Overley, F.

Washington State University  institutional repository

Stations Circular No. 140 March 1951 ORCHARD TREE SPACING AND RENEWAL ti F. L. Overley * ~ * * * * * * * * * * * * * * * * * The State College of Washington Institute of Agricultural Sciences Washington·Agricultural Experiment Stations Tree Fruit Experiment Station Wenatchee 61;)~.~1 I I l))l~i\l\AC. .,tv~tJ _/4fv ORCHARD TREE SPACING AND RENEWAL F. L. Overley, Horticulturist ~ Tree Fruit Experiment Station Every fruit grower faces a tree spacing program as his trees grow large enough so the branches almost touch adjoining trees, Tall orchard trees are generally the result of crowding. These trees may produce unprofitable, low­grade fruit. And they often require severe pruning and heading back. A tree spacing experiment was conducted at the Tree Fruit Experiment Station, Wenatchee, 1940 to 1943, inclusive. A 5-acre tract of Winesap apple trees about thirty-five years old was divided into two blocks. In Block 1, the semi-permanent trees were removed, leavii{g twenty-seven trees per acre. The tree spacing for Block 2 was' 40 x 40 feet on the square system. The orchard was in h~avy production at the time. Block 1 averaged 972, 1,091, 1064, and 718 packed boxes, re 9 pectively, for the 4 years of the studies. Block 2 averaged 61, 72, 77, and 100 .3 per cent production of Block 1. Th~~, it required 4 years for the trees in the tree -spaced area to equal the clo_sely planted trees. If production in an orchard is low because of crowding, the production after spacing will surpass the same trees in a crowded condition in less time . At the end of the experiment, all semi-permanent trees were removed, leaving the whole orchard with twenty-seven trees per acre on a 40 x 40 feet square system. The crop of 1950- -the seventh after tree removal- -averaged 1,156 packed boxes per acre for the entire tract . With more room and more sunlight in and about the trees, the fruit developed better color. The extra fancy fruits were increased as follows: 1942- 56 per cent, 1943- 66 per cent, 1949- 88 per cent, and in 1950- 98 per cent. Other orchar d management practices, however, may have an influence on color of fruit. Some of these are cover crops, fertilizer applications, fruit thinning, and insect control. In 1950, Block 2 averaged 1,132 packed boxes of extra fancy colored fruit per acre. Fruit size varies from year to year, due to length of growing season, winter injury to trees, vigor in trees from fertilizer, cover crops, irrigation, and time and amount of thinning. There is apparently no correlation between size of fruit and production per acre, as shown in the following table. I ,JII -~, ·· 2 -Table 1. Size of Fruit and Production per Acre of a 5-Acre Block of Winesap. Ye ar Size of frui \ ; Production per packed box 42 lbs. per acre J 944 164 713 boxes 1945 167 480 boxes 1946 159 867box es 1947 145 626 boxes 1948 179 534 box es 194 9 107 526 boxes 1950 143 1,066 box es The largest fruit was produced in 1949. But the crop was only s 1 ightly larger than in 1945 when the fruit was much smaller. The increased size was partly due to the winter injury from the severe winter of 1948-1949. Apples may be exceptionally large even in a season with heavy production, following a winter where trunk and crotch injury occur . Injury to these tissues has an effect on fruit and foliage similar to a mechanical girdling or mouse injury. The good size of the Wiriesaps in 1950, combined with heavy production, even with a very late blossom date, is probably due to two causes: (1) the trees were blossom thinned and (2) the exceptionally good fall was inducive to good foliage functioning till late, even right up to harvest. With good tree spacing, the actual height of the tree can be lowered where it has been forced upright and tall by crowded conditions . Given sufficient .space, branches and leaders will spread laterally . If they aren t headed back by pruning, the weight of the fruit and foliage will cause the growth to spread outward and pull the leaders down. This reduces the length of ladders necessary for harvesting. As the result of tree spacing and pruning, the trees in this experiment were reduced about 4 feet in height. Since favorable results can be obtained with a tree spacing program with heavy producing Winesaps, a more pronounced result should be pos s ible ( 1) with trees in low production due to crowded conditions, (2) with an orchard producing low percentage of extra fancy fruit due to crowded and shaded conditions, and (3) with trees that are being forced too tall by crowding. In a limited number of tests and observations, the regular Delicious will respond to tree spacing program equal to or better than most other varieties , A tree spacing program in an old orchard is simple if the right system of planting was used, In the early days of orchard planting, many growers attempted to economize on land by putting in as many trees as they could without any consideration to tree spacing . One system was the hexagonal -3 -method, There were many variations of this method. In general, it was a rectangular spacing method with trees planted in the center of each rectangle. The trees were generally planted close together in rows with a wider spacing between rows. !{exagonal System of Tree Spacing 'I This system of planting had much in its favor in growing young trees. It allowed wider centers in one direction for inter-cropping and space between rows for spraying or orchard operations. Many growers had to produce a cash crop on the soil while they were bringing their orchards into bearing. This system made tree spacing somewhat difficult. Figure 1 (A) shows original planting where one to three varieties may be used, They are marked P, S, and X--P for permanent trees, 's for semi. fillers, and X for the first fillers to be removed. If the original trees were all planted ·15 feet in the rows and with rows 1 7½ feet apart, it would allow approximately 166 trees to the acre. In the first tree spacing program, one -third of the trees are removed as indicated in (A), leaving approximately 112 trees per acre, It allows only more open space on three s..ides of each tree . In the next spacing program (B), one -half of the remaining trees are removed. The remaining trees are now 45 fe e t apart in rows, with the rows 17 ½ feet apart . This leaves approx imately fifty-six tre es per acre. The plan still leaves the mature trees too close together for inte rplanting or orchard renewal and for the use of mechanized spray equipment. For interplanting, remove on e -half of the remaining trees, leaving approximately twenty -eight trees per acr e . The trees are now 45 feet apart in rows and the rows are 35 feet apart as indicated in Figure 1 (C). Square System of Tree Spacing The square system, now generally recommended for new planting s, works well for an orchard renewal program or a rotation of varieties in an old and bearing orchard. New trees of a different variety can be reset where t•he last trees were removed , They grow without severe crowding for a number of years. As soon as the n ew trees require the space, all old trees 'can be remov ed , leaving a y oung o rchard permanently spaced and ready to pro~uce The first spacing program i.s shown in Figure 2' (D) where one - half of the trees are removed on an original 20 x 20 foot planting of 108 trees, leaving fifty-four trees per acre. The second removal program under (E) removes one -half of the remaining trees, reducing th e planting to the twenty ­seven permanent trees per acre (F). This is a good permanent spacing for most varieties of apple trees in central Washington, This is an e x cellent p s p s s ~ p s p p s p A "' ( ~ p s p s s~ s~p p p s p p p p p p p p B p p p p p p p p p p p p p p p p p p p p p p p pC p p p p p p p p Fig. 1. Hexagonal s y stem of tree spacing, showing tree removal. p D p p p p Q ,, f ~ s s s p p p p p p p p p .1 I t E p p p p p p p p p p p p p p p F p p p p p Fig. 2. Square system of tree spacing, showing tree removal. I' -ti-method for starting young orchards and is very simple for a grower to lay out. Rectangular System of P fanting The rectangular system of planting is similar to the square system. The only difference is that the trees are spaced further apart in the rows. This system is generally used on hilly ground or where a contour - planting program is to be used. The number of trees per acre will vary according to the planting distances . Cutting Back Filler Trees Before Tree Removal Many growers very successfully practice' the plan of cutting and heading back filler trees before tree removal. The filler trees are marked several years in advance of removal. They can then be cut back and pruned as severely as necessary to avoid interference with the growth and development of the permanent trees. This practice may be followed as long as the filler trees produce profitably . Advantages of a Tree .Spacing Program In general, a good tree spacing and orchard renewal program may be conducted over 3 to 4 years without too greatly reduced production. Economically, there are several advantages of tree spacing: ( 1) Labor is saved in orchard operation as pruning, thinning, propping, harvesting, and handling of low-grade fruit. (2) Color of fruit should be improved and percentage of extra fancy fruits increased. (3) Size of fruit will be increased. (4) Injury to trees from excess pruning and heading back is reduced. (5) · Fruit production will show an increase, providing production was originally reduced by crowding. (6) Cover crops make a better growth and are more easily maintained. (7) Insects and diseases are more easily controlled. (8) An interplanting and orchard removal program may be initiated following the last removal of the semi ~permanent trees. Table 2 shows the different systems of planting with relation to tree and row location on an acre basis. The quincunx system of planting (triangular system) is obtained by planting a tree in the center of each square or rectangle. The square system becomes a triangular system after the first tree spacing program is completed. I 7 Table 2. Tree Stand and Removal Table for Differe'nt Systems of Planting. Trees per acre Trees per acre Original stand Trees per acre after fi st after second planting distance removal removal Ft. Square Hexagonal Square Hexagonal Square Hexagonal 15 196 223 87 152 44 76 I 18 134 154 67 103 34 51 20 108 124 54 83 27 41 22 90 104 45 70 23 30 24 76 87 38 58 18 29 25 70 80 35 54 27 26 64 74 32 50 25 28 56 64 28 43 23 30 48 55 24 37 32 43 49 21 33 

English

Orchard Tree Spacing and Renewal

https://rex.libraries.wsu.edu/esploro/outputs/report/Orchard-Tree-Spacing-and-Renewal/99900634725101842

Orchard Tree Spacing and Renewal

Abstract

Similar works

Full text

Available Versions

Washington State University institutional repository