A letter dated August 4, from Mr. Countryman, indicates that a hard frost on the morning of April 24 when the temperature dropped to 22 degrees, did considerable damage to the new growth and catkins on the lower half of the Carpathian walnut trees. He estimates not to exceed one-third of a crop on these Carpathian trees this year; but he says that since the freeze the trees have made good growth, the new terminals being about 18 inches in length and the nuts on them are very large.
To sum up the walnut situation, then, the encouraging thing is that no walnut orchards have been called to my attention that were completely killed. Several badly neglected orchards and two orchards where it is said that the temperature dropped lower than minus 25 degrees F. are so severely damaged that it is impractical to try to save them, but even these are not completely killed.
Injury to Filberts
From the less comprehensive observations made on filberts following the severe winter just past, it appears in general that when the filbert tree has gone into dormancy it is more tolerant of cold than the walnut. The difference of one month in time of occurrence of the cold in the two winters seems to have had more bearing on the damage to filberts than the difference in temperature. In the Forest Grove, Oregon, area, and in Clark County, Washington, filbert trees, however did suffer severely from the cold last winter, but these two areas were the "cold spots" of the Northwest.
It seems as if the same factors that accentuate winter damage in walnuts work in a similar way on filberts, except that the elevation factor does not seem to be of so great importance. Age of tree, level of nutrition, and size of preceeding year's crop seem to be more important than elevation. Young filbert orchards, on either hillside or valley-floor sites, seem to be much less severely hurt than older orchards on the same sites. It is the acreage of young filbert trees that will make good the agricultural statistician's estimate of 40 to 50 percent of a filbert crop this year.
I have seen one 32-acre orchard of 24-year-old filbert trees that was injured beyond repair, but they were crowded and unfertilized. At the very same location a 14-acre orchard of 15-year-old filberts with adequate spacing was not seriously injured, even though the trees were not fertilized.
One other orchard in a poor location and on waterlogged soil, which has had little or no care, has likewise been lost. Filberts definitely were hurt in the two "cold spots" previously mentioned, but official reports of minus 18 degrees F. were common in that area.
There was a noticeable difference in damage to catkins between Daviana and DuChilly. Very few Daviana catkins produced pollen; but DuChilly seemed to be fairly normal.
Injury in filberts was confined mostly to the catkins and twigs. Excessive sucker growth up and down the main trunk and branches has taken place in the filberts, as is the case in walnuts.
In neither walnuts nor filberts was there much splitting of the bark on the trunk. This was probably because there was no sudden fluctuation in temperatures and sunshine was not excessive during the critically cold days.