macdougal: tree root systems 
67 
complete destruction of elm wood is difficult to ensure. Although city 
and town authorities have endeavored to prevent the storing of elm wood, 
the task was too great and it is believed that many wood piles will pro¬ 
vide beetle breeding material in abundance. In addition, there are 
many woodland areas in which wind-felled elms will be left on the 
ground. Every possible effort will be made to clean up such material 
before spring, but it seems highly probable that the .bark beetle situa¬ 
tion will be the most important factor in the Dutch elm disease work in 
Connecticut for the next year at least. 
However, much has been accomplished during the past five years by 
the Dutch elm disease eradication forces, in spite of many handicaps 
and obstacles. If the Bureau of Entomology and Plant Quarantine 
can be supplied with adequate budgetary funds to provide for proper 
scouting and supervision, the extra hazards created by the hurricane will 
not prove insuperable. It seems to me that the results already secured 
in Connecticut, plus the encouraging results secured in New York State, 
warrant optimism for the future. 
STUDIES OF ROOT SYSTEMS OF TREES 
By D. T. MacDougal, Coastal Laboratory , Carnegie Institution of Washington , 
Carmel , Calif. (Read by W. J. Robbins) 
Systematized information as to stature and disposition of roots of 
trees beyond the seedling and nursery stage is very fragmentary. The 
trunk and crown are under constant observation and much is known as 
to the changes which are important in the physiology of the tree, silvi¬ 
culture, timber production, and ornamental planting. Similar delinea¬ 
tion or measurements of the development and maturity of root-systems 
are extremely scanty and very few generalizations may be founded upon 
them. 
In my own studies of the Monterey pine, measurements of root- 
systems could be made only by excavations at a cost of $15.00 to 
$25.00 per tree of an age over 20 years. A dozen large trees were thus 
dug out and a number which had been uprooted by storms were also 
available. The arrangement of the results made it possible to conclude 
that of the woody material constructed from the leaf-products of this pine 
tree as much as one-fourth or as little as one-seventh of the total amount 
in trunks and branches was used in the construction of the root- 
systems 1 . 
!See MacDougal, Life History of a Pine Tree. Chapter VIII, Tree Growth. 1938. 
Leiden. 
