8 2 Yearbook^ of Agriculture 1949 



of short needles, in clusters on pendu- It is adapted both to home and road- 



lous branchlets, is green or glaucous- side planting if space is ample, 

 green in color. This cedar is relatively 



fast growing and long-lived. De- W. W. WAGENER, a forest pathol- 



servedly it is the most popular conifer ogist in the Bureau of Plant Industry, 



for planting in the region, for it is al- Soils, and Agricultural Engineering, 



most free of insects and diseases and is in charge of the field headquarters 



most 



successful in coastal and interior dis- 

 tricts. It requires added summer mois- 

 ture in the drier parts of the interior. 



of the Division of Forest Pathology in 

 San Francisco. Dr. Wagener is a grad- 

 uate of Yale University. 



SHADE TREES FOR THE NORTH PACIFIC AREA 



T. W. CHILDS 



The northern part western Wash- 

 ington and Oregon of the Pacific 

 coast region resembles the southern 

 part in several respects, but three dif- 

 ferences greatly influence the kinds of 

 shade trees that can be used in the two 

 areas. In western Washington and Ore- 

 gon, precipitation is greater and more 

 frequent than farther south, average 

 temperatures are lower, and the sum- 

 mer dry season is much shorter. The 

 Pacific coast itself, a long, narrow strip 

 to the west of the barrier ranges, is 

 divided naturally into the northern and 

 southern (that is, California) subdivi- 

 sions by the main summit of the Siski- 

 you Mountains. 



The unusually favorable climate in 

 western Washington and Oregon per- 

 mits the use of a wide range of tree 

 species, both native and introduced. 



East of the Cascade Range, environ- 

 mental conditions are ordinarily much 

 less favorable, and the species listed 

 are not generally suitable for that area. 



COMMON HAGKBERRY develops here 

 into a round-topped tree with a ma- 

 ture height of 40 to 60 feet. Its growth 

 is moderately rapid and it is moderate- 

 ly long-lived. Its shade is of medium 

 density; leaves appear in late April or 

 early May. It resists drought, cold, and 

 wind ; twig brooming ( witches' -broom ) 

 is not serious. Although inferior to 

 American elm in some respects, com- 

 mon hackberry should be a good yard 



and street tree in many localities east 

 of the Cascade Range. Its smaller size 

 and relative resistance to pests make it 

 a desirable substitute for elm along nar- 

 row streets and in places where the elm 

 leaf beetle is destructive. 



THE AMERICAN YELLOWWOOD is a 

 widespreading tree, 50 to 60 feet high 

 when mature. Growth is moderately 

 rapid and it is moderately long-lived. 

 Its small white flowers in long clus- 

 ters appear in early June. The leaves 

 turn bright yellow in late fall. It is 

 resistant to cold. It is fairly resistant to 

 drought, and relatively free from insect 

 and fungus pests. American yellow- 

 wood has not been planted extensively, 

 but it deserves to become more popu- 

 lar as a street tree and as a yard tree. 

 It is well adapted to the territory west 

 of the Cascade Range and should also 

 do well in the Columbia River Valley 

 and on the Snake River Plain if it is 

 watered occasionally. 



SWEETGUM., a rounded, pyramidal 

 tree, has a mature height of 80 to 120 

 feet. It is moderately rapid in growth, 

 long-lived, fairly resistant to cold and 

 relatively free from pests, but it is sus- 

 ceptible to injury by drought and by 

 wind. Its star-shaped leaves, about 6 

 inches across, turn crimson or wine 

 purple in the fall. The bark is deeply 

 furrowed. It casts a moderately dense 

 shade and makes rather heavy de- 



