A study of the framework of the apple tree and its relation to longevity / by W.A. Ruth and Victor W. Kelley.

Abstract

The authors have tested methods of heading with three successive plantings of nursery trees. The methods are described under each experiment. This part of the work was started in the spring of 1924 on the University farm at Urbana and has been continued up to the present time. Demonstrations and tests of the methods suggested by these experiments were started in commercial orchards in 1926 by R. S. Marsh," Extension Specialist in Horticulture. Long-time demonstrations, in which the results are watched from year to year, are in progress in thirty-two counties. Orchards in all parts of the state are included. Shallow, infertile, poorly drained clay soils, sandy soils, and various types of deeper and more fertile soils are represented. 'limiting factor' in many discussions." As might be expected, when estimates of the life of the apple tree have been made in restricted localities, the variation that has been found has usually been considerable, and there has been an equally great variation in the estimated period of productivity. Brierley 20 estimates the life of apple trees in Minnesota as 16.9 to 37.5 years, according to variety; these trees begin to bear when they are 6 or 8 years old, reach their maximum at 20, and gradually fail. According to Crane, 37 while the largest returns in New York are from orchards 40 to 55 years old, in West Virginia only 1 percent of the trees in two important counties are over 30 years old. In one of these counties the greatest profits are from trees 15 to 26 years old; in the other county trees from 15 to 22 years old are most profitable. In more mountainous regions of the state, trees are profitable at 40 to 50 years of age, and trees 75 to 100 years old can be found. At Wooster, Ohio, the behavior of an orchard, as reported by 1932] FRAMEWORK OF THE APPLE TREE 513 Ellenwood, 50 has been more constant. Yields increased from the seventeenth year, when the yields were first recorded, to the thirty-second. The varieties included were Wealthy, Oldenburg (Duchess), Transparent, Northern Spy, Jonathan, Baldwin, Rhode Island Greening, Rome, and Grimes. Yields in 1929, the thirty-seventh year from planting, were greater from all varieties except Baldwin and Oldenburg. The conclusion is drawn that in that section maximum production may be expected at 35 to 40 years from planting. OPINIONS OF ILLINOIS FRUIT GROWERS Reports of average longevity in other regions and of exceptionally long-lived trees outside of Illinois are interesting but of less significance to the Illinois grower than data concerning longevity in this state. To obtain local information the growers themselves were asked to reply to a series of questions. Information obtained in this way has an advantage over that obtained from a more exact study of a limited number of orchards in that it gives a better picture of the effect of the variety of conditions and cultural practices that occur in so extensive a territory as the state of Illinois. The questions asked were the following: How long do apple trees live ? Between what age...

Branch-to-Stem Diameter Ratio Affects Strength of Attachment

“…In the early and middle part of the last century, MacDaniels (1923) and others (Ruth and Kelley 1932;Verner 1955) believed that the strength of branch attachment was largely governed by the angle of attachment. Each showed elegant data supporting their conclusion.…”

Segmental pigmentation disorder

“…15 with hypopigmentation. The di,tribution varied as follows: over the back (9). the chest ( 12), and the abdomen ( 16).…”

“…Lerner and others (3,6) suggested the existence of an enzymatic stimulant resulting f r om a neuro genic provocation, that regulates the pigment pro duction or destruction. Such a simulant may explain the appearance of vitiligo with a dermatomal distri bution or a zosteriform lentigenous nevus (9). If such a neurogenic enzymatic stimulant is real!y active-the SPD too might be affected by it.…”

Fracture properties of green wood formed within the forks of hazel (Corylus avellana L.)

“…In the previous studies, branch-trunk diameter ratio and branch angle have primarily been investigated to identify the best predictor for a fork's strength. A number of researchers have reported that the attachment angle is the most closely related to the strength of attachment (MacDaniels 1923;Ruth and Kelley 1932;Verner 1955;Buckley et al 2015); however, others found no relationship between branch angle and strength of bifurcation (MacDaniels 1932;Lilly and Sydnor 1995;Gilman 2003;Pfisterer 2003;Kane 2007). On the other hand, some researchers have indicated that the strength of the junction was mainly correlated with an increase in the branch-trunk diameter ratio (MacDaniels 1932;Miller 1959;Shigo 1985;Farrell 2003;Gilman 2003;Kane 2007;Kane et al 2008;Buckley et al 2015) in such a way that relatively larger forces were required to pull apart narrow branches attached to thick ones; forks with branches of equal diameter were considered weakest (Matheny and Clark 1994;Gilman 2003;Kane et al 2008).…”