CHAPTER VII: HOW TREES ARE MEASURED 



I WAS walking one day with a forester trained in the Black 

 Forest. A beautiful shagbark of unusual height attracted my 

 attention. I asked how tall he thought it was. Imagine my 

 surprise when he shut up like a jack-knife his hips the hinge, 

 his head between his knees, his back to the tree. Not satisfied 

 with the first inverted glimpse he thus obtained, he moved a step 

 or two nearer to the tree and looked again. Then he straightened 

 up, smiled at my bewilderment, paced the distance to the foot 

 of the tree, and said that it was about ninety feet high. 



MEASURING HEIGHT 



This method of estimating the heights of trees is common 

 among German foresters. At a distance just equal to the tree's 

 height, the observer, with his head between his knees, sees the 

 top of the tree and no higher. To get this location is very easy; 

 then there is left nothing to do but to pace off the distance. 



The tree's shadow on bright days may be measured, then 

 the shadow of any short object standing erect a man, a fence post 

 or a sapling. As the man's shadow is to his height, so is the tree's 

 shadow to its height. Suppose a six-foot man casts a ten-foot 

 shadow, and the tree's shadow is seventy feet. The proportion 

 reads : 



6 X "70 



io:6::7o:x; then ^ =x. The tree is forty-two feet high. 



lO y o 



A third simple method is interesting. Set a perpendicular 

 pole about five feet high in the ground at a distance about equal 

 to the tree's height from the base of it. Between this short 

 pole and the tree, in line with both, set a taller pole, near enough 

 so that, sighting from the top of the short pole to the top of the 

 tree, the line of vision crosses the tall pole. Have this point 

 marked. Now sight the base of the tree, and mark the place 

 where the line of vision crosses the taller pole. Measure now the 



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