NORTHEASTERN FOREST EXPERIMENT STATION 

Upper Darby, Pennsylvania 

No. 62 

Injury To White Pine Crowns 

In Northern Mew England In 1955 

Unusual development of white pine terminal shoot s--due 

to some sort of damage--was observed during the summer of 

1955 throughout northern New England. In at least one instance it was also observed in pitch pine, and it may have 

occurred in other species. 

The damage took many forms but several features have 

been widely observed. Only the 1955 growth was injured. Most 

noticeable was the failure of the terminal-bud cluster to develop in the spring of 1955. Abnormal size of needles and 

abnormal number of needles per fascicle was common. Many 

leaders that did develop were distorted. Injury was usually 

followed by the extension of spur shoots in the area where 

injury occurred. 

Some or all of these symptoms have occurred together 

in varying combinations, but there seem to be two general 

forms that occur repeatedly. The first, and most common, was 

failure of the terminal-bud cluster to develop. Usually the 

terminal bud and all but one or two of the lateral buds were 

affected. In some, growth was arrested during the swelling 

stage; others elongated perhaps 0.1 to 0.2 inch before they 

died. The injured buds were persistent unless accidentally 

knocked off; but they were dried out, became dark brown in 

color, and had a pitch mass at the tip. 

Recovery took place through the uninjured lateral buds. 

The shoots from these buds were occompained by few to many 

shorter shoots that arose from needle fascicles scattered 

without order around the node. The shoots from buds generally grew to 9 or 10 inches in length, but those from needle 

fascicles were only 1 to 5 inches long. 

The second type of injury appears to have occurred 

later in the growing season. The terminal shoots--whether 

normal or the outgrowth of previous in jury--apparently had 

their growing points killed. A cluster of new shoots arose 
around the growing point. Because of their irregular arrangement and the lack of a terminal bud, all of these new shoots 

appeared to originate from needle fascicles. They were seldom 

more than 5 inches long. Frequently the original shoot displayed slight to moderate crook in one or more planes. Typical frost ring was also found in these shoots, but was not 

foundinthefirsttypeofinjury. Onlyafewof eachtype 

were examined for frost ring. 

A symptom usually associated with both types of injury 

was abnormalnumberandsizeof needles. From2toasmany 

as 11 needles have been observed (2) in a single fascicle. 

They were larger and more vigorous than normal needles, and 

they seemed to occur close to the area of injury and on the 

shoots arising from dormant buds. However, the needles on the 

spur shoot extensions were usually short and appeared to lack 

vigor. 

The injury has been observed most commonly on trees 3 

to 8 feet high where it is easy to see, and the damage to the 

terminal shoot has attracted the greatest attention. However, 

it is also evident on trees up to 30 feet high. It may usually be found on upper lateral branches and sometimes on lower branches as well. 

Possible causes. --So far, no completely sntisfactory 

explanation has been advanced (3). Winter feeding by grosbeaks (2) and squirrels has been suggested as a cause. Their 

feeding was observed to have been hezvier than usual, but was 

not considered extensive enough to cause as milch damage as 

has been observed. 

Walker ('7) suggests pine spittlebug as a cause. He 

found the insects on the terminal buds but was not sure they 

were in feeding position. He found no evidence of bud borers 

but thought some tissue feeder was probably involved because 

the pitch mass sgpplanted tissue in the bud tips. Our observations do not support this theory. Most of the affected 

buds that we have examined appeared externally to be intact. 

P . B. Dwoden reports o or the astern Forest Experiment 

Station office report) that damaged twigs from southwestern 

Maine had been infested with Eucosma gloriola, a moth whose 

larva bores into white pine shoots, causing 6 or 8 inches of 

the twig to die. However, he did not think that this insect 

was responsible for the damage under discussion, nor did he 

find evidence that any other insects were involved. 

Thomson (2) has discussed the development of shoots 

from spur shoots or needle fascicles and the abnormal development of needles after injury. He regards the condition as 

a traumatic reversion to a more primitive organization of the 

pine. Another variation of the same response is the development of asparagus-like shoots such as those occasionally observed in the present case (a. These abnormalities are not 
symptomatic of any particular cause of injury. 

In at least two instances, similar damage in earlier 

years has been attributed to frost; 

Stone (4) reported an unusual crooking of white, red, 

jack, Scotch, and ponderosa pine leaders in New York in 1951. 

The crook was often in more than one plane and was similar 

to, but generally more severe than, that found in 1955 in 

white pine. In most cases the leaders maintained apical dominance but if the tip or the entire leader was killed, new 

shoots developed at the lowest point of death. Frost ring 

wss also found in the injured leaders. Stone thought a midJune frost caused the injury. 

Several variations of damage like that of the first 

type described above were discussed by Kienholz (1, who 

found them in the 1930 growth of red pine in New Hampshire. 

He noted that short shoots, abnormal needles, development of 

lateral buds that had been dormant at the time of injury, and 

frost ring in the stem were common. Two frosts occurred in 

the spring of 1910, which he cited as the causes of injury. 

Spring weather.--An examination was made of the 1955 

spring weather records ( of 54 stations in the area of 

northern New England where white pine commonly occurs. There 

were no great weather differences among most of these stations. The average temperature for the month of April was 2 I to 3O F. higher than normal for the month, but the first half 

of the month was unusually warm, even though minimum temperatures of 32' or lower were regularly reported for most stations until April 12. For example, the records at East Deering, Massabesic Lake, and Durham, N. H., show an average of 

24 days when the maximum temperature was 50' F. or more. 

Fourteen of them occurred from April 1 to 16. At these statigns there were 12 to 16 days with maximum temperatures of 

60 or more, and two-thirds of them occurred from April 1 to 

16. 

From ~pril 12 until April 17, few stations reported 

freezing or near-freezing temperatures. From April 17 to 

April 21, 51 of the stations reported a minimum temperature 

of 3p or lower at least 1 day and usually 2 or 3 days. Nearfreezing minimums were recorded throughout the period, but 

the daily maximums remained relatively high. 

The next record of freezing temperatures was on April 

30 and May 1. It occurred at 27 stations, most of which were 

located in New Hampshire and Maine. The last frost was the 

period May 17 to 20, when 35 stations (most of them in New 

Hampshire and ~ermont) had freezing minimum temperatures for 

at least 1 day. 

Relation of frost to white pine growth period.--The 

average date for height growth of white pine to begin is between May 1 and May 15 throughout the white pine region, al- 
though it may vary from this about 2 weeks from year to year 

or from northern to southern sections. In 1955 B. Husch (u~Tversity of New Hampshire, Department of ~orestry) observed 

April 21 as the starting date in Fremont, N. H. The abovenormal temperatures during the first half of April may have 

brought on this early growth. 

At any rate, since growth mas early, the buds were 

active and probably were particularly sensitive to frost injusy during the general but normal frost period April 13 to 

21. This coincidence of starting growth and frost suggests 

that the death of buds in the first type of injury described 

above could have occurred during this period. In some localities the April 30 to May 1 frost also may have killed buds. 

The last frost of May 17-20 occurred after terminal 

growth was well started at Fremont and may have been responsible for damage of the second type where buds were not affected. 

Literature Cited 

(1) Kienholz, Raymond. 

1933. Frost damage to red pine. Jour. Forestry 31: 

392-393, illus. 

(2) Maine Forest Service. 

1955. Abnormal shoot development of white pine. Maine 

Forest Sew. Forest Insect Motes No. 2:6. 

1955. Abnormal shoot development of white pine. Maine 

Forest Serv. Forest Insect Notes No. 3: 6. 

(4) Stone, E. L., Jr. 

1952. An unusual type of frost injury in pine. Jour. 

Forestry 50: 560, illus. 

(5) Thornson, Robert Boyd. 

1914. The spur shoot of the pines. Bot. Gaz. 57: 

362-385, illus. 

(6) U. S. Weather Bureau. 

1955. Climatological data, New England 67 (4-6). 

(7) Walker, E. B. 

1955. Terminal bud dormancy or sterility in white 

pine. Vermont Forest Serv. Bugbites 3 (1). 

--R. W. WILSON, JR. 

Northeastern Forest Experiment Station 

Forest Service, U.S. Dept. Agriculture 

Laconia, N. H. 

AGRICULTURE-FOREST SERVICE-UPPER DARBY