (fig. 4). 



At the same time there goes on in the forest a vigorous struggle 

 for the prime necessities of tree life — water, sunlight, and space in 

 which to grow. Battling to get ahead of each other, the large trees 

 push up towards the light, without which their leaves cannot digest 

 the food necessary for growth. Their crowns may fill the space 

 overhead. Their lower branches, thus shut away from the sun- 

 light, die and drop off, and in this way is developed the typical 

 forest tree with long clean trunk, or great upward-stretching 

 branches, and narrow crown high above the ground. Such trees 

 make the best lumber. Trees grown in the open develop wide- 

 spreading branches, and their lower limbs branch out from the 

 trunk nearer to the ground. 



178430°— 33 2 



