16 BULLETIN 680, IT. S. DEPARTMENT OF AGRICULTURE. 



open on cut-over areas where the forest floor is moist. Burned-over 

 areas, as a rule, are restocked only sparingly at first by this species, 

 because, such light-demanding trees as Douglas fir, pine, larch, fir, 

 etc., come in first. • 



LONGEVITY. 



Western hemlock is a long-lived tree, which grows slowly in height 

 and diameter. Trees 16 or 17 inches in diameter are from 195 to 

 200 years old. Large trees are from 300 to 500 years old, and it is 

 believed that very much older trees will be found. 



MOUNTAIN HEMLOCK; BLACK HEMLOCK. 



Tsuga mertensiana (Bong.) Sargent. 



COMMON NAME AND EARLY HISTORY. 



Tsuga mertensiana is known to few people except botanists and 

 woodsmen who travel in its high mountain habitat. The woods- 

 men and settlers often call it " spruce hemlock," probably because 

 of its remote resemblance to the spruces and likeness to the well- 

 known western hemlock of lower altitudes. "Black hemlock" is a 

 common name often applied to it, probably on account of the notably 

 dark green foliage. "Mountain hemlock" would seem to be a most 

 appropriate name for this species, because it refers to the character- 

 istic habitat of the tree. 23 



Tsuga mertensiana was first discovered in 1827 on Baranoff Island 

 (off the northwest coast of British Columbia) by the German explorer 

 and naturalist, Karl Heinrich Mertens, 24 in honor of whom this species 

 was technically named for the first time "Pinus mertensiana 

 Bongard" in 1832, and on which the present accepted name, Tsuga 

 mertensiana (Bong.) Sargent, is based. It was next found in 1851 

 by John Jeffrey "on the Mount Baker range of mountains" (south of 

 Fraser River) in northern Washington. 25 Mountain hemlock was 

 found for the first time in our Rocky Mountain region by Dr. Sereno 

 Watson, who discovered it in Idaho, in 1880. Mr. H. B. Ayres next 

 reported it in northern Montana, in 1893. 26 The botanical history 

 of mountain hemlock is complicated by a large synonymy including 

 some sixteen different botanical names which various authors have 

 applied to it during the 80 years this tree has been known to 



2 3 The application in 1867 of the technical names "Tsuga pattoniana Senec." (based on "Abies pat- 

 toniana Balf.," published in 1853), and of "Tsuga hookeriana Carr." (based on "Abies hookeriana 

 Murray," published in 1855), gave rise to such book names as "Patton's spruce" and "Hooker's hem- 

 lock, " which are still maintained for this tree by European writers, but which have not gained current 

 use in the native range of the species. 



24 "Voyage autour du Monde execute par ordre de sa Majeste l'Empereur Nicolas I. sur La Carvette Le 

 Semiavine dans les Annees, 1826, 1828 et 1829, par Frederic Lutki," III, 337 (fide Sargent, Silva XII, 80, 

 1898). 



25 "Jeffrey's Report to the Oregon Committee," 1852. 

 28 Fide Sargent, Silva XII, 79, 1898. 



