Extermination of Willows.

New Zealand Journal of Agriculture, Volume 57, Issue 6, 20 December 1938, Page 484

Extermination of Willows.

Ring-barking and Poisoning Methods.

Wm. C. Hyde,

Horticulturist, Wellington.

In an inquiry to the Journal, R.S.B. (Bay of Islands) writes : “We in this district view with alarm the rapid increase in willowtrees along the main creeks (usually called . : - : rivers), and we shall have to exterminate them by some means. There are various opinions as to the proper time for ringing, and some also maintain that in order to speed up the death of the tree it is necessary - to strip the bark from the ring down to the roots. When I tell you that during the last twenty years the bed of one river has silted up at least 4 ft. simply through the increase of willow-trees you will readily understand that we have need of drastic measures.” IN soil which is always moist—and especially beside fresh-water rivers and lakes —the willow, or - sallow, Ts • commonly found in most countries. In the Arctic regions it is but a prostrate shrub, but it makes a good bid among hardwood plants for the record for endurance. in that climate. Mostly deciduous, and consisting of some three hundred species and many hybrids, the willows are dioeciousthat is, the flowers are not only separately staminate and pistillate, but they * are on separate trees. . The seeds are short-lived, but the branches are brittle, and pieces becoming imbedded , in mud or wet soil readily establish themselves. . . The willows are invaluable for binding embankments, and they provide quick shade and shelter for stock and crops. Also, the fine, tough, white wood is useful for many purposes. It makes the best charcoal, and because of its light weight and tough character it is preferred forbottoms of drays and barrows. It makes good flooring, and has been used in the construction of fast sailing-ships. The withies or osiers are used for basketware, and in some countries they are still used as ties in the garden and orchard.

The wood is, of course, unexcelled for the making of cricket-bats, and the foliage and twigs are popular with browsing animals. The bark has even been dried, ground, and mixed with oatmeal for the consumption by people in times of scarcity. Salicin is a bitter glucoside found in the bark which has many uses, including medicinal. Many species are ornamental, especially those with a “ weeping ” habit, coloured. bark, or showy catkins.

Aggressive Character.

With all of these useful and ornamental qualities these trees have an aggressive character which, while placing them readily at man’s disposal, sometimes makes them * troublesome. Along the banks of rivers they form a stable margin, but where the rivers are shallow branches broken off in a high wind soon ground and grow. If this is allowed to continue unchecked in any part of a river-bed,

serious obstruction soon arises ; - the bed silts up, and the river has to find another channel. v To prevent this taking place obstructive trees should be grubbed and hauled out with a winch, grubber, or other gear. If this is not possible or convenient the trees may be killed and burnt. Most trees may be killed by ring-barking, but in the case of willows, and others which have a strong suckering habit, something more is required. To prevent suckers growing from the stump below the ringing it is customary to poison the tree. Further, if this is to be effective it should be done at the right season, which is just as the tree is passing into a dormant stage. The quickest way to ring the tree is to “ frill ” it by a succession of downward cuts with . a sharp axe, cutting well; through the bark and each cut overlapping the next, so that no portion of the, bark is left to enable the sap to flow across. This operation should also be carried out as close down on to the crown of the root as possible. A strong solution of any good weed-killer in an old kettle or other vessel with a spout which will enable it ? to be poured economically should then be poured into the cuts to wet the surfaces thoroughly.

Solution for Poisoning.

A solution very commonly used is arsenite of soda, made by boiling white arsenic in soda water for half an hour or so until it is dissolved. One pound each of arsenic and washing-soda and 4 gallons of water make a strong solution for this purpose. Take 1 gallon or 2 gallons of water, dissolve the washing-soda, stir ,in the arsenic which has previously been made into a paste, and place it on a good fire. After boiling for half an hour and the arsenic is dissolved make up the solution to 4 gallons, and it is ready for use. Care should be taken to avoid breathing the fumes from this mixture, as they will cause sickness. A method which is claimed to be easier and quite satisfactory is to place 1 lb. of arsenic and a J lb. of caustic soda in a bucket; mix well in a dry state, add water slowly, stir well until the arsenic is dissolved, and then make it up to 4 gallons. ■> <■ ■fl-

an u 1 hi u 11 1 1 ih 1 1 1 11 1 1 lin 11 us e . .. g I'' • i g I I Concern at the rapid | | increase in willow-trees | I along the main-creeks is j | expressed by a corre- | | spondent, who asks for . | | the best method of I I exterminating them. The I | following article deals fully | | with the subject and makes I | suggestions for accom- j ! plishing this object. | § * 1 S.iCiiiiin :iiiil|!iiiiiiir hiiiiiiiiuii.iiiiuiiii. I i;iiui;ii!riur I I II I I i.mii iniJiiii-iJiirhiiiiui uimii 1 i.iiii;;iiii;iiiiit Ir