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heaf '-Seasoning Timber 



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Green timber contains such a large amount of water tliat in 

 a great many eases it is impossible to float logs without allowing 

 them to dry out somewhat. This isn't important when logs 

 are hauled to mill but when they are to be driven or floated 

 it means a great deal. Leaving the logs in the woods or along 

 the river bank for a considerable time to season during the hot 

 months is usually poor policy because of the danger from sap- 

 stain and from too serious checking. 



Partially seasoning standing timber by girdling is an old 

 practice with a few important species, particularly cypress in 

 America and teak in India. In the cypress forests of the South 

 the trees are usually girdled in early winter and if the sapwood 

 is cut through, the loss of water from the leaves will tend to 

 dry out the trunk. The leaves may, in a crude way, be compared 

 to so many little pumps which are slowly pumping the water 

 out of the stem into the branches and out into the air. When 

 the trees are cut the summer following girdling, a sufficient 

 amount of water has been given off so that in a majority of 

 cases the logs can be floated. 



Teak, which is one of the most useful timbers in the world, 

 is not felled green but is completely girdled and allowed to 

 season in the tree. Dr. Brandis, an authority on Indian timbers, 

 says: "Timber well girdled dries completely and seasons evenly, 

 for it is on all sides freely e.\posed to sun and wind. Smaller 

 trees dry sufficiently if left standing for one or two years after 

 girdling; larger trees must stand longer. When a teak tree is 

 felled green, that side of the trunk which is in contact with 

 the ground takes a long time to dry, the timber seasons unevenly, 

 it is less useful and less durable, and when thrown into the 

 ■water it does not float readily. ' ' 



Another authority recommends that the dense Australian tim- 

 bers should, like teak, be ringed while standing. "This should 

 be done a year or more before felling, and between April and 

 August, when the sap is quiescent. The tree is most thoroughly 

 drained of its sap when thus left vertical. This process has, how- 

 ever, been objected to because it causes or intensifies heart- 

 shake, and, by drying the wood too rapidly, renders it brittle 

 and inelastic." 



This method of seasoning standing timber has also been tried 

 to some extent with our tupelo gum, but has not been successful, 

 since it is difficult to girdle them deep enough to' prevent the 

 sap from rising. 



In cutting paper birch in this country it is the common practice 

 to bolt and haul it. A marked variation from the usual method 

 of operation is in the few cases where the logs are driven or 

 rafted to the mill. When this is done the logs are never cut 

 into bolts in the woods, but the whole stem is put into the 

 water. Contrary to common belief, green paper birch will float 

 for a while, and it is sometimes put into the water in this condi- 

 tion. But, since seasoned wood is lighter, it is usually first 

 seasoned to some extent. An effective method is to cut the 

 trees in summer and leave the tops on. The leaves continue 

 to transpire moisture for a while, with the result that a large 

 quantity is removed from the tree at once and the wood is left 

 in a comparatively seasoned condition. The tops may then be 

 cut off and the stem put into the water immediately. Another 

 method is to remove the tops at once and then let the logs stay 

 in the woods for about a year to season. This method is probably 

 not so effective, since birch seasons very slowly when left with 

 the bark on. If cut in summer the logs are also likely to stain 

 badly, at least at the ends. 



The red gum is a tree in which the drying out of the trunk 

 by means of the leaves offers particularly favorable conditions. 

 It was noted that when a green tree is cut down the leaves 

 remain stiff and unwilted for many days, and this even in 

 the hottest weatJier in June and July. The explanation of this, 



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according to Dr. Von Schrenck, is as follows: "When a tree i& 

 cut down the evaporation of water from the leaves will continue 

 for a time, the duration of this evaporation depending upon the 

 amount of water in the leaves. In most broad-leaved trees, 

 owing to, the fact that water evaporates from both the upper 

 and lower surfaces, the leaves dry very soon after the tree is- 

 cut down. The rate at which water can pass from the smaller 

 branches to the leaf petiole and thence to the leaf is very much 

 slower than the rate at which the water evaporates from the- 

 leaf surfaces. As a result the leaves soon drop and dry up. 

 In the red gum, however, only one of the surfaces of the leaf, 

 the lower, is provided with stomates so that the evaporation 

 of water takes place only from one surface and that the most 

 protected one. The rate at which water passes from the trunk 

 to the branches and thence in time to the smaller branches, 

 leaf petioles, and the leaves is evidently very nearly the same 

 as that at which the water evaporates from the leaf surface. 

 For this reason the leaves remain green and turgid for a com- 

 paratively long time." 



In order to determine wlipthcr there was any practical result 

 to be obtained by giving the leaves an opportunity to remove 

 as much water as they could, some experiments were conducted 

 by the United States Bureau of Plant Industry. About twenty- 

 five trees were cut down in August, and instead of sawing 

 the timber into logs immediately after felling them they were 

 left intact until the leaves had become absolutely shriveled 

 and dry. This took some two weeks or more. After that the 

 trunks were cut into logs. These logs were skidded to the river 

 just as other logs were skidded. One or more rolled down the 

 bank, and instead of sinking, as a red gum log usually would 

 after but two weeks' seasoning, these logs floated, though not 

 very high out of the water. Tlie leaf seasoned logs were made 

 into a separate raft and were brought to the sawmill. 



After they were sawed a number of boards were taken at 

 random from the leaf-seasoned logs and a similar number from 

 ordinarily seasoned logs. These were carefully measured and 

 weighed, care being taken to separate sap and heart boards. 

 The average weight per cubic foot of the leaf-seasoned sapwood 

 lumber was T)?." pounds against 68 pounds for that ordinarily 

 seasoned; for hcartwood the weights were .'50 pounds, leaf -seasoned, 

 against 61.6 pounds, ordinarily seasoned. In other words, the 

 boards from leaf-seasoned logs were much lighter than those 

 from logs seasoned in the ordinary manner. Both sapwood and 

 heartwood of the leaf-seasoned logs were lighter than water 

 (62.36 pounds per cubic foot) which means they would float 

 while in the other case a log containing sapwoo<l would sink. 



In cemmenting on the results the investigator said: "While 

 the experihient is but a crude one, the results obtained therefrom 

 are believed to be absolutely trustworthy. The testimony of 

 experienced millmen who floated the leaf-seasoned logs bears 

 out the evidence shown in the table. It may be objected that 

 it will be an expensive matter to saw down trees and leave 

 them to dry, and then to go back several weeks later to cut 

 off the branches. While this is certainly true, the expense 

 may be justifiable if one can reduce the time of holding the logs 

 on the river bank and thereby reduce the chances of fungous 

 attack. ' ' 



Up to the present time cedar has been the principal crosstie 

 wood of Michigan, but a decided change to treated hardwood is 

 now in progress. Recently the Michigan Central began to treat 

 hardwood ties at Toledo, O. The Grand Rapids & Indiana has 

 contracted for a large number of hardwood ties w-hich will be 

 treated at a plant to be built at Reed City, -Mich., this summer. 

 The Fere Marquette is also planning to use treated hardwoods, 

 showing that the change of policy is general throughout the state. 

 Beech is the chief wood i'ni]il(ivpd. 



