74 



Structure and Growth of.. Wood. 



surveyor, the growth from the side will gradually close over the in- 

 jury, and fill iu the inequalities, so that, when afterwards split off, 

 it will often show in relief any depressions or cuts on the original 

 i- trunk. Many Forest Academies 



in Europe have in their museums 

 specimens of timber-marks thus 

 cut or stamped into w r ood, with the 

 cast taken by nature from the 

 mold. The land-marks of surveyors 

 have thus been found more than a 

 hundred years afterwards. Some 

 scar, or, in coniferous trees, per- 

 haps a gum-spot, would be noticed 

 upon the outside, and by cutting 

 down through as many rings of 

 growth as there had been years 

 since the former survey, the marks 

 of the ax would be found. 



Growth of the Trunk and Branches. 



262. The successive layers of 

 wood in the trunk and branches 

 extend over their whole surface, 

 more or less uniformly, as is shown 

 in the accompanying sketch. The 

 inequalities in thickness, often seen, 

 are caused by differences of nutri- 

 tion from particular roots and 

 branches. They will fill up the 

 slight irregularities of early years, 

 so that a sapling may be somewhat 

 crooked, and yet form a tree that 

 is perfectly straight and symmetri- 

 es. Section showing the Growth of the ca l- 



263. The actual size and form of 



the tree, at every stage of its former life (excepting as modified by 

 the loss of branches), is preserved within, and might be shown by 



1 From Ross m ass ler's work " Dcr WaldS 



